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TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (typewriters B41J; order telegraphs, fire or police telegraphs G08B; visual telegraphy G08B, G08C; teleautographic systems G08C; ciphering or deciphering apparatus per se G09C; coding, decoding or code conversion, in general H03M; arrangements common to telegraphic and telephonic communication H04M; selecting H04Q)
Definition statement
This subclass/group covers:

Transmission of signals having been supplied in digital form, e.g. data transmission, telegraphic communication, or methods or arrangements for monitoring.

As the scope of H04L covers a diversity of subject matter, the user is referred to the definitions for the main groups of H04L. The following list is intended to assist the user.

Systems:

Arrangements of general application:

  • security: errors; secrecy, see definition for groups H04L1/00H04LH04L 9/00;
  • multiple communications, see definition for groups H04L5/00H04LH04L 7/00;
  • other arrangements, apparatus or systems, see definition for group H04L 29/00.
References relevant to classification in this subclass
This subclass/group does not cover:
Arrangements applicable to telegraphic or telephonic communication
Informative references
Attention is drawn to the following places, which may be of interest for search:
Typewriters
Order telegraphs, fire or police telegraphs
Visual telegraphy
Teleautographic systems
Ciphering or deciphering apparatus per se
Coding, decoding or code conversion, in general
Selecting
Spread spectrum techniques in general
Arrangements for detecting or preventing errors in the information received (correcting synchronisation H04L 7/00; [N: for digital computers G06F 11/00]; arrangements in the transmission path H04B)
Definition statement
This subclass/group covers:

Codes for error detection or error correction, i.e. theoretical code construction and coding circuit architecture designs are classified in H04M 13/00; the application of such codes in transmission systems is covered by H04L 1/00 subgroups.

References relevant to classification in this group
This subclass/group does not cover:
Codes for error detection or error correction per se, i.e. theoretical code construction and coding circuit architecture designs
Transmission
Informative references
Attention is drawn to the following places, which may be of interest for search:
Computer systems
Error correction or detection in electrical digital data processing
Coin-feed or like apparatus with coded identity card or credit card
Error correction in speech coding
G10L19/00E
Diversity Systems for radio transmission systems
Error correction in synchronization
Error detection and correction for transmission of compressed video (e.g. MPEG)
Special rules of classification within this group

Classification into the main group H04L 1/00 itself should be avoided and instead its relevant subgroups should be used by identifying the particular error technique used. If no other group can be assigned for error control applicable to transmission systems, then it may be assigned to this main group.

In addition an Indexing Code can be given under H04L 2001/0092 for network topology, which is of interest to H04L 1/00.

Synonyms and Keywords

In patent documents the following abbreviations are often used:

AM
Acknowledged Mode
AMC
Adaptive Modulation and Coding
AMR
Adaptive Multirate
ARQ
Automatic Repeat reQuest
BCCH
Broadcast Control Channel
BCH
Broadcast Channel
BER
Bit Error Rate
BLER
Block Error Rate
BPSK
Binary Phase Shift Keying
BW
Bandwidth
C-RNTI
Cell Radio Network Temporary Identity
CDMA
Code Division Multiple Access
CE
Cyclic Extension
CP
Cyclic Prefix
CQI
Channel Quality Indicator
CRC
Cyclic Redundancy Check
CSI
Channel State Information
DCCH
Dedicated Control Channel
DCI
Downlink Control Information
DFT
Discrete Fourier Transform
DL
Downlink
DL-SCH
Downlink Shared Channel
DRA
Dynamic Resource Allocation
DRX
Discontinuous Reception
DTCH
Dedicated Traffic Channel
DTX
Discontinuous Transmission
E-UTRA
Evolved UMTS Terrestrial Radio Access
E-UTRAN
Evolved UMTS Terrestrial Radio Access Network
EPC
Evolved Packet Core
FDD
Frequency Division Duplex
FDM
Frequency Division Multiplexing
FDMA
Frequency Division Multiple Access
FEC
Forward Error Correction
H-ARQ
Hybrid ARQ
HSDPA
High Speed Downlink Packet Access
HSUPA
High Speed Uplink Packet Access
IP
Internet Protocol
IPSec
Internet Protocol Security
LTE
Long Term Evolution
MAC
Medium Access Control
MAC
Message Authentication
NACK
Negative ACK
NAS
Non-Access Stratum
OFDM
Orthogonal Frequency Division Multiplexing
PAPR
Peak-to-Average Power Ratio
PDCCH
Physical Dedicated Control Channel
PDCP
Packet Data Convergence Protocol
PHICH
Physical Hybrid ARQ Indicator Channel
PUCCH
Physical Uplink Control Channel
PUSCH
Physical Uplink Shared Channel
QAM
Quadrature Amplitude Modulation
QPSK
Quadrature Phase Shift Keying
RRC
Radio Resource Control
SDMA
Space (or Spatial) Division Multiple Access
SIMO
Single Input Multiple Output
SIP
Session Initiation Protocol
SIR
Signal-to-Interference Ratio
STC
Space Time Coding
UEP
Unequal error protections
UM
Unacknowledged Mode
VoIP
Voice over Internet Protocol
WCDMA
Wideband Code Division Multiple Access
[N: Systems modifying transmission characteristics according to link quality, e.g. power backoff (adaptive data allocation for multicarrier modulation H04L 5/0044; controlling transmission power for radio systems H04W 52/04)]
Definition statement
This subclass/group covers:

General link adaptation techniques, including power control for non-radio links, and handshaking procedures involving link adaptation.

References relevant to classification in this group
This subclass/group does not cover:
Splitting-up the transmission path, e.g. time, frequency etc.
Allocating sub-channels of the transmission path
Negotiation of transmission parameters unrelated to channel quality
Multichannel equalizers (attention: Indexing Code)
Adaptation of equalizers (attention: Indexing Code)
Transmit line pre-equalization, e.g. precoding, MIMO calibration
Allocation of payload for multicarrier modulation system
Adaptation of timing of transmitters in a network
Mode change for facsimile transmission
Network traffic and resource management
Communication route selection based on channel quality
Control of transmission power in radio systems
Wireless resource allocation
Special rules of classification within this group

Adaptive techniques are covered by specific subgroups under H04L 1/0001 unless they are other aspects, e.g. frequency hopping, adaptive slew rate, adaptive interleaving, DSL power back-off.

ARQ adaptive retransmission aspects should be classified mainly under the H04L 1/16, H04L 1/18 subgroups.

[N: by adapting the transmission rate]
Definition statement
This subclass/group covers:

The end raw rate at which bits are transmitted through the channel, e.g. after encoding.

References relevant to classification in this group
This subclass/group does not cover:
Allocation of payload for multicarrier modulation system
H04L27/00C4
Management of data rate of a bus
Network nodes adapting their rate to physical link properties
Network congestion
H04L12/56D16, H04L12/56D17
Negotiation of communication rate in wireless communication systems
Power control taking into account the transmission rate
[N: by switching between different modulation schemes]
Definition statement
This subclass/group covers:

Also adaptive CDMA and direct sequence spread spectrum is covered by this subgroup.

References relevant to classification in this group
This subclass/group does not cover:
CDMA system aspects
Management of data rate of a bus
Network nodes adapting their rate to physical link properties
Negotiation of communication rate in wireless communication systems; network traffic / resource management
Special rules of classification within this group

Adaptation of modulation is classified in H04L 1/0003 even if line bitrate remains constant, e.g. switch-over from 8-QAM to 8-PSK.

Adaptation of modulation and coding schemes (MCS/AMR) are classifed also under H04L 1/0009.

Particular ARQ physical mapping aspects should be classified mainly under the H04L 1/1893 or H04L 1/1861.

[N: applied to control information]
Special rules of classification within this group

If the adaptation concerns both control and payload then only H04L 1/0003 is used.

[N: applied to payload information]
Special rules of classification within this group

If the adaptation concerns both control and payload then only H04L 1/0003 is used.

[N: by adapting the transmission format]
Definition statement
This subclass/group covers:

This group covers adaptive formatting aspects, e.g. adaptive slot allocation, or adaptive packet formats other than coding.

References relevant to classification in this group
This subclass/group does not cover:
Channel / frequency assignment
Adaptation of format of signaling
[N: by modifying the frame length]
Definition statement
This subclass/group covers:

Frame or packet length adaptation at lower OSI layers.

References relevant to classification in this group
This subclass/group does not cover:
Maximum packet size (MTU) for TCP/IP
H04L12/56D27
[N: by adapting the channel coding (H04L 1/1812 takes precedence)]
Definition statement
This subclass/group covers:

Also switching between uncoded and coded modes.

References relevant to classification in this group
This subclass/group does not cover:
Unequal or adaptive error correction protection
Adapting channel coding for congestion
H04L12/56D29
Special rules of classification within this group

ARQ redundancy schemes are classified under the subgroups of H04L 1/1812.

Repetition coding per se is classified also in H04L 1/08; other types of codes under the subgroups of H04L 1/004.

Adaptation of space-time coded transmissions, in particular modification of the space-time matrix is classified under the subgroups of H04L 1/0618.

Adaptation of modulation and coding schemes (MCS) are classified also under H04L 1/0003.

[N: applied to control information]
Special rules of classification within this group

If the adaptation concerns both control and payload then only H04L 1/0009 is used.

[N: applied to payload information]
Special rules of classification within this group

If the adaptation concerns both control and payload then only H04L 1/0009 is used.

[N: Rate matching, e.g. puncturing or repetition of code symbols]
Definition statement
This subclass/group covers:

The coding rate must be adapted in rate matching operations for link adaptation.

Special rules of classification within this group

Use of multiple puncturing patterns is covered by H04L 1/0068; general rate matching without regard to link quality is covered H04L 1/0067.

[N: by adapting the source coding]
References relevant to classification in this group
This subclass/group does not cover:
Adaptive speech coding per se, no transmission involved
Adaptive video coding per se, no transmission involved
[N: characterised by the adaptation strategy]
Definition statement
This subclass/group covers:

This class is used for special adaptation strategies for adopting a transmission mode, e.g. select an MCS mode, which do not fall within its subclasses. For example, use of special utility or cost functions is classified here.

[N: involving special memory structures, e.g. look-up tables]
Definition statement
This subclass/group covers:

This class is used for uncommon memory structures, e.g. switching tables, look-up tables and the like.

[N: where the mode-switching is based on Quality of Service requirement]
Definition statement
This subclass/group covers:

Guarantee of QoS and interaction of QoS parameters of higher layers and of the physical and data link layers. Adaptation takes into account types of data, e.g. real-time data.

References relevant to classification in this group
This subclass/group does not cover:
Wireless network traffic management
[N: based on latency requirement]
Special rules of classification within this group

Latency aspects per se should be classified only here and not in any higher subgroups.

[N: in which mode-switching is based on a statistical approach]
Definition statement
This subclass/group covers:

Special statistical approaches for mode-switching including future system or channel conditions mode-switching decision, e.g. calculation of confidence intervals or sequential testing for early decisions.

[N: Algorithms with memory of the previous states, e.g. Markovian models]
Definition statement
This subclass/group covers:

Algorithms explicitly using Markov chains.

[N: in which the algorithm uses adaptive thresholds]
Definition statement
This subclass/group covers:

Algorithms in which the adaptation thresholds themselves are adapted according to e.g. state of transmitter or receiver.

[N: in which mode-switching is influenced by the user]
Definition statement
This subclass/group covers:

E.g. during the negotiation phase.

References relevant to classification in this group
This subclass/group does not cover:
Re-negotiation phase of parameters unrelated to channel quality
[N: characterised by the signalling]
Definition statement
This subclass/group covers:

Signaling conveying adaptation commands or channel quality indicators, scheduling and formatting aspects thereof.

References relevant to classification in this group
This subclass/group does not cover:
Antenna switching / beamforming based on receiver feedback
MIMO systems with feedback
Channel quality measurement, e.g. SIR for testing/monitoring
Feedback of measurements to the transmitter for testing/monitoring
Signaling for administration of a divided path
Special rules of classification within this group

The appropriate sub-group should be assigned and the main sub-class be avoided.

Signal quality per se is classified in H04L 1/20.

[N: Transmission of mode-switching indication]
Definition statement
This subclass/group covers:

Both for forward and reverse direction.

[N: Transmission of channel quality indication]
References relevant to classification in this group
This subclass/group does not cover:
Channel quality measurements of the receiver with feedback to the transmitter, said feedback not used for adaptation purposes per se
[N: Formatting]
Definition statement
This subclass/group covers:

How the actual signaling is conveyed.

Special rules of classification within this group

The appropriate sub-group should be assigned and the main sub-class be avoided. Mere error control coding of signaling is not assigned by this class.

[N: Reduction of the amount of signalling, e.g. retention of useful signalling, differential signalling (power control H04W 52/04)]
References relevant to classification in this group
This subclass/group does not cover:
Wireless Transmission Power Control
Special rules of classification within this group

Protection of CQI (channel quality indicator) or TFCI (or transport format combination indicator) with error control is classified in H04L 1/0072.

[N: Multiple signaling transmission(H04L 1/1664, F15 take precedence)]
References relevant to classification in this group
This subclass/group does not cover:
Systems acting by means of fluids in general; Fluid-pressure actuators, e.g. servo-motors; Details of fluid-pressure systems, not otherwise provided for
F15
Details of the supervisory signal being transmitted together with payload signals; piggybacking
Special rules of classification within this group

The class should not be assigned if the commands include an acknowledgement indication.

Piggybacked acknowledgements or transmission of command with acknowledgement indication is classified in H04L1/00F13, H04L1/00F15.

[N: Without explicit signalling]
Special rules of classification within this group

Implicit signaling is not classified here either but in relevant subgroups under H04L 1/0033, H04L 1/0036.

[N: arrangements specific to the transmitter]
Definition statement
This subclass/group covers:

Specific parameters of transmitter aspects, i.e. circuit or computer-based implementation, e.g. amplifying circuit, etc. according to channel quality.

Special rules of classification within this group

The class should be assigned only if its subclass is not relevant.

[N: where the transmitter decides based on inferences, e.g. use of implicit signalling]
Definition statement
This subclass/group covers:

Mode switching based on ACK/NACK indications (ACK/NACKs are used as derivative channel quality indicators).

[N: arrangements specific to the receiver]
Definition statement
This subclass/group covers:

Specific parameters of receiver aspects, i.e. circuit or computer-based implementation, e.g. demodulator, etc. according to channel quality.

Special rules of classification within this group

The class should be assigned only if any subclass is not relevant.

[N: Blind format detection(for detection of modulation format H04L 27/0012)]
References relevant to classification in this group
This subclass/group does not cover:
CDMA code identification
Identification of modulation type
[N: other detection of signalling, e.g. detection of TFCI explicit signalling (H04L 1/0046, H04L 27/0012 and H04L 25/0262 take precedence)]
References relevant to classification in this group
This subclass/group does not cover:
Code rate detection or code type detection
Arrangements for identifying the type of modulation
Arrangements for detecting the data rate of an incoming signal
Special rules of classification within this group

Code rate detection of code type detection are classified in H04L 1/0046.

[N: by using forward error control (H04L 1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M 13/00)]
Definition statement
This subclass/group covers:

Application of FEC codes in transmission systems.

References relevant to classification in this group
This subclass/group does not cover:
Error correction or detection in electrical digital data processing
Error correction in speech coding
G10L19/00E
Error detection/correction (code construction per se, coding and decoding architectures)
Codes for error detection or error correction per se
Space-time coding
Error correction in synchronization
Error correction for video transmission (e.g. MPEG)
Special rules of classification within this group

Adaptive FEC is classified in H04L 1/0009.

Space-time/frequency coding/decoding is classified in H04L 1/0618, H04L 1/0606

Repetition coding is classified in H04L 1/08.

Hybrid ARQ redundancy schemes (ARQ combined with FEC) are classified under the subgroups of H04L 1/1812.

[N: Arrangements at the transmitter end]
Definition statement
This subclass/group covers:

Hardware circuit design or functional computer-implemented arrangements.

[N: Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape (H04L 1/0067 takes precedence)]
Definition statement
This subclass/group covers:

The FEC encoding operation is specifically designed by taking into account other signal generation operations (e.g. properties of the modulator or local oscillator).

References relevant to classification in this group
This subclass/group does not cover:
Rate matching
For PSK signal shaping, e.g. trellis shaping, coset coding
QAM signal shaping, e.g. trellis shaping, coset coding
Special rules of classification within this group

Classes H04L 1/0058, H04L 1/006, H04L 1/0067 are considered first before giving the above subclass.

[N: Arrangements at the receiver end]
Definition statement
This subclass/group covers:

Hardware circuit design or functional computer-implemented arrangements.

[N: Code rate detection or code type detection (H04L 1/0038 takes precedence; detection of the data rate H04L 25/0262; for packet format H04L 1/0091)]
References relevant to classification in this group
This subclass/group does not cover:
Data rate detection
Blind format detection
Packet format detection
Special rules of classification within this group

Adaptive code rate or code type detection is classified in H04L 1/0038.

Packet format detection is classified in H04L 1/0091.

[N: Decoding adapted to other signal detection operation (in conjunction with sequence estimation or equalization H04L 25/03286)]
Definition statement
This subclass/group covers:

The FEC encoding operation is specifically designed by taking into account other signal generation operations (e.g. properties of the demodulator, sensitivity to errors of later signal processing stages).

References relevant to classification in this group
This subclass/group does not cover:
Sequence estimation or equalization
[N: in conjunction with detection of multiuser or interfering signals, e.g. iteration between CDMA or MIMO detector and FEC decoder (for spatial equalizer H04L 25/03286)]
References relevant to classification in this group
This subclass/group does not cover:
In conjunction with spatial equalization
Synchronization based on error correcting/detecting codes
with channel-decoding circuitry
[N: Iterative decoding, including iteration between signal detection and decoding operation]
References relevant to classification in this group
This subclass/group does not cover:
Turbo coding and decoding per se
Turbo equalization
[N: Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms]
References relevant to classification in this group
This subclass/group does not cover:
Sequence estimation, e.g. Viterbi decoding arrangements
[N: Systems characterized by the type of code used (H04L 1/08 takes precedence)]
References relevant to classification in this group
This subclass/group does not cover:
By repeating transmission, e.g. Verdan system
Special rules of classification within this group

Repetition coding is classified in H04L 1/08.

[N: Block codes (H04L 1/0061, H04L 1/0064 take precedence)]
Definition statement
This subclass/group covers:

Block codes such as Reed-Solomon codes, LDPC codes, etc.

References relevant to classification in this group
This subclass/group does not cover:
Error detection codes
Concatenated codes
Special rules of classification within this group

Classes H04L 1/0061 and H04L 1/0064 take precedence.

[N: Block-coded modulation]
References relevant to classification in this group
This subclass/group does not cover:
Coded modulation with block coding per se
[N: Trellis-coded modulation]
References relevant to classification in this group
This subclass/group does not cover:
Coded modulation with trellis coding per se
[N: Rate matching (H04L 1/0013 and H04L 1/08 take precedence)]
References relevant to classification in this group
This subclass/group does not cover:
By repeating transmission, e.g. Verdan system
Special rules of classification within this group

Adaptive rate matching according to link quality is covered by H04L 1/0013.

Repetition coding is covered by H04L 1/08.

[N: Puncturing patterns]
Definition statement
This subclass/group covers:

Puncturing patterns (adaptive and non-adaptive).

[N: Unequal error protection (for format H04L 1/0078; for codes per se H03M 13/35)]
References relevant to classification in this group
This subclass/group does not cover:
Unequal error protection
Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors
Special rules of classification within this group

Unequal error protection formatting arrangements is covered by H04L 1/0086.

General aspects of UEP is covered by old Indexing Code H04L 2001/0098. (not used anymore).

[N: Use of interleaving (interleaving per se H03M 13/27)]
Definition statement
This subclass/group covers:

Use of interleavers, which interchange data elements in the time domain in transmission systems.

Relationship between large subject matter areas

Diversity arrangements, see H04L 1/02.

References relevant to classification in this group
This subclass/group does not cover:
Interleaving per se and its memory designs
Spatial/frequency diversity for radio communication
Assignment of physical channels and/or subcarriers
Special rules of classification within this group

Turbo coding interleavers are not classified here since they are considered integral part of the turbo coder.

Non-adaptive formatting arrangements is covered by H04L 1/0086.

[N: Error control for data other than payload data, e.g. control data]
Special rules of classification within this group

Adaptive FEC for control data is covered by H04L 1/001.

[N: Special arrangements for feedback channel]
Definition statement
This subclass/group covers:

Details of FEC of feedback such as CQI, ACK.

Special rules of classification within this group

ACK/NACK repetition coding is covered by H04L 1/1858.

[N: Transmission of coding parameters to receiver (H04L 1/0023 takes precedence)]
Definition statement
This subclass/group covers:

Details concerning transmission of FEC related parameters related to signaling information.

Special rules of classification within this group

Transmission of signaling for adaptation purposes is covered by H04L 1/0023.

[N: Distributed coding, e.g. network coding, involving channel coding (coding in both space and time H04L 1/0618; cooperative diversity H04B 7/022)]
Definition statement
This subclass/group covers:

Details of error control at intermediate node, e.g. exclusive OR signal coding or stronger re-encoding arrangements at relay.

References relevant to classification in this group
This subclass/group does not cover:
Cooperative diversity
Active relay systems
Special rules of classification within this group

Coding in both space and time is covered by H04L 1/0618.

Topology aspect is covered by H04L 2001/0097.

[N: Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location (forward error control, e.g. FEC, CRC H04L 1/004; adaptive formatting H04L 1/0006; mappings H04L 27/00)]
References relevant to classification in this group
This subclass/group does not cover:
Physical mapping
Special rules of classification within this group

Adaptive formatting is covered by H04L 1/0006.

FEC coding, e.g. CRC is covered by H04L 1/004.

[N: Formats for control data (H04L 1/16 takes precedence; training sequences H04L 25/00 and H04L 27/00)]
References relevant to classification in this group
This subclass/group does not cover:
By using return channel in which the signals are sent back to the transmitter to be checked
Training sequences
Baseband systems
Modulated-carrier systems
Special rules of classification within this group

Acknowledgement formats is covered by H04L 1/16 and H04L 1/1607.

[N: fields explicitly indicating existence of error in data being transmitted, e.g. so that downstream stations can avoid decoding erroneous packet; relays]
Special rules of classification within this group

Arrangements for preventing errors in the return channel, e.g. handshaking are covered by Indexing Code H04L 2001/125.

[N: Unequal error protection (H04L 27/00 and H04L 1/004 take precedence for layer 1/2 aspects, e.g. bit loading)]
References relevant to classification in this group
This subclass/group does not cover:
Constellation mapping aspects
Bit loading is covered by
by using forward error control
Special rules of classification within this group

UEP for coding is covered by H04L 1/007.

General aspects of UEP is covered by old Indexing Code H04L 2001/0098. (not used anymore).

[N: arrangements specific to transmitters]
Definition statement
This subclass/group covers:

Hardware circuit design or functional computer-implemented functions.

[N: arrangements specific to receivers, e.g. format detection (detection of data rate H04L 25/0262; detection of coding rate H04L 1/0046)]
Definition statement
This subclass/group covers:

Hardware circuit design or functional computer-implemented functions.

References relevant to classification in this group
This subclass/group does not cover:
Data rate detection is covered by
Special rules of classification within this group

Code rate detection is covered by H04L 1/0046.

by diversity reception (in general H04B 7/02)
Definition statement
This subclass/group covers:

Space-time coding techniques (i.e. for radio) are classified beneath, see relevant subclasses.

In addition, non-radio diversity arrangements involving redundant, simultaneous signal transmission.

References relevant to classification in this group
This subclass/group does not cover:
Radio diversity arrangements (except space-time coded arrangements) are covered by
Special rules of classification within this group

The class should be assigned only if any subclass is not applicable.

using frequency diversity
References relevant to classification in this group
This subclass/group does not cover:
Radio frequency diversity is covered by
[N: Space-time modulation]
Definition statement
This subclass/group covers:

Arrangements with constellation plane partitioning taking space-time diversity into account in equivalence to trellis coded modulation in non-diversity schemes.

[N: Space-time coding]
References relevant to classification in this group
This subclass/group does not cover:
Radio space diversity arrangements
[N: Transmitter arrangements]
Definition statement
This subclass/group covers:

Hardware circuit design or functional computer-implemented arrangement.

[N: Receiver arrangements]
Definition statement
This subclass/group covers:

Hardware circuit design or functional computer-implemented arrangement.

References relevant to classification in this group
This subclass/group does not cover:
Sphere detection
[N: block codes]
Definition statement
This subclass/group covers:

Transmitted space-time matrices that are considered each as one block coded entity.

Special rules of classification within this group

For symbol block coding prior to space-time matrix transmission H04L 1/0057.

[N: by means of convolutional encoding]
Special rules of classification within this group

For symbol convolutional coding prior to space-time matrix transmission H04L 1/0059.

[N: Limited orthogonality systems]
Definition statement
This subclass/group covers:

Semi-orthogonal space-time matrix arrangements to increase the transmission rate.

[N: characterised by the signaling]
Definition statement
This subclass/group covers:

Signaling pertaining to the space-time matrix.

Special rules of classification within this group

For normal adaptive transmissions H04L 1/0001.

by repeating transmission, e.g. Verdan system [N: (H04L 1/1858 and H04L 1/189 take precedence)]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Adaptive and non-adaptive rate matching
Transmission or retransmission of more than one copy of a message
Transmission or retransmission of more than one copy of an acknowledgement message
by using return channel
Special rules of classification within this group

Arrangements for preventing errors in the return channel, e.g. handshaking are covered also by Indexing Code H04L 2001/125.

in which the signals are sent back to the transmitter to be checked [N: echo systems]
References relevant to classification in this group
This subclass/group does not cover:
Echo cancellation
Informative references
Attention is drawn to the following places, which may be of interest for search:
Loop-back testing
in which the return channel carries supervisory signals, e.g. repetition request signals
References relevant to classification in this group
This subclass/group does not cover:
Status reports for improving the reliability of multicast or broadcast data in data switching networks
[N: Group acknowledgement, i.e. the acknowledgement message defining a range of identifiers, e.g. of sequence numbers]
Definition statement
This subclass/group covers:

Explicit indications of ranges of acknowledged data packets, e.g. sequence numbers SN:5 to 16, 23 to 25. Rules may be involved to further compress the sequence number or other signaling.

[N: List acknowledgements, i.e. the acknowledgement message consisting of a list of identifiers, e.g. of sequence numbers]
Special rules of classification within this group

Bitmaps where list acknowledgements appear as 0s and 1s are in H04L 1/1614.

Automatic repetition systems, e.g. van Duuren system; [N: ARQ protocols]
References relevant to classification in this group
This subclass/group does not cover:
TCP / IP protocols per se
[N: Details of sliding window management]
References relevant to classification in this group
This subclass/group does not cover:
Window size / update for TCP/IP
[N: for semi-reliable protocols, e.g. for less sensitive applications such as streaming video (buffer level management for video bitstream receiver H04N7/24C2)]
References relevant to classification in this group
This subclass/group does not cover:
Buffer level management for video bitstream receiver.
H04N7/24C2
[N: Transmission or retransmission of more than one copy of acknowledgement message (repetition in general H04L 1/08)]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Repetition coding in general
[N: Physical mapping arrangements (for ACK signaling see also H04L 5/0053)]
Definition statement
This subclass/group covers:

Constellation / mapping rearrangements due to retransmissions, and mapping of receiver-initiated transmissions to resource blocks.

References relevant to classification in this group
This subclass/group does not cover:
Allocation of signaling
[N: ARQ related signaling (H04L 1/1607 takes precedence)]
Special rules of classification within this group

Acknowledgement signaling per se is classified in H04L 1/1607.

[N: Details of sliding window management]
References relevant to classification in this group
This subclass/group does not cover:
Window size / update for TCP/IP
[N: for semi-reliable protocols, e.g. for less sensitive applications like streaming video (buffer level management for video bitstream control arrangements H04N7/24C2)]
References relevant to classification in this group
This subclass/group does not cover:
Buffer level management for video bitstream receiver
H04N7/24C2
[N: Transmission or retransmission of more than one copy of a message (repetition in general H04L 1/08)]
Special rules of classification within this group

Repetition coding in general H04L 1/08.

[N: Physical mapping arrangements (physical resource mapping in general H04L 5/00)]
Definition statement
This subclass/group covers:

Constellation / mapping rearrangements due to retransmissions, and mapping of transmitter-initiated transmissions to resource blocks.

References relevant to classification in this group
This subclass/group does not cover:
Physical resource mapping in general
using signal quality detector
References relevant to classification in this group
This subclass/group does not cover:
Measurement characteristics of individual pulses
Measurement of noise, signal-to-noise
Measurement of channel quality parameters at receivers
Measurement of signal quality by testing
Measurement of optical signal-to-noise, bit error rate, quality factor
H04B10/08A1P2
[N: Frame classification, e.g. bad, good or erased (frame indication per se H04L 1/0082)]
Special rules of classification within this group

Frame indication per se H04L 1/0082.

[N: jitter monitoring]
References relevant to classification in this group
This subclass/group does not cover:
Jitter measurement by testing
Measurement of noise, signal-to-noise
using redundant apparatus to increase reliability [N: see G06F 11/08 to G06F 11/20]
Definition statement
This subclass/group covers:

E.g. redundant stand-by links.

References relevant to classification in this group
This subclass/group does not cover:
Error detection / correction
Switching spare elements
Redundant control systems
Redundant systems in computer networks
Redundancy in electrical buses
Other transmission systems with redundant channels
Testing correct operation
Definition statement
This subclass/group covers:

Testing correct operation.

References relevant to classification in this group
This subclass/group does not cover:
Arrangements for testing circuits and fault location
Testing storage memories
Testing of line transmission systems
Testing of transmitters / receivers
Testing / monitoring arrangements
Monitoring / testing of exchanges
Testing arrangements for wireless transmission
SDH/SONET monitoring
Testing for optical arrangements
H04B10/08
Measurement of non-linear distortion
Measuring characteristics of individual pulses, e.g. deviation from pulse flatness, rise time, duration
[N: at the transmitter, using a loop-back]
Special rules of classification within this group

Echo systems are in H04L 1/14.

Arrangements affording multiple use of the transmission path (multiplex communication in general H04J)
Definition statement
This subclass/group covers:

Arrangements for dividing a transmission path, for allocating sub-channels, signalling for multiple channel indication and duplex/half-duplex systems.

This group works at the physical layer, for wireless or line communications (ADSL).

The arrangements for dividing the transmission path involve multiple access techniques capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access techniques include Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, multicarrier Code Division Multiple Access (multicarrier CDMA) systems, i.e. any combination of multicarrier signals and a code division.

An OFDM system may implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMax), IEEE 802.20, Flash-OFDM, etc.

3GPP Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA, which employs OFDM on the downlink and SC-FDMA on the uplink.

References relevant to classification in this group
This subclass/group does not cover:
Spread-spectrum techniques
Frequency hopping for spread spectrum
Spatial multiplexing for diversity systems (the same signal is transmitted by the different antennas).
Time division multiple access (TDMA)
Orthogonal CDMA (i.e. using Walsh codes)
Code division multiple access (CDMA)
Code allocation
Multicarrier modulation techniques
Multicarrier demodulation techniques
Multicarrier synchronisation aspects
Wireless communication networks; Local resource management
Informative references
Attention is drawn to the following places, which may be of interest for search:
Multiplex communication in general
Conditioning for two-way transmission in general
Data switching networks
Systems using multi-frequency codes
Special rules of classification within this group

When the multiple access scheme relies on the use of multicarrier signals, and if what is important is how the signal is modulated/demodulated, or "hardware" aspects in the transmitter or the receiver to produce or recover (like synchronisation) such signal or aspects related to the peak power reduction, then the classes under H04L 27/2601 are relevant. Otherwise, to indicate that the signal involved is, for example, an OFDM signal, then the class under H04L 5/0007 is used instead.

Subgroups H04L 5/22, H04L 5/225, H04L 5/24, H04L 5/245, H04L 5/26 are inactive. The classification should be done in H04J 3/00.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
ADSL
Asymmetric Digital Subscriber Line
DMT
Discrete Multi-Tone
MC-CDMA
Multicarrier CDMA
OFDM
Orthogonal Frequency Division Multiplexing
OFDMA
Orthogonal Frequency Division Multiple Access
SC-FDMA
Single-Carrier Frequency Division Multiple Access
CC
Component Carrier
CoMP
Cooperative Multi-point
FDM
Frequency Division Multiplexing
FDMA
Frequency Division Multiple Access
IFDMA
Interleaved Frequency Division Multiple Access
MIMO
Multiple-Input Multiple-Output
PRB
Physical Resource Block
RA
Resource Allocation
SDMA
Spatial Division Multiple Access
SRS
Sounding Reference Signal
TDD
Time Division Duplex
Synonyms and Keywords

In patent documents the expression "pilot signals" is often used with the meaning of "Reference Signals" or "training signals" or "sounding signals".

In patent documents the expression "persistent allocation" is often used with the meaning that the resources allocated to the user equipment (UE) are valid until the UE receives another allocation which will then override the previous one. This would typically happen in case the channel conditions have changed (or AMR codec changes) and, thus, the previous allocation would no longer be suitable for the user.

[N: Arrangements for dividing the transmission path (duplexing H04L 5/14; multiplexing of different sources on one path H04J)]
Definition statement
This subclass/group covers:

This group answers the question "How is the transmission path split up?". Since the signals are digital, it is considered that there is always a time dimension, and thus, the minimum number of dimensions is two.

References relevant to classification in this group
This subclass/group does not cover:
Two-way operation using the same type of signal
Multiplex communication in general
[N: the frequencies being orthogonal e.g. OFDM(A), DMT]
Definition statement
This subclass/group covers:

The case of an access method allowing multiple users to share the same frequency band by subdividing the band into orthogonal frequency channels. If the frequencies are not orthogonal then the group H04L 5/0005 should be given instead.

Frequency hopping for multicarrier signals, SC-FDMA and IFDMA are also covered by H04L 5/0007.

[N: in which a distinct code is applied, as a temporal sequence, to each frequency]
Special rules of classification within this group

This group should contain the cases of spreading codes in the time domain, where chips of the code are applied in sequence, once at a time, to each of the subcarriers.

[N: in which one code is applied, as a temporal sequence, to all frequencies]
Special rules of classification within this group

This group should contain the cases of spreading codes in the time domain, where each frequency sees the same spreading code (for example, multicarrier DS-CDMA).

[N: in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA]
Special rules of classification within this group

This group should contain the cases of spreading codes in the frequency domain. Each chip of the spreading code is transmitted through a different subcarrier.

[N: Time-frequency-space]
Definition statement
This subclass/group covers:

The combination OFDM and MIMO; or frequency reuse.

[N: Variable division (signaling therefor H04L 5/0092)]
Definition statement
This subclass/group covers:

Changes from time-frequency to time-frequency-space, for example.

References relevant to classification in this group
This subclass/group does not cover:
Indication of how the channel is divided
[N: Arrangements for allocating sub-channels of the transmission path]
Definition statement
This subclass/group covers:

Sub-channels are what the path is split up into according to H04L 5/0001.

[N: Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation]
Definition statement
This subclass/group covers:

This group answers the question of "Who makes the allocation?". Cooperative allocation (for example in CoMP systems or cognitive radio systems or when dealing with ICIC, Inter-cell Interference Cancellation) is classified under H04L 5/0032, which implies a plurality of base stations that cooperates or exchanges information to perform the allocation.

[N: Inter-user or inter-terminal allocation]
Definition statement
This subclass/group covers:

The allocation for plurality of users, thus, to indicate which user gets what.

[N: intra-user or intra-terminal allocation]
Definition statement
This subclass/group covers:

Single user case, what a single user does with its resources.

[N: allocation of payload]
Definition statement
This subclass/group covers:

Allocation of payload or data in the available subchannels.

[N: Determination of how many bits are transmitted on different sub-channels]
Definition statement
This subclass/group covers:

The case of having different modulations in the different subcarriers.

[N: Allocation of pilot signals, i.e. of signals known to the receiver]
Definition statement
This subclass/group covers:

Pilot or reference signal patterns.

[N: Allocation of signaling, i.e. of overhead other than pilot signals]
Definition statement
This subclass/group covers:

Where (for example, in the time-frequency grid) to send ACK/NacK signals, CQI (Channel Quality Indicator) signals and in general any control signalling which is not a known signal to the receiver (pilots, sounding reference symbols, SRS, or synchronisation signals are known to the receiver and they are classified under H04L 5/0048). In order words, which physical resources are used for signalling.

[N: Rate requirement of the data, e.g. scalable bandwidth, data priority]
Special rules of classification within this group

According to QoS (Quality of Service) is also classified here.

[N: Timing of allocation]
Definition statement
This subclass/group covers:

The subgroups answer the question "How often the allocation is updated?". For Persistent allocation (if the update is due to channel conditions change, then H04L 5/0085), fixed allocation (H04L 5/008).

[N: Indication of how the channel is divided]
Definition statement
This subclass/group covers:

How the channel is divided, for instance, for indicating that the whole frequency band is divided into a certain number of subcarriers, or that the base station informs the mobile how according to H04L 5/0001 the channel is divided. Both uplink or downlink.

[N: Indication of how sub-channels of the path are allocated]
Definition statement
This subclass/group covers:

The signalling of the Content of the allocation. For example, which carriers are allocated, how many bits are allocated to each subcarrier, etc. Both uplink or downlink.

the signals being represented by different frequencies (combined with time-division multiplexing H04L 5/26)
Definition statement
This subclass/group covers:

FDM. Different data signals for transmission on a single communications channel are multiplexed, whereby each signal (single carrier) is assigned a non-overlapping frequency range within the main channel.

References relevant to classification in this group
This subclass/group does not cover:
combined with the use of different frequencies
Two-way operation using the same type of signal, i.e. duplex ([N: duplex repeaters H04L 25/22]; conditioning for two-way transmission in general H04B 3/20; [N: for interconnection between telephone switching centres H04Q 3/00])
Definition statement
This subclass/group covers:

ADSL systems. FDD systems.

References relevant to classification in this group
This subclass/group does not cover:
Repeaters for converting two wires to four wires
Reducing echo effects or singing
Selecting arrangements
[N: for modulated signals (H04L 5/1469 takes precedence)]
Definition statement
This subclass/group covers:

For example, Zipper (a time-synchronised frequency division duplex implementation of discrete multi-tone, DMT, modulation).

Arrangements for synchronising receiver with transmitter [N: (synchronisation of electronic time-pieces G04G 7/00; synchronisation of generators of electric oscillations or pulses H03L; synchronising in TV system H04N 5/04; regeneration of clock signals for television systems H04N 7/0352)]
Definition statement
This subclass/group covers:

Bit or symbol synchronization of digital receivers.

Synchronization of packets or bursts in radio or optical transmission.

Bit or symbol synchronization of digital recording system, if this system is not specially adapted to recording.

Bit or symbol synchronization of in a memory system, if the system is not specially adapted to memorizing.

References relevant to classification in this group
This subclass/group does not cover:
Synchronisation of electronic time-pieces
Synchronisation of generators of electric oscillations or pulses
Synchronising in TV system
Regeneration of clock signals for television systems
Synchronization of OFDM
Synchronization in CDMA
Synchronization of frames and in TDM networks, including timestamps
Informative references
Attention is drawn to the following places, which may be of interest for search:
PLL or DLL
Memory systems
Recording
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
OFDM
Orthogonal Frequency Division Multiplexing
CDMA
Code Division Multiple Access
TDM
Time Division Multiplex
PLL
Phase Locked Loop
DLL
Delay Locked Loop
[N: Initialisation of the receiver (H04L 7/0075 and H04L 7/10 take precedence)]
Definition statement
This subclass/group covers:

Calibration of synchronizers.

Special rules of classification within this group

H04L 7/0075 and H04L 7/10 take precedence.

[N: Synchronisation information channels, e.g. clock distribution lines]
Definition statement
This subclass/group covers:

Source synchronous systems.

Transmission of clock on a dedicated channel, line or link.

Clockwise and counterclockwise clock distribution.

Clock distributed as sinus or standing wave

References relevant to classification in this group
This subclass/group does not cover:
Clock distribution in computers or integrated circuits
Clock distribution in semiconductor memory systems
Informative references
Attention is drawn to the following places, which may be of interest for search:
[N: by comparing receiver clock with transmitter clock]
Definition statement
This subclass/group covers:

The received clock is compared with a local clock of the receiver. The comparison controls the synchronisation.

References relevant to classification in this group
This subclass/group does not cover:

The data is not used in the detection of the error or in other parts of the synchronisation. Using the received data for synchronization is classified under H04L 7/02 or H04L 7/04.

Special rules of classification within this group

Synchronization of received clock and local clock by PLL or DLL, H03L 7/00 takes precedence.

[N: correction by interpolation]
Definition statement
This subclass/group covers:

Applies also to clock interpolation in the transmitter for the purpose of synchronisation.

Special rules of classification within this group

If clock interpolation for synchronization is performed at the transmitter, also H04L 7/0091 should be applied.

[N: interpolation of clock signal]
Definition statement
This subclass/group covers:

Covers interpolation of received clock of source synchronous systems.

Covers interpolation of local, e.g. interpolation among several local phase shifted clocks.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Selection out of many clock phases for synchronisation, e.g. phase picking, if the control uses transitions of the received data
[N: interpolation of received data signal]
Definition statement
This subclass/group covers:

Also covers interpolation by equalizers.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Digital Filters, e.g. FIR Filter
Detection of synchronization error by monitoring at least on equalizer tap weight
Rate adaption
Equalizers per se
Synonyms and Keywords

In patent document the following abbreviations are often used:

SRC
Sample Rate Conversion
[N: correction by delay]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Selection out of many clock phases for synchronisation, e.g. phase picking, if the control uses transitions of the received data
[N: correction by an elastic buffer]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronisation using elastic buffers in time multiplexing systems or packet multiplexing systems
Elastic buffers in computer systems
Rate adaption, e.g. from 8 kHz to 9.2 kHz
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
FIFO
First-In First-Out buffer
[N: Detection of the synchronisation error by features other than the received signal transition (by means of signal transition H04L 7/033)]
Definition statement
This subclass/group covers:

Synchronization by sample processing, e.g. Wave-Difference-Method.

Determination of gradients.

References relevant to classification in this group
This subclass/group does not cover:
By means of signal transition
Special rules of classification within this group

Synchronization by determining maximum of first derivation of sampled waveform as estimate of zero or threshold crossing: H04L 7/0334 takes precedence.

Synchronization by determining zero of the second derivation of the sampled waveform: H04L 7/007 takes precedence.

[N: detection of error based on equalizer tap values]
Definition statement
This subclass/group covers:

Detection of error by monitoring of equalizer taps, e.g. center tap tracking.

[N: detection of error based on data decision error, e.g. Mueller type detection]
Definition statement
This subclass/group covers:

Error of the data decision, e.g. subtracting input from output of the decision device, to control synchronisation.

Timing Function: Combining of the error with input signals or not decided symbols.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronization based on data transition by sample processing of at least three levels, e.g. soft decisions.
[N: detection of error based on transmission code rule]
Definition statement
This subclass/group covers:

Synchronization using properties of line codes like Manchester, PPM or RZ. Synchronization using properties of block codes as 4b/5b.

Also covers violations of such coding rules to transmit synch information.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Line coding
Block coding mb/nb
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
PPM
Pulse Position Modulation
[N: detection of error based on maximum signal power, e.g. peak value, maximizing autocorrelation]
Definition statement
This subclass/group covers:

Covers SCCL detectors, Sample Correlate Choose Largest.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronization by maximum signal power on symbols known to the receiver, e.g. fixed synchronization information or UW. Correlation of UW for synchronization
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
UW
Unique Word
[N: with photonic or optical means]
Definition statement
This subclass/group covers:

This group covers clock synchronisation using at least one optical device that is essential for the functioning of the synchronizer. A synchronizer used in an optical transmission system but using exclusively electrical means for synchronization has to be classified in the other respective groups of H04L 7/00.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Optical regenerators and retiming, e.g. 2R,3R
H04B10/17
Optical TDM, alignment of optical frames and time slots
Computer systems or integrated circuits with clock distribution at least partially optical
Non-linear optical devices
Laser devices
Synonyms and Keywords

In patent document the following abbreviations are often used:

NOLM
Non-linear Optical Loop Mirror
TOAD
Terahertz Optical Asymmetric Demultiplexer
[N: taking measures against momentary loss of synchronisation, e.g. inhibiting the synchronisation, using idle words or using redundant clocks]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Fail safe clock arrangements in TDM equipment
Introducing fill or idle bits into the data to maintain synchronization
H04L7/04B7
PLL or DLL with redundancy
PLL or DLL with arrangements for protection against power supply fail
Error detection or correction of clock faults in computer systems
Special rules of classification within this group

This class can be applied additionally to any other class in H04L 7/00

[N: Processing of received signal for adaption to synchronisation, e.g. code conversion, pulse generation, edge detectors]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronization by spectral filtering
[N: Transmitter details]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronization in computer networks, e.g. Time of Day
Buffers between clock domains
Speed or phase control by the received code signals, the signals containing no special synchronisation information [N: (H04L 7/0075 takes precedence; tuning or selecting resonant circuits H03J; using the properties of error detecting or correcting codes H04L 7/048)]
Definition statement
This subclass/group covers:

The error is based on the received code signal.

Synchronisation is achieved by intermediate buffering, multiple phases and/or intermediate clocks. Synchronisation of interfaces or among equipments having different clock phases or clock domains

References relevant to classification in this group
This subclass/group does not cover:
with photonic or optical means
Tuning resonant circuits
using the properties of error detecting or error correcting codes
Informative references
Attention is drawn to the following places, which may be of interest for search:
Computer systems with synchronization between clock domains
Bistable circuits with means to increase reliability, e.g. avoid metastability
Computer systems with buffering between clock domains
Synchronization based on transition of the received code signal
extracting the synchronising or clock signal from the received signal spectrum, e.g. by using a resonant or bandpass circuit
Definition statement
This subclass/group covers:

A spectral line at clock rate of NRZ data can be generated, e.g. by squaring or differentiating and subsequent filtering, e.g. SAW filter or FFT.

Covers detection of synchronization error by measuring a spectral property of a known code signal, e.g. UW or dotting.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Repeaters with retiming
Manipulating pulses with desired output intervals by the use of time reference signals, e.g. clock signals
Manipulating pulses by resonant circuits
Synonyms and Keywords

In patent document the following abbreviations are often used:

Dotting
Sequence of alternating pulses, e.g. 1010..
UW
Unique Word
using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop
Definition statement
This subclass/group covers:

PLL with edge detectors, and at least partial analog loop elements, e.g. VCO;

Edge detectors like HOGGE type or ALEXANDER type.

The term "control" does not limit the scope to "tracking" or "closed loop" but includes also feed-forward control.

Informative references
Attention is drawn to the following places, which may be of interest for search:
PLL or DLL
Transition or edge detectors
Measuring phase angle between a voltage and a current
Special rules of classification within this group

Initialization of the PLL is further classified in H04L 7/0004.

Special adaptions for preventing loss of synchronization or loss of lock are also classified in H04L 7/0083

[N: with a digital phase-locked loop (PLL) processing binary samples, e.g. add/subtract logic for correction of receiver clock (H04L 7/0337 takes precedence)]
Definition statement
This subclass/group covers:

This group also covers detection of the synchronization error by measuring the length of the received bits, e.g. by oversampling and sample processing of binary samples.

Covers correction of the synchronization error by add/subtract logic.

Digital implementation of DTTL.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronization by integrate/dump
Selection or interpolation among plural phase shifted clocks
DPLL in general
Comparing the phase or frequency
Special rules of classification within this group

H04L 7/0337 takes precedence

For the pulse length measurement is done by analogue means, e.g. integrate/dump, H04L 7/0332 takes precedence.

Synonyms and Keywords

In patent document the following abbreviations are often used:

PWD
Pulse Width Distortion
DTTL
Data Transition Tracking Loop
[N: with an integrator-detector]
Definition statement
This subclass/group covers:

Analogue techniques of determining the synchronization error by measuring a pulse length esp. for line codes with a transition in the bit cell like Manchester coding or NRZI.

Analogue implementation of DTTL.

References relevant to classification in this group
This subclass/group does not cover:
Digital implementation of DTTL
Informative references
Attention is drawn to the following places, which may be of interest for search:
Line coding
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
DTTL
Data Transition Tracking Loop
[N: Processing of samples having at least three levels, e.g. soft decisions]
Definition statement
This subclass/group covers:

Samples processed of more than binary values, if the processing evaluates a symbol transition.

First and also higher order derivatives of the sampled waveform, if a transition is detected.

Statistical analysis of the samples, e.g. histogram.

References relevant to classification in this group
This subclass/group does not cover:
Synchronization by detection of decision error of samples
Informative references
Attention is drawn to the following places, which may be of interest for search:
Demodulators
[N: Selecting between two or more discretely delayed clocks or selecting between two or more discretely delayed received code signals]
Definition statement
This subclass/group covers:

The selected phase is looped back into the phase error detection.

Comparison of the actually selected phase with a previously selected phase is not feed backward under this definition. Such a comparison functions as a filter, e.g. for reducing large phase jumps or jitter.

Phase aligners in switches of communication networks or packet receivers.

Phase aligners for electronic displays, e.g. DVI or HDMI interfaces, if the invention is not specially adapted to such a display, e.g. using special signals.

Synchronization by phase picking.

Covers also interpolation among different clock phases.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronization in a TDM node
Electronic displays
Computer interfaces or busses
Special rules of classification within this group

Selection in an open loop control: H04L 7/0338 takes precedence.

Speed or phase control by synchronisation signals [N: (H04L 7/0075 takes precedence)]
Definition statement
This subclass/group covers:

Documents that only refer to the use of a synchronisation signal, e.g. UW, without further specifying their structure or the way it is detected.

Comma free codes.

Forbidden code words.

Relationship between large subject matter areas

Synchronization signals in TDM frames: H04J 3/0602.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Synchronization information for carrier synchronization in demodulators
Buffers between clock domains
Special rules of classification within this group

Special synchronisation signals, e.g. midambles or variable UW: H04L 7/041.

Synonyms and Keywords

In patent document the following abbreviations or words are often used:

Dotting
Alternating 1010... sequence or sequence of complex phase reversal, e.g. ABAB constellation points during training of a MODEM
UW
Unique Word as generic synonym for synchronisation data in the received signal.
[N: Using special codes as synchronising signal]
Definition statement
This subclass/group covers:

Code construction.

Theory of codes used for synchronization.

Training sequences or midambles.

Variable Synchronization codes, e.g. according to synchronization state or for transmission of low rate data like signalling.

References relevant to classification in this group
This subclass/group does not cover:
Corresponding special codes for TDM frames
Training sequences for carrier synchronization
[N: Detectors therefore, e.g. correlators, state machines (digital correlators in general G06F 17/15)]
Definition statement
This subclass/group covers:

Cross-correlation or auto-correlation.

Peak detection, threshold control at the output of the correlator.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Selective call receivers
Correlation computing
Detectors of FAW in TDM frames
Special rules of classification within this group

Windowing around expected location of the synchronization information, H04L 7/08 takes precedence.

Synchronization state machines or diagrams for acquisition, search, verify or lock, H04L 7/10 takes precedence.

Synonyms and Keywords

In patent document the following abbreviations are often used:

UW
Unique Word. This term is even used even if the bits of the synchronization information could occur in other places of the received data, e.g. mimic in the payload
[N: Pseudo-noise (PN) codes variable during transmission (synchronisation of spread spectrum receivers H04B 1/69)]
Definition statement
This subclass/group covers:

PN codes used for synchronisation, if the PN synchronisation signals is varying during transmission, e.g. by a feedback shift-register. Fixed synchronisation signals, e.g. unique words, FAW signals, are not to be classified in this group. This also applies even if the synchronisation signal can be presented as a state of such a PN-code generator. Only if the generator is active and shifts, then the document is classified here.

References relevant to classification in this group
This subclass/group does not cover:
Synchronisation of Spread Spectrum receivers
PN codes for synchronization of TDM frames
Scrambling
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
PN code
Pseudo-Noise or pseudorandom code
FAW
Frame Alignment Word
[N: using a single bit, e.g. start stop bit]
Definition statement
This subclass/group covers:

Synchronization by using a start bit or start/stop bit, incl. the use of the transition of the stop bit to the adjacent start bit.

Covers single synch pulses with differing length from information pulse length.

References relevant to classification in this group
This subclass/group does not cover:
Two or more pulses with differing length compared to the length of the data bits
Informative references
Attention is drawn to the following places, which may be of interest for search:
Start/Stop transmission in general
[N: using a dotting sequence]
Definition statement
This subclass/group covers:

Complex phase reversals used for symbol synchronization in digital demodulators.

References relevant to classification in this group
This subclass/group does not cover:
Transmission of a dotting sequence without further transmission of user data is a transmission of a clock signal
Informative references
Attention is drawn to the following places, which may be of interest for search:
If the dotting is degraded at the receiver to a sinus
H04L7/04B12
Detection of dotting by spectral analysis, e.g. filter around basic frequency
Digital demodulators
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Dotting sequence
Alternating sequence, e.g. 1010... , 01010, ABAB
[N: using the properties of error detecting or error correcting codes, e.g. parity as synchronisation signal]
Definition statement
This subclass/group covers:

Use of Error Correcting or detecting codes for alignment of packets or ATM cells.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Error Detection or correction codes in general, e.g. ECC or FEC
Synchronisation based on error coding or decoding or code conversion
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
ATM
Asynchronous Transfer Mode
the synchronisation signals differing from the information signals in amplitude, polarity or frequency [N: or length]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Detection of the differing length by a digital means
Single pulse for synchronization
Detection the differing parameter based on the coding rule
Line codes and detectors therefore
[N: and superimposed by modulation]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Amplitude modulation of the synchronization information
The synchronization information is multiplexed as a differing type of modulation
the synchronisation signals recurring cyclically
Definition statement
This subclass/group covers:

Detection by windowing around the expected recurring location of the synchronization information.

References relevant to classification in this group
This subclass/group does not cover:
Frame synchronization of TDM frames
Arrangements for initial synchronisation
Definition statement
This subclass/group covers:

Variable synchronization information for initialisation.

During initialisation, variable means of the detector, e.g. low detection threshold and increasing threshold when synchronisation information is detected.

Signalling or handshaking for initialisation.

References relevant to classification in this group
This subclass/group does not cover:
Details of the phase-locked loop for assuring initial synchronisation
Special rules of classification within this group

Other means for synchronisation, H04L 7/0004 takes precedence.

Start/Stop bit detection, H04L 7/044 takes precedence.

Dotting detection, H04L 7/046 takes precedence.

[N: Cryptographic mechanisms or cryptographic] arrangements for secret or secure communication [N: (network architectures or network communication protocols for network security H04L 63/00 or for wireless network security H04W 12/00; security arrangements for protecting computers or computer systems against unauthorized activity G06F 21/00)]
Definition statement
This subclass/group covers:

Cryptographic mechanisms including cryptographic protocols and cryptographic algorithms, whereby a cryptographic protocol is a distributed cryptographic algorithm defined by a sequence of steps precisely specifying the actions required of two or more entities to achieve specific security objectives (e.g. cryptographic protocol for key agreement), and whereby a cryptographic algorithm is specifying the steps followed by a single entity to achieve specific security objectives (e.g. cryptographic algorithm for symmetric key encryption).

H04L 9/00 focuses on cryptographic mechanisms such as encryption schemes, digital signatures, hash functions, random number generation, key management, said cryptographic mechanisms providing information security such as privacy or confidentiality, data integrity, message authentication, entity authentication, authorization, validation, certification, time-stamping, anonymity, revocation, non-repudiation.

H04L 9/00 covers also countermeasures against attacks on cryptographic mechanisms.

Relationship between large subject matter areas

H04L 63/00 Networking architectures and network communication protocols for securing the traffic flowing through data packet networks and providing secure exchanges among applications communicating through data packet networks.

H04L 63/00 covers specifically network architectures and network communication protocols for supporting:

  • filtering (e.g. transferring, blocking, dropping) traffic according to security rules;
  • authenticating and authorizing the entities sending and/or receiving the traffic;
  • protecting the data packets against unauthorized reading or modification;
  • detecting intruders and preventing the transmission of unauthorized, malicious or forged packets;
  • lawful interception for legally authorised parties to access protected information.

H04L 63/00 focuses on network architectures (i.e. network entities involved, roles played by these entities) and network communication protocols (i.e. how these network entities communicate) regardless of the specifics of the cryptographic mechanism used.

G06F21/00N Security arrangements for protecting computers or computer systems against unauthorised activity, where the cryptographic mechanisms are not relevant.

References relevant to classification in this group
This subclass/group does not cover:
Finite field arithmetic over elliptic curve (if not intended for cryptographic purposes)
Pseudo-random number generators (if not intended for cryptographic purposes)
Coding or ciphering apparatuses as cryptographic typewriters
Visual cryptography
Network architectures or network communication protocols for network security
Security arrangements
Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
Informative references
Attention is drawn to the following places, which may be of interest for search:
Smarts-cards and PIN encryption
Protection against unauthorized use of memory
Character or pattern recognition
Payments on Internet
Electronic commerce or auctions
Copy protection
Aspects related to secret communication for (analogue) speech signals
Secrecy systems for scanning, transmission or reproduction of documents
Subscription TV encryption
Content distribution
Special rules of classification within this group

Invention information and additional information should be classified as follows:

Invention information is to be classified with EC.

Additional information is to be classified with Indexing Code.

The classification of additional information is not seen as mandatory; it will be up to the classifier to decide whether the additional information should be classified or not (is pertinent or not). If considered pertinent, it should also be given an Indexing Code.

Indexing Codes are to be used as orthogonal cross with the EC.

Invention may be assign more than one EC/Indexing Code if necessary.

Examples: US2007061572 is to be classified under H04L 9/0863, H04L 9/3273 and H04L 9/3226 since the subject-matter relates to different aspects.

Synonyms and Keywords

In patent documents the following abbreviations are often used:

MAC
Message authentication code
DPA
Differential power analysis
SPA
Simple power analysis
PRNG
Pseudo random number generator
PKI
Public key infrastructure
KDC
Key distribution server
TTP
Trusted third party
CA
Certificate authority
IBE
Identity based encryption
DH
Diffie-Hellman
QKD
Quantum key distribution
TPM
Trusted platform module
PUF
Physically unclonable function
CRL
Certificate revocation list

In patent documents the words "encryption" and "ciphering" are often used as synonyms.

[N: countermeasures against attacks on cryptographic mechanisms(network architectures or network communication protocols for protection against malicious traffic H04L 63/1441)]
Definition statement
This subclass/group covers:

Subject-matter directed to protection and enhancement of cryptographic mechanisms against cryptographic attacks as replay, brute force or birthday attacks.

References relevant to classification in this group
This subclass/group does not cover:
Countermeasures against malicious traffic
[N: involving public key infrastructure [PKI] trust models (network architecture or network communication protocol for supporting authentication of entities using certificates in a packet data network H04L 63/0823)]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication infrastructures based on public-key cryptography.

References relevant to classification in this group
This subclass/group does not cover:
using certificates
[N: involving homomorphic encryption]
Definition statement
This subclass/group covers:

Subject-matter directed to homomorphic cryptographic mechanisms.

the encryption apparatus using shift registers or memories for block-wise [N: or stream] coding, e.g. DES systems [N: or RC4; Hash functions; Pseudorandom sequence generators]
Definition statement
This subclass/group covers:

Subject-matter directed to symmetric-key encryption as DES, (i.e. same keys are used for encryption and decryption), hash functions as MD5, stream ciphers as RC4 or pseudorandom sequence generation.

[N: Block ciphers, i.e. encrypting groups of characters of a plain text message using fixed encryption transformation]
Definition statement
This subclass/group covers:

Encrypting groups of characters of a plain text message using a fixed encryption transformation.

[N: with splitting of the data block into left and right halves e.g. Feistel based algorithms, DES, FEAL, IDEA or KASUMI]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms as Feistel based algorithms, DES, FEAL, IDEA or KASUMI algorithms.

[N: substitution permutation network (SPN), i.e. cipher composed of a number of stages or rounds each involving linear and nonlinear transformations, e.g. AES algorithms]
Definition statement
This subclass/group covers:

Ciphers composed of a number of stages/rounds each involving linear or nonlinear transformations, as AES algorithm.

[N: Modes of operation, e.g. cipher block chaining [CBC], electronic codebook [ECB] or Galois/counter mode [GCM]]
Definition statement
This subclass/group covers:

Subject-matter directed to modes of operation for block ciphers, as CBC (cipher block chaining), CFB (cipher feedback) or OFB (output feedback).

[N: Hash functions, e.g. MD5, SHA, HMAC or f9 MAC]
Definition statement
This subclass/group covers:

The design, structure or function of cryptographic hash functions, as message authentication codes (MAC) or modification detection codes (MDC).

[N: Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3]
Definition statement
This subclass/group covers:

Subject-matter directed to synchronous or asynchronous stream ciphers (i.e. encrypting individual characters of a plaintext message one at a time, using an encryption transformation which varies with time), and to key-stream generation.

[N: pseudorandom key sequence combined element-for-element with data sequence, e.g. one-time-pad [OTP] or Vernam’s cipher]
Definition statement
This subclass/group covers:

Subject-matter directed to encryption (combination) of data with (pseudo)random key-stream.

[N: with particular pseudorandom sequence generator]
Definition statement
This subclass/group covers:

Subject-matter directed to the design, structure, functionality or mechanism of pseudorandom sequence generators.

[N: producing a non-linear pseudorandom sequence]
Definition statement
This subclass/group covers:

Subject-matter directed to the design, structure, functionality or mechanism of pseudorandom sequence generators using non-linear functions.

key distribution [N: or management, e.g. generation, sharing or updating, of cryptographic keys or passwords (network architectures or network communication protocols for supporting key management in a packet data network H04L 63/06)]
Definition statement
This subclass/group covers:

Subject-matter directed to management of secret material including generation, distribution, sharing, updating of cryptographic keys or passwords.

References relevant to classification in this group
This subclass/group does not cover:
for supporting key management in a packet data network
[N: Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use]
Definition statement
This subclass/group covers:

Subject-matter directed to processes or cryptographic protocols whereby a secret (as cryptographic key, password) becomes available to two or more parties, for subsequent cryptographic use.

[N: Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) (network architectures or network communication protocols for key distribution in a packet data network H04L 63/062)]
Definition statement
This subclass/group covers:

Subject-matter directed to key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to other(s).

References relevant to classification in this group
This subclass/group does not cover:
for key distribution, e.g. centrally by trusted party
[N: using key encryption key]
Definition statement
This subclass/group covers:

Subject-matter directed to managing (e.g. transport, distribute) cryptographic keys for securing information by using key encryption keys. Before transmission/distribution the cryptographic keys are encrypted with the key encryption keys. Passwords may be also used as cryptographic keys for encryption.

[N: using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates]
Definition statement
This subclass/group covers:

Subject-matter directed to managing (e.g. transport, distribute) cryptographic keys for securing information by using public key encryption. The cryptographic key is either encrypted with a private key (i.e. signature) and decrypted with the corresponding public key, or it is encrypted with a public key and decrypted with the corresponding private key. A public key infrastructure (PKI) may be also used wherein the public keys are certified.

[N: involving distinctive intermediate devices or communication paths (network architectures or network communication protocols using different networks H04L 63/18)
Definition statement
This subclass/group covers:

Subject-matter directed to exchanging/distributing cryptographic keys between communication partners by using distinctive intermediate devices or communication paths/channels. The paths/channels may be out-of-band channels or virtual paths.

References relevant to classification in this group
This subclass/group does not cover:
using different networks or paths for security
[N: involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]]
Definition statement
This subclass/group covers:

Subject-matter directed to centralized key units as key distribution center (KDC), trusted third party (TTP) or key translation center (KTC) that are used for cryptographic key management.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 546-549.

[N: involving conference or group key (network architectures or network communication protocols for key management in group communication in a packet data network H04L 63/065)]
Definition statement
This subclass/group covers:

Subject-matter directed to secure mechanisms for distributing cryptographic group keys to different communication entities. To ensure the security of a multi-party communication, the multi-party communication messages are transmitted in encrypted form. The group key used for encrypting and decrypting the multi-party communication messages are only known to the group members, so as to ensure that the encrypted messages may be interpreted only by the group members.

References relevant to classification in this group
This subclass/group does not cover:
for group communications
[N: using tree or hierarchical structure]
Definition statement
This subclass/group covers:

Subject-matter directed to mechanisms for distributing cryptographic conference or group keys to different communication entities involving tree or hierarchical structures wherein the central key unit is the root and the group members are the leafs.

[N: key agreement, i.e. key establishment technique in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these (network architectures or network communication protocols for key exchange in a packet data network H04L 63/061)]
Definition statement
This subclass/group covers:

Subject-matter directed to key establishment techniques in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these, ideally such that no party can predetermine the resulting value.

References relevant to classification in this group
This subclass/group does not cover:
for key exchange
[N: involving Diffie-Hellman or related key agreement protocols]
Definition statement
This subclass/group covers:

Subject-matter directed to key agreement protocols that allow users or entities to exchange public key values and from these values and knowledge of their own corresponding private keys, securely compute a shared key, allowing for further secure communication.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 515-516.

[N: with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys]
Definition statement
This subclass/group covers:

Subject-matter directed to key agreement protocols providing user authentication or key authentication, to schemes as ElGamal, MTI, MQV or related protocols, to key agreement protocols using implicitly-certified keys, or to password-authenticated key agreement mechanisms as PAKE (password-authenticated key exchange), EKE (encrypted key exchange) or SPEKE (simple password exponential key exchange).

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 517-523.

[N: involving identity based encryption [IBE] schemes]
Definition statement
This subclass/group covers:

Subject-matter directed to key agreement protocols involving IBE schemes (the public key of a user is the binary sequence corresponding to information identifying him in a non-ambiguous way).

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 561-562.

[N: secret sharing or secret splitting , e.g. threshold schemes]
Definition statement
This subclass/group covers:

Subject-matter directed to distribution of a secret amongst a group of participants, each of which is allocated a share of the secret; the secret can be reconstructed only when a sufficient number of shares are combined together; individual shares are of no use on their own (threshold schemes).

[N: Quantum cryptography (transmission systems employing electromagnetic waves other than radio waves, e.g. light, infra-red H04B 10/00; wavelength-division multiplex systems H04J 14/02)]
Definition statement
This subclass/group covers:

Subject-matter directed to quantum key distribution (QKD), i.e. the process of using quantum communication to establish a shared key between two parties without a third party learning anything about that key, even if said third party can eavesdrop on all communication between said two parties.

References relevant to classification in this group
This subclass/group does not cover:
Transmission systems employing electromagnetic waves other than radio-waves
Wavelength-division multiplex systems
[N: involving additional nodes, e.g. quantum relays, repeaters, intermediate nodes or remote nodes]
Definition statement
This subclass/group covers:

Subject-matter directed to QKD involving additional nodes as quantum relays, repeaters, intermediate or remote nodes.

[N: Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding]
Definition statement
This subclass/group covers:

Subject-matter directed to reconciliation, error correction, privacy amplification, polarisation or phase coding for QKD systems.

[N: Generation of secret information including derivation or calculation of cryptographic keys or passwords]
Definition statement
This subclass/group covers:

Subject-matter directed to generation, derivation, calculation or extraction of cryptographic keys or passwords.

[N: involving passwords or one-time passwords (network architectures or network communication protocols for using one-time keys in a packet data network H04L 63/067)]
Definition statement
This subclass/group covers:

Subject-matter directed to derivation or generation of encryption keys from passwords.

References relevant to classification in this group
This subclass/group does not cover:
using one-time keys
[N: involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic key derivation or extraction involving user or device identifiers as serial number of a device, measurable physical characteristics provided by a device like a PUF (physical unclonable function), or biometrical information of a user.

[N: involving random numbers or seeds]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for cryptographic keys generation involving random numbers or seeds.

[N: using geo-location information, e.g. location data, time, relative position or proximity to other entities]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic key derivation/generation using data regarding geographical position, time, relative or proximity position to other entities.

[N: based on channel impulse response [CIR]]
Definition statement
This subclass/group covers:

Subject-matter directed to mechanisms for cryptographic key generation / derivation using channel characteristics.

[N: using additional device, e.g. trusted platform module [TPM], smartcard, USB or hardware security module [HSM]]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic keys generation using secure crypto-processors as trusted platform modules, smartcards or hardware security modules.

[N: Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms (network architectures or network communication protocols for using time-dependent keys in a packet data network H04L 63/068)]
Definition statement
This subclass/group covers:

Subject-matter relating to cryptographic techniques (as control vectors, key notarization) for restricting cryptographic keys to pre-authorized uses, to crypto-periods of keys (long-term, short-term, ephemeral keys), or to controlling encryption strength (export regulation for cryptographic algorithms).

References relevant to classification in this group
This subclass/group does not cover:
using time-dependent keys
[N: Revocation or update of secret information, e.g. encryption key update or rekeying]
Definition statement
This subclass/group covers:

Subject-matter relating to cryptographic keys revocation (compromised keys have to be revoked) or updating (old key is replaced by new key).

[N: Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for secret key escrow (user traffic is encrypted such that the session keys used for the encryption are available to properly authorized third parties under special circumstances), for secret key recovery (encrypted data have to be recovered following loss or destruction of keying material due to equipment failure or malicious activities), or for storing/restoring of secret keys (as backups).

[N: involving additional devices, e.g. trusted platform module [TPM], smartcard or USB]
Definition statement
This subclass/group covers:

Subject-matter directed to involving additional (portable) units (as TPM, smartcards) in the cryptographic mechanisms for escrow, recovery or storing of secret information.

using a plurality of keys or algorithms [N: (network architectures or network communication protocols wherein the sending and receiving network entities apply hybrid encryption, i.e. combination of symmetric and asymmetric encryption H04L 63/045)]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms using a plurality of keys or algorithms (as hybrid encryption, i.e. combination of symmetric and public-key encryption) for providing information security.

References relevant to classification in this group
This subclass/group does not cover:
wherein the sending and receiving network entities apply hybrid encryption
the keys or algorithms being changed during operation
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms using a plurality of keys or algorithms changing dynamically or during operation.

Public key, i.e. encryption algorithm being computationally infeasible to invert and user's encryption keys not requiring secrecy
Definition statement
This subclass/group covers:

Subject-matter directed to asymmetric-key or public key cryptography.

[N: underlying computational problems or public-key parameters]
Definition statement
This subclass/group covers:

Subject-matter directed to the interaction between the intractability of several computational problems (as the quadratic residuosity problem) and the security of public-key cryptosystems, or to details relating to public-key parameters (as generators and elements of high order).

[N: involving the discrete logarithm problem, e.g. ElGamal or Diffie-Hellman systems]
Definition statement
This subclass/group covers:

Subject-matter directed to public-key schemes based on the discrete logarithm problem.

[N: involving the integer factorization problem, e.g. RSA or quadratic sieve [QS] schemes]
Definition statement
This subclass/group covers:

Subject-matter directed to public-key schemes based on the integer factorization problem.

[N: details relating to polynomials generation, e.g. generation of irreducible polynomials]
Definition statement
This subclass/group covers:

Subject-matter directed to polynomials generation in public-key schemes.

[N: details relating to pseudo-prime or prime number generation, e.g. primality test)]
Definition statement
This subclass/group covers:

Subject-matter directed to pseudo-prime or prime number generation in public-key schemes.

[N: based on error correction codes, e.g. McEliece]
Definition statement
This subclass/group covers:

Subject-matter directed to public-key schemes involving error correction codes.

[N: involving algebraic varieties, e.g. elliptic or hyper-elliptic curves]
Definition statement
This subclass/group covers:

Subject-matter directed to details of the algebraic or abelian varieties used in the public-key cryptographic schemes, as algebraic groups, rings, fields or elliptic curves.

[N: involving pairings, e.g. identity based encryption [IBE], bilinear mappings or bilinear pairings, e.g. Weil or Tate pairing]
Definition statement
This subclass/group covers:

Subject-matter directed to public-key schemes involving pairings or mappings, as identity based encryption (IBE) schemes.

[N: involving Lattices or polynomial equations, e.g. NTRU scheme]
Definition statement
This subclass/group covers:

Subject-matter directed to public-key schemes involving Lattices (e.g. vector spaces) or polynomial equations.

including means for verifying the identity or authority of a user of the system [N: or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials] ([N: network architectures or network communication protocols for supporting entities authentication in a packet data network H04L 63/08; applying verification of the received information H04L 63/12;] computer systems G06F; coin-freed or like apparatus with coded identity card or credit card G07F 7/08)
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for authentication or identification, including mechanisms (involving cryptographic primitives or data structures as signatures, certificates, credentials) for authorization, entity authentication, message authentication, data integrity, key authentication, non-repudiation, verification or proof of knowledge.

References relevant to classification in this group
This subclass/group does not cover:
for supporting authentication of entities communicating through a packet data network
Applying verification of the received information
Electrical digital data processing
by coded identity card or credit card
[N: involving a third party or a trusted authority]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for authentication between two devices involving a third device.

[N: using tickets or tokens, e.g. Kerberos (network architectures or network communication protocols for entities authentication using tickets in a packet data network H04L 63/0807)]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for authentication using tickets or tokens (as Kerberos authentication protocols).

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 501-502.

References relevant to classification in this group
This subclass/group does not cover:
using tickets
[N: involving the use of a plurality of channels(network architectures or network communication protocols using different networks H04L 63/18)]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication involving the use of a plurality of channels, as for example the use of a wire channel and a wireless channel.

References relevant to classification in this group
This subclass/group does not cover:
using different networks or paths for security
[N: using proof of knowledge, e.g. Fiat-Shamir, GQ, Schnorr, or non-interactive zero-knowledge proofs]
Definition statement
This subclass/group covers:

Subject-matter directed to identification mechanisms using knowledge proofs, as (NIZKP) non-interactive zero-knowledge proofs (Fiat-Shamir, Schnorr protocols).

[N: interactive zero-knowledge proofs]
Definition statement
This subclass/group covers:

Subject-matter directed to identification mechanisms using interactive zero-knowledge proofs.

[N: using a predetermined code, e.g. password, passphrase or PIN (network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L 63/083)]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for authentication or authorization using predetermined codes as passwords, passphrases, personal identification numbers (PIN).

References relevant to classification in this group
This subclass/group does not cover:
using passwords
[N: One-time or temporary data, i.e. information which is sent for every authentication or authorization, e.g. one-time-password, one-time-token or one-time-key]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication or authorization using predetermined codes, said predetermined codes comprising information which is sent for every authentication or authorization, as one-time-password, one-time-token or one-time-key.

[N: Biological data, e.g. fingerprint, voice or retina (network architectures or network communication protocols for supporting authentication of entities using biometrical features in a packet data network H04L 63/0861)]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for identification or verification of an individual using biometrical data as fingerprint, voice or retina.

References relevant to classification in this group
This subclass/group does not cover:
using biometrical features
[N: involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token (network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L 63/0853)]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for authentication or authorization involving hardware tokens like trusted platform module (TPM), smartcard, USB or software tokens.

References relevant to classification in this group
This subclass/group does not cover:
using an additional device
[N: using cryptographic hash functions]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms using cryptographic hash functions.

[N: involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms involving modification detection codes (MDC's) as MD5, SHA or RIPEMD, also called non-keyed hash functions.

[N: involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms involving message authentication codes (MAC's) as CBC-MAC or HMAC, also called keyed hash functions.

[N: involving digital signatures]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms involving digital signatures.

[N: using RSA or related signature schemes, e.g. Rabin scheme]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms involving RSA or related signature schemes, as the Rabin signature scheme.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 433-447.

[N: using DSA or related signature schemes, e.g. elliptic based signatures, ElGamal or Schnorr schemes]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms involving DSA or related signature schemes, as elliptic curve digital signature algorithm ECDSA or ElGamal signature scheme.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 452-462.

[N: using group based signatures, e.g. ring or threshold signatures]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms using digital signatures where signers can establish groups such that each member of the group can produce signatures anonymously on behalf of the group.

[N: using blind signatures]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms using signatures schemes in which the content of a message is disguised before it is signed.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Page 475.

[N: involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements (network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L 63/0823)]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms involving digital certificates as public key certificates or attribute certificates, or to public key infrastructure (PKI) based authentication/verification using certificates.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 559-561.

References relevant to classification in this group
This subclass/group does not cover:
using certificates
[N: using certificate chains, trees or paths; Hierarchical trust model]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication mechanisms involving multiple certification authorities (CA) in public-key systems. Trust relationships between the CA's determine how certificates issued by one CA may be utilized or verified by entities certified by distinct CA's. Hierarchical trust models for certification and cross-certificates are also covered by this subgroup.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 572-575.

[N: using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms involving certificate generation, validation, registration, distribution (pull, push model) or revocation (certificate revocation list CRL).

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 576-577.

[N: using challenge-response]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms comprising protocols where a verifier sends a claimant a challenge (usually a random value or a nonce) that the claimant combines with a shared secret (often by hashing the challenge and secret together) to generate a response that is sent to the verifier. The verifier knows the shared secret and can independently compute the response and compare it with the response generated by the claimant.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 397-405.

[N: for mutual authentication (network architectures or network communication protocols for achieving mutual authentication in a packet data network H04L 63/0869)]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication between parties that may corroborate their identities to the other.

References relevant to classification in this group
This subclass/group does not cover:
for achieving mutual authentication
[N: using physical unclonable functions (PUF)]
Definition statement
This subclass/group covers:

Subject-matter directed to authentication using PUF.

[N: involving time stamps, e.g. generation of time stamps]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms for authentication involving time stamps or generation of timestamps.

Examples: "Handbook of Applied Cryptography" by A.J. Menezes, P.C. van Oorschot, S. A. Vanstone, 5th Edition, June 2001, Pages 581-583.

Bits, or block of bits, of the telegraphic message being interchanged in time [N: (for speech signals H04K 1/06)]
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms involving interchanging in time bits or block of bits of the message.

References relevant to classification in this group
This subclass/group does not cover:
by transmitting the information of elements thereof at unnatural speeds or in jumbled order or backwards
with means for detecting characters not meant for transmission
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms involving means for detecting characters not meant for transmission.

Encryption being effected by mechanical apparatus, e.g. rotating cams, switches, keytape punchers
Definition statement
This subclass/group covers:

Subject-matter directed to cryptographic mechanisms involving encryption effected by mechanical apparatus, as rotating cams, switches or key-tape punchers.

Data switching networks (interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units G06F 13/00)
Definition statement
This subclass/group covers:

Transfer of information having been supplied in digital form in data switching networks, e.g.

Systems characterised by network topology;

Systems in which paths are physically permanent during the communication, e.g. connection oriented communication, virtual circuits;

Systems in which the path identification data is included in each information unit, e.g. connectionless communication, datagram;

Hybrid switching systems;

Arrangements for connecting networks having different types of switching systems;

Topology management and discovery;

Local area networks and interworking arrangements there between;

Flow control and congestion control. Traffic scheduling and balancing;

Routing, pathfinding;

Access control and network resource allocation;

Asynchronous transfer mode networks.

References relevant to classification in this group
This subclass/group does not cover:
Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
Interprocessor communication using networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Communication control
Data transfer characterised by protocol
Multiplexing systems in general
Selecting equipment
Conferences, e.g. video conferences
Automatic or semi-automatic exchanges
Manual exchanges
Telephony conferences arrangements
Computer-aided management of electronic mail
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Circuit switching
A system in which a communication path is physically permanent during the communication
Packet switching
A system in which information is divided into discrete data units, characterised by a data payload and an address part known as a header part. The data units are able to travel over different communication paths to the destination
Message switching systems
A system in which a message is sent into a network with the address of its destination added and it is routed to its destination through the network, e.g. electronic mail network systems
Hybrid switching
Combinations of different switching systems (e.g. packet switching systems and circuit switching systems)
Gateway
Arrangements for connecting between networks having different types of switching systems
Synonyms and Keywords

In patent documents the following expressions/words "packet", "cell" and "frame" are often used as synonyms.

Current supply arrangements
Definition statement
This subclass/group covers:
  • Usage of an independent power supply network
  • Extracting power from the data signal in the line
  • Power-over-Ethernet technologies (PoE, PoE+, PoE plus, IEEE 802.2af, IEEE 802.3at)

This groups contains documents dealing with different ways to supply power to terminals connected to a network.

References relevant to classification in this group
This subclass/group does not cover:
Transmission of data over power lines
Current supply to telephones
Internal power supply in a computer
Informative references
Attention is drawn to the following places, which may be of interest for search:
Details regarding the feeding of energy to the node from the bus
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

PoE
Power-over-Ethernet
PSE
Power Sourcing Equipment
PD
Powered Device
Arrangements for remote connection or disconnection of substations or of equipment thereof
Definition statement
This subclass/group covers:
  • Transition between different power-saving modes
  • Conditions of entry into a sleep mode
  • Wake-on LANs
  • Energy Efficient Ethernet (IEEE 802.3az)

It covers activation or deactivation of terminals or nodes connected to a network. Sometimes, a power on/off is involved, while other documents deal more with logical (de-)activations.

References relevant to classification in this group
This subclass/group does not cover:
Power modes management in wireless networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Details regarding the setting of the power status of a node according to activity on a bus
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

WoL
Wake-on-LAN
[N: Metering, ] charging [N: or billing] arrangements [N: specially adapted for data wireline or wireless communications (payment schemes, architectures or protocols per se G06Q 20/00)]
Definition statement
This subclass/group covers:

Aspects of billing, charging, accounting, tariffing for the transport of data packets in wireless or wireline data networks, including data sub networks of voice networks.

Relationship between large subject matter areas

G06Q: data processing systems or methods, specially adapted for administrative, commercial, financial, managerial, supervisory or forecasting purposes.

H04M: telephonic communication.

H04W: wireless communications networks.

References relevant to classification in this group
This subclass/group does not cover:
Payment schemes, architectures or protocols "as such".
Billing for commerce in data processing systems or methods specially adapted for administrative, commercial, financial, managerial, supervisory or forecasting purposes. This includes the non technical aspects which relate to billing and charging in data networks.

Examples of places where the subject matter of this group is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Metering arrangements in telephonic communication, such as billing and charging of telephone calls or the billing architecture of telephonic networks.
Prepayment voice telephony systems
Accounting or billing for services or facilities specially adapted for wireless communication
Arrangements for maintenance or administration with service quality level based billing
Special rules of classification within this group

Features for which there is no matching subgroup under H04L 12/14 should be classified under H04M 15/00 or H04M 17/00 if appropriate subgroups are provided there.

[N: Architecture for metering of charging or billing]
Definition statement
This subclass/group covers:

This group is used for features related to the interrelation between network nodes, addition of new network nodes, software downloaded to user, self-billing, sampling, backup of billing data, etc. for charging purposes.

[N: Policy-and-charging control [PCC] architecture]
Definition statement
This subclass/group covers:

Charging aspects of the Policy and Charging Rules Function / Policy Charging Rules Node, or Policy and Charging Control architectures.

Special rules of classification within this group

If flow control or admission control aspects are relevant, this is classified in H04L12/56D11, H04L 12/5695 or H04W 28/10.

If network maintenance or administration aspects are relevant, this is classified in H04L 12/244.

[N: in real-time]
Definition statement
This subclass/group covers:

Advice of charge (AoC) during a communication.

[N: Advice of charge with threshold, e.g. user indicating maximum cost]
Definition statement
This subclass/group covers:

Advice of charge (AoC) with a threshold, e.g. user indicating maximum cost.

[N: Indication of expected costs]
Definition statement
This subclass/group covers:

This includes e.g. providing the user a preview of estimated costs before he/she starts a communication, for example before start of a file transfer.

[N: involving dedicated fields in the data packet for billing purposes]
Definition statement
This subclass/group covers:

Special fields, for example in IP-headers of SIP-headers, used for charging or billing.

[N: Invoice generation, e.g. customization, lay-out, database processing, algorithms for calculating the bill or formatting invoices as WWW pages (invoicing in general G06Q30/00B )]
References relevant to classification in this group
This subclass/group does not cover:
Invoicing in general
G06Q30/00B
[N: Metric aspects]
Definition statement
This subclass/group covers:

This group is used for metric aspects whereby the charging is based neither on volume nor on time, for instance based on distance / number of hops, or the use of more complicated formulas for determining the charging.

[N: volume-based]
Definition statement
This subclass/group covers:

This group is used for exceptional volume based charging, for instance only charging for volume of useful data, not overhead data (overhead data being for example: session set-up / tear down, retransmission of erroneous packets).

[N: time-based]
Definition statement
This subclass/group covers:

This group is used for exceptional time based charging, for example only charging for actual transmission time, or time based charging where this would otherwise be uncommon.

[N: inter-operator billing]
Definition statement
This subclass/group covers:

This includes for example: clearing of revenue, format conversion, meta format for billing.

[N: trading network capacity or selecting route based on tariff]
Definition statement
This subclass/group covers:

This includes for example the exchanges for trading the capacity, or selecting operators / routes based on tariff.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements for maintenance or administration with service quality level based billing,
[N: Methods or systems for payment or settlement of the charges for data transmission involving significant interaction with the data transmission network]
Definition statement
This subclass/group covers:

Aspects of payment or settlement of charges involving interaction with the data transmission network, see the subgroups below.

[N: using digital cash]
Definition statement
This subclass/group covers:

Payment using e-cash, credit units, tokens, points.

[N: involving prepayment]
Definition statement
This subclass/group covers:

Features related to prepayment accounts are classified here.

Special rules of classification within this group

The on-line / real-time metering / charging aspects are additionally classified under "Architecture" by tagging with the subgroup code H04L 12/1403.

More detailed features are classified under H04M 17/00.

[N: the splitting involving a third party]
Definition statement
This subclass/group covers:

Cost splitting involving a third party, such as an advertiser, a sponsor.

This could include a discount to the user based on the acceptance of an advertisement where e.g. the advertiser pays the remaining amount.

Even when the third party bears the full cost, this is still classified here.

[N: the splitting involving only the communication parties]
Definition statement
This subclass/group covers:

Cost splitting involving only the communication parties, e.g. the "A" party and the "B" party in a standard two-party communication, or additional parties in case of teleconferencing.

[N: involving use of telephony infrastructure for billing for the transport of data, e.g. call detail record [CDR] or intelligent network infrastructure]
Definition statement
This subclass/group covers:

This includes e.g. the use of call detail record CDR, or the Intelligent Network infrastructure.

[N: Tariff-related aspects]
Definition statement
This subclass/group covers:

This includes variable tariff dependent on subscription-contract, time-of day, flow, QoS/diffserv, bandwidth usage.

Aspects related to network maintenance or administration with service quality level based billing are also classified under H04L 12/2475.

[N: dependent on congestion]
Definition statement
This subclass/group covers:

This includes variable tariffs dependent on congestion, i.e. congestion pricing.

[N: negotiation of tariff]
Definition statement
This subclass/group covers:

This includes negotiation of the tariff, between the user and the provider, or between providers. Also automatic negotiation by algorithms, i.e. without user involvement, is classified here.

[N: involving discounts]
Definition statement
This subclass/group covers:

Discounts on the overall charge where only one communication party, typically the "A" party, pays the cost.

Special rules of classification within this group

If another communication party is involved, this is classified under H04L12/24P5A.

for broadcast or conference [N: , e.g. multicast (multicast or broadcast switches H04L12/56S3A)]
Definition statement
This subclass/group covers:
  • Computer conferences, e.g. whiteboard applications or multimedia conferences, which take place (at least partially) over a data switching network.
  • Multicast transmission, since it is considered as a kind of restricted broadcast.

It is a subgroup of H04L 12/00 and hence contains only documents with broadcast, multicast or conference arrangements in data switching networks, and where there is a disclosure of subject-matter relevant for the broadcast, multicast or conference per se.

Further details of subgroups

This subgroup is not active and contains networks adapted for stock quotations. Computer supported buying and selling of stocks without network aspects is classified in G06Q40/00B.

This subgroup is not active and contains networks specifically adapted for auctions. Computer supported auctioneering such as Internet auctions without network aspects is classified in G06Q30/00C4.

This subgroup includes documents regarding data exchange in real-time between a group of user equipment connected to a data-switching network. The documents provide solutions suitable for groups of more than two pieces of user equipment but do not exclude two users in a degenerate situation.

Instant messaging is classified in H04L 12/581.

This subgroup contains documents related to conference administration arrangements for setting up and starting a conference. It covers aspects related to events before the actual conference takes place.

This subgroup contains documents related to conference administration arrangements during the conference itself.

Examples of documents classified here: US2007274460, US7408890, US7426540.

This subgroup contains documents directed to solving problems such as transmission errors and/or delays, and terminals with limited capabilities.

Examples of documents classified here: EP1876755, WO2004008336

This subgroup contains documents directed to the recording of conference content, participant activities and/or behaviour, etc. for later retrieval.

This subgroup contains documents where not all the receivers of the broadcast or multicast data are connected through the same kind of networks, which influences the broadcast/multicast service.

This subgroup contains documents where not all the receivers have the same capabilities, which influences the broadcast/multicast service.

Layered encoding of data as such is classified in H04N 7/26.

The size of the location is not relevant; the data transmission can take place within a room, a building, a city, or a nation etc. (protocols for adapting network applications to user terminal location H04L 29/08657; services specially adapted for wireless communication networks making use of the location of users or terminals H04W 4/02)

This subgroup contains inter alia documents related to the IGMP or MLD protocols for joining and leaving a multicast group.

It also contains documents dealing with changes to the multicast service as the result of a node failure or a member joining or leaving the group.

Routing tree calculation is classified in H04L12/56C120.

This subgroup contains documents dealing with systems where the data forwarding to every receiver is also the responsibility of the receivers themselves, e.g. application layer multicast.

This subgroup covers documents where the multicast or broadcast aspect is relevant for the push service, such as pushing common data to a group of users. Arrangements for push based network services in general, such as pushing personal data to (a) user(s), are classified in H04L 29/08693.

Push systems in relation to Internet retrieval, see G06F 17/30864.

This subgroup contains documents dealing with the problem of how to make sure that each receiver has received the data and what to do when this is not the case.

This subgroup contains documents dealing with any action (e.g. verifications, increased resources, alternative paths, etc.) taken prior to transmission in order to ensure network reliability. Arrangements for detecting or preventing errors in received information in general, see H04L 1/00.

This subgroup contains documents concerning the transmission order of multicast and/or broadcast data packets onto the network, e.g. vis-à-vis unicast data.

The restrictions are for instance applied to avoid flooding of data by dividing the recipients into multicast groups or using subnets or subdomains.

This subgroup only contains documents dealing with multicast or broadcast problems that are a result of (at least some) network links being wireless, e.g. intermittent connectivity or bandwidth constraints.

Documents concerned with the wireless part of the network for broadcast or multicast services such as MBMS are classified in H04W 4/06, e.g. radio channel allocation.

This subgroup contains documents where real-time information is unidirectionally communicated to a group of recipients.

Relationship between large subject matter areas

H04H: Broadcast communication in broadcast networks, e.g. radio or television networks.

H04N: Pictorial communication, e.g. television.

References relevant to classification in this group
This subclass/group does not cover:
Routing aspects for multicast
H04L12/56C101
Flow control for multicast
H04L12/56D5
Packet switches for multicast or broadcast
H04L12/56S3A
One-way streaming of real-time multimedia data
Telephone conferences
Video conferences
Arrangements for the radio link of a wireless network for broadcast or multicast services such as MBMS, e.g. radio channel allocation
Push-to-talk systems
Informative references
Attention is drawn to the following places, which may be of interest for search:
Signalling and protocols for real-time multimedia conferences
Special rules of classification within this group

The rule for classification in this group is "multiple places, no priority". This means that a document should be classified in all the subgroups that are appropriate for the document.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

Chat room
A chat room is a special type of computer conference where the users normally are not aware of the (true) identities of other participants' before joining the chat. The chat room application executes mainly on a server which is often accessed through a web browser. No participant has control over the admission of other participants.
Instant messaging, IM
Instant messaging is data exchange in real-time between at least two end users connected to a packet-switching network where the users are aware of the identity and the presence of the other party or parties before starting the data exchange.
Arrangements for preventing the taking of data from a data transmission channel without authorisation (means for verifying the identity or the authority of a user of a secure or secret communication system H04L 9/32 )
Definition statement
This subclass/group covers:

This subclass/group covers:

This subgroup is not used.

Relationship between large subject matter areas

This subgroup was initially used to classify network security aspects, which are now classified in:

  • H04L 63/00: Network architectures or network communication protocols for network security and/or
  • H04W 12/00: Network architectures or network communication protocols for wireless network security
References relevant to classification in this group
This subclass/group does not cover:
Cryptographic means for verifying the identity or authority of a user of the system
Arrangements for maintenance or administration
Definition statement
This subclass/group covers:

Aspects relating to operation, administration, maintenance, and provisioning of heterogeneous packet-switched data networks (e.g. IP, Ethernet, ...) both using proprietary and standardised network management architecture and protocols (e.g. TMN, SNMP) irrespective of the physical transport medium and the type of service carried.

Although typical Network Management functions, aspects related to accounting/billing and security are in general not classified here. The only exceptions are Service quality based billing and security of the network management system (e.g. authorised access to the manager, security of management messages).

Relationship between large subject matter areas

Aspects related to the management of the fulfilment of an agreement between two different parties (usually not within the same network/domain), typically known as Service Level Agreement (SLA), are classified under the H04L 12/2464 subgroups.

Aspects related to the monitoring of the performance of a network communications are classified under the H04L 12/2602 subgroups (e.g. monitoring of QoS parameters).

Aspects related to the testing of a network or a network element are classified under H04L 12/2697.

References relevant to classification in this group
This subclass/group does not cover:
Detection or prevention of error at physical layer
Account or billing for the transport of the data-packets
Arrangement for network security
Controlling or operating of remote end-user devices' applications
Network management of traditional telephonic (circuit-switched) networks
Operation and Maintenance of homogeneous ATM networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Interconnection arrangements between voice switching centres. Network operation, administration, maintenance or provisioning
Arrangements providing connection between exchanges
Wireless communication networks. Supervisory, monitoring or testing arrangements
Wireless communication networks. Network traffic or resource management
Selecting arrangements for multiplex systems using optical techniques
Special rules of classification within this group

In these subgroups, at each hierarchical level, unless otherwise indicated, classification is made in the first appropriate place (first place priority Rule). When several particular technical subjects are disclosed, this rule is separately applied to each of them.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

Network Management, NM
Refers to the activities, methods, procedures, and tools that pertain to the operation, administration, maintenance, and provisioning of networked systems.
Network Management functions
Functions that are performed as part of network management include Fault, Configuration, Accounting, Performance Security management (FCAPS).
Operation
Deals with keeping the network up and running smoothly.
Administration
Deals with keeping track of resources in the network and how they are assigned. It includes all the "housekeeping" that is necessary to keep the network under control.
Maintenance
Is concerned with performing repairs and upgrades—for example, when equipment must be replaced, when a router needs a patch for an operating system image, when a new switch is added to a network. Maintenance also involves corrective and preventive measures to make the managed network run "better", such as adjusting device configuration parameters.
Provisioning
Is concerned with configuring resources in the network to support a given service. For example, this might include setting up the network so that a new customer can receive the requested service.
Network Manager
An entity that acts in a manager role for performing the network management functions.
Agent
A software module that performs management functions requested by a Manager.
Network element, NE, managed device, managed node
Means manageable logical entity uniting one or more physical devices which are networked. Network elements usually have management agents responsible for performing the network management functions. They can be any type of device, including, but not limited to: hosts, gateways, terminal servers, routers, switches, bridges, hubs, modem, IP telephones, IP video cameras, computer hosts, and printers.
Managed object
An abstract representation of network resources of the network element that is managed.
Synonyms and Keywords

In patent documents the following abbreviations are often used:

ITU
International Telecommunication Union
IETF
International Engineering Task Force
OMA-DM
Open Mobile Alliance - Device Management
3GPP
3rd Generation Partnership Project
NM
Network Management
NMS
Network Management System
TMN
Telecommunications Management Network
SNMP
Simple Network Management Protocol
MIB
Management Information Base
TR-069
Technical Report 69 (Broadband forum standard)
SOAP
Simple Object Access Protocol

In patent documents the word "management" is often used with the meaning of "controlling", "commanding" , "operating".

In patent documents the expression "configured to" is often used with the meaning "adapted to", "suitable for" defining functional features of structural elements.

[N: involving integration or standardization]
Definition statement
This subclass/group covers:

Use of standards NM protocols, standards architecture, arrangement and representation instrumental for an integrated management.

Special rules of classification within this group

This group covers a hierarchy of different miscellaneous aspects focusing on integration and standardisation. Classification is preferably made in the appropriate subdivision below.

[N: using standardized network management architectures, e.g. TMN [Telecommunication Management network], UNMA [Unified Network Management Architecture]
Definition statement
This subclass/group covers:

Aspects related to the specific type of standards NM architecture used.

Special rules of classification within this group

If the type of standardized architecture is merely cited as general information the group is not to be allocated.

[N: using standardized network management protocols, e.g. SNMP [Simple Network Management Protocol], CMIP [Common Management Interface Protocol]
Definition statement
This subclass/group covers:

Aspects related to modification or specific use of standards NM protocols. Additional examples are TR-069, OMA-DM.

Special rules of classification within this group

If the type of standardized protocol is merely cited as general information the group is not to be allocated.

[N: Multivendor or multistandard integration]
Definition statement
This subclass/group covers:
  • Managing network equipments from different vendors following different communication protocols and standards technologies;
  • Integration products capable of communicating with different managed nodes in their own protocol and capable of representing a unified network view to the network managers.

Examples: EP1162784

[N: Mapping or translation of multiple network management protocols]
Definition statement
This subclass/group covers:

Using different NM protocols, conversion of NM commands and reports from one protocol (e.g. CMIP) into another protocol (e.g. SNMP), mapping between different version of the same NM protocols (SNMP v2 and v3).

Examples: EP1720286

[N: using object oriented techniques, e.g. CORBA [Common Object Request Broker Architecture for representation of network management data]
Definition statement
This subclass/group covers:

Using object oriented techniques (e.g. CORBA) for representation of NM data. Processing managed entities as Objects.

Special rules of classification within this group

This class is to be allocated for OO-Techniques other than the typical use of objects in, e.g., SNMP (e.g. MIB’s objects or OMA) which can be considered in the class H04L 12/2403.

[N: using relational databases for representation of network management data, e.g. managing via SQL [Structured Query Language]
Definition statement
This subclass/group covers:

Use of networks being modelled by a (1:1) image in a relational database, e.g., management is done by issuing respective (SQL) commands.

[N: using Internet technology, e.g. a standard Web Browser at the management workstation]
Definition statement
This subclass/group covers:
  • NM from a Workstation connected to the Internet, e.g. using a standard Internet Browser;
  • Transfer of NM information via internet messages (email, html, xml);
  • Web-service NM, OMA, SOAP.
[N: Architectural aspects of network management arrangements]
Definition statement
This subclass/group covers:
  • Aspects on how the NMS is structurally organised;
  • Aspects on how the NMS is connected for retrieving the management information.
[N: Arrangements involving multiple distributed management centers cooperatively managing the network]
Definition statement
This subclass/group covers:
  • Multiple NM centres or NM units communicating with each other and managing the network together - often each manager being responsible for his own NM domain and all managers being on the same hierarchical level - peer to peer relation;
  • Replacement of failed NM node by a peer one.
Special rules of classification within this group

In group H04L 12/2404, the different multivendor network managers, do not necessarily cooperates with each other but they operate independently.

[N: Arrangements involving a hierarchical management structure]
Definition statement
This subclass/group covers:

Hierarchical structures like main manager > medium (mid - level -) managers > sub-managers.

Examples: EP0838919, US2002174207

[N: Aspects of network management Agents]
Definition statement
This subclass/group covers:

Usage of NM (mobile) agents.

Management agents are usually implemented in the managed network nodes themselves or reside "close" to the managed nodes in the network. They usually support the standard NM protocols or provide a mapping functionality between the nodes' proprietary and the managers standardized protocol (e.g. proxy). Mobile management agents can be often programmed in JAVA.

Examples: EP0831617

Special rules of classification within this group

This class is to be allocated for use and features of Agents other than the typical use already done in, e.g., SNMP standardised protocols, which can be considered in the class H04L 12/2403.

[N: Arrangements involving CNM [Customer Network Management]
Definition statement
This subclass/group covers:

Giving the customer (limited) access to NM functions.

[N: involving network analysis]
Definition statement
This subclass/group covers:

Aspects related to the (on-line) analysis of the operating network.

Special rules of classification within this group

This group covers miscellaneous aspects focusing on the analysis of the network.

Classification is preferably made in the appropriate subdivision below.

[N: using statistical methods, e.g. distribution tests, or establishing statistical profiles or calculating probabilities]
Definition statement
This subclass/group covers:

Evaluation of monitored data applying advanced statistical methods and tests going beyond basic counting and averaging of frames, errors. The analysis is based on-line while the network is fully operative.

[N: for automatically determining the actual topology of a network (Topology discovery in routers H04L12/56C1)]
Definition statement
This subclass/group covers:
  • Determination, retrieval or use of network topology (also based on routing table information) for network management purposes (e.g. fault localisation, network analysis, configuration, graphical representation...).
  • Discovery of links, network elements and adjacencies;
  • Aspects relating to topology change after migration;
  • Planning of the appropriate topology.
References relevant to classification in this group
This subclass/group does not cover:
Topology discovery for routing purposes
H04L12/56C1
Topology discovery in wireless networks
[N: involving management of faults or events or alarms]
Definition statement
This subclass/group covers:

Fault detection, localization, issuing alarms, handling of special events.

References relevant to classification in this group
This subclass/group does not cover:
Alarm or messages triggered by the user, customer (trouble ticket)
Informative references
Attention is drawn to the following places, which may be of interest for search:
Fault management in exchanges' connections
[N: Alarm or event filtering, e.g. for reduction of information]
Definition statement
This subclass/group covers:

Reduction of the "alarm stream" to filter out the relevant alarms, events, etc. Often the network manager is overwhelmed with floods of alarms in complex networks. Filters can be set to only show these events the network managers considers "relevant" at a given time.

[N: Alarm and event correlation]
Definition statement
This subclass/group covers:
  • Correlating events (alarms) usually for determining the common cause of these alarms as being the "real" problem causing a flood of alarms;
  • Determination of the root of a problem in general.
[N: Automatic restoration of network faults]
Definition statement
This subclass/group covers:
  • Automatically "repairing" broken links, nodes, routes by a NMS;
  • Network disaster recovery.
[N: involving Artificial Intelligence algorithms, e.g. expert systems, rule based systems, genetic algorithms]
Definition statement
This subclass/group covers:

Applying artificial intelligence methods (expert systems, rule based systems, genetic algorithms) in NM usually for finding the cause of problems or for predicting network behaviour and proactive error prevention.

[N: Configuration management of network or network elements (management of devices network applications for proprietary or special purpose network environments H04L 29/08567; automatic configuration in wireless networks H04W 24/02)]
Definition statement
This subclass/group covers:

(Automatic) Configuration of network components, nodes, network elements.

References relevant to classification in this group
This subclass/group does not cover:
Management of device's network applications for proprietary or special purpose network environments
Informative references
Attention is drawn to the following places, which may be of interest for search:
Automatic Configuration of system equipment in wireless networks
[N: Bandwidth or capacity management, i.e. automatically increasing or decreasing capacities, e.g. bandwidth on demand]
References relevant to classification in this group
This subclass/group does not cover:
Traffic shaping and scheduling, protocols for congestion control, protocols for resource reservation
Informative references
Attention is drawn to the following places, which may be of interest for search:
Bandwidth allocation and management in exchanges' connections
[N: Assignment of logical groupings to network elements; Policy based network management or configuration]
Definition statement
This subclass/group covers:
  • Assignment of logical grouping to network elements;
  • Policies for Group Memberships;
  • Management using a pre-defined policy.
[N: Hardware and software tools for network management]
Definition statement
This subclass/group covers:

Simulation tools, software tools, graphical interface aspects, specific hardware devices.

Special rules of classification within this group

This group covers miscellaneous aspects relating to software or hardware tools.

Classification is preferably made in the appropriate subdivision below.

[N: for network design, e.g. with integrated simulation and design testing]
Definition statement
This subclass/group covers:
  • Network design tools (e.g. with integrated simulation and design testing) which operates off-line;
  • Modelling or abstraction of the network for behaviour simulation.
Informative references
Attention is drawn to the following places, which may be of interest for search:
Network design in exchanges connections
[N: Network management software packages]
Definition statement
This subclass/group covers:

NM software tools like HP Openview, Netview 6000, with GUIs (Graphical User Interfaces) capable of managing large and complex data networks.

[N: using GUI [Graphical User Interface]
Definition statement
This subclass/group covers:
  • Using a GUI to represent the architecture of the network, monitoring results for NM purposes;
  • which/how the management information are displayed.
[N: using dedicated network management hardware]
Definition statement
This subclass/group covers:
  • (portable) hardware equipment for managing (e.g. configuring, logging management data, etc.) a device at a time;
  • Craft terminals used by fields technicians;
  • Built-in NM hardware.
[N: using dedicated tools for LAN [Local Area Network] management]
Definition statement
This subclass/group covers:

Usually NM tools operating at MAC level.

[N: Security in network management, e.g. restricting network management access (protocols or architecture for network security H04L 29/06551)]
Definition statement
This subclass/group covers:
  • Only security related to the NM system;
  • Aspects relating to keeping the manager and the management data secure;
  • Restricting access control to the NMS, encryption of management data.
References relevant to classification in this group
This subclass/group does not cover:
Protocols or architecture for network security
[N: Decision processes by autonomous network management units using voting and bidding]
Definition statement
This subclass/group covers:
  • Process for electing a unit as a master;
  • Bidding and electing units based on best QoS level.
[N: Specific management aspects for broadband networks]
Definition statement
This subclass/group covers:

NM for traditional broadband digital cross-connect switches supporting user's communication, now being replaced by ATM or DSL-based infrastructure.

[N: Network service management, ensuring proper service fulfilment according to an agreement or contract between two parties, e.g. between an IT-provider and a customer]
Definition statement
This subclass/group covers:

Aspects relating to Service level management between parties for service deployment, assurance and review over heterogeneous packet-switched data networks (e.g. IP, Ethernet, etc.) irrespective of the physical transport medium and the type of service carried.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

Service Level Management
Provides for continual identification, monitoring and review of the levels of IT services specified in the Service Level Agreements (SLAs). Service Level Management ensures that arrangements are in place with internal IT Support-Providers and external suppliers in the form of Operational Level Agreements (OLAs) and Underpinning Contracts (UCs), respectively.
Service Level Management functions
Ensuring that the agreed IT services are delivered when and where they are supposed to be; Liaising with Availability Management, Capacity Management, Incident Management and Problem Management To ensure that the required levels and quality of service are achieved within the resources agreed producing and maintaining a Service Catalogue (a list of standard IT service options and agreements made available to customers) Ensuring that appropriate IT Service Continuity plans exist to support the business and its continuity requirements.
Service Level Agreement, SLA
Service level agreement is a part of a service contract where the level of service is formally defined.
Quality of Service, QoS
Quality measure relating to specific network parameters of traffic packets (bit rate, delays, packet loss...) which describe the treatment experienced by the packets while passing through the network .
SLA vs QoS
In order to meet the SLA requirements specific internal QoS management processes are to be implemented. SLA is namely directed to an 'aggregation' of (end-to-end) QoS parameters rather than to specific internal network metrics or is directed to QoS related to a customer (QoE).
Quality of Experience, QoE
A subjective measure of a customer's experiences with a service.
Synonyms and Keywords

In patent documents the expression "QoS" is often used with the meaning "Service Level performance".

[N: Managing SLA [Service Level Agreement] or interaction between SLA and QoS [Quality of Service]]
Definition statement
This subclass/group covers:
  • General aspects relating to the description of the terms or properties of the SLA;
  • Aspects relating to mapping/converting SLA requirements into QoS parameters.

ITU-T Rec. E.860 (Figure)

[N: Defining or negotiating SLA contracts, guarantees or penalties (SLA negotiation in wireless networks H04W 28/24)]
Informative references
Attention is drawn to the following places, which may be of interest for search:
SLA negotiation in wireless networks
[N: Measuring SLA quality parameters, e.g. against possible contract or guarantee violations (Monitoring performance metrics on a simple network level H04L 12/2634)]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Monitoring performance metrics on a simple network level
[N: determining service performance, i.e. performance on service level, e.g. response time or MTBF [Mean Time Between Failure]]
Definition statement
This subclass/group covers:
  • Aspects relating to the benchmarking for specific services;
  • Aspects relating to mean time to failure (MTTF), mean time to recover (MTTR);
  • Aspects relating to the overall performance of a network, e.g. delay, reliability.
[N: Ensuring SLA (flow or congestion control at network level H04L 12/569)]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Flow or congestion control at network level
[N: by proactively reacting to service quality change (e.g. degradation or upgrade) by reconfiguration (mere restoration of network faults H04L 12/2422)]
References relevant to classification in this group
This subclass/group does not cover:
Restoration of network faults
[N: Service quality level based billing, e.g. dependent on measured service level customer is charged more or less (general charging or billing for transport of data packets H04L 12/14)]
References relevant to classification in this group
This subclass/group does not cover:
General charging or billing for transport of data packets
[N: Generating service level reports]
Definition statement
This subclass/group covers:

Generating a report based on data showing the performance levels for individual customers or individual services.

[N: Measuring contribution of individual network components to actual service level (alarm or event correlation H04L 12/2421)]
Definition statement
This subclass/group covers:

Identifying network entities, such as nodes, links, applications, that affect or are responsible for actual quality of service, such as service failure or service quality degradation.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Alarm or event correlation
[N: Testing of service level quality]
Definition statement
This subclass/group covers:
  • Simulating service usage by active agents to automatically measure service level compliance.
  • Testing based on artificial traffic, artificial customer's behaviour.
[N: Automatic provisioning of the service triggered by the service manager, e.g. concrete service implementation by automatic configuration of network components (for initializing configuration, i.e. provisioning of network or devices H04L 12/2425)]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Initializing Configuration, i.e. provisioning of network or devices
[N: Service discovery by the Service Manager (automatically determining the actual topology of a network H04L 12/2416; topology discovery in routers H04L12/56C1; arrangements for service discovery, e.g. Service Location Protocol (SLP) H04L 29/08648)]
Definition statement
This subclass/group covers:

Identifying service elements or services and dependencies among the elements and services of a network

Informative references
Attention is drawn to the following places, which may be of interest for search:
Automatically determining the actual topology of a network
Topology discovery in routers
H04L12/56C1
Arrangements for service discovery, e.g. Service Location Protocol (SLP)
[N: Customer care]
Definition statement
This subclass/group covers:

Order and problem handling, Informing end-user of service situation.

[N: Customer Relationship Management (for arrangements involving Customer Network Management, i.e. giving the customer access to network management functions H04L 12/2413)]
Definition statement
This subclass/group covers:
  • Handling of customer data, contracts, customer history
  • Monitoring and recording customer interactions with the provider
  • Data mining techniques for customer's data processing
References relevant to classification in this group
This subclass/group does not cover:
Arrangements involving Customer Network Management, i.e. giving the customer access to network management functions
Arrangements involving CNM
[N: Customer-centric QoS [Quality of Service] measurement]
Definition statement
This subclass/group covers:
  • Aspects relating to the quality or satisfaction as perceived by the customer/user, Quality of Experience (QoE)
  • Aspects relating to reports provided by the customer about the service quality
[N: Filtering out customers affected by service problems]
Definition statement
This subclass/group covers:

Identifying customers affected by service problems as network element failures, network congestion or service degradation

[N: Handling of Trouble Tickets]
Definition statement
This subclass/group covers:

Aspects relating to the generation of error messages or notifications originated by a customer or a customer's terminal to be treated by the Service Provider.

References relevant to classification in this group
This subclass/group does not cover:
Alarm messages (automatically) triggered by faulty network elements
[N: Managing simple transport services, i.e. providing only network infrastructure]
Definition statement
This subclass/group covers:

Aspects wherein access to the network itself is the service.

[N: based on type of value added network service under agreement]
Special rules of classification within this group

The H04L12/26S6 subgroups should be allocated only in combination with at least one of the groups from H04L 12/2464 to H04L 12/249 and only if essential for the characterisation of the service management aspects.

[N: wherein the managed service relates to web hosting (web hosting as such H04L 29/0809, web-browsers G06F 17/30861, video-hosting H04N 21/2743)]
References relevant to classification in this group
This subclass/group does not cover:
Web-browsers
Web hosting
Video-hosting
[N: wherein the managed service relates to voice services (protocols for real-time multimedia communications H04L 29/06176; management of telephonic communication services H04M 3/22; management of VoIP services H04M 7/0081)]
References relevant to classification in this group
This subclass/group does not cover:
Protocols for real-time multimedia communications
Management of telephonic communication services
Management of VoIP services
[N: wherein the managed service relates to audio / video / TV (protocols for real-time multimedia communications H04L 29/06176 ; interactive television or VoD H04N 21/00)]
References relevant to classification in this group
This subclass/group does not cover:
Protocols for real-time multimedia communications
Interactive television or VoD
[N: wherein the managed service relates to messaging (messaging, such as e-mail in packet-switching networks H04L 12/58)]
References relevant to classification in this group
This subclass/group does not cover:
Messaging, such as e-mail in packet-switching networks
[N: wherein the managed service relates to chat services (conducting a computer conference H04L 12/1822; instant messaging H04L 12/581)]
References relevant to classification in this group
This subclass/group does not cover:
Conducting a computer conference
Instant messaging
Monitoring arrangements; Testing arrangements
References relevant to classification in this group
This subclass/group does not cover:
Aspects related to monitoring and testing of service level agreed between two different parties (usually not within the same network/domain), typically known as Service Level Agreement (SLA) compliance
Special rules of classification within this group

In these subgroups, at each hierarchical level, unless otherwise indicated, classification is made in the first appropriate place (first place priority Rule). When several particular technical subjects are disclosed, this rule is separately applied to each of them.

[N: Monitoring arrangements]
Definition statement
This subclass/group covers:
  • Monitoring aspects, that means basically observing the network by measuring passing traffic or setting counters here and there at different points in the network;
  • Aspects of testing in the sense of "active monitoring", by introducing new packets or modifying data packets;
  • Monitoring QoS parameters of packets irrespective of the use and application;
  • Monitoring of metrics of network element;
  • Measuring performance at network/link level (availability, status)
  • Report of monitored parameters.
References relevant to classification in this group
This subclass/group does not cover:
Monitoring at physical layer
Monitoring for security reasons
Monitoring of networked distributed applications
Special rules of classification within this group

Aspects related to testing, with the meaning that something is done upon the network to see its reaction, e.g. by means of test packets or dummy traffic are classified under H04L 12/2697 only if a corresponding entry is not available under H04L 12/2602 or in case network elements are tested off-line while the network is not yet operative.

Synonyms and Keywords

In patent documents the word "testing" is often used with the meaning of "monitoring".

[N: involving a reduction of monitoring data]
Definition statement
This subclass/group covers:

Aspects relating to the selection of specific type/group of packets .

[N: using sampling of monitoring data, i.e. storing only a selection of packets]
Definition statement
This subclass/group covers:

Aspects relating to the storing of selection of packets.

[N: using adaptive sampling]
Definition statement
This subclass/group covers:

Dynamically adjusting the sampling rate according to specific criteria, e.g. traffic burstiness, packet rate, statistics.

[N: using flow; Flow generation]
Definition statement
This subclass/group covers:
  • Aggregating captured packet data into flows, a flow being defined as a unidirectional sequence of packets all sharing same network parameters;
  • Monitoring flow, wherein the flow is usually characterised by a n-tuple of network parameters, e.g. Source/Destination address, Port number, protocol number (e.g. IETF IPFIX, NetFlow);
  • Monitoring of flow on different OSI-layers.
[N: using filtering (alarm or event filtering H04L 12/242)]
Definition statement
This subclass/group covers:
  • Reduction of monitored data by applying filters to extract specific type of packets or part of packets;
  • Deep packet inspection (e.g. BPF, libpcap);
  • Using hashing, masking for extracting and storing packets or part of packets.
References relevant to classification in this group
This subclass/group does not cover:
Alarm or event filtering
[N: processing of captured monitoring data]
Definition statement
This subclass/group covers:
  • Aspects focusing on aggregation and post-processing of the monitored data;
  • Storing of (part of) monitored packets.
[N: for graphical visualization of monitoring data (graphical user interfaces H04L 12/2458)]
Definition statement
This subclass/group covers:

Displaying, showing of the monitoring data/result in graphs, x-y axis, drawings.

References relevant to classification in this group
This subclass/group does not cover:
Use of a GUI as a tool for monitoring or managing a network
[N: for traffic related reporting]
Definition statement
This subclass/group covers:

Reporting the overall traffic on a Tap-Point in the network

[N: for device related reporting (reporting of sensed information of home appliances H04L 12/2803)]
Definition statement
This subclass/group covers:

Reporting traffic characteristics for a specific device or network node

References relevant to classification in this group
This subclass/group does not cover:
Reporting of sensed information of home appliances managing a network
[N: for time frame related reporting]
Definition statement
This subclass/group covers:

Formatting traffic reports with respect to certain time intervals, e.g. per second, minute, hour, day or week, or configurable timeframes

[N: Monitoring using or based on specific metrics]
Definition statement
This subclass/group covers:
  • Aspect of monitoring of packets on a network (link/node) level including QoS parameters;
  • Aspect of monitoring of network elements' parameters (temperature, power consumption, etc.) via network protocols.
Informative references
Attention is drawn to the following places, which may be of interest for search:
Measuring performance on a service level
[N: based on connectivity]
Definition statement
This subclass/group covers:
  • Monitoring whether a link is active or a device is connected
  • Checking or verifying both physical and logical connectivity, e.g., by using connectivity check messages
  • Use of techniques at layer 2 or 3 of the OSI-stack.
[N: based on functioning (monitoring the activity of the application user H04L 29/08675; monitoring appliance functionality of home appliances H04L 12/2803)]
Definition statement
This subclass/group covers:

Monitoring the status of the connected device, e.g. whether the device is or working properly, monitoring network element resource metrics like CPU or memory utilization or printer utilization.

References relevant to classification in this group
This subclass/group does not cover:
Monitoring the activity of the application user
Monitoring appliance functionality of home appliances
[N: using errors (management of events, faults or alarms H04L 12/2419)]
References relevant to classification in this group
This subclass/group does not cover:
Management of events, faults or alarms
[N: using packet loss]
Definition statement
This subclass/group covers:

Monitoring of transmission data loss for all upper layers (Layers 2, 3 and above), as e.g. packet/frame/PDU loss, is classified in subgroups H04L 12/2649, H04L 12/2652.

A loss is often recognized via expiration of a timer (timeout) and can be caused by full buffer, overloading, discarding.

[N: based on transmission error]
Definition statement
This subclass/group covers:

Monitoring of transmission errors include all layer independent errors which can be recognized after reception of any transmitted data as bit errors (as e.g. CRC/checksum errors), packet errors (as e.g. duplicate packet errors, packets received after close errors), framing errors (frames too long/short), alignment errors, framing checksum (FCS) errors, bad header errors, carrier sense errors, packet collisions, late collision errors, excessive collision errors, backward errors, duplicate message acknowledgements (ACKs), out of order packet errors.

[N: based on delays]
Definition statement
This subclass/group covers:

Different type of packet delays (transition time), also due to node or stack processing, buffering.

Special rules of classification within this group

This class and the subgroups refer to delays irrespective of the use that is done of the delay information. For example the use of delay information for synchronizing time/clock is to be classified in H04J 3/0635.

[N: based on utilization of link capacity]
Definition statement
This subclass/group covers:

Level of congestion, i.e. percentage or absolute value of link capacity available or used.

[N: based on throughput]
Definition statement
This subclass/group covers:

Observing the time required to get a certain amount of bits across a link or path, thus the ratio of bits per time unit.

[N: based on packet rate]
Definition statement
This subclass/group covers:

Monitoring bandwidth or packet data rate used by a traffic stream.

[N: using threshold monitoring]
Definition statement
This subclass/group covers:

Monitoring if observed parameters or metrics are within upper or lower thresholds.

[N: using protocol analyzers]
Definition statement
This subclass/group covers:

Use and protocols of protocol/packet analyzer for network monitoring purposes.

[N: Testing equipment; Routine testing]
Definition statement
This subclass/group covers:
  • Testing, with the meaning that something is done upon the network to see its reaction, e.g. by means of test packets or dummy traffic.
  • Aspects relating to use of test traffic for interoperability measurement;
  • Generation of specific type of testing traffic and routine;
  • Characterisation of the type of test traffic to be used;
  • Aspects relating to testing network or network elements, when the network or network element are not yet operative by simulating with quasi-real traffic.
  • Hardware test elements, e.g. test-on-chip
References relevant to classification in this group
This subclass/group does not cover:
Testing of service level quality under SLA
Informative references
Attention is drawn to the following places, which may be of interest for search:
Testing in Wired Telephony
Testing in Wireless Networks
Testing in ATM
Special rules of classification within this group

This subgroup is used for classification of aspects related to testing in the sense of "active monitoring", e.g. by introducing new packets or modifying data packets, only if a corresponding entry is not available under H04L 12/2602.

characterised by path configuration, e.g. local area networks (LAN), wide area networks (WAN)
Definition statement
This subclass/group covers:

Header group accommodating those networks whose topology respond to regular LAN topologies (bus, ring or star). His head group contains also WAN and MAN topologies. Documents dealing with very generic network topologies on Layer 2 should be classified here.

[N: Broadband local area networks]
Definition statement
This subclass/group covers:
  • DOCSIS-related technologies (cable modems, cable modem termination systems);
  • MoCA networks;
  • HFC networks.

This group concerns mostly cable modems and developments of data services on existing cable infrastructures. One can find in this group variations on the basic IEEE 802.14 standard for accessing an optical cable using mostly TDMA. Some architectures for access to video on demand networks using HFC (Hybrid Fibre Coax) physical media. Of course some LANs using ATM as transport technology are also to be fund in the group.

References relevant to classification in this group
This subclass/group does not cover:
Multimedia protocols
Video on demand and video coding
Telephony over cable networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Point-to-multipoint connection of the data network to end users in an access network
Arrangements for combining access network resources elements, e.g. channel bonding
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

DOCSIS
Data Over Cable Service Interface Specification
CMTS
Cable Modem Termination System
CM
Cable Modem
MoCA
Multimedia over COAX Alliance
[N: Home automation networks]
Definition statement
This subclass/group covers:

Network of appliances in a same home exchanging within said network messages which are generic with regard to the type of appliance.

This group covers all network aspects of domotics.

It covers:

  • Transmission media such as power transmission lines or dedicated wiring for controlling home appliances;
  • Using the home telephone wiring for building a LAN. HomePNA(Phone-line Networking Alliance).
  • Addressing issues concerning the identification of devices in different
  • areas of a dwelling
  • Network control. Using e.g. a regular TV receiver or dedicated terminal Tapping devices used to connect appliances to the selected wiring (Echelon's LON network).
  • Some standard architectures for home control use: CEBUS or FieldBus, PNA.
References relevant to classification in this group
This subclass/group does not cover:
Factory automation
Transmission of data over power lines
Remote control of lights using a control bus
Informative references
Attention is drawn to the following places, which may be of interest for search:
Retrieval from the Internet
Arrangements for transmitting signals characterised by the use of a wireless electrical link
Device-related reporting
H04L1/26M2B2
Monitoring functionality
Access arrangements
High-speed IEEE 1394 serial bus
Single bridge functionality
Protocol conversion
Arrangements for network security
Protocols for network applications involving the use of web-based technology
Arrangements for service discovery
Protocols for network applications involving the use of web-based technology for remote control or remote monitoring
Telephonic communication systems adapted for combination with telemetering systems
Telephonic communication systems adapted for combination with remote control systems
Receiver circuitry for displaying additional information being controlled by a remote control apparatus
Adaptations of television systems for transmission by electric cable for domestic distribution
Home network arrangements specially adapted for distribution of digital video signals
H04N7/24N
Adaptation of digital video signals for transport over a specific home network
H04N7/24T6
Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
Special rules of classification within this group

This group covers all network aspects of domotics.

The following topics are well represented in the group:

Use of networks (involving wireless links, power transmission lines, home telephone wiring) for controlling or monitoring home appliances or for exchanging control messages between audio video appliances.

In the definition above, the following criteria are emphasized:

  • There should be at least one network of appliances; this condition is not fulfilled for a simple application of remote control of a heating system by telephone or Internet;
  • The devices connected to the network are appliances, i.e. devices having a sensor or actor role in the home automation; a network involving printers and computers (these computers having no appliance function) only does not fulfill this condition;
  • There should be general aspects of the network, i.e. aspects which are not specific to a single type of application; this is the case for instance when the invention relates to a message data field used for controlling appliances, but not if the invention concerns specifically the use of a few commands to accomplish a certain operation; this difference can be understood as a difference of layer;

The subgroup relates to control or monitoring with several appliances in a same home; this condition is not fulfilled when the appliances are communicating only via the Internet or the mobile cellular network; this condition is also not fulfilled by the interconnection of audio-video devices with their broadcast network; hotels can be considered as home if the privacy concept coincides with the hotel; building automation of purely mechanical and lighting devices can be considered as a home if it is separate from the city infrastructure.

[N: Home Audio Video Interoperability (HAVi) networks]
Definition statement
This subclass/group covers:

HAVi networks encompasses connections to control Audio and Video hardware using FireWire.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

HAVi
Home Audio Video Interoperability
[N: Exchanging configuration information on appliance services in a home automation network (address allocation H04L 29/12207; arrangements for maintenance or administration involving network analysis for automatically determining the actual topology of a network H04L 12/2416; hardware or software tools for network management using graphical user interfaces H04L 12/2458)]
Definition statement
This subclass/group covers:

Exchange and retrieval of information regarding which element having which attributes are present in the network.

References relevant to classification in this group
This subclass/group does not cover:
Network management of home networks, for instance by initialisation of the network, configuration and self-configuration of the network
Configuration of devices by assignment of identifiers and addresses
Address allocation
for automatically determining the actual topology of a network
using GUI (Graphical User Interface)
[N: indicating that an appliance service is present in a home automation network (monitoring functionality H04L 12/2642; arrangements for service discovery H04L 29/08648)]
Definition statement
This subclass/group covers:

Exchange of information indicating which services or operations are available on the home network appliances.

References relevant to classification in this group
This subclass/group does not cover:
Discovering of devices as part of configuration
Arrangements for service discovery, e.g. Service Location Protocol
Address allocation to terminals or nodes connected to a network
based on functioning
[N: indicating a format for calling an appliance service function in a home automation network (protocols for network applications involving the use of web-based technology H04L 29/08099)]
Definition statement
This subclass/group covers:

Description of capabilities of devices and services in a home network.

Exchange of information describing access methods and parameters of devices or services available on the home network appliances.

Emphasis is on "description", i.e. the data structure indicating the commands and parameters with which control of the operation of a device's appliance can be triggered.

References relevant to classification in this group
This subclass/group does not cover:
for remote control or remote monitoring
[N: describing content present in a home automation network, e.g. audio video content (retrieval from the Internet G06F 17/30861)]
Definition statement
This subclass/group covers:

Description of contents available in a home network. Exchange of information describing contents available on the home network appliances. Emphasis is on "contents".

References relevant to classification in this group
This subclass/group does not cover:
Information retrieval from the Internet
Protocols for network applications involving the use of web-based technology, e.g. Hyper Text Transfer Protocol (HTTP)
[N: Exchanging control software or macros for controlling appliance services in a home automation network (arrangements for maintenance or administration involving configuration of the network and network elements H04L 12/2424)]
Definition statement
This subclass/group covers:

Self explanatory, pieces of software, firmware used to control home appliances.

References relevant to classification in this group
This subclass/group does not cover:
Programme loading or initiating
Protocols for network applications
Configuration management of network or network elements
[N: Controlling appliance services of a home automation network by calling their functionalities (arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station; in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom H04Q 9/00 )]
Definition statement
This subclass/group covers:

Exchange of information that triggers action of at least one device.

References relevant to classification in this group
This subclass/group does not cover:
Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
[N: from a device located outside both the home and the home network (access arrangements H04L 12/2856; protocols for network applications involving the use of web-based technology for remote control or remote monitoring H04L 29/08099; telephonic communication systems adapted for combination with remote control systems H04M 11/007; arrangements for transmitting signals characterised by the use of a wireless electrical link G08C 17/00 )]
Definition statement
This subclass/group covers:

Complex home network provisions for being remotely accessed. Access to a home network (with at least two appliances) from a device outside the home network.

In that example, a device control processor which communicates with a remote access service unit and operating a home network device using universal plug and play (UPnP) message, stores list of controlled devices, each device state, event list and service request list.

The processor converts request/message received from service unit/UPnP device into message/request for transmission to respective units.

References relevant to classification in this group
This subclass/group does not cover:
Remote control by local wireless signals
Remote control by Internet
Remote control via a telephone connection
Arrangements for transmitting signals characterised by the use of a wireless electrical link
[N: based on user interaction within the home (receiver circuitry for displaying additional information being controlled by a remote control apparatus H04N 5/44582)]
Definition statement
This subclass/group covers:

User interaction from within network for the control of appliances, e.g. through remote controller, PDA, cell phone, RF ID etc.

References relevant to classification in this group
This subclass/group does not cover:
Receiver circuitry for displaying additional information being controlled by a remote control apparatus
User interface for managing and configuring a home network
[N: Avoiding conflicts related to the use of home appliances (arrangements for network security H04L 29/06551)]
Definition statement
This subclass/group covers:

The home appliance or another device prevents the home appliance from having to execute commands which disturb ongoing operations.

References relevant to classification in this group
This subclass/group does not cover:
Access control according to access rights are classified only in network security
H04L29/06C6
Arrangements for network security
[N: Reporting information sensed by appliance or service execution status of appliance services in a home automation network (device-related reporting H04L1/26M2B2; arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom H04Q 9/00)]
Definition statement
This subclass/group covers:

Exchange of information for reporting or monitoring the operation of home appliances so as to trigger operation of other home appliance functions. The status of a service or the sensed situation of an appliance is advertised on a home network for reaction by other home devices to create an environment conforming to specific rules or profiles.

In that document, the rules of device interaction may include instructions that are to be transmitted from the aggregator in response to the aggregator receiving change of state messages from devices of the environment.

References relevant to classification in this group
This subclass/group does not cover:
Alarm systems in general
Advertising the status of network devices
Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
[N: Reporting to a device located outside the home and the home network (access arrangements H04L 12/2856; protocols for network applications involving the use of web-based technology for remote control or remote monitoring H04L 29/08099; telephonic communication systems adapted for combination with telemetering systems H04M 11/002)]
Definition statement
This subclass/group covers:

Self-explanatory : reporting the operation of home appliances or a particular network event affecting a home appliance to one or more external devices, i.e. to devices outside the home network.

References relevant to classification in this group
This subclass/group does not cover:
Access arrangements
Protocols for network applications involving the use of web-based technology for remote control or remote monitoring
Telephonic communication systems adapted for combination with telemetering systems
[N: Reporting to a device within the home network; wherein the reception of the information reported automatically triggers the execution of a home appliance functionality]
Definition statement
This subclass/group covers:

Self explanatory: in contrast to the preceding class, the exchange of messages only occurs among home appliances within the same home automation network.

[N: involving user profiles according to which the execution of a home appliance functionality is automatically triggered]
Definition statement
This subclass/group covers:

Self explanatory: a user profile defines rules or a policy for triggering specific actions or the emission of a command to a device in response to the occurrence of an event at a given home appliance.

[N: Processing of data at an internetworking point of a home automation network]
Definition statement
This subclass/group covers:

Device adapted to communicate with different types of networks.

[N: Interconnection of the control functionalities between home networks (single bridge functionality H04L 12/4625 )]
Definition statement
This subclass/group covers:

Bridges between home networks (e.g. HAVi/UPNP).

Home gateway performing interface adaptation (also lower layer adaptation, kind of bridge).

References relevant to classification in this group
This subclass/group does not cover:
Bridging devices
Protocol conversion
Devices adapted for communicating using different protocols
Single bridge functionality
[N: Switching of information between an external network and a home network (access arrangements H04L 12/2856)]
Definition statement
This subclass/group covers:

Switching (or forwarding, routing) at a gateway between external network(s) and home network(s). Contains operational details on residential/home gateways.

References relevant to classification in this group
This subclass/group does not cover:
Bridging devices
Multiplexing of signals from an external network for distribution to the home network
Access arrangements
[N: Protocol conversion between an external network and a home network (protocol conversion H04L 29/06068; adaptation of digital video signals for transport over a specific home network H04N7/24T6; controlling appliance services of a home automation network from a device located outside the home and the home network H04L 12/2818)
Definition statement
This subclass/group covers:

Protocol conversion between home network(s) and external network(s). If the conversion is only from one controlling protocol to another, the corresponding Indexing Code entry should be used.

References relevant to classification in this group
This subclass/group does not cover:
Protocol conversion
Devices adapted for communicating using different protocols
from a device located outside both the home and the home network
[N: Distribution of signals within a home automation network, e.g. involving splitting/multiplexing signals to/from different paths (adaptations of television systems for transmission by electric cable for domestic distribution H04N 7/106; hybrid transport H04L 12/6418; home network arrangements specially adapted for distribution of digital video signals H04N7/24N)]
Definition statement
This subclass/group covers:

Distribution of signals within a home network. Data signal distribution from/to appliances within the home network. The mere transmission of signals in a home network without a particular way to convey said signal in the home network should not be classified here.

Example: WO2006100515.

The main aspect of the document is that the signals are all distributed in the home through one Ethernet cable on which all packets are transmitted according to TCP/IP. There are no improvements to the TCP/IP no details on the head end and the switching within the head end. No details about control of devices, that's why signal distribution appears to be the only main aspect within home network.

Second example: US6751441

Signals from cable network are split into TV and data signals; the data signals are modulated at the WLAN frequency but distributed to the rooms along the cables. Within the rooms the signals are radiated through an antenna.

References relevant to classification in this group
This subclass/group does not cover:
Domestic distribution of TV signals
Hybrid transport
[N: Metropolitan area networks]
Definition statement
This subclass/group covers:

A MAN, Metropolitan Area Network, refers to the access technology as well as to the size. The reference book "Computer Networks" written by Tanenbaum gives a definition of it: "A MAN is a network that covers an entire city, but uses LAN technology".

[N: Wide area networks, e.g. public data networks]
Definition statement
This subclass/group covers:

This group is very general about WANs. It contains public data networks such as Frame Relay and X.25 packet networks.

[N: Access arrangements, e.g. Internet access (asynchronous transfer mode networks H04L 12/5601; broadband local area networks H04L 12/2801; optical access or distribution networks H04Q 11/0067; access to open networks H04L 12/5691; digital subscriber line end-user equipment and bit-level processing of data on a PSTN-based network H04M 11/00; home network gateways H04L 12/2834 ; wireless access networks H04W)]
Definition statement
This subclass/group covers:

An access network is a part of a global wired communication network that connects subscribers to their service providers in the public data network.

It consists generally of end-user equipments connected to an access multiplexer. The access multiplexer is connected to an access server through an aggregation network, wherein the access server is the interface between the access network and the public data network.

References relevant to classification in this group
This subclass/group does not cover:
Management of WDM parameters in optical multiplex systems
Access arrangements for providing telephone service in networks other than PSTN/ISDN
Circuit-switched access networks
Transfer of video data (multimedia streaming) from a video content server to a subscriber
Telephonic communication systems adapted for combination with other electrical systems
Switching of information between an external network and a home network
Wireless communications networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Access to a packet-switched data network over a hybrid coaxial infrastructure
Asynchronous Transfer Mode (ATM) networks
Admission & flow control, QoS management
Access to open networks
Establishment of secure connections and subscriber authentication
Addressing and naming aspects
Digital subscriber line end-user equipment, DSL modems, xDSL splitters, and bit-level processing of data on PSTN-based network
Provision of optical access or distribution networks
Wireless access networks
[N: Access network architectures]
Definition statement
This subclass/group covers:

There are various ways to deploy an access network, but most of them rely on an existing wired infrastructure. Originally, access to the Internet was mostly provided by DSL access technologies, where a point-to point connection between a subscriber and a service provider is provisioned via a PPP over ATM connection, thereby re-using the existing wired network and their functionalities (ATM PVCs). Nowadays, the trend is clearly to integrate Ethernet as carrier technology for access network segments while remaining the main carrier for the backbone networks, thereby coping with the increasing demand for value-added services such as VoIP, HDTV, IPTV and Triple-Play. In parallel to the development of DSL access technologies, broadcast networks such as cable and optical networks are more and more employed to convey data packets in addition to other signal types, such as video or audio streaming.

References relevant to classification in this group
This subclass/group does not cover:
Access to open networks, incl. selection between different service providers
[N: Point-to-point connection between the data network and the subscribers (encapsulation H04L 12/4633; virtual LANs H04L 12/4641; routing of packets H04L 12/5689 )]
Definition statement
This subclass/group covers:

This group covers essentially the original access technologies wherein a connection between an end-user and the service provider is established by means of a point-to-point protocol, over various types of aggregation networks, such as ATM or Ethernet (PPPoX sessions). This group also includes pseudo-wire techniques, i.e. encapsulation over an IP-based access network.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Packet Encapsulation
Virtual Local Area Networks
ATM networks
Routing of packets
Special rules of classification within this group

This group has a quite broad definition and ideally should not be the only symbol allocated to a document dealing with access networks. Only documents focusing on the access network infrastructure taken as a whole, i.e. from the public data network to the end-user device, implementing a form of point-to-point technology shall be allocated this subclass as unique symbol.

[N: Point-to-multipoint connection from the data network to the subscribers]
Definition statement
This subclass/group covers:

In this entry, new access technologies relying on the existing cable infrastructure (e.g. DOCSIS, MoCA) or optical networks (PONs) are addressed. Data is transmitted over a shared communication medium on the downlink and the uplink. On the downlink, data is broadcast by the service provider to all subscribers, and each subscriber extracts the data which is aimed to him, out of the stream of multiplexed data.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Broadband Local Area Networks
Provision for optical access or packet networks
Special rules of classification within this group

See the reasoning for the symbol H04L 12/2859.

[N: Arrangements for combining access network resources elements, e.g. channel bonding (multichannel protocols H04L 29/06088; routing of packets H04L 12/5689; modem pooling H04L 25/14 )]
Definition statement
This subclass/group covers:

Aspects related to an optimized usage of the available access network resources in order to enable provision of greedy multimedia services over bandwidth-limited access networks. This could consist of bundling subscriber lines, arranging a logical combination of network resources, such as frequency bands on a HFC network or the simultaneous usage of multiple PPPoX connections for transporting the same data service.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Routing of packets
Modem pooling
Multichannel protocols
Virtual concatenation in SDH/OTN networks
[N: Logical combinations]
Definition statement
This subclass/group covers:

Essentially, comprises arrangements for multiplexing individual subscriber connections or grouping of frequency slots on a cable network. The emphasis is on the combination of logical or abstract entities, i.e. frequency or bandwidth resources combinations, not physical entities such as cables or hardware elements.

[N: Physical combinations]
Definition statement
This subclass/group covers:

Refers to the concept of grouping or combining physical access network resources such as devices, interfaces, wires, cables, in order to enhance the total throughput provided to a given subscriber.

[N: Operational details of access network equipments (admission control or resource allocation in access networks H04L 12/5692 )]
Definition statement
This subclass/group covers:

Functional characteristics of various devices commonly present in an access network.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Admission control & resource allocation in access networks
[N: Remote access server, e.g. BRAS]
Definition statement
This subclass/group covers:

A remote access server is a device that routes traffic to and from an access multiplexer (e.g. DSLAM) on a public data network.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this group, the following expressions are used with the meaning indicated:

BRAS
Broadband Remote Access Server
BAS
Broadband access server
[N: Termination of subscriber connections]
Definition statement
This subclass/group covers:

Covers essentially the handling of PPPoX sessions : how the Point-to-Point sessions are initiated, maintained, or terminated. Only PPPoX-related operations at the remote access server are covered by this subclass.

[N: Processing of data for distribution to the subscribers]
Definition statement
This subclass/group covers:

Details about specific data processing operations for distributing various multimedia flows, originally formatted to optimize their transport through an IP network, over the access network to the subscribers.

The emphasis is on a particular way to re-arrange or adapt a flow received at a remote access server from the public data network before distributing the flow to subscriber(s) over the access network, wherein this particular way reflects the characteristics of the access networks.

Example: a remote access server adds MAC address tag information to a packet received from an ISP.

[N: Handling of subscriber policies (group policies management H04L 12/244)]
Definition statement
This subclass/group covers:

Differentiated policies for distributing data to subscribers, based for instance on user profiles, time of the day, traffic volume etc.

References relevant to classification in this group
This subclass/group does not cover:
Group management policies
[N: Access multiplexer, e.g. DSLAM (generic distributed time multiplexers, e.g. TDM/TDMA H04J 3/1694 )]
Definition statement
This subclass/group covers:

Operational details of an access multiplexer is a device, located normally in a telephone exchange or in multi-dwelling units of a service provider, that connects multiple end-user terminals to a public data network access node (e.g. a BRAS) through an aggregation network. Examples : DSLAM, fiber distribution hubs or active splitters, etc.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Generic distributed time multiplexers, e.g. TDM/TDMA
DSL modem with DSLAM functionalities
[N: characterised by the network type on the uplink side, i.e. towards the service provider network]
Definition statement
This subclass/group covers:

Self-explanatory : this group characterizes the access multiplexer by the type of aggregation network used on the uplink (not to the end-user equipment).

[N: Arrangements interfacing with optical systems]
Definition statement
This subclass/group covers:
  • Optical Line Terminals
  • Cable modem Termination System.
References relevant to classification in this group
This subclass/group does not cover:
Determination of optical signal parameters (e.g. wavelength) as a function of data characteristics from Layer-2 or above, like VLAN number, IP address, subscriber profile
Optical multiplexers
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

OLT
Optical Line Terminals
CMTS
Cable Modem Termination System
[N: characterised by the offered subscriber services]
Definition statement
This subclass/group covers:

Self-explanatory: in contrast to the group H04L 12/2879, this group covers the type of connection linking the access multiplexer to subscriber devices.

Special rules of classification within this group

Normally, a document shall be allocated one of the symbols from this group only when the document focuses on the communication services offered between the access multiplexer and the subscriber devices.

[N: Multiservice, e.g. MSAN]
Definition statement
This subclass/group covers:

A Multi-service access Node, also known as a Multi-service access gateway is a device typically installed in a telephone exchange (although sometimes in a roadside serving area interface cabinet) which connects customers' telephone lines to the core network, to provide telephone, ISDN, and broadband such as DSL all from a single platform.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this group, the following terms are used with the meaning indicated:

MSAN
Multi-service Access Node
MSAG
Multi-service Access Gateway
[N: Single service]
Definition statement
This subclass/group covers:

Self-explanatory. Essentially one DSL type is supported by the access multiplexer.

[N: characterised by the access multiplexer architecture]
Definition statement
This subclass/group covers:

This group covers specific implementation designs of an access multiplexer, e.g. specific hardware resources or line cards arrangements.

References relevant to classification in this group
This subclass/group does not cover:
DSLAM modems
[N: Centralized processing]
Definition statement
This subclass/group covers:

All complex traffic processing (e.g. classification, filtering, QoS, etc.) is performed on a single central chip, e.g. on the uplink card.

[N: Distributed processing, e.g. on line cards]
Definition statement
This subclass/group covers:

Some or all complex traffic processing is off-loaded to the line cards, which may include dedicated processors.

Examples : US6587476, US2002159462, US2008101401.

[N: Subscriber equipments (DSL modems H04M 11/062; cable modems H04L 12/2801 )]
Definition statement
This subclass/group covers:
  • Optical Network Units, Optical Line Terminals
  • Set-top boxes
  • Home network access point
  • Cable modems in cable networks, e.g. DOCSIS

Entry concerning the design of devices carrying out generic L2 or L3 data processing operations, located at the interface between a private or home environment and the access network.

References relevant to classification in this group
This subclass/group does not cover:
DSL modems and xDSL splitters
Home network gateways, residential gateways
Broadband local area networks
Special rules of classification within this group

This subclass shall only be allocated to documents giving operational details of subscriber equipments which interact with other access network devices, e.g. via the exchange of messages. The sole description of a stand-alone end-user device without any active connection to an access network shall not be classified in H04L 12/2898.

Bus networks
Definition statement
This subclass/group covers:

A bus network includes one or a plurality of shared communication lines interconnecting at least 3 distant stations, wherein data is transferred serially in the form of frames or bitstrings along the bus.

References relevant to classification in this group
This subclass/group does not cover:
Bus networks employed restrictively for a specific automotive application (e.g. power steering, brake-by-wire)
Bus to control actuators/sensors or any other industrial appliance in an automation system
Parallel bus systems
Data transfer in the environment of a computer (ISA, PCI, USB, I2C, PCMCIA, DMA, PCI bridges...)
Point-to-point communication between 2 stations over a bus
G06F13/32P
Transmission of data and power over a link, and not over a bus network as defined above
Serial data transmission over a shared medium having a ring or star topology
Fibre-channel aspects related to topology, i.e. ring, or switch architecture
Bus networks including at least one bridging device
Wireless networks comprising several communication nodes using contention resolution mechanisms
Informative references
Attention is drawn to the following places, which may be of interest for search:
Bus systems being deployed on an airplane specifically for controlling parts of an aircraft
Daisy chain buses using an embedded synchronisation
[N: Architecture of a communication node (intermediate storage or scheduling H04L 12/5694; current supply arrangements H04L 12/10)]
Definition statement
This subclass/group covers:

Details on the hardware elements comprised in a bus communication node. In particular, this class covers the inter-working of the various hardware components and implementation details of specific hardware components. A document shall get an EC code from this group only if the document deals with a particular inventive hardware or software realization. If the document includes the mere illustration of a hardware or software design for implementing a protocol, this document shall only get an Indexing Code in this group.

Example : A FlexRay communication node:

Informative references
Attention is drawn to the following places, which may be of interest for search:
Hardware architecture of a processing unit in general
Current supply arrangements for the communication nodes
Intermediate storage or scheduling
[N: Details regarding a bus controller]
Definition statement
This subclass/group covers:

A bus controller refers to a microprocessor that is dedicated to input and output of data by a node on a bus. Structure of a carrier sense functionality is also classified here.

[N: Details regarding a bus master]
Definition statement
This subclass/group covers:

A bus master is a device controlling which node accesses the bus at particular time. See also H04L 12/403 for access control aspects

[N: Details regarding a bus guardian]
Definition statement
This subclass/group covers:

A bus guardian is a device monitoring the timing of node accesses on the bus, used for instance in FlexRay systems to avoid babbling idiots (faulty, continuously sending nodes).

References relevant to classification in this group
This subclass/group does not cover:
Passive fault-masking in a computer environment
[N: Details regarding a bus interface enhancer]
Definition statement
This subclass/group covers:

Interface between the communication line and the other elements of the communication node, having some autonomous functionalities such as message pre-filtering, bus monitoring...

[N: Details regarding the setting of the power status of a node according to activity on the bus]
Definition statement
This subclass/group covers:

Power management aspects, such as management of the transition between various power states (sleep, active or stand-by). These documents shall also be classified in H04L 12/12

Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements for remote connection or disconnection of substations or of equipment thereof
[N: Details regarding the feeding of energy to the node from the bus]
Definition statement
This subclass/group covers:

Refers to field devices for instance, which use the voltage and/or current level present on the bus to draw energy from the bus. Note that H04L 12/10 contains documents classified before 2008 having this functionality.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Current supply arrangements
[N: High-speed IEEE 1394 serial bus (bus transfer protocol on a daisy chain bus using an embedded synchronisation G06F 13/426)]
Definition statement
This subclass/group covers:

All documents dealing primarily with transmission on a Firewire bus.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Bus transfer protocol on a daisy chain bus using an embedded synchronisation
[N: Isochronous transmission]
Definition statement
This subclass/group covers:

Documents referring generally to synchronization aspects of Firewire communication, incl. jitter compensation and clock synchronizations.

[N: Bandwidth and channel allocation (home automation networks H04L 12/2803; flow control H04L 12/569 )]
Definition statement
This subclass/group covers:

Aspects of resource allocation for Firewire networks.

References relevant to classification in this group
This subclass/group does not cover:
Home automation networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Flow control aspects
[N: Packet processing; Packet format (packet switches H04L 12/5696; intermediate storage or scheduling H04L 12/5694; Adaptation of digital video signals for transport over a specific network H04N7/24T6 )]
Definition statement
This subclass/group covers:

Self-explanatory, deals with operations on packets in a Firewire bus system.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Packet switches
Intermediate storage or scheduling
Adaptation of digital video signals for transport over a specific network
H04N7/24T6
[N: Bus configuration (home automation networks H04L 12/2803; Arrangements for maintenance or administration H04L 12/24 )]
Definition statement
This subclass/group covers:

Typically bus reset operations on Firewire.

References relevant to classification in this group
This subclass/group does not cover:
Home automation networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements for maintenance or administration
[N: Bus arbitration]
Definition statement
This subclass/group covers:

Control to the access to the communication medium on Firewire.

[N: Bus bridging (LAN interconnection over a bridge based backbone H04L 12/462; single bridge functionality H04L 12/462)]
Definition statement
This subclass/group covers:

Interconnection aspects in Firewire bus systems.

Informative references
Attention is drawn to the following places, which may be of interest for search:
LAN interconnection over a bridge based backbone
Single bridge functionality
[N: Interconnection with other networks (LAN interconnection over a bridge based backbone H04L 12/462; single bridge functionality H04L 12/462)]
Definition statement
This subclass/group covers:

Gateway to other network sections, to other Firewire networks.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Bridging devices in local area networks
[N: Security; Encryption; Content protection (arrangements for network security H04L 29/06551)]
Definition statement
This subclass/group covers:

Security aspects in Firewire networks.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements for network security
[N: Wireless (wireless communication networks H04W)]
Definition statement
This subclass/group covers:

Should not be used anymore for classification. Wireless communication networks are now classified in H04W.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Wireless communication systems
[N: Interconnection of audio or video/imaging devices]
Definition statement
This subclass/group covers:

Interconnection with multimedia devices over a FireWire bus.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Home automation networks
Bitstream network arrangements specially adapted for distribution of digital video signals
H04N7/24N
[N: Interconnection of computers and peripherals (printer information exchange with computer G06F 3/1293 )]
Definition statement
This subclass/group covers:

Interconnection of computers with specific extension elements such as peripherals over a Firewire bus.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Printer information exchange with computer
[N: Management of data rate on the bus (systems modifying transmission characteristics according to link quality H04L 1/0001; negotiation of transmission parameters of transmission speed prior to communication H04L 5/1446; adaptive data allocation for multicarrier modulation H04L 27/2608)]
Definition statement
This subclass/group covers:

Documents referring generally to the selection of a particular data rate on a bus network, based on different factors, i.e. instantaneous network load. Rate adaptation on a bus maybe be necessary for achieving optimal transmission performance, by finding a good trade-off between packet loss and transmission speed. A LIN bus supports for instance various bitrates.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Systems modifying transmission characteristics according to link quality
Negotiation of transmission parameters of transmission speed prior to communication
Adaptive data allocation for multicarrier modulation
[N: Nodes adapting their rate to the physical link properties (LAN switches H04L12/56S8A)]
Definition statement
This subclass/group covers:

Physical link properties include bus capacity such as 10Mbit/s or 100Mbit/s Ethernet network.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Rate adaptation according to physical link properties such as the detection of the bus capacity being 10Mbit/s or 100Mbit/s Ethernet network at a LAN switch
H04L12/56S8A
[N: involving priority mechanisms (intermediate storage or scheduling H04L 12/5694; hybrid switching fabrics H04L 12/6402; time-division multiplex systems H04J 3/00)]
Definition statement
This subclass/group covers:

Documents related to the introduction of certain criteria to prioritize the transmission of data on the bus. On a vehicle bus for instance, information about car safety shall have priority over messages carrying monitoring data.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Time-division multiplexing
Intermediate storage or scheduling
Hybrid switching fabrics
[N: by scheduling the transmission of messages at the communication node]
Definition statement
This subclass/group covers:

Queue management at the transmitting node.

[N: by using dedicated slots associated with a priority level]
Definition statement
This subclass/group covers:

In a TDMA bus communication system, certain time slots might be reserved for transmission of data having a high level of priority.

[N: by assigning priority to messages according to a message field]
Definition statement
This subclass/group covers:

Typically a message field or tag indicates a priority level, which can be read by any node connected to the bus.

[N: Flexible bus arrangements (arrangements for maintenance or administration involving management of faults; events, alarms H04L 12/2419; automatic restoration of network faults H04L 12/2422 )]
Definition statement
This subclass/group covers:

Documents covering various flexibility aspects, such as fast network re-configuration, flexible topology change, seamless connection or disconnection of a new node to/from the bus. In general, this class covers scalability of bus networks and reconfiguration aspect.

References relevant to classification in this group
This subclass/group does not cover:
Arrangements for maintenance or administration involving management of faults; events, alarms
Automatic restoration of network faults
[N: involving redundancy (error detection or correction of the data by redundancy in hardware using active fault-masking in interconnections G06F 11/2002; error detection or correction of the data by redundancy in hardware using active fault-masking in storage systems using spares or by reconfiguring G06F 11/2053)]
Definition statement
This subclass/group covers:

Different forms of redundancy which do not correspond to the following related fields.

References relevant to classification in this group
This subclass/group does not cover:
Error detection or correction of the data by redundancy in hardware using active fault
G06F11/20E
Error detection or correction of the data by redundancy in hardware using active fault-masking masking faults in storage systems using spares and/or by reconfiguring
G06F11/20L
where persistent mass storage functionality or persistent mass storage control functionality is redundant
[N: by using a plurality of communication lines]
Definition statement
This subclass/group covers:

A single bus system may comprise at least one back-up communication line, in case of failure of the main communication line. Each station has then typically two or more bus drivers, one for each communication line.

[N: by using a plurality of bus systems]
Definition statement
This subclass/group covers:

Two bus systems running independently of each other may provide protection against problems affecting the whole active bus system.

[N: by using a plurality of nodes]
Definition statement
This subclass/group covers:

Duplication of a part or of an entire communication node in order to ensure fast recovery from a node defect without affecting the bus operations.

[N: by using a plurality of master stations]
Definition statement
This subclass/group covers:

Switching from an active master station to a back-up master station is needed for safety-critical bus systems with centralized access control. See also H04L 12/403.

with centralised control, e.g. polling
Definition statement
This subclass/group covers:

Contains documents with a central control node controlling the transmissions on the bus. Polling is known for a long time so a "new" polling scheme could be found in rather old documents (<1970).

[N: in which slots of a TDMA packet structure are assigned based on a contention resolution carried out at a master unit (TDM/TDMA multiplex systems per se H04J 3/1694; hybrid switching systems H04L 12/64 )]
Definition statement
This subclass/group covers:

Self-explanatory. Shall not be used for documents dealing with FlexRay in general.

References relevant to classification in this group
This subclass/group does not cover:
Allocation of channels in TDM/TDMA networks
Hybrid switching systems
with decentralised control
Definition statement
This subclass/group covers:

This is a subgroup with general aspects of decentralized control. It contains documents about implicit token passing and some slotted buses.

With Random Access, e.g. carrier-sense multiple- access with collision detection (CSMA-CD)
Definition statement
This subclass/group covers:

Deals with access schemes in which access to the medium is granted at random after an arbitration process in case several nodes send requests simultaneously (collision). CSMA/CD (carrier sense multiple access with collision detection) also called Ethernet (basic document by Xerox US4063220) is one of these schemes. Ethernet aspects not linked with CSMA/CD shall not be classified in this class, but documents concerning some specific Ethernet functionalities such as contention resolution, back-off or interframe gap shall be classified in this group.

[N: using bit-wise arbitration]
Definition statement
This subclass/group covers:

This is a special case for relatively low transmission speeds and/or short buses. Nodes competing for bus access read the superposed signals back from the bus and stop transmission when the bus signal is not identical with the transmitted signal. Many bus systems used e.g. in vehicles can be found in this subgroup.

References relevant to classification in this group
This subclass/group does not cover:
Computer buses with bit-wise arbitration
Special rules of classification within this group

CAN bus aspects not linked with bit-wise arbitration shall not be classified in this class.

With Deterministic Access, e.g. token passing
Definition statement
This subclass/group covers:

Contains documents with access schemes granting access to requests within a predetermined time limit. On token buses nodes are arranged in a logical ring passing the access right (token) from node to node. Bus networks having a master are not classified here. Aspects of FlexRay related to the deterministic access to static time slots are also classified here.

Loop networks
Definition statement
This subclass/group covers:

Deals with networks in which nodes are connected in a physical ring.

[N: Synchronisation for ring networks (Time Division Multiplex ring networks, e.g. SDH/SONET H04J 3/085)]
Definition statement
This subclass/group covers:

Deals with link by link synchronization between nodes and network

synchronization.

References relevant to classification in this group
This subclass/group does not cover:
Synchronization in general
for ring networks
Informative references
Attention is drawn to the following places, which may be of interest for search:
Time division multiplex systems
Special rules of classification within this group

Double classification with H04J 3/00 is allowed.

with centralised control, e.g. polling
Definition statement
This subclass/group covers:

Same as for bus networks but in a physical ring network.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Bus networks with centralized control
with decentralised control
Definition statement
This subclass/group covers:

Analog to bus networks, see H04L 12/417.

References relevant to classification in this group
This subclass/group does not cover:
Bus networks with decentralized control
with synchronous transmission, e.g. time division multiplex (TDM), slotted rings
Definition statement
This subclass/group covers:

Slotted rings; can be with fixed time slot allocation to the nodes or with access schemes for transmission access to a part of the bandwidth (slot).

with asynchronous transmission, e.g. token ring, register insertion
Definition statement
This subclass/group covers:

Nodes having the access right (token) can transmit. When finished, the token is other nodes is buffered in a register until a node has finished its own transmission. This is the main group for FDDI and Fiber Channel rings when the access method is the issue.

Ring fault isolation or reconfiguration [N: (for SDH/SONET ring networks H04J 3/085 )]
Definition statement
This subclass/group covers:

Rings are vulnerable to faults. This subgroup contains documents dealing with recovery from faults like loop-backs or subrings when a ring systems is cut.

References relevant to classification in this group
This subclass/group does not cover:
Fault recovery systems for SDH/SONET(Protection Switching) ring networks
Fault recovery in general
Star or tree networks
Definition statement
This subclass/group covers:

Deals with networks in a physical star or tree configuration.

In case of Ethernet repeaters or hubs, transmission is broadcast and the bus access schemes are applied (e.g. Ethernet in 10baseT).

Interconnection of networks
Definition statement
This subclass/group covers:
  • Interconnection of network segments of different types. e.g. between Fire Wire and Ethernet segments;
  • Internetworking in CEBUS, MAP/TOP, CAN and other application oriented topologies;
  • Repeaters (LAN segmentation).

This group contains general documents on internetworking in packet-switched networks.

References relevant to classification in this group
This subclass/group does not cover:
Coupling between buses internal to a computer
G06F13/40D9
[N: LAN interconnection over a backbone network, e.g. Internet, Frame Relay]
Definition statement
This subclass/group covers:
  • Header group for network backbone functionality
  • SONET, SMDS, DQDB
  • XNS, SNA, CATV
  • Internet
References relevant to classification in this group
This subclass/group does not cover:
TCP/IP and the Internet protocol itself
[N: LAN interconnection over ATM networks]
Definition statement
This subclass/group covers:
  • LAN emulation
  • IP or other proprietary protocols (e.g. IPX, SNA, netBIOS, Appletalk...) over ATM. MPOA.
  • VP switching for multiplexing connections in VLAN/BVPN Connectionless support in ATM for LAN interconnection (type D service. I.364 rec., ATM Forum's scheme).
  • Some documents about remote address resolution (ARP,NHRP).
[N: LAN interconnection over narrowband networks, e.g. N-ISDN, PSTN, X.25]
Definition statement
This subclass/group covers:
  • Internetworking over the PSTB
  • Narrowband ISDN both using BA or PR access, Channel B or D
  • X.25 based internetworks
[N: LAN interconnection over a LAN backbone]
Definition statement
This subclass/group covers:

Contains mainly documents about LAN interconnection using a FDDI backbone. Do not forget that some SNA implementations use a Token Ring backbone, so if you do not find your document here have a look to the H04L 12/4604 just in case.

[N: LAN interconnection over a bridge based backbone]
Definition statement
This subclass/group covers:

Topology aspects: where the bridges are placed. Bridging different type 802.X LAN's. General documents on Source Routing, Spanning Tree or DLS (no much detail on how the actual routing is carried out.

References relevant to classification in this group
This subclass/group does not cover:
Routing of packets
Informative references
Attention is drawn to the following places, which may be of interest for search:
Layer 2 routing, e.g. Ethernet-based MAN's
H04L12/56C129
Routing tree calculation
H04L12/56C120
Special rules of classification within this group

Spanning tree protocol shall be classified in this group, but also possibly H04L 12/5689 and subgroups when applied on a generic routing protocol that can be applied on Layer 2 as well as Layer 3 networks.

[N: Single bridge functionality, e.g. connection of two networks over a single bridge]
Definition statement
This subclass/group covers:

Bridge functionalities.

It covers:

  • Multistandard for heterogeneous 802.X LAN environment
  • Address learning and filtering with the suitable table lookup or CAM techniques. Address caching.
  • Internal buffer and memory management.
  • Bridges doing repeater functions or routing (Brouters)
References relevant to classification in this group
This subclass/group does not cover:
Router functionalities or routing protocols
Informative references
Attention is drawn to the following places, which may be of interest for search:
Fast packet switching
Special rules of classification within this group

It is difficult to determine whether to begin the search in H04L 12/462 or in H04L 12/4625. As a rule of thumb you could say that bridge/router functionality that does not require cooperation among bridges/routers, should be classified in H04L 12/4625. Therefore, network aspects that involve exchange among bridges/routers are meant to be in H04L 12/462.

[N: Interconnection of networks using encapsulation techniques, e.g. tunneling]
Definition statement
This subclass/group covers:

Encapsulation is the embedding of a protocol in another protocol at the same or different OSI layer. This technique is often used in a backbone to be able to deal with a plurality of end user protocols using a common transport entity.

Tunneling is a very important part of this group (e.g. L2TP).

References relevant to classification in this group
This subclass/group does not cover:
Pseudo-wire emulation, e.g. IETF WG PWE3
H04L12/56C130
Informative references
Attention is drawn to the following places, which may be of interest for search:
Protocol conversion
Point-to-point connection between the data network and the subscriber in access networks (e.g. PPPoX protocols)
Virtual LANs
VPN tunnels for security
[N: Interconnected ring systems]
Definition statement
This subclass/group covers:
  • Complex meshes of rings; Topological aspects
  • MAN, WAN ring based architectures
  • Hierarchical ring topologies
  • Streets of Manhattan, interlaced rings and similar architectures
Informative references
Attention is drawn to the following places, which may be of interest for search:
FDDI WANs
[N: Virtual LANs, VLANs, e.g. virtual private networks [VPN] (virtual private networks for security H04L 29/06612; routing of packets H04L 12/5689; encapsulation techniques H04L 12/4633; LAN interconnection over a bridge based backbone H04L 12/462; packet switches H04L 12/5696)]
Definition statement
This subclass/group covers:

Virtual local area network, virtual LAN or VLAN. A group of hosts with a common set of requirements that communicate as if they were attached to the same broadcast domain, regardless of their physical location. Networks with the same attributes as a physical local area network (LAN), but that allow for end stations to be grouped together even if they are not located on the same network switch.

References relevant to classification in this group
This subclass/group does not cover:
LAN interconnection over a bridge based backbone
Encapsulation techniques
Routing of packets
Packet switches
Virtual private networks for security
[N: Details on frame tagging (routing of packets H04L 12/5689; support for virtual LAN H04L12/56S8D)]
Definition statement
This subclass/group covers:

Details on tagging of a frame with VLAN information, involving mainly the use of a dedicated field for tagging a frame. When a packet enters a VLAN, a switch adds a VLAN field to the packet including a VLAN ID, the tag. Covers converting untagged frames to tagged frames. A typical VLAN tagged frame:

References relevant to classification in this group
This subclass/group does not cover:
Routing of packets using label swapping, e.g. MPLS
H04L12/56C121
Switching devices with support for virtual LAN
H04L12/56S8D
Routing of packets
Special rules of classification within this group

Multi-tagging of frames shall not be classified in H04L 12/4645, only in H04L 12/465 or the subgroups of it.

[N: wherein a single frame includes a plurality of VLAN tags]
Definition statement
This subclass/group covers:

Description and creation of single frames including a plurality of VLAN tags.

Frequently refers to QinQ (see IEEE standard 802.1ad) and the derivatives of this protocol. Covers tagging an already tagged packet, thereby producing a "multiple-tagged" frame, or a VLAN stack. A typical QinQ frame:

References relevant to classification in this group
This subclass/group does not cover:
Encapsulation of packets
Special rules of classification within this group

A document shall only be allocated this class if no relevant subgroup of this class can be found. On the other hand, different classes from this group (i.e. H04L 12/4654, H04L 12/4658, H04L 12/4662) might be assigned to a single document.

[N: wherein a VLAN tag represents a customer VLAN, e.g. C-Tag]
Definition statement
This subclass/group covers:

In multi-tagged frames, a VLAN tag representing a customer VLAN is a VLAN tag uniquely associated to a particular end user, subscriber or

local network entity (computer, user station).

[N: wherein a VLAN tag represents a service provider backbone VLAN, e.g. B-Tag, S-Tag]
Definition statement
This subclass/group covers:

Covers the outer tagging of Ethernet packets in PBB (Provider Backbone Bridge) networks, see IEEE Standard 802.1ah. A service provider backbone VLAN spans over a carrier network, not over a single LAN

Informative references
Attention is drawn to the following places, which may be of interest for search:
Encapsulation techniques
[N: wherein a VLAN tag represents a service instance, e.g. I-SID in PBB]
Definition statement
This subclass/group covers:

Covers documents associating a VPN with a PBB and assigning an I-SID. FIG. 3 below (US2008170573) is a simplified representation of a frame format 150 for VPN data packets transmitted through a PBB tunnel. The frame format 150 includes a PBB header 152 comprised of a backbone destination address (B-DA) 154, a backbone source address (B-SA) 156, a backbone VLAN ID (B-VID) 158, and a backbone I-component service ID (I-SID) 160.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
PBB
Provider Backbone Bridge
[N: Operational details on the addition or the stripping of a tag in a frame, e.g. at a provider edge node]
Definition statement
This subclass/group covers:

Covers operations carried out on a packet header, such as adding and/or removing tags, usually according to a particular algorithm or specific structure. An emphasis is put on the operational details of adding or stripping VIDs, at a particular node, e.g. US2010226368:

Special rules of classification within this group

The mere tagging of packets or removal of tags without particular operational details shall only be classified in H04L 12/4645 or in the subgroups of H04L 12/465

[N: Arrangements for supporting untagged frames, e.g. port-based VLANs]
Definition statement
This subclass/group covers:

The port is assigned to a specific VLAN independent of the user or system attached to the port. All users attached to the port should be members in the same VLAN. Usually the port configuration is static. A port based VLAN switch determines the membership of a data frame by examining the configuration of the port that received the transmission.

Special rules of classification within this group

Classes from the H04L 12/4645 subgroups and the class H04L 12/467 might be allocated to a single document only if two VLAN operational modes (i.e. tag-based VLANs and port-based VLANs) are presented in the document as part of the invention

[N: Dynamic sharing of VLAN information amongst network nodes (configuration of the network or of network elements H04L 12/2424)]
Definition statement
This subclass/group covers:

Sharing of information between networks elements: information about the identifier, about the member status, about the port based VLAN distribution. Sometimes this layer 2 information is intended to be displayed or monitored. Even though failure recovery is not covered in this class, Layer-2 information might be dynamically shared between the elements on the network after detection of a network failure.

References relevant to classification in this group
This subclass/group does not cover:
Failure recovery
Configuration of the network, or of network elements
[N: Arrangements for the registration or de-registration of VLAN attribute values, e.g. VLAN identifiers, port VLAN membership]
Definition statement
This subclass/group covers:

Registration or de-registration of VLAN memberships. Also includes removing, discovering and identifying VLAN members. Covers also the exchange of messages for modifying an entry in a mapping table for switches supporting port-based VLANs.

References relevant to classification in this group
This subclass/group does not cover:
Configuration of switching devices
[N: characterized by the protocol used]
Definition statement
This subclass/group covers:

Details on a specific standardized or proprietary protocol for maintaining a VLAN, for registering, de-registering VLAN members

References relevant to classification in this group
This subclass/group does not cover:
Group membership management
Special rules of classification within this group

Only for defining particular routines, packets types or format when maintaining VLANs. Can include extensions or modifications of an existing protocol

[N: MVRP [multiple VLAN registration protocol] ]
Definition statement
This subclass/group covers:

A commonly-used VLAN registration protocol generic framework defined by the IEEE 802.1ak revision to the IEEE 802.1Q standard.

[N: GVRP [GARP VLAN registration protocol] ]
Definition statement
This subclass/group covers:

This is a standards-based Layer 2 network protocol, for automatic configuration of VLAN information on switches. It was defined in the 802.1ak amendment to 802.1Q-2005.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
GARP
Generic Attribute Registration Protocol
Synonyms and Keywords

In patent documents the following abbreviations are often used:

MVRP
Multiple VLAN Registration Protocol
[N: VTP [VLAN trunking protocol] ]
Definition statement
This subclass/group covers:

VTP is a proprietary protocol that propagates the definitions of Virtual Local Area Networks (VLAN) on a whole local area network.

Packet switching systems
Definition statement
This subclass/group covers:

Basic functionality of packet switching networks. Namely: routing, flow control, admission control, switching architectures and other general issues on packetized data handling.

Relationship between large subject matter areas

Examples of places where the subject matter of this class is covered when specially adapted, used for a particular purpose, or incorporated in a larger system: Arrangements for packet switching specially adapted for wireless networks H04W

References relevant to classification in this group
This subclass/group does not cover:
Interprocessor communication
Packet based communication in satellite networks
Networks specially adapted for the exchange of pictorial information
Informative references
Attention is drawn to the following places, which may be of interest for search:
Error detection or correction
Packet multiplexing
Synonyms and Keywords

In patent documents the following abbreviations are often used:

ATM
Asynchronous Transfer Mode
TCP/IP
Transmission Control Protocol/Internet Protocol
[N: Transfer mode dependent, e.g. ATM]
Definition statement
This subclass/group covers:

Asynchronous Transfer Mode(ATM) technical aspects.

References relevant to classification in this group
This subclass/group does not cover:
Routing in wireless networks
Message switching systems, [N: e.g. electronic mail systems]
Definition statement
This subclass/group covers:

This is a subgroup of H04L 12/00 and therefore covers message switching systems in data switching networks. A message switching system is a system that switches messages on the application layer in the user plane. The messages have one or more individually identified recipients, although a user may have defined them to be part of a distribution list. Typical examples are electronic mail systems and instant messaging systems.

References relevant to classification in this group
This subclass/group does not cover:
Message passing systems for program control, e.g. messaging middleware
G06F9/46R6M
Computer aided management of electronic mail, such as the handling of e-mail on a local workstation
G06Q10/00F2
Message management on portable communication terminals, e.g. mobile telephones
Voice mail systems for telephonic communication
Client devices for e-mailing in television systems
Messaging specially adapted for wireless communication networks, e.g. SMS
[N: Real time or near real time messaging, e.g. instant messaging [IM]]
Definition statement
This subclass/group covers:

Further details of subgroups

This subgroup contains documents relating to messaging systems in which the message is sent to a recipient who is reachable at the time the message is sent. Messages for recipients that are not reachable are lost.

  • Chat rooms are classified in H04L 12/1813.
  • H04L 12/5815: Use or manipulation of presence information in messaging
  • Documents relating to presence management as such are classified in H04L 29/08684.
  • H04L 12/583: This subgroup contains documents where there is an intentional adaptation of the content. This can include the deletion of graphics or attachments or removing unwanted parts of the message, e.g. parental guidance.
  • H04L 12/5835: This subgroup contains documents where the format of the message is adapted, e.g. changing a picture from BITMAP to JPEG format or text-to-speech conversion. Although this may lead to loss of information due to different compression techniques or content that cannot be converted, the content is not intentionally adapted. This subgroup also contains documents where the message as a whole is converted, e.g. SMS to e-mail.
  • H04L 12/584: This subgroup contains documents where the transmission or handling of the message in the network is influenced by the fact that it includes annexed information.
  • H04L 12/5845: This subgroup contains documents where the transmission or handling of the message in the network is influenced by the fact that it includes multimedia information.
  • H04L 12/585: This subgroup contains documents dealing with filtering in general and spam in particular. If malicious content is involved, such as computer viruses, see also H04L 29/06877. Messages are either blocked or sent onwards; adaptation of the message in order to remove unwanted content is classified in H04L 12/583.
  • H04L 12/5855: Documents classified in this subgroup typically relate to systems where an intermediate node between the node sending the message and the node ultimately receiving the message forwards messages depending on preferences indicated in a profile. For profiles in general, see H04L 29/08918.
  • H04L 12/5865:This subgroup contains documents where the transmission or handling of the message in the network is influenced by the location of the sender's and/or recipient's terminal.
  • H04L 12/587: This subgroup contains documents related to ways of notifying a user that a message has been received, for example if the user is not online when an e-mail is received at the server. User interface notifications created locally on the client device, such as pop-ups, are classified elsewhere (see G06Q10/00F2, H04M 1/72547 and G06F 9/4443).
  • H04L 12/5875: This subgroup contains documents where the sender receives a return message when the recipient has received or read the message, or when a fault occurs such that the recipient does not receive the message.
  • H04L 12/588: This subgroup contains documents where the structure or characteristics of a social network is used for transmitting or handling a message in the network.
  • H04L 12/5885: This subgroup contains documents where the progress of a message through the network is recorded, for example in a log file. A common usage case is that proof must be provided that a user has received a specific message, e.g. due to legal requirements.
  • H04L 12/589 :This subgroup contains documents where the user can access his messages in different, user selected ways. For example, the user can access his e-mail using his telephone thanks to text-to-speech conversion. The message is very often retained in its original form on the server or converted into a common format. Documents that also disclose details about format conversion of messages should additionally be classified in H04L 12/5835.
  • H04L 12/5895: This subgroup contains documents where the wireless nature of the system has an impact on the messaging system itself, for example unreliable or intermittent network connections, or bandwidth constraints. Documents concerning multimedia messaging, MMS, are also classified here. Documents concerning the service centre of the short message service, SMS, or the signalling between and transmission of the message to or from the service centre and the mobile telephone are classified in H04W 4/14 or H04W 88/184. Other aspects of the SMS service are classified here.
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subgroup, the following terms are used with the meaning indicated:

Instant messaging, IM
Instant messaging is data exchange in real-time between at least two end users connected to a packet-switching network where the users are aware of the identity and the presence of the other party or parties before starting the data exchange.
Chat room
A chat room is a special type of computer conference where the users normally are not aware of the (true) identities of other participants' before joining the chat. The chat room application executes mainly on a server which is often accessed through a web browser. No participant has control over the admission of other participants.

Details of the apparatus or circuits covered by groups H04L 15/00 or H04L 17/00
References relevant to classification in this group
This subclass/group does not cover:
Apparatus or local circuits for transmitting or receiving dot-and-dash codes
Apparatus or local circuits for transmitting or receiving codes wherein each character is represented by the same number of equal-length code elements
Apparatus or local circuits for transmitting or receiving dot-and-dash codes, e.g. Morse code (teaching apparatus therefor G09B; keyboard switches in general H01H 13/70, H03K 17/94; telegraph tapping keys H01H 21/86; coding in connection with keyboards or like devices, in general H03M 11/00)
References relevant to classification in this group
This subclass/group does not cover:
Educational or demonstration appliances; appliances for teaching or communicating with, the blind, deaf or mute; models; planetaria; globes; maps; diagrams
having a plurality of operating members associated with different sets of contacts
characterised by the way in which the control signal is generated
Switches with abutting contact carried by operating part
coding in connection with keyboards or like devices
Apparatus or local circuits for transmitting or receiving codes wherein each character is represented by the same number of equal-length code elements, e.g. Baudot code (keyboard switches in general H01H 13/70, H03K 17/94; coding in connection with keyboards or like devices, in general H03M 11/00)
References relevant to classification in this group
This subclass/group does not cover:
having a plurality of operating members associated with different sets of contacts
characterised by the way in which the control signal is generated
coding in connection with keyboards or like devices
Apparatus or local circuits for step-by-step systems
Apparatus or local circuits for mosaic printer telegraph systems
Apparatus or local circuits for systems other than those covered by groups H04L 15/00 to H04L 21/00
References relevant to classification in this group
This subclass/group does not cover:
Apparatus or local circuits for transmitting or receiving dot-and-dash codes
adapted for orthogonal signalling
Definition statement
This subclass/group covers:

Code Shift Keying and CCK (Complementary Code Keying).

The generation of sequences, like orthogonal CAZAC, Zadoff-Chu or Generalized Chirp sequences that are used for signalling purposes.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Codes types for Code Division Multiplex systems (CDMA)
Generation of orthogonal codes for CDMA
Baseband systems
Definition statement
This subclass/group covers:

Baseband aspects of digital data transmission.

Arrangements for supplying electrical power along data transmission lines.

Channel estimation techniques.

Arrangements for detecting the data rate of an incoming signal.

Arrangements for coupling to transmission lines.

Line equalizers (digital).

Shaping networks in transmitter or receiver.

Digital equalizers: structure and adaptation algorithms.

Arrangements involving sequence estimation techniques.

Electric or magnetic storage of signals before transmitting or retransmitting for changing the transmission rate.

Decision circuits providing symbol by symbol detection; DC level restoring means; Bias distortion correction.

Modifications for reducing interference in line transmission.

Digital repeater/relay circuits.

Line codes.

Pulse width modulation; pulse position modulation.

References relevant to classification in this group
This subclass/group does not cover:
Joint detection techniques in CDMA
H04B1/70105
Interference related aspects of DSSS
Details on optical domain processing
H04B10/155F4
Systems for transmitting signals via power distribution lines
Error correction coding
Arrangements for synchronising receiver with transmitter
Informative references
Attention is drawn to the following places, which may be of interest for search:
Digital adaptive filters
Matched filters
Kalman filters
Circuits in general for handling pulses
Coupling arrangements in general
Coding in general
Conversion to or from representation by pulses
Details in line transmission systems in general
Echo cancellation
Reducing cross-talking
MIMO diversity systems
Feedback content
Wireless repeaters in general
Interference aspects in orthogonal multiplex systems (i.e. using Walsh codes)
Bus networks
Modelling or characterizing the propagation channel
Special rules of classification within this group

The groups under H04L 2025/0335 classify the type of signal the equalizer is intended for.

The groups under H04L 2025/03433 provide further details on the equalizer structure implementation.

The groups under H04L 2025/03592 deal with details of the adaptation algorithms for equalisation.

The groups under H04L 2025/03777 provide details on signalling.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

DFE
Decision Feedback Equaliser
SVD
Singular Value Decomposition
FIR
Finite Impulse Response
FDE
Frequency Domain Equalizer
GPRS
General Packet Radio Service
ICI
Inter-Carrier Interference
ISI
Inter-Symbol Interference
LLR
Log-Likelihood Ratio
LMMSE
Linear Minimum Mean Squared Error
LMS
Least Mean Square
LS
Least Squares
MAP
Maximum A-posteriori Probability
MLD
Maximum Likelihood Detector
MMSE
Minimum Mean Squared Error
RLS
Recursive Least Square
Synonyms and Keywords

In patent documents "pilot signals" can be called sometimes "Reference signals", "Sounding signals" or "Training signals".

[N: of each channel individually]
Special rules of classification within this group

This subgroup should not be used for classifying. Instead H04L 25/0204 should be given.

[N: of the composite channel]
Special rules of classification within this group

This subgroup should not be used for classifying. Instead H04L 25/0204 should be given.

[N: of impulse response]
Definition statement
This subclass/group covers:

The delay spread estimation.

[N: sounding signals per se]
Definition statement
This subclass/group covers:

The structure of the sounding signals or the pilot pattern. For details of the allocation of the sounding signals: H04L 5/0048.

[N: with direct estimation from sounding signals]
Definition statement
This subclass/group covers:

This group answer the question of how the sounding signals are used to derive an estimation. For example, by averaging.

[N: with extension to other symbols]
Definition statement
This subclass/group covers:

Use of data (in addition to the sounding signals) for channel estimation

[N: using estimation of the other symbols]
Definition statement
This subclass/group covers:

Iterative channel estimation for the same symbol, for example the EM (maximum expectation).

[N: using blind estimation]
Definition statement
This subclass/group covers:

Using only data per se.

[N: with factorisation]
Definition statement
This subclass/group covers:

For example: Cholesky, LU.

[N: Eigen-space methods]
Definition statement
This subclass/group covers:

Singular value decomposition, SVD.

[N: using least-mean-square (LMS) method]
Definition statement
This subclass/group covers:

All iterative algorithm (not for the same symbol), for example: RLS.

[N: Arrangements for coupling transmitters, receivers or transceivers to transmission lines; Line drivers (duplexing arrangements H04L 5/14)]
References relevant to classification in this group
This subclass/group does not cover:
Line drivers (duplexing arrangements
Special rules of classification within this group

This group should not be used. Subject-matter is classified under H04L 25/0264.

[N: Arrangements for detecting the data rate of an incoming signal]
Definition statement
This subclass/group covers:

This involves frequency estimation or detection, but not synchronisation.

[N: Arrangements for impedance matching]
Definition statement
This subclass/group covers:

The arrangements are at either end.

[N: Arrangements specific to the transmitter end]
Definition statement
This subclass/group covers:

How to couple the driver to the transmission line or how to configure the driver.

[N: the shape being matched to the transmission line (pre-equalisation per se H04L 25/03343)]
Definition statement
This subclass/group covers:

Implies some knowledge of the actual line, although it might be rather vague, such as "this is 100 m long". Thus, the coupling provides the pre-emphasis, otherwise, if it is not in the coupling, H04L 25/03885 is the proper place to classify.

References relevant to classification in this group
This subclass/group does not cover:
the shape being matched to the transmission line (pre-equalisation per se
[N: Arrangements for removing intersymbol interference]
Definition statement
This subclass/group covers:

The subgroups under H04L 25/03006 cover digital equalisation and detection techniques. Digital equalisers not only try to make the channel flat and remove ISI, but they also implement detection and decision.

[N: with a recursive structure (H04L 25/03031 takes precedence)]
Definition statement
This subclass/group covers:

For example, DFE equalisers.

[N: Arrangements involving sequence estimation techniques]
Definition statement
This subclass/group covers:

MLSE techniques, and in general the estimation of a sequence of symbols (not just one symbol).

In the case of multiuser environment, it covers the estimation of the different users.

[N: Joint sequence estimation and interference removal (joint detection of several desired signals H04L 25/03331)]
Definition statement
This subclass/group covers:

The cases where desired user is estimated and the other users are seen as interferences, such that their estimation is removed (for example, by subtraction).

References relevant to classification in this group
This subclass/group does not cover:
Joint sequence estimation and interference removal (joint detection of several desired signals
[N: Arrangements at the transmitter end]
Definition statement
This subclass/group covers:

Pre-equalisation.

Pre-coding for MIMO channels can be seen as a pre-equaliser or as a beam-former.

The selection of codebook or precoding matrix for MIMO diversity systems is classified under H04B 7/0456, while the design of the codebook matrices is classified under H04L 25/03898.

[N: providing soft decisions, i.e. decisions together with an estimate of reliability (H04L 25/068 and H04L 25/069 take precedence; sequence estimation techniques H04L 25/03178
Definition statement
This subclass/group covers:

When the soft decisions are part of a sequence estimation, then the place to classify is H04L 25/03318, otherwise, when the soft decisions are symbol by symbol is classified in H04L 25/067.

References relevant to classification in this group
This subclass/group does not cover:
Sequence estimation techniques
By sampling faster than the nominal bit rate
By detecting edges or zero crossings
Channel dividing arrangements [N: in which a single bit stream is divided between several baseband channels and reassembled at the receiver]
Definition statement
This subclass/group covers:

The parallel transmission of a single bit stream and the reassembling (skew compensation) of all the content of the parallel channels at the receiver in order to retrieve the single bit stream.

Repeaters for converting two wires to four wires (in general H04B); Repeaters for converting single current to double current
Definition statement
This subclass/group covers:

Wired digital repeaters. For wireless repeaters see classes under H04B 7/15.

References relevant to classification in this group
This subclass/group does not cover:
Repeaters for converting two wires to four wires
[N: using self-synchronising codes, e.g. split-phase codes]
Definition statement
This subclass/group covers:

For example: Manchester code; Biphase space or mark code (e.g. double frequency code).

[N: using multilevel codes]
Definition statement
This subclass/group covers:

For example: PAM with more than 2 levels.

[N: using levels matched to the quantisation levels of the channel]
Definition statement
This subclass/group covers:

PCM modems V.90.

by correlative coding, e.g. partial response coding or echo modulation coding [N: transmitters and receivers for partial response systems (transversal equalizers H04L 25/03; partial response continuous phase modulation systems H04L 27/18)]
Definition statement
This subclass/group covers:

For example: Tolimson-Harashima precoding, Trellis precoding, GPRS.

References relevant to classification in this group
This subclass/group does not cover:
response systems (transversal equalizers
partial response continuous phase modulation systems
Modulated-carrier systems [N: (code shift keying in combination with frequency multiplexing H04L 5/06; simultaneous bidirectional transmission of ac signals H04L 5/143; code shift keying H04L 23/02; polarisation shift keying H04B 14/008; transmission of data during the active part of a television frame H04N 7/025)]
Definition statement
This subclass/group covers:

Modulated-carrier systems.

Passband aspects of data transmission, e.g. modulating and demodulating, arrangements for provision and recovery of carriers.

The most fundamental digital modulation techniques: ASK, FSK, PSK and QAM.

Multicarrier modulation systems.

The modulated carrier systems covered in this groups are independent on the type of physical signal, i.e. the signal can be audio, RF, optical,..., but the signals must be digital.

Relationship between large subject matter areas

When the multiple access scheme relies on the use of multicarrier signals,

and if what is important is how the signal is modulated/demodulated, or "hardware" aspects in the transmitter or the receiver to produce or recover (like synchronisation) such signal or aspects related to the peak power reduction, then the classes under H04L 27/2601 are relevant. Otherwise, to indicate that the signal involved is, for example, an OFDM signal, then the class under H04L 5/0007 is used instead.

References relevant to classification in this group
This subclass/group does not cover:
Delta modulation
Details on optical domain processing
H04B10/155F4
Analogue modulations
Block-coded modulation
Code Shift Keying; CCK (complementary code keying)
Pulse width modulation
Pulse position modulation
Pulse amplitude modulation
Modulated-carrier systems [N: (code shift keying in combination with frequency multiplexing
simultaneous bidirectional transmission of ac signals
polarisation shift keying
transmission of data during the active part of a television frame
Informative references
Attention is drawn to the following places, which may be of interest for search:
Modulator circuits in general (analogue modulators)
Demodulator circuits in general (analogue demodulators)
Modifications in amplifiers to reduce non-linear distortions, by pre-distortion
CORDIC
Arrangements affording multiple use of the transmission path
Trellis-coded modulation
Special rules of classification within this group

The scheme under H04L 27/0014 is intended for classifying in more detail the carrier recovery aspects.

For multicarrier signals, the carrier recovery should be classified only in H04L 27/2657, and not in the scheme of H04L 27/0014.

H04L 27/0006: this class is related to spectrum sensing or spectrum pooling techniques to determine unused spectrum which may opportunistically use while avoiding interference with primary users (in case of cognitive radio, for example). The allocation per se of frequency carriers, subcarriers, tones or bands is in H04L 5/00. This class is for How it is assessed that there is "a gap", for example: by energy detection or signal strength level detection and threshold comparison; by match filtering; by detection based on cyclostationarity properties, etc.

H04L 2027/0026: the correction of carrier offset implies correction of frequency offset and/or phase offset.

H04L 27/186: PSK signal shaping, e.g. Trellis shaping, coset coding.

H04L 27/2078: this group covers, for example, π/4-DPSK.

H04L 27/2271, H04L 27/2272, H04L 27/2273, H04L 27/2275, H04L 27/2276, H04L 27/2277: these groups should not be used for classifying (only for searching).

To classify the aspects covered by these groups, the main group H04L 27/227 is given in combination with:

Glossary of terms In this subclass/group, the following terms (or expressions) are used with the
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

meaning indicated:

ASK
Amplitude Shift Keying
CPM
Continuous Phase Modulation
FSK
Frequency Shift Keying
OOK
On-Off Keying
PSK
Phase Shift Keying
DPSK
Differential Phase Shift Keying
QAM
Quadrature Amplitude Modulation
Synonyms and Keywords

In patent documents the following expression "multiresolution systems" is often used as synonym of non-uniform or asymmetric or layered modulation or hierarchical modulation or superposed modulation.

Systems using multi-frequency codes (H04L 27/32 takes precedence)
Definition statement
This subclass/group covers:

All techniques related to the multiple carriers processing of electrical signals (at the transmitter and receiver), to the structure of such signals (pilot signals, guard interval), and problems related to the frequency domain processing of such signals (Peak to Average Power Ratio PAPR).

Example of systems covered: OFDM, OFDMA, SC-FDMA, IFDMA, LTE, DVB, DSL, Optical OFDM ...

Practically the coverage of this subgroup in term of features is:

  • within a transmitter, it starts at the serial to parallel transformation of the data and ends after the IFFT (or any other frequency domain to time domain converter) or post-PAPR processing, and includes the PAPR processing, the pilot insertion, and if present the DFT precoding of the data (for SC-FDMA systems).
  • within a receiver, it starts at the FFT (or any other time domain to frequency domain converter) and includes the synchronisation arrangements (time, frequency).
References relevant to classification in this group
This subclass/group does not cover:
Details of Fourier transforms
Optical transmitters.
H04B10/155F
Channel estimation techniques
Interference cancellation techniques (Inter Carrier Interference, multiusers)
Pulse shaping
Resource allocation techniques
Bit loading of the subcarriers for OFDM(A) systems
Pilot allocation for OFDM(A) systems
Techniques like MC-CDMA involving code and frequency multiplexing
Higher Layer (network, routing) techniques
Special rules of classification within this group

Classification as secondary class for additional information:

When the main invention does not lie within this subgroup but interacts with the OFDM multiplexing in a particular way, a secondary class can be given in one of the main groups (H04L 27/2601, H04L 27/2626 for transmitter related aspects or H04L 27/2647 for receivers related aspects).

However only cases where the choice of OFDM as multiplexing is clearly linked with the invention should be classified there.

This is the first class in the hierarchy mentioning the use of multiple frequencies. However this class is almost never used for classification of multicarrier aspects. Instead the next class H04L 27/2601 is used as top class for multicarrier aspects.

[N: Multicarrier modulation systems]
Special rules of classification within this group

Although mentioned as modulation, it can of course be interpreted as multiplexing depending on the way the processing is interpreted. In a way it is a modulation since the main carrier signal is mixed with a modulating signal being the output of the IFFT after cyclic prefix addition. However it is also multiplexing since data being either from one user or from multiple users are orthogonally mapped to the subcarriers.

This group is generally given to aspects not covered by any of the following lower subgroups, or to documents where OFDM is a secondary technical aspect.

[N: Signal structure]
Special rules of classification within this group

The two main aspects under this group are the cyclic prefix classified under H04L 27/2605 and the pilot structure under H04L 27/261.

Basically documents classified here have their main feature in the mapping of particular data to the subcarriers or properties of the resultant OFDM time domain signal after IFFT, rather than particular means for processing the signal.

[N: Multiresolution systems (by means of multiresolution subcarriers H04L 27/183, H04L 27/3488)]
Definition statement
This subclass/group covers:

Different constellations (modulations) used on the subcarrier. For the allocation aspect (i.e. waterfilling for instance), see H04L 5/0044.

References relevant to classification in this group
This subclass/group does not cover:
Multiresolution modulation methods
[N: Symbol extensions]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Delay spread measurement
Symbol synchronization (locating the FFT window within a useful data portion + guard period)
Special rules of classification within this group

Most of the OFDM systems (except OQAM OFDM) use a cyclic extension added in time domain after each symbol in order to capture all multipath components that would result otherwise in Inter Symbol Interference (H04L 25/03006). Documents classified here either use a particular extension (adaptive or with a specific pattern) or provide for a specific processing of this extension.

Synonyms and Keywords

In patent documents, the following expressions "Symbol Extension", "Cyclic Prefix/Postfix/Suffix/Extension" and "Guard Period/Interval" are often used as synonyms.

[N: Cyclic extensions]
Special rules of classification within this group

The Guard Period is a repetition of a portion of the useful data segment of the symbol transmitted.

[N: Allocation of payload]
Special rules of classification within this group

This class although still officially present is no longer active and documents dealing with allocation of subcarriers or allocation of bits to the subcarriers are now classified under H04L 5/003.

[N: Details of reference signals (H04L 27/262 takes precedence)]
References relevant to classification in this group
This subclass/group does not cover:
Reduction thereof by selection of pilot symbols
Special rules of classification within this group

Since the allocation of pilot tones has now been moved to H04L 5/0048, only the subgroup H04L 27/2613 remains active.

[N: Distribution thereof]
Special rules of classification within this group

Allocation of pilot tones is now classified under H04L 5/0048

[N: Structure of the reference signals per se]
Definition statement
This subclass/group covers:

Properties of the reference sequences used as preamble or pilot sequence.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Linked to code properties
CAZAC sequences
[N: Peak power aspects]
Special rules of classification within this group

The Inverse Fourier transform at the transmitter transforms modulated symbols on each subcarrier, modulated by usual constellation patterns (QPSK, QAM), to time domain symbols presenting high peak to average power ratio. This problem is a recurrent problem in OFDM systems.

This high PAPR creates linearity problems at the following power amplifiers and must be remedied for in the time domain (i.e. after the IFFT, for instance by clipping) or in the frequency domain (i.e. before the IFFT) using iteration and feedback loop (using empty subcarrier, constellation extension ...).

When none of the following subclasses matches the technique used in the document, this class H04L 27/2614 has to be given.

Synonyms and Keywords

In patent documents the following expressions/words "peak to average power ratio", "PAPR " and "Crest factor" are often used as synonyms.

[N: Reduction thereof using coding]
Special rules of classification within this group

Through coding the series of bits before the modulation and the serial to parallel transformation, the situation where all modulated symbols on each subcarrier have the same phase thus generating the highest power is avoided. (See Jones and Wilkinson: "Block coding scheme for reduction of peak-to-average envelope power ratio of multicarrier transmission systems", 1994).

[N: Reduction thereof using auxiliary subcarriers]
Definition statement
This subclass/group covers:

For instance: Tone Injection or Tone Reservation. A subset of subcarriers is used for generating a PAPR reduction signal c added to the remaining signal transmitted.

[N: Reduction thereof by selection of pilot symbols]
Definition statement
This subclass/group covers:

Selection between multiple possible training sequences.

[N: Reduction thereof using phase offsets between subcarriers]
Definition statement
This subclass/group covers:

One of the most active subfields of PAPR reduction: Encompasses techniques like Selective Mapping (SLM) or Partial Transmission Sequence (PTS). Considering N subcarriers, SLM performs M multiple parallel N point IFFTs, each using a different N-phase vector (one phase value applied to each subcarrier) and selects out of the M outputs the resulting time domain OFDM with the lowest PAPR value. PTS divides the N subcarriers in V disjoint subcarriers subsets, multiplies each by a phase value and performs V partial IFFT before adding the resulting V outputs producing the OFDM symbol to be sent.

From Tao Jiang & al. "An Overview: Peak-to-Average Power Ratio Reduction Techniques for OFDM Signals"

[N: Reduction thereof by clipping]
Definition statement
This subclass/group covers:

Large field: Can happen in time domain (usual understanding where the parts outside the allowed power region are filtered or clipped out) but also in frequency domain (modulated symbols on each subcarrier are moved, see Active Constellation Extension). Can consist in decreasing higher power samples (by filtering or clipping) or enhancing low power samples (see nonlinear companding transforms using for instance μ-law companding from speech processing). Modify the dynamics of the signal.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Clipping in the frequency domain of the modulated symbols
[N: by soft clipping]
Definition statement
This subclass/group covers:

Based on Quantization aspects (linked to digital to analog conversion as well), see for instance the nonlinear companding method.

[N: Arrangements specific to the transmitter]
Definition statement
This subclass/group covers:

As depicted below, the features covered under this class extend from the serial to parallel conversion to the Guard Interval insertion and/or PAPR reduction block.

From US2007153673

[N: Modulators]
Definition statement
This subclass/group covers:

This part concerns the frequency domain to time domain conversion using either the classical Fourier transform, the filter bank approach or direct modulation of individual subcarriers.

[N: Inverse Fourier transform modulators, e.g. IFFT/IDFT (DFT or FFT computation methods or devices in general G06F 17/141)]
References relevant to classification in this group
This subclass/group does not cover:
General DFT and FFT computation methods and devices
[N: modification of IFFT/IDFT modulator for performance improvement]
References relevant to classification in this group
This subclass/group does not cover:

This class does not deal with the details of the IFFT/IDFT which are found under G06F 17/141, but rather with the parameterisation, configuration of the IFFT/IDFT or unobvious interaction between the IDFT and other circuits.

[N: with polyphase implementation]
Definition statement
This subclass/group covers:

Filter bank applications.

Synonyms and Keywords

In patent documents the following abbreviations are often used:

FMT
Filtered Multitone
[N: using partial FFTs]
Definition statement
This subclass/group covers:

Less subcarriers processed than the actual number of subcarriers to be transmitted.

[N: IFFT/IDFT in combination with other circuits for modulation (DFT or FFT computation methods or devices in general G06F 17/141)]
References relevant to classification in this group
This subclass/group does not cover:
DFT or FFT computation methods or devices in general
Informative references
Attention is drawn to the following places, which may be of interest for search:
Modulation circuits in general (Amplitude modulation)
Frequency modulation
Phase modulation
Combined modulation, like QAM
[N: with FFT/DFT, e.g. standard SC-FDMA transmitter or DFT-SOFDM]
Definition statement
This subclass/group covers:

A DFT precoding of the symbols to be transmitted is performed prior to the IDFT. This gives good PAPR properties to the resulting signal.

Conventional SC-FDMA Transmitter

[N: with direct modulation of individual subcarriers]
Definition statement
This subclass/group covers:

The frequency domain to time domain conversion is not performed using any inverse Fourier transform.

[N: Discrete cosine transform modulators]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Details on Discrete Cosine Transform
[N: Filterbank Multicarrier (FBMC)]
References relevant to classification in this group
This subclass/group does not cover:

Loss of orthogonality between the carriers due to the use of synthesis and analysis filter banks instead of the rectangular pulse of OFDM. Advantages: More freedom for the choice of pulses which can be more confined in time and frequency. No guard interval needed. Often combined with the use of higher density of basis functions (twice if only orthogonality in real domain should be ensured) like OQAM scheme.

[N: Wavelet transform modulators (wavelets in general H04L 27/0004; wavelet-division H04L 5/0008)]
Definition statement
This subclass/group covers:

Discrete Wavelet Multitone, Wavelet based multicarrier ...

References relevant to classification in this group
This subclass/group does not cover:
Wavelet transforms per se
Using Wavelet for dividing the transmission path
[N: using symbol repetition, e.g. time domain realization of distributed FDMA]
Definition statement
This subclass/group covers:

For the uplink of some standards.

[N: with oversampling]
Definition statement
This subclass/group covers:

More than one sample per subcarrier. Oversampling OFDM.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Filtered Multitone
H04L2/26M3A1P
[N: using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length]
References relevant to classification in this group
This subclass/group does not cover:
[N: Arrangements specific to the receiver (equalisation H04L 25/03006, H04L 27/01)]
Definition statement
This subclass/group covers:

This is the mirror part to H04L 27/2626.

From US2007153673

References relevant to classification in this group
This subclass/group does not cover:
[N: Synchronisation arrangements]
Definition statement
This subclass/group covers:

The synchronisation of multicarrier signals received implies a three-step synchronisation: a symbol synchronisation, a frequency synchronisation and a frame synchronisation.

Reference Article: "Robust Frequency and Timing Synchronization for OFDM"; Timothy M. Schmidl and Donald C. Cox, Fellow, 1997, IEEE

Also linked to Primary Synchronisation Signal (PSCH) and Secondary Synchronisation Signal (SSCH) in LTE.

Relationship between large subject matter areas
Determination of the cell ID (cell search)
Carrier Synchronisation not specific to multicarrier systems
Synchronisation at the physical level not specific to multicarrier systems
Synchronisation protocols at higher layers
[N: Frame synchronisation]
Definition statement
This subclass/group covers:

Frame synchronisation is generally achieved by time domain correlation using a repetition preamble. Technique is similar as that for achieving symbol synchronisation.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Preamble design
Symbol synchronisation
[N: Carrier synchronisation]
Definition statement
This subclass/group covers:

Carrier Synchronisation in OFDM systems often consists in a first round for identifying an offset corresponding to an integer number of subcarrier spacings (coarse synchronisation), and a second round identifying the fractional subcarrier spacing offset (i.e. less than a subcarrier spacing).

Special rules of classification within this group

In H04L 27/2657, only the cases not decomposing the synchronisation in these coarse and fine steps should be classified. Otherwise the subgroups H04L 27/2659 and H04L 27/266 should be used.

Synonyms and Keywords

In patent documents the following expressions "frequency offset", "frequency shift", "frequency drift", "frequency error", "frequency correction", "carrier recovery" are often used in relation with this subgroup.

[N: Coarse or integer frequency offset determination and synchronisation]
Definition statement
This subclass/group covers:

An integer subcarrier spacing frequency offset causes at the receiver a shift of the subcarriers in the frequency domain.

Coarse frequency offset determination is often performed in the frequency domain: It consists in identifying the amount of subcarrier shifts by correlating the received signal after FFT with a reference signal.

[N: Fine or fractional frequency offset determination and synchronisation]
Definition statement
This subclass/group covers:

A fractional subcarrier spacing offset causes at the receiver an attenuation of each subcarrier symbol in the frequency domain.

Usually this fractional offset is identified by autocorrelating the received preamble in the time domain.

[N: Symbol synchronisation]
Definition statement
This subclass/group covers:

The same distinction between coarse and fine synchronisation as for the frequency synchronisation applies.

The symbol boundaries replace the carrier spacing: While the coarse symbol synchronisation will align the received symbol stream with a reference time, the fine symbol synchronisation mainly consists of synchronisation within the symbol boundaries (i.e. including the Guard Interval) and the best positioning of the FFT window within these boundaries.

Special rules of classification within this group

As for frequency synchronisation, this class H04L 27/2662 should only be allocated to cases not decomposing the synchronisation in these coarse and fine steps. Otherwise the subgroups H04L 27/2663 and H04L 27/2665 should be used.

[N: Coarse synchronisation, e.g. by correlation]
Definition statement
This subclass/group covers:

Generally coarse symbol synchronisation is achieved by autocorrelation in the time domain of the preamble sequence.

[N: Fine synchronisation, e.g. by positioning the FFT window]
Definition statement
This subclass/group covers:

A FFT window of length corresponding to the useful symbol part must be positioned within the wider part including the Guard Interval. The ideal FFT location minimizes Inter Symbol Interference (ISI) and ensures the highest desired signal energy captured.

[N: Acquisition of further OFDM parameters, e.g. bandwidth, subcarrier spacing, or guard interval length]
Definition statement
This subclass/group covers:

In some systems using OFDM, transmission parameters like the Guard Interval length, the carrier spacing and/or bandwidth are variable or unknown to the receiver and thus have to be determined at the receiver (without any control channel). This class covers the different algorithms and methods to determine these parameters at the receiver.

References relevant to classification in this group
This subclass/group does not cover:
Allocation of subcarriers
[N: Details of algorithms]
Definition statement
This subclass/group covers:

This class has been foreseen as a complementary class to the synchronisation classes above. It aims at further describing the synchronisation algorithm performed. Multiple classes may be allocated to describe the algorithm as precisely as possible.

[N: characterised by the domain of operation]
Definition statement
This subclass/group covers:

This first subclass concerns the domain (time or frequency) in which the algorithm takes place. For mixed domain (files where parts of the algorithm takes place in time domain and other parts in frequency domain), this class H04L 27/2669 should be allocated.

[N: Time domain]
Definition statement
This subclass/group covers:

The main algorithm of the invention has its essential steps performed in time domain.

[N: Frequency domain]
Definition statement
This subclass/group covers:

The main algorithm of the invention has its essential steps performed in frequency domain.

[N: characterised by synchronisation parameters]
Definition statement
This subclass/group covers:

This subclass should be allocated to describe which part of the received signal is used for achieving synchronisation: This can be known symbols (a preamble or pilot symbols), or it can be blind by using only unknown symbols (the decision of these symbols or their cyclic extension, or the presence of a repetition pattern).

[N: Pilot or known symbols (structure of pilot symbols H04L 27/2613; cell search in orthogonal multiplex systems H04J 11/0069; allocation of pilot signals H04L 5/0048)]
References relevant to classification in this group
This subclass/group does not cover:
Cell search in orthogonal multiplex systems
Allocation of pilot signals
Informative references
Attention is drawn to the following places, which may be of interest for search:
Structure of pilot symbols
Special rules of classification within this group

Classification here should take place when the synchronisation algorithm of the document uses known symbols and their location at the receiver to achieve synchronisation. The value of these symbols is known.

[N: Blind, i.e. without using known symbols]
Definition statement
This subclass/group covers:

In this case, the algorithm does not use any known symbols (the value of these symbols and their location is not known in advance).

[N: using cyclostationarities, e.g. cyclic prefix or postfix]
Definition statement
This subclass/group covers:

The Guard Interval structure (when the Guard Interval consists of a cyclic repetition of the useful symbol part, see H04L 27/2607) or any other cyclostationarity of the received signal is used for achieving synchronisation.

The use of a repetition pattern (where instead of a preamble, a data symbol is sent twice, and the receiver uses only the location and the fact that repetition occurred) is considered as being blind and belongs to this class since it uses a kind of cyclostationarity in the received signal.

[N: Decision-aided]
Definition statement
This subclass/group covers:

The algorithm has a feedback loop where decision on received symbols are used to achieve synchronisation.

[N: characterised by constraints]
Definition statement
This subclass/group covers:

The constraints given to the algorithm or in other words, the advantage of the algorithm versus conventional algorithms.

[N: Precision]
Definition statement
This subclass/group covers:

The algorithm of the document achieves a better precision (in time or frequency) than conventional algorithms.

[N: Complexity]
Definition statement
This subclass/group covers:

The algorithm of the document has a lesser complexity than conventional algorithms.

[N: Speed of convergence]
Definition statement
This subclass/group covers:

The algorithm of the document reaches synchronisation more quickly than conventional algorithms.

[N: Range of frequencies or delays tested]
Definition statement
This subclass/group covers:

The algorithm of the document has a wider range of frequencies or delays tested than conventional algorithms.

[N: Resistance to perturbation, e.g. noise, interference or fading]
Definition statement
This subclass/group covers:

The algorithm of the document is more resistant to such perturbations or errors than conventional algorithms.

[N: Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation]
Definition statement
This subclass/group covers:

This particular subgroup applies when a synergistic effect is present between the synchronisation arrangement and any other circuit in the course of the synchronisation process (example: Locating the FFT window is often associated with particular peak tracking arrangements for channel estimation).

[N: involving interference determination or cancellation (interference mitigation or coordination in orthogonal multiplex systems in general H04J 11/0023)]
Definition statement
This subclass/group covers:

For the cases where the synchronisation process interacts non-obviously with an interference estimation/cancellation circuit.

Interference aspects are covered in many other classes:

Relationship between large subject matter areas
Interference in receivers
Further interference aspects at the receiver (EMI)
Interference due to the multiplexing of users (inter-users, inter-cell, adjacent channel)
Inter Symbol Interference removed in Equalizers
[N: with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver]
Definition statement
This subclass/group covers:

The preamble sent by transmitter is constructed or negotiated in the light of the synchronisation process/algorithm used at the receiver.

[N: with channel estimation, e.g. determination of delay spread, derivative or peak tracking (channel estimation per se H04L 25/0202)]
Definition statement
This subclass/group covers:

As mentioned in the example above, the synchronisation process may interact with a particular channel estimation/tracking method.

References relevant to classification in this group
This subclass/group does not cover:
Channel quality measurements
Channel estimation per se
[N: in combination with other modulation techniques]
Definition statement
This subclass/group covers:

This subclass like H04L 27/2634 above covers interaction between the OFDM multiplexing and other circuit components.

[N: double density OFDM/OQAM system, e.g. OFDM/IOTA system]
Definition statement
This subclass/group covers:

OFDM/OQAM generally has a real value modulated on each subcarrier and does not necessitate any Guard Interval to be inserted between contiguous symbols. It generally necessitates well localized (in time as well as in frequency domain) pulse shaping function.

References relevant to classification in this group
This subclass/group does not cover:
Pulse shaping
Special rules of classification within this group
Arrangements, apparatus, circuits or systems, not covered by a single one of groups H04L 1/00 to H04L 27/00 (interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units G06F 13/00 ) [N: contains provisionally no documents]
[N: Arrangements for maintenance or administration or management of packet switching networks]
[N: Arrangements for monitoring or testing packet switching networks (networking arrangements or communications protocols for supporting networked applications for tracking the activity of the application user H04L 67/22; monitoring of computing systems G06F 11/30; monitoring of computer activity G06F 11/34)]
References relevant to classification in this group
This subclass/group does not cover:
networking arrangements or communications protocols for supporting networked applications for tracking the activity of the application user
monitoring of computing systems
monitoring of computer activity
[N: Routing or path finding of packets in data switching networks (specially adapted for wireless routing H04W 40/00)]
References relevant to classification in this group
This subclass/group does not cover:
Routing or path finding of packets in data switching networks (specially adapted for wireless routing
[N: Traffic regulation in packet switching networks (arrangements for detecting or correcting errors in the information received H04L 1/00)]
References relevant to classification in this group
This subclass/group does not cover:
Traffic regulation in packet switching networks (arrangements for detecting or correcting errors in the information received
[N: Packet switching elements (selecting arrangements for multiplex arrangements using optical switching H04Q 11/0001)]
References relevant to classification in this group
This subclass/group does not cover:
Packet switching elements (selecting arrangements for multiplex arrangements using optical switching
[N: Arrangements for user-to-user messaging in packet-switching networks, e.g. e-mail or instant messages]
[N: Network arrangements or network protocols for addressing or naming]
Definition statement
This subclass/group covers:

The following aspects of addressing and naming in data networks:

  • Conversion and mapping of addresses, which includes mapping between different types of addresses, e.g. ARP or mapping between telephone numbers and IP addresses and mapping between the same type of addresses, e.g. NAT;
  • Directories and name-to-address resolution, e.g. DNS, LDAP, X.500, address books;
  • Allocation of addresses, e.g. DHCP;
  • Logical names, in particular aspects relating to the registration, conversion and structure of e.g. domain names, e-mail addresses, SIP-URIs etc.;
  • Non-standard use of addresses implementing a special functionality, e.g. QoS, billing etc.
References relevant to classification in this group
This subclass/group does not cover:
Accessing, addressing or allocating within memory systems or architectures
Bus transfer protocol, e.g. handshake; Synchronisation
Information retrieval from the Internet by using information identifiers, e.g. URLs
Routing or path finding of packets in data switching networks
Interconnection arrangements between switching centres
Network addressing or numbering for mobility support
Network layer protocols in wireless communication networks, e.g. mobile IP
Informative references
Attention is drawn to the following places, which may be of interest for search:
Protocols for interworking or protocol conversion
Directory assistance systems
Details of addressing, directories or routing tables of networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol
Details of addressing, directories or routing tables for working between exchanges having different types of switching equipment, where the types of switching equipment comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN,
Information retrieval using distributed data base systems
Network arrangements or protocols for real-time communications; Signalling, control or architecture; Session control; Registration
Network-specific arrangements or communication protocols supporting networked applications; Service discovery or service management
Network-specific arrangements or communication protocols supporting networked applications; Presence management
Message switching systems, e.g. electronic mail systems
Exchanging configuration information on appliance services in a home automation network
Processing of mobility data,Registration at HLR or HSS
Telephone directories in user terminals
Arrangements for maintenance or administration or management of packet switchingnetworks; Configuration management of network or network elements
Network-specific arrangements or communication protocols supporting networked applications involving the movement of software and/or configuration parameters
Network architectures or network communication protocols for network security for supporting authentication of entities communicating through a packet data network
Network-specific arrangements or communication protocols supporting networked applications adapted for proprietary or special purpose networking environments
Data switching networks characterised by a path configuration; Bus networks
Network topologies; Self-organizing networks, e.g. ad-hoc networks or sensor networks
Electric or fluid circuits specially adapted for vehicles for supply of electrical power to vehicle subsystemsusing multiplexing techniques
Data switching networks; Arrangements for providing special services to substations for broadcast or conference
Network layer protocols in wireless communication networks, e.g. mobile IP
Network data management; Mobility data transfer
Network-specific arrangements or communication protocols supporting networked applications in which an application is distributed across nodes in the network for accessing one among a plurality of replicated servers, e.g. load balancing
Network-specific arrangements or communication protocols supporting networked applications for the provision of proxy services, e.g. intermediate processing or storage in the network
Network architectures or network communication protocols for network security for separating internal from external traffic, e.g. firewalls
Network architectures or network communication protocols for network security for providing a confidential data exchange among entities communicating throughdata packet networks
Network architectures or network communication protocols for network security for separating internal from external traffic; Firewall traversal, e.g. tunneling or creating pinholes
Network arrangements or protocols for real-time communications
Arrangements for maintenance or administration or management of packet switchingnetworks using standardized network management protocols
Data switching networks characterised by a path configuration; Home automation networks
Data switching networks characterised by a path configuration; Interconnection of networks using encapsulation techniques, e.g. tunneling
Administration, e.g. office automation or reservations
Commerce, e.g. shopping or e-commerce
Devices specially adapted for wireless communication networks
High-speed IEEE 1394 serial bus
Network addressing or numbering for mobility support
Devices specially adapted for wireless communication networks adapted for operation in multiple networks
Registration; Multiple registrations, e.g. multihoming
Special rules of classification within this group
Synonyms and Keywords
ARP
Address Resolution Protocol
DHCP
Dynamic Host Configuration Protocol
DNS
Domain Name System
GRUU
Globally Routable UA URI
LDAP
Lightweight Directory Access Protocol
NAT
Network Address Translation
RARP
Reverse Address Resolution Protocol
STUN
Session Traversal Utilities for NAT
TURN
Traversal Using Relay NAT
URI
Uniform Resource Identifier
[N: Network architectures or network communication protocols for network security (cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L 9/00; network architectures or network communication protocols for wireless network security H04W 12/00; security arrangements for protecting computers or computer systems against unauthorised activity G06F 21/00)]
Definition statement
This subclass/group covers:

Networking architectures and network communication protocols for securing the traffic flowing through data packet networks and providing secure exchanges among applications communicating through data packet networks. The group covers specifically network architectures and network communication protocols for supporting:

  • filtering (e.g. transferring, blocking, dropping) traffic according to security rules;
  • authenticating and authorizing the entities sending and/or receiving the traffic;
  • protecting the data packets against unauthorized reading or modification;
  • detecting intruders and preventing the transmission of unauthorized, malicious or forged packets;
  • lawful interception for legally authorised parties to access protected information.

H04L 63/00 focuses on network architectures (i.e. network entities involved, roles played by these entities) and network communication protocols (i.e. how these network entities communicate) regardless of the specifics of the cryptographic mechanism used.

Further details of subgroups

Legal interception documents are classified in the head group H04L 63/00.

Here are classified the documents related to the (logical) separation of traffic/(sub-) networks to achieve protection.

Here are classified the devices and arrangements like firewalls, perimeter networks, bastion hosts, demilitarized zones, etc. that are placed at the interface between two (sub-networks), usually a private network (e.g. intranet) and the public network.

The term "distributed firewall" coined by Bellovin (XP002313944) is used to refer to systems where every host (network interface card or dedicated security box) includes firewall capabilities (e.g. WO0191418, US6067620). Some documents classified here refer to systems where firewalls communicate to share attack information and improve their efficiency. This group also contains documents dealing with multiple firewall nodes (cluster) for high-availability, load-distribution (see H04L 67/1002).

Aspects related to how traffic is filtered are classified here (note that the filtering of email messages is classified in H04L 12/585). The following subclasses provide further details.

Documents related to filtering of traffic based on addressing information (e.g. IP-address, URL), packet header information (e.g. protocol number, port number).

Filtering of information is performed based on the contents of the application payload (e.g. US2003061568). When the application payload is inspected specifically to detect viruses, worms, exploits etc., the documents are classified in H04L 63/145. When the document refers to content filtering in general and simply mentions virus scanning as a possible application, the document is classified here (and H04L 63/145 may also be allocated as additional information). Documents specific to parental control, rating systems etc. where the filtering depends on user or machine profile are also classified in H04L 63/10 (e.g. WO03009172), see also G06F21/00N9A. For documents disclosing specialized CPUs or hardware for application information filtering/parsing consider also classification in H04L 69/22.

A stateful firewall is a firewall that keeps track of the state of network connections (such as TCP streams) travelling across it. The firewall is programmed to know what legitimate packets are for different types of connections. Only packets which match a known connection state will be allowed by the firewall; others will be rejected. The most CPU intensive checking is performed at the time of setup of the connection. All packets after that (for that session) are processed rapidly because it is simple and fast to determine whether it belongs to an existing, pre-screened session. Once the session has ended, its entry in the state-table is discarded.

Documents related to the monitoring of connection state to detect and mitigate attacks (e.g. SYN attacks) are classified in H04L 63/1441 and subgroups.

Aspects related to how the filtering rules are organized, defined evaluated and added in a firewall are classified here. For rule matching, evaluation strategies see also the Indexing Codes H04L 2212/00. Aspects related to rule management in the sense of access control rules to access to network resources (authorisation) are classified in H04L 63/101, security policies in general are classified in H04L 63/20.

A VPN can be defined as a restricted-use, logical computer network that is constructed from the system resources of a relatively public, physical network (such as the Internet), often by using encryption, and often by tunnelling links of the virtual network across the real network (e.g. using IPsec ESP between security gateways). Non security aspects of VPN are classified in H04L 12/4641.

Proxies are computer process--often used as, or as part of, a firewall-- that relay a protocol between client and server computer systems, by appearing to the client to be the server and appearing to the server to be the client. Instead of a client in the protected enclave connecting directly to an external server, the internal client connects to the proxy server which in turn connects to the external server. The proxy may be transparent to the clients, or they may need to connect first to the proxy server, and then use that association to also initiate a connection to the real server. Proxies may provide protocol/application specific functionality (e.g. HTTP Proxy) or may provide generic connection services (e.g. SOCKS). Proxies can provide security service beyond that which is normally part of the relayed protocol, such as access control based on peer entity authentication of clients, or peer entity authentication of servers when clients do not have that capability. These aspects should be classified in the appropriate sub-groups. Note that H04L 67/28 contains documents where processing is performed in an intermediate network node. Using a proxy for authentication is classified here in combination with H04L 63/08. Non-security aspects of proxies are classified in H04L 67/28 which contains documents where processing is performed in an intermediate network node.

The mechanisms for achieving connections through firewalls are classified here. Examples are:

  • tunnel the application protocol in a protocol that is allowed through the firewall (e.g. HTTP, SMTP)
  • use of an application layer gateway which understands the application message and opens the appropriate pinholes in the firewall (proxy class may also be appropriate in some cases).

For NAT traversal H04L61/40A8.

This subclass contains network architectures and communication protocols for implementing confidentiality of information transmitted over a data packet network, most often by applying cryptographic mechanisms. The cryptographic mechanisms per se are classified under H04L 9/00, as detailed below. Documents which disclose networking architectures and protocols for anonymous communications are also classified here. Documents adapted to wireless networks are classified in H04W 12/02 and the appropriate H04L 63/04 subgroup is also assigned.

Documents related to protecting the identity of a party (origin or destination) against disclosure to a third party (eavesdropper) or the other party. Protecting personal data, e.g. for financial or medical purposes: G06F21/00N9A2P.

Identity only known to the other party or parties involved in the communication. Protecting the party's identity usually involves specific techniques which are different from message confidentiality, since the identity is used for routing and authentication purposes.

The identity of one of the parties is not disclosed to the other party. Some techniques involve the use of aliases, anonymizer proxies, onion routing, etc. The cryptographic techniques for anonymity (e.g. electronic voting, cryptographic pseudonyms) are classified under H04L 9/32. Protecting personal data by anonymising data G06F21/00N9A2P1.

Deals with documents where the communication protocols used protect the information exchanged through the networks. Also are classified here architectural arrangements to achieve the protection, e.g. encryption proxies. The subclasses identify specific techniques therefore.

The corresponding cryptographic mechanisms for symmetric encryption are classified under H04L 9/06.

The corresponding cryptographic mechanisms for asymmetric encryption are classified under H04L 9/30.

Symmetric and asymmetric encryption is combined. Usually symmetric encryption is used to protect the message and the symmetric (session) key is encrypted using asymmetric encryption, so no one other than the intended recipient can "open" the message. The combination of the encrypted data and the encrypted key is usually referred to as digital envelope. The cryptographic mechanisms using a plurality of keys or algorithms are classified under H04L 9/14.

Stream encryption, i.e. serially and continuously modifying data streams. The corresponding cryptographic mechanisms for stream encryption are classified under H04L 9/0643.

This covers mechanisms where the contents are decrypted and re-encrypted (e.g. by a proxy) during the transmission.

This covers hardware and software architectures (e.g. IPsec offloading) specifically adapted for improving the process of encrypting and decrypting packets and handling the security association tables.

This subclass covers specific network architectures and communication protocols for the negotiation, transport, validation, and update of security keys or credentials (i.e. specific network entities involved and the network protocols used) regardless of whether they are used for confidentiality (privacy), authentication, access control or for integrity validations in order to strictly differentiate between the initialisation phase (i.e., key distribution/exchange phase) of any secure communication and the secure communication itself.

Key management specially adapted for wireless networks is classified in H04W 12/04. The cryptographic mechanisms for key management are classified in H04L 9/08.

Exchanging the respective security keys directly between two communicating parties such as e.g. in peer-to-peer networks; typical standardised protocols for key exchange are IKE (Internet Key Exchange) or ISAKMP (Internet Security Association and Key Management Protocol). The cryptographic mechanisms or cryptographic arrangements for key agreement are classified in H04L9/08B4.

Distributing the respective security keys from a central trusted party such as a Key Distribution Centre (KDC) to the attached network nodes; a typical (hierarchical) architecture for key distribution is represented by PKI (Public Key Infrastructure). The cryptographic mechanisms or cryptographic arrangements for key distribution involving a central third party are classified in H04L9/08B2H.

Key exchange or distribution within multicast/broadcast networks typically by using a group key for confidentiality and/or authentication purposes (typical protocol standard: GKMP (Group Key Management Protocol). The cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key are classified under H04L9/08B2H2.

Keys are only used once. The cryptographic mechanisms or cryptographic arrangements for generation of one-time passwords are classified in H04L 9/0813.

Periodically changing keys, e.g., based on time stamps; aspects related to password renewal are classified in H04L 63/0846. The cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information are classified in H04L 9/0816.

Documents related to verifying the identity of a user, device or application trying to gain access to (resources of) a network. Documents describing authentication protocols and specific network architectures are to be classified here. Those documents where the network aspects are not relevant should be classified under G06F21/00N5A. The cryptographic mechanisms for entity authentication are classified under H04L 9/32.

The selection of an authentication mechanism is classified in H04L 63/08 in combination with H04L63/20E or H04L 69/24. Using a proxy for authentication is classified here in combination with H04L 63/0281. Authentication using multiple network paths is classified in appropriate H04L 63/08 subgroup in combination with H04L 63/18. When the authentication is specially adapted for wireless networks, the document should be classified also in H04W 12/06, in combination with the appropriate H04L 63/08 subgroup. (Informative reference: Active credit-cards provided with means to personalise their use G07F 7/1008).

This subgroup contains documents related to ticket-based authentication mechanisms, e.g. Kerberos, SESAME. Tickets may be transmitted in different ways, e.g. in a cookie. When the same ticket enables the authentication to a plurality of network resources, the document is classified in H04L 63/0815 Single-Sign-On. The cryptographic mechanisms or cryptographic arrangements for entity authentication using tickets or tokens are classified in H04L9/32B2. (Informative reference: G06F21/00N5A2C2 digital data processing restricting access to computer systems by authenticating users, devices or programs using a predetermined code using a certificate from a trusted centre or via a trusted hierarchical route).

Documents describing mechanisms where a user/device supplies a single authentication credential and gets access to a plurality of resources in a network are classified here.(Informative reference: G06F21/00N5A2S).

Documents where authentication is based on certificates are described here. Also documents describing the issuing, retrieval of certificates are classified here. Documents related to the use of certificates for authorization (e.g. attribute certificates) are classified in combination with H04L 63/10. The cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates are classified under H04L 9/3271.

(Informative reference: G06F21/00N5A2C).

Contains documents where a string of characters, not only actual words, but also passcodes (like PIN), software tokens or keys, is used for authentication. The cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code are classified under H04L 9/3226.

Passwords, used only once.

Time synchronisation exists between the supplicant and the authenticator; periodically changing passwords; password expiration and password ageing aspects are also classified here.

The authentication is performed using additional devices, e.g. smartcards, a SIM for authentication, an additional communication device (e.g. using a mobile telephone for authenticating a session established through a computer connected to a data network). When the additional device establishes and additional channel for performing the authentication, the document is also classified in H04L 63/18. (Informative references: G06F21/00N5A2D digital data processing restricting access to computer systems by authenticating users, devices or programs using a predetermined code in combination with an additional device; Payment schemes, architectures or protocol characterised by the use of a wireless device are classified under G06Q20/00K5; active credit cards G07F 7/1008).

Authentication based on fingerprint, retina-scan; see also G06F21/00N5A2B.

Authentication of both parties; see also G06F21/00N5A4, H04L 9/3273.

Documents relating to Authorization are classified here. Mechanisms to allow or restrict the access to a network or to some network elements or resources, for example by restricting access to a particular group of computers or contents based on their address or based on the identity of the network user (e.g. list of forbidden websites, parental control). Authorization usually occurs after a party's identity has been established and implies determining what the party (user, device) is allowed to access or to do in the network. For wireless networks, the document should be classified also in H04W 12/08, in combination with the appropriate H04L 63/08 subgroup. Restricting network management access H04L 12/2461. (Informative references: G06F21/00N7 for protection of software against unauthorized usage (e.g. DRM) and G06F21/00N9 for protection of data against unauthorized access or modification).

Authorization is implemented via access control lists.

Documents are classified here when they focus on the use of entity profiles, e.g. device profiles or user profiles to manage access decisions. Also documents related to identity management are classified here.

Mechanisms for implementing access control to group or groups of entities. Role based access control (each entity is associated to a group/role, and each role has a different privilege level) is classified in H04L 63/105.

Mechanisms for implementing multiple levels of security or different access rights according to entities (e.g. device or user) security clearance, to security profiles, roles or to security perimeters (i.e. different zones of a network need different security clearance/levels; data pump i.e. low level security is able to communicate with higher level and not vice versa).

Documents describing network architectures and communication protocols mechanisms for guarantying the integrity of the information exchanged through a packet data network are classified here. The most common techniques include using signatures and MAC/MIC codes, but other techniques can be part of the communication protocols. Both the aspect of verifying the content and the identity of the source are classified here. Documents emphasizing one of the subaspects are classified in the corresponding subclass. The cryptographic mechanisms or cryptographic arrangements for data integrity and verification are classified under H04L 9/32. When specially adapted to wireless networks, the documents should be classified also in H04W 12/10, in combination with the appropriate H04L 63/12 subgroup. (Informative reference: Protecting data against unauthorised access or modification, protecting integrity: G06F21/00N9C).

Documents focusing on how the network ensures that the content has not been tampered with during transmission through the network.

Documents where verification of the identity of the original source of received data is applied(non-repudiation with proof of origin, non-repudiation with proof of receipt, trust level of identity and/or source).

This subgroup contains documents related to the detection and protection against network. As a difference to G06F21/00N3, documents in the H04L 63/14 contain specific network aspects. Network intrusion detection systems are classified in H04L 63/1408. Detection and protection aspects specific of wireless networks (e.g. detection of rogue entities, access points) are classified under H04W 12/12. The corresponding H04L 63/14 subgroup is also assigned if appropriate. G06F21/00N3J contains documents where the intrusion is detected based on the activity within a computer (e.g. controlling the memory access, watching the execution of the programs, watching traces of failed login attempts, etc.), this is what usually is referred to in the bibliography as Host-based IDS. G06F21/00N3V contains documents related to virus detection algorithms. In the case that network aspects are important they should be (also) classified in H04L 63/145).

Detection of attacks involves monitoring the traffic on the network. For general traffic monitoring aspects see H04L 12/2602. Detection can be performed by different means; anomaly detection (comparing monitored traffic against normal traffic); misuse detection (detecting specific traces which imply an attack).

Documents dealing with the real time detection of attacks or intrusion attempts (e.g. "misuse detection") are classified here.

Traffic logging for security purposes (e.g. detecting normal or anomalous behaviour; comparing behaviour; offline analysis using data mining, network security audit); non-real detection for deferred analysis.

Documents related to active probing of the network looking for vulnerable points is classified here (e.g. performing port scans, sending malformed packets and checking if they are detected).

Here are classified documents dealing with a the detection and mitigation of particular types of attacks.

The mechanisms for protection against external network viruses such as worms or trojans are classified here, while the algorithms for virus detection themselves are classified in G06F21/00N3V.

Documents dealing with the mitigation of denial of service attacks (also referred to as flooding, overload or congestion attacks) are classified here. Some techniques involve identification of the path followed by the attack. Some other techniques include rate limitation (throttling) or QoS (separation in different class of service). For the later H04L 12/569 may be also relevant (documents should be circulated correspondingly). Some documents relate to black-hole attacks, wherein a malicious node discards all or part of the traffic (black-hole, gray-hole, worm-hole). Usually related to ad-hoc environments (ad-hoc code may be assigned as additional information H04W 84/18).

Documents dealing with the protection against active wiretapping in which the attacker attempts to seize control of a communication association are classified here (e.g. packet injection or modifying, hijacking sessions, TCP sequence number attacks, piggyback attacks, man-in-the-middle attacks, spoofing etc.).

Passively monitoring an existing session without the session participants noticing; e.g. eavesdropping or listening without modification of the traffic monitored.

Documents where the security solution is specific to a certain protocol layer are classified here. These entries provide additional information. The documents classified here will also have a class in further appropriate network security subgroup or subgroups (e.g. H04L 63/0428, H04L 63/08).

Subgroups are defined for the different OSI layers. Particular aspects of OSI protocol layers in general are classified in H04L 69/32.

Documents in which the network traffic is secured by transmitting information through different paths of networks are classified here. Two examples are:

  • placing an order over the internet and using a telephone to communicate credit card information,
  • or using a password received via SMS to obtain access to a remote computer (see also G06F21/00N5A2V).

Note that this subgroup includes documents related to authentication, confidentiality, key management, etc. These aspects will be also classified in the corresponding subgroups. The cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/08B2F; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L 9/3215.

This concerns the management of security in a network, e.g. managed services, deciding where to put firewalls, which data to encrypt, which authentication method to use, etc. Documents dealing with security policies in general are classified here but packet filtering policies are classified in H04L 63/0227 and subgroups. Note that the documents related to the security of the network management functions are classified in H04L 12/2461, e.g. a firewall filtering SNMP messages, or a system ensuring that only certain users are allowed to perform system administration tasks. For such documents the corresponding security aspects, if relevant, will be classified in the appropriate H04L 63/00 subgroups. The classification in combination with H04L 63/08, H04L 63/04, H04L 63/10 is given to documents involving the selection of a particular authentication or confidentiality methods or access privileges by negotiation, according to capabilities or policies. The negotiation of communication capabilities in general is classified in H04L 29/06537.

Relationship between large subject matter areas

H04W 12/00 Wireless networking architectures and wireless network communication protocols for securing the traffic flowing through wireless data packet networks and providing secure exchanges among applications communicating through wireless data packet networks. The group covers

specifically wireless network architectures and wireless network

communication protocols for supporting:

  • Authenticating and authorizing the entities sending and/or receiving the traffic;
  • Protecting the data packets against unauthorized reading or modification;
  • Detecting intruders, rogue entities and preventing the transmission of unauthorized, malicious or forged packets;
  • Lawful interception for legally authorised parties to access protected information.

H04W 12/00 focuses on wireless network architectures (i.e. wireless network entities involved, roles played by these entities) and wireless network communication protocols (i.e. how these network entities communicate) regardless of the specifics of the cryptographic mechanism used.

Details for wireless network security are classified by the combination of H04W 12/00 subgroup and H04L 63/00 detailed subgroup.

H04L 12/22 subject-matter is always classified in the corresponding subclasses of H04L 63/00 and or H04W 12/00.

H04L 9/00 Cryptographic mechanisms including cryptographic protocols and cryptographic algorithms, whereby a cryptographic protocol is a distributed cryptographic algorithm defined by a sequence of steps precisely specifying the actions required of two or more entities to achieve specific security objectives (e.g. cryptographic protocol for key agreement), and whereby a cryptographic algorithm is specifying the steps followed by a single entity to achieve specific security objectives (e.g. cryptographic algorithm for symmetric key encryption).

H04L 9/00 focuses on cryptographic mechanisms such as encryption schemes, digital signatures, hash functions, random number generation, key management, said cryptographic mechanisms providing information security such as privacy or confidentiality, data integrity, message authentication, entity authentication, authorization, validation, certification, time-stamping, anonymity, revocation, non-repudiation.

H04L 9/00 covers also countermeasures against attacks on cryptographic mechanisms.

G06F21/00N Security arrangements for protecting computers or computer systems against unauthorised activity, where the network communication aspect is not important.

References relevant to classification in this group
This subclass/group does not cover:
Registering, indicating or recording the time of events or elapsed time, e.g. time-recorders for work people
Security in Network Management, e.g. restricting network management access
Non security aspects of network monitoring arrangements,in particular data switching networks monitoring arrangements involving a reduction of monitoring data using filtering
Non security aspects of VPN are classified in
Protection against unsolicited messages, e.g. Spam
Non security aspects of communications control adapted for proprietary and special purpose networking
Unsolicited communication attempts in real-rime communications, e.g. SPIT = Spam in IP Telephony
Lawful interception of POTS calls
Secrecy in the context of scanning, transmission or reproduction of documents or the like
Security in selective content distribution, e.g. interactive television, VOD
Secrecy and Subscription systems in television systems
cryptographic mechanisms or cryptographic arrangements for secret or secure communication
network architectures or network communication protocols for wireless network security
security arrangements for protecting computers or computer systems against unauthorised activity

Examples of places where the subject matter of this group is covered when specially adapted, used for a particular purpose, or incorporated in a larger system:

Systems for paying without using coins or banknotes, e.g. smart cards.
Informative references
Attention is drawn to the following places, which may be of interest for search:
Documents related to vehicle alarm
Documents related to electronic door lock
Payment schemes, architectures or protocols
Documents related to burglar, theft and intruder alarm
Documents related to combined burglar and fire alarm
Documents related to alarm, in which the location of the alarm is signalled to a central station
Special rules of classification within this group

Classification of the additional aspects of an application in H04L 63/00 is mandatory.

In some cases specific protocols (e.g. IPsec, EAP, TLS) and/or architectures (firewalls, AAA) are used. In other cases existing network protocols, architectures and services are modified to achieve the security goals. In such cases, the documents are classified both in the corresponding security subclasses and in the field of application (e.g. addressing, mobility, routing, cryptographic mechanisms).

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this subclass/group, the following terms (or expressions) are used with the

meaning indicated:

Authentication
Identify if the entity is the one he/she claims to be. Remark: authentication and authorisation are sometimes used with the other meaning in patent literature as well as in non patent literature
Authorisation
Identify which rights are assigned to an entity. Remark: authentication and authorisation are sometimes used with the other meaning in patent literature as well as in non patent literature
Handover Interface
Lawful interception handover interface HI1, HI2, and HI3 to hand over warrant, intercept related information and communication content between service provider and lawful authorities
RFC 4949
Internet Security Glossary, Version 2; definition of Internet Security Terms
Synonyms and Keywords

In patent documents the following abbreviations are often used:

ALG
Application Level Gateway
AKA
Authentication and Key Agreement

In patent documents the following synonyms are often used:

Firewall
Application level gateway
[N: Network arrangements or protocols for real-time communications (computer conference H04L 12/1813; real time or near real time messaging in message switching systems e.g. instant messaging H04L 12/581; television systems H04N 7/00; selective video distribution H04N 21/00; interconnection arrangements between switching centres for working between exchanges having different types of switching equipment where the types of switching equipment comprise PSTN/ISDN equipment and equipment of networks other than PSTN/ISDN H04M 7/1205; systems providing special services to telephonic subscribers H04M 3/42; network applications in general H04L 67/00)]
Definition statement
This subclass/group covers:

Only communications which fulfill the following two conditions:

  • They are based on packet data;
  • There is real-time or pseudo-real-time temporal association between source and destination, or source and network, or destination and network.
  • Provided that the above two conditions are met, this group covers arrangements relating to:
  • The transmission of the multimedia data itself,
  • The user-to-user, user-to-network, inter-network or intra-network signalling supporting,
  • The establishment of a session for the subsequent transmission of the multimedia data, or
  • The maintenance of the session or
  • The application services available to the user during the session (unless explicitly excluded in certain cases).
Relationship between large subject matter areas

Generally H04L 65/00 has relationships with the following general areas: H04L 67/00, H04L 69/00, H04N 21/00, H04N 7/00, H04N 5/00, H04L 12/18, H04L 12/58, H04L 12/24, H04L 12/26, H04M, H04Q 11/00.

As already mentioned, Real Time Multimedia Communications within the context of H04L 65/00 cover communications which have the following two characteristics:

  • Data Packet based;
  • Real-time or pseudo-real-time temporal association between source and destination, or source and network or destination and network.

The above definition covers both the arrangements or protocols related to the transmission of the multimedia data itself, as well as the user-to-user or user-to-network signalling supporting the establishment of a session for the subsequent transmission of the multimedia data, the maintenance of the session and the application services available to the user during the session (unless explicitly excluded in certain cases). The above definition/limitation of the scope of H04L 65/00 must always be borne in mind in interpreting the relationship of H04L 65/00 with all other fields.

Excluded from the scope of H04L 65/00 are arrangements for multimodal data communications which do not have the above two characteristics.

Examples of what is excluded are (if not in combination with a communication arrangement covered by the above definition, as in e.g. combinational or collaboration systems):

  • Non-real-time multimedia file transfer (H04L 67/06);
  • Multimedia Store and Forward Messaging as in e-mail, MMS, etc. (H04L 12/58);
  • Analogue multimedia streaming, e.g., in analogue television (H04N 5/00, H04N 7/00, H04N 21/00));
  • Bit streaming (i.e. not packet) as in ISDN (H04Q11/40).

Relationship between H04L 65/00 and legacy telephony (H04M)

Specifically, the dividing line between legacy telephony covered by subclass H04M and packet-based multimedia telephony in its wider sense (i.e. both video and voice interactive communication between persons) covered by subgroup H04L 65/00 is defined as:

  • Systems and arrangements in which the legacy non-packet-based core telephony network (circuit switched PSTN or ISDN) represents a major part, are covered by the appropriate H04M subclass entries;
  • Systems and arrangements in which the legacy non-packet-based core telephony network (circuit switched PSTN or ISDN) represents a trivial or insignificant part or is totally absent, and the packet-based network (e.g. Internet, IMS) represents the only or the major and the most significant part are covered by the H04L 65/00;
  • Signalling adaptation-interworking between SIP and SS7 is covered by H04M 7/00.

Examples of H04M - H04L 65/00 interface are:

  • A CPE gateway or Terminal Adapter allowing a legacy user telephone device to connect to the packet-based network is covered by H04L 65/00;
  • A signalling gateway interfacing two core networks, one legacy and one packet-based (e.g. SIP-SS7 gateway) is covered by H04M;
  • A transparent IP pipe interconnecting two legacy circuit switched networks, with no details on the IP pipe itself, is normally covered by H04M;
  • A transparent dial-up or leased circuit-switched line interconnecting two packet-based networks, with no details on the dial-up circuit-switched line itself, is normally covered by H04L 65/00;
  • An IP-gateway allowing a call to be selectively branched off to either a legacy network or a packet-based network is normally covered by H04M. However, if no significant details of the legacy network aspects are discussed apart from it being mentioned as an alternative, the IP-gateway may be covered by H04L 65/00.

Further comments and explanations regarding the H04L 65/00 subgroup and its relations with other related classes:

In order to avoid confusion with classes of other neighbouring fields, whose definitions use wording similar to that used in this class, references to these fields will be mentioned with specific disclaimers if possible. In case a reference is unintentionally omitted, the above defined limitation in the scope of the H04L 65/00 subclass entries must always be borne in mind.

References relevant to classification in this group
This subclass/group does not cover:
Multimedia store or forward messaging as in e-mail, MMS or the like
Instant messaging
Non-real-time multimedia file transfer
Analogue multimedia streaming, as in analogue television systems
Bit streaming, i.e. not packet-based, as in ISDN
computer conference
interconnection arrangements between switching centres for working between exchanges having different types of switching equipment where the types of switching equipment comprise PSTN/ISDN equipment and equipment of networks other than PSTN/ISDN
systems providing special services to telephonic subscribers
network applications in general
Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements for broadcast or distribution combined with broadcast
Arrangements for broadcast applications with a direct linkage of broadcast information
Data switching systems for broadcast or conference
Data network management
Data network testing or monitoring
Flow control
Message switching systems
Instant messaging
Arrangements for connecting between networks having differing types of switching systems
Arrangements for addressing or naming in data networks
Arrangements for network security
Network applications in general
WEB based applications
Adaptation for terminals and/or networks with limited resources or for terminal portability
Non-real-time multimedia file transfer
Terminal emulation
Arrangements to access one among a plurality of replicated servers, e.g. load balancing
Arrangements for peer-to-peer networking in network applications
Non-real-time session management in network applications
Network application being adapted for the location of the user terminal
Arrangements for push based network services
Intermediate processing in the network with arrangements for data reduction or adaptation
H04L67/28L
Terminal profiles
Arrangements for scheduling or organising the servicing of requests whereby quality of service or priority requirements are taken into account
Telewriting, virtual reality or network gaming
Protocols for data compression
Protocols for interworking or protocol conversion
Multichannel or multilink protocols
Header parsing or analysis
Negotiation of communication capabilities
Substation equipment for use by subscribers
Systems providing special services to telephonic subscribers
Circuit switched PBXs
Arrangements for screening incoming telephone calls
Information services comprising voice
Contact center services
Telephonic conference systems
Services and arrangements where telephone services are combined with data services
PBX networks
Interconnection arrangements between switching centres for working between exchanges having different types of switching equipment where the types of switching equipment comprise PSTN/ISDN equipment and equipment of networks other than PSTN/ISDN
Decomposed PSTN/ISDN-IP gateways
Television systems in general
Television conferencing systems
Television systems using two way working
Transmission of television signals using pulse code modulation
Bit streaming, i.e. not packet-based, as in ISDN
Selecting or control in telephonic networks
Wireless communication networks in general
Wireless location based services
Push-to-Talk services in wireless networks
Special rules of classification within this group

The different entries and subentries of H04L 65/00 are not mutually exclusive. On the contrary, a document has to be normally assigned more than one classes. For instance, a document describing the SIP call setup for a distributed control conference, the conference at first being audio only and later adding video as well, will be assigned the classes: H04L 65/1006 (SIP), H04L 65/1069 (session setup), H04L 65/4046 (Distributed controlled conference) and H04L 65/1089 (Adding or removing media).

When an entry is further subdivided in subentries, documents which are relevant to the subentries should be classified directly in these subentries. Documents relevant to the parent entry but not to any of its subentries, should be classified in the parent entry, unless a subentry called "other" exists.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used wit