The transmission of information carrying signals, the transmission being independent of the nature of the information. Monitoring and testing arrangements and the suppression and limitation of noise and interference.

The user is referred to the IPC definitions of individual main groups of subclass H04B:

Transmission systems characterised by the waveband used for transmission:

Radio waves - see definition for main group H04B 7/00.

Light, infrared waves or corpuscular radiation - see definition for main group H04B 10/00.

Ultrasonic, sonic or infrasonic waves - see definition for main group H04B 11/00.

Transmission systems characterised by the medium used for transmission:

Conductors - see definition for main group H04B 3/00.

Free-space propagation - see definition for main groups H04B 5/00, H04B 7/00, H04B 10/00, H04B 11/00.

Earth, water or body - see definition for main group H04B 13/00.

Transmission systems characterised by the carrier modulation used for transmission:

Pulse modulation - see definition for main group H04B 14/00.

If the transmission systems are specially adapted for particular applications classification is also made in subclasses listed in section "Informative references".

Transmission systems characterised by the medium used for transmission or by band of employing waves should be classified in groups H04B 3/00- H04B 11/00 or in residual group H04B 13/00.

Transmission systems characterised by the use of carrier modulation or sub-carrier should be classified in group H04B 14/00 and details thereof in group H04B 1/00.

Details of transmission systems that are general for transmission systems covered by two or more groups H04B 3/00-H04B 13/00.

Details of transmission systems not characterized by the medium used for transmission.

If the transmission systems are specially adapted for particular applications classification is also made in subclasses listed in section "Informative references".

Systems wherein components typically implemented in hardware, e.g. filters

modulators/demodulators, are implemented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain.

selecting a frequency channel within the SDR system

selecting a frequency channel within the SDR system

Older documents covering circuits with vacuum tubes are placed in H04B 1/28.

Additionally, super-regenerative receivers can be found in this group

Cradles ; Car kits ; boosters

Spread spectrum techniques representing methods by which communication energy generated in a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth.

With regard to code multiplexing, the borderline between H04B 1/69 and H04J 13/00 should be determined based on whether the features relevant for classification are focused on the code multiplexing aspects or the implementation of the spread-spectrum technique (e.g. details of how the signals are physically transmitted, received and processed).

Classification of invention and additional information:

The invention information (main focus of the document) is classified in CPC groups and is compulsory.

Additional information is classified in Indexing Codes corresponding to the CPC groups. Classification of additional information is compulsory.

Indexing Codes which have no corresponding CPC group are used to classify invention information (compulsory) or additional information (compulsory). When classifying invention information, the most appropriate CPC group must also be assigned.

Examples:

Invention relating to spread spectrum chirp is assigned H04B 2001/6912 and H04B 1/69

Invention relating to spread spectrum time hopping with additional information on frequency hopping is assigned H04B 2001/6908 and H04B 1/69 and H04B 1/713

Invention relating to impulse radio with additional information on time hopping is assigned H04B 1/7163 and H04B 2001/6908

Combinations

For cases where the invention relates to combining the features of two or more subgroups, the following should be applied:

If the relevant information relates only to the fact that the aspects are combined, the documents are classified with CPC in the group above the concerned subgroups and assigned an Indexing Code in each of the concerned subgroups. If there is a dedicated entry for combinations this CPC is assigned instead of the headgroup.

If, besides the combination, aspects relating to the subgroups are also relevant, then multiple CPC groups may be assigned as appropriate.

Examples:

Invention relating to frequency hopping/direct sequence combination is assigned H04B 1/692, H04B 1/707, H04B 1/713

Invention relating to frequency hopping/direct sequence system with a focus on frequency hopping interference issues is assigned H04B 1/692, H04B 1/707, H04B 1/715

Invention relating to frequency hopping interference issues which can applied to Frequency hopping/Direct Sequence systems is assigned H04B 1/715, H04B 1/692, H04B 1/707

Inventive combination of parallel and subtractive interference cancellation for direct sequence system is assigned H04B 1/7107, H04B 1/71072, H04B 1/71075

Note(s)

When classifying in this group, any aspect of code division multiplexing, which is considered to represent information of interest for search, may also be classified in group H04J 13/00.

Hybrids of spread spectrum techniques, e.g. frequency hopping/direct-sequence systems, time-hopping/direct-sequence systems.

Direct-sequence spread-spectrum techniques which directly modulate the data being transmitted by a spreading code whose frequency (chip rate) is much higher than the modulated bandwidth of the data signal (symbol rate).

An example of direct sequence modulation is CDMA (Code Division Multiple Access). Examples of systems are IS-95 (Interim Standard 2000), CDMA 2000, UMTS (Universal Mobile Telephone System), WCDMA (Wideband Code Division Multiple Access).

Frequency-hopping spread spectrum techniques which involve transmitting radio signals by switching a carrier among many frequency channels, using a hopping sequence known to both transmitter and receiver.

Impulse radio spread spectrum which involve an ultra-wideband (UWB) communication system that transmits baseband pulses of very short duration (typically of the order of a nanosecond) with bandwidths that span from near dc to several GHz.

From 01/04/2011 documents relating to pulse-related aspects are classified in H04B 1/717 and the backlog for such documents is continuously being reclassified from H04B 1/7163.

This group is not used. See H04W 52/00 or H04L 25/00

Transmission systems characterized by the medium being electrical conductors (e.g. wires, metal cables) or waveguides.

subgroups H04B 3/00-H04B 3/50, H04B 3/34-H04B 3/52 cover

Data or signal transmission using twisted pair, coaxial cable, submarine cables, wave guides. These subgroups deal as well with the reliability of the line transmission system, including testing of the line transmission parameters, compensation of echo due to impedance mismatching, equalizing and interference

These subgroup deal with all technical aspects concerning crosstalk compensation or cancellation in a multi-wire line transmission.

Data communication using existing mains power cable already installed in the building infrastructure or in vehicles. This subgroup contains as well data transmission over high voltage (HV) power cables.

Indexing Codes for the subgroups H04B 3/54-H04B 3/58, to be used for classifying additional information:

H04B 2203/54

Methods of transmitting or receiving signals via power distribution lines

H04B 2203/5408

using protocols including special data frame format, hybrid networks

H04B 2203/5412

by modifying waveform of the power source. Including interrupting power mains waveform via a switch, Triac, Scr.

H04B 2203/5416

by adding signals to the wave form of the power source. Injecting in the mains a modulated signal at much higher frequency of the mains

H04B 2203/542

using zero crossing information

H04B 2203/5425

improving S/N ratio and or coupling factor by impedance matching, noise reduction, gain control

H04B 2203/5429

Applications for powerline communications

H04B 2203/5433

Remote metering, smart grids, AMR

H04B 2203/5437

Wired telephone (Eg. PSTN, ADSL). Including interfaces between power line network and wired telephone network

H04B 2203/5441

Wireless systems or telephone. Including interfaces between power line network and wireless network (e.g.. GSM, RF transmission, Infrared)

H04B 2203/5445

Local network. Using the power line to create a local network

H04B 2203/545

Audio/video application, (e.g. interphone, audio video broadcasting)

H04B 2203/5454

Adapter and plugs. Including Home Plug and smart sockets.

H04B 2203/5458

Monitor sensor, Load control or drive; Alarm systems, Home automation, Zigbee.

H04B 2203/5462

Systems for power line communications

H04B 2203/5466

using three phases conductors

H04B 2203/547

via DC power distribution e.g. vehicles

H04B 2203/5475

adapted for drill or well combined with data transmission H04B 2203/5479 using repeaters

H04B 2203/5483- H04B 2203/5487

using coupling circuits, cables

H04B 2203/5491

using filtering and bypassing

H04B 2203/5495

having measurements and testing channel

Short-range transmission systems and their components, e.g. wherein the signal transmission is inductive or capacitive, e.g. by inductive loops. This group also covers leaky coaxial [LCX] transmission systems.

Antennas specially adapted for near-field transmission.

Group H01Q 7/00 covers loop antennas in general. Group G06K 19/077 covers instead details of antennas specially adapted for record carriers.

Radio transmission systems wherein the information signal transmission is by electromagnetic waves other than light or infrared.

Reducing phase shift to compensate for Doppler effect

Aspects related to diversity, beamforming and antenna weighting:

Antenna redundancy, namely the inclusion of spare antennas for the easy replacement of malfunctioning antennas, is not considered to be a multi-antenna system and therefore is not covered by this group. Details of transmission systems for increasing reliability, e.g. using redundancy, are covered by group H04B 1/74.

Example of documents classified here: see US2010034146 (figure 7):

Example of documents classified in this group: see e.g. US2011070840 (abstract): "... The antenna(s) are spatially translated in an arbitrary trajectory. As the antenna(s) is being spatially translated, a data processing means samples the incoming signal at set intervals based on a clock signal provided by a system clock. By sampling the incoming signal at different times at different spatial locations on the arbitrary trajectory, the system acts as a synthetic antenna array. The different samplings of the incoming signal at different times and positions provide signal diversity gain as well as different readings which can be used to estimate and/or calculate various parameters of the incoming signal.".

Plurality of spaced independent aerials, both correlated (beamforming) or non-correlated (diversity) at transmitter or receiver or both, either using simultaneous transmission/reception (e.g. for beamforming) or successive transmission/reception (antenna switching/selection).

Example of documents classified here: see WO2009046409 (figures 4, 7)

transmission of a plurality of different signals from different antennas, wherein at least one of said signals is transmitted (potentially weighted) from more than one antenna; for example MIMO transmission for N different streams via M different antennas, where M linear combinations of the N streams are transmitted, each linear combination being transmitted from each antenna.

This group takes precedence over the transmit/receive diversity groups H04B 7/06 and H04B 7/08.

Example of documents classified here: US2004179627 (figure 3):

Example of document classified here: see e.g. US2008004016 (abstract): "A base station for establishing a picocell is configured so as to provide multiple sectors, with spatial diversity between sectors. The combination of the multiple sectors and the spatial diversity reduces signal power requirements in the air interface within a confined space and provides improvements in quality of service."

Plurality of spaced independent aerials at the transmitter (correlated or uncorrelated)

H04B 7/0686 takes precedence.

Example of documents classified in this group: see e.g. WO2008157620 (fig. 2 and paragraph [0031]):

Example of document classified here: see e.g. WO2008157620 (fig. 2 and paragraph [0031]).

Example of document classified here: see US2006068791 (fig. 2, paragraph [0031]):

or abstract of Seeger A; Sikora M, "Antenna weight verification for closed loop transmit diversity, GLOBECOM'03. 2003 - IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE. CONFERENCE PROCEEDINGS. SAN FRANCISCO, CA, DEC. 1 - 5, 2003; [IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE], 20031201; 20031201 - 20031205, NEW YORK, NY : IEEE, US, XP010678496: "Closed loop transmit diversity (CLTD) for FDD WCDMA relies on low-rate feedback to achieve both beamforming and diversity gain. Since the feedback channel is not immune to errors, occasionally base station (BS) uses different antenna weight vector from the one requested by mobile station (MS).

Surprisingly, most of the resulting performance degradation is caused not by reduced power of the Rx signal, but by erroneous dedicated channel estimation at the MS relying on knowledge of used weight vector. In this paper we introduce a general trellisbased antenna weight verification algorithm, which attempts to detect feedback errors and determine the most likely weight vector."

For example error detection/ correction of feedback bits at diversity transmitter.

Example of document classified here: see US2006056531 (abstract): "Feedback bandwidth may be reduced in a closed loop MIMO system by Householder transformations, vector quantization using codebooks, and down-sampling in the frequency domain. A column of a beamforming matrix is quantized using a codebook, a Householder reflection is performed on the beamforming matrix to reduce the dimensionality of the beamforming matrix, and the quantizing and performing of Householder reflection on the previously dimensionality reduced beamforming matrix is recursively repeated to obtain a further reduction of dimensionality of the beamforming matrix."

Example of document classified here: see WO0011806 (abstract and figure 1):

Example of documents classified here: see US2006172710 (abstract) for phase sweeping diversity.

Example of document classified here: see e.g. EP2276305 (figure 5):

Example of document classified here: see e.g. US2003235147:

Plurality of spaced independent aerials at the receiver (correlated or uncorrelated).

Example of documents classified here for receive antennas switched to a single receiver circuit; see US2010075603 (figure 1):

Example of document classified here: where the selection criterion is not necessarily identified, see WO2008003029 (figure 1):

Example of documents classified here: see US2009097577 (figure 1):

Example of documents classified here: see US6115406 (figure 5):

Beamforming at the receiver included here.

Example of documents classified here: see EP1257070 (figure 1):

Radio relay systems are divided into passive relay systems (H04B 7/145) and active relay systems (H04B 7/15).

A passive relay is a relay on which a signal is only reflected.

Active relay systems are used by communication arrangements to receive, to process and to retransmit signals between devices separated by air or space.

Mobility is possible between the devices of the active relay system and the transmission can be unidirectional or bidirectional.

The processing within the relay is of a wide range. For instance the relay processing covers the following issues. The signals relayed can be a multiplex of a plurality of signals. The processing minimizes the interference between the signal received and retransmitted. Signal are regenerated, signals are switched in the relay before retransmission. Further processing details are indicated in the subgroups of H04B 7/15.

Moreover, as indicated below, the active relay systems are further subdivided into ground based relay stations, airborne relay stations and space based relay station (satellites).

A passive relay is a relay on which a signal is only reflected. No processing is done by such a relay. A passive relay is used to scatter a signal.

Radio waves, below a certain frequency, are reflected by the ionosphere. This allows propagation beyond the horizon.

Meteor burst communication or meteor scatter communication uses the ionized trail of a meteor for radio wave reflection.

Two antennas linked by a waveguide assure radio relaying. This is used for example to allow reception in a tunnel.

Reflection can be achieved by the use of a passive airborne platform.

To enable radio wave transmission in buildings, passive antennas, material transparent to radio waves … are used.

Relays are used for range extension, to cover shadowed regions, to allow communication with the inside of a building, to transmit signals over long distances.

Microwaves relays working from 2 to 5 GHz with fixed stations in line of sight allow point to point high data rate transmission for telephony or broadcasting signals.

Shortwave relay are used for broadcasting.

Relays are used in a wireless network for radio cell extension.

Cooperative relays are used for signals diversity.

H04B 7/204 takes precedence

Group for consultation only. Documents are classified in H04B 7/15564 .

Group for consultation only. Documents are classified in H04B 7/15564 .

H04B 7/204 takes precedence.

The stations are navigating in the stratosphere (below 50 km).

The airborne station is an unmanned airborne device or an aircraft covering a region (for example in case of an emergency situation when communications are disrupted during a catastrophically event). The relay is a lighter than air device, a balloon, a dirigible, a device called HALE (High Altitude Low Expenditure), HAAP (High Altitude Atmospheric Platform), SHARP (Stationary High Altitude Relay Platform) or an unmanned aerial vehicle (UAV).

The airborne station works alone or is part of a network of other stations. The communications can then be handed over to another platform. A satellite can be part of the network. The technical characteristics of these devices, their trajectory are adapted for communication. The relays are drifting in the sky or they are stabilized in position and altitude.

Communications with or from an aircraft without relaying through a satellite.

The system are communication systems for commercial aircrafts and used for transmission between the passengers and the ground for voice or data communication. The systems are as well for communications between the cockpit and earth control stations for air traffic control, for aircraft short messages service …

Such systems are as well used for transport devices like a bus or ship.

The communications are multiplexed on the up and down link and must be demultiplexed. Antenna aspects in such systems.

A network of ground stations is necessary to follow the aircraft. A call is handed over between ground stations.

A network can be established between aircrafts. Other aircrafts must be localized.

The aircraft flies over regions with different ground systems and regulations

A communication network exits on board allowing on board broadcasting to the passengers or communications between users and the crew. Data transmission for in-flight entertainment, for use of Internet.

The aircraft can be equipped with terminals or the user can use his own voice or data terminal. Security. The use of a terminal is potentially dangerous because of its radiations.

A user on board of an aircraft must be localized by the ground system to establish the link and for billing.

Communication equipment and specific aircraft devices like navigation apparatuses are integrated on board. Relaying toward earth of aircraft sensor values.

Communications with or from an aircraft with relaying through a satellite for commercial aircrafts and for communications between the cockpit and earth control. Systems for aircrafts and for devices like a bus or ship.

The communication aspects covered are identical as for H04B 7/18506 but at least one satellite is involved in the aircraft-ground link.

Use of geostationary satellites or not. Localisation of the satellites by the aircraft.

Handover between satellites.

The antennas of the aircraft are oriented towards the satellite.

The transmission delay is increased with use of a satellite.

Particular application: video broadcasting.

Satellites are used for relaying communications.

Satellite systems for varied applications exit. Communication aspects for such systems. Satellite applications can be: earth observation, weather forecast data transmission, emergency calls, fleet tracking, space based radar, aircraft guidance and navigation, navigation systems using satellites, land observing satellites.

H04B 7/18508, H04B 7/18521 take precedence.

For providing specific services H04B 7/18523 - H04B 7/18576

All aspects relating to communications in uplink and downlink in a satellite system such as:

Equipment on board of the satellite. Telecommunication payload, bus and platform equipments.

All equipment on-board involved in transmission such as: transponder, amplifier, multiplexer, demultiplexer, on-board digital processors, antennas.

All equipments used in earth-based stations.

These stations can be: a hub station, a control station, a gateway, a user terminal, a Small Aperture Terminal.

Spare satellite. Replacement satellite. Backup satellite. Reconfiguration of a satellite.

Measuring performance of a system. Calibration of a system. Reception quality. Fault diagnostic.

Monitoring, control, telemetry.

Satellite attitude and orbital control to optimize communication performance.

System simulation.

The link between satellites can be radio or optical.

Constellation of satellites with inter-satellite links to route a communication through the network of satellites.

Simulcast (simultaneous broadcasting). Multicasting (transmission to a group of users). Geocast (transmission to geographic areas).

Feedback from the user (thru satellite or thru terrestrial network) for interactive system.

On-board transponders.

This group in not used if the satellite is transparent to the broadcast service.

Mainly for Very Small Aperture Terminal (VSAT) system.

Fixed satellite service. for telephony, telecommunication and data communication.

The satellites used are geostationary, geosynchronous.

Transport of data or signalling messages. Transport of voice channels.

Traffic channels, dedicated control channels, broadcast channels, paging channels, beacon signal, pilot channels, synchronisation channels.

Spot beams antennas for creation of communication cells.

In particular for diversity used to increase link quality.

Resources seamlessly added or subtracted.

Transmission with multidirectional antennas from the base station to achieve diversity.

Shadowing due to blockage of signals. Use of an additional terrestrial relay or other techniques.

Allocation of radio resources for establishing or releasing a connection.

Resource allocation for load balancing.

Determination and dissemination of information through the network of gateway for resource planning.

Frequency planning.

Frequency attributed according to need, to a reuse pattern, to limit interference.

Power control in real and non real time.

Time slot allocation.

Channel allocation: fixed, borrowed, dynamic.

A communication is handed over from one satellite to another according to the satellites rotations.

Handoff beam to beam, satellite to satellite, frequency to frequency.

Network controlled handover, mobile controlled handover, mobile assisted handover.

Terminal registration process. Local or global registration.

Location update of terminal.

Registration in a local and global database with user identification and position.

Re-registration. Periodic registration of a mobile, registration after loss of a signal (outage), terminal unavailability.

Geolocalisation of a user for radio localisation, call barring, call billing, synchronisation.

Measure of propagation delay variation, Doppler frequency variation, power variation, beam identification.

Measure of time delay satellite-user.

Routing through terrestrial network with only node-satellite-terminal links.

Mobile to mobile call.

Mobile to fixed, fixed to mobile call.

Routing tables used are changed according to network topology (link usage, congestion, failure, shutdown).

Optimization of transmission path (minimum hop route, packet delay).

Satellite in relation with more than one node for control.

Use of a terrestrial and a satellite system (dual mode).

Protocol conversion between different satellites, terrestrial systems.

Use of a terminal adapted for the two systems. Characteristics differ: antenna used (orientation), power transmitted (higher for a satellite system, user head protection).

Use of a minisatellite, a microsatellite. Miniaturized satellites. Milli, micro, nano, picosatellites.

Little LEO. Smaller low cost satellites on a low earth orbit.

Satellite formation flying, trailing formation, cluster formation.

Fractionated spacecraft.

Systems for data, asset or vehicle tracking, messaging, emergency, alert services, disaster, medicine, education, data acquisition, meter reading, e-mail, fax, store and forward messaging.

Terminals adapted to system function.

Data communication for users which can be mobile using a satellite as relay between the user and a control station. The data transported are of large band.

Description of the transmission equipments of the system. Satellite, terminal and control station. Description of the transport of the information. Modulation, demodulation, antenna, radio link between earth and satellite, bit synchronisation.

Construction of the frame, preamble, multiplexing, demultiplexing, TDMA, CDMA, FDMA, frequency hopping, frame synchronisation, error control (ARQ, FEC), data packet queuing or scheduling.

Segmentation and reassembly.

Connection oriented, connectionless communication. Establishment of the physical links.

Transport of bits, bytes, packets.

Multiplexing, demultiplexing on a single link.

Congestion control. Flow control.

Fiability of the transport.

Error detection and recovery (forward error correction, repetition, automatic repetition).

Encryption. Decryption. Use of SIM card. Adaptor card or conditional access. Scrambling, descrambling. Billing.

The satellite is on a geostationary, an equatorial, a geosynchronous orbit or semi-synchronous orbit.

Description of the constellation of satellites, of the orbital parameters.

The orbits are low earth orbit (LEO), medium earth orbit (MEO) or high earth orbit (HEO) according to the altitude of the satellite. Mixed constellation.

Inclined orbit, polar orbit, sun synchronous orbit, circular orbit, elliptical orbit, Molnia, Tundra.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Antennas. Multi-beams antenna. Beam forming network. Phased array antenna. Multispots antenna.

Scanning beams. Grid of multiple fixed beams. Beam rotation for satellite roaming compensation. Beam hopping. Beams alternatively transmitting, receiving. Panels. Grids of complex shape (hexagonal).

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

On board of a satellite.

Group for consultation only. Documents are classified in H04B 7/18515.

Use of ionosphere, troposphere reflexion or meteor scatter.

In such systems, the radio propagation is not a line of sight propagation between two devices. The signals are reflected, refracted or scattered by natural components of the earth atmosphere. A network using such reflexions and the radio link between the divers network components are described. Passive relay are described in H04B 7/145.

Radio waves are refracted by the ionized layers of the upper atmosphere. These layers are influenced by the sun. Such communications are used for amateur radio, marine and aircraft communications, shortwave broadcast.

Tropospheric scatter is a method of communication in which signals at particular frequencies are randomly scattered by the upper layers of the troposphere allowing the transmission of signals on a distance of hundred of kilometres. Only a small amount of the transmitted power is received. A narrow frequency band is generally used.

A meteor burst communication system uses the ionized meteor trails as radio reflector between two stations. These trails exit at an altitude of approximately 100 km and allow a long range, low data rate intermittent communication of a few seconds on a distance of 2000 km.

Auroral ionization, rain, lightning can create scattering.

In a communication network, the physical link and the signals transmitted between the divers network components are described. The link can be wired or wireless, the network components are fixed in this head group, mobile in the different sub-groups.

Transmission medium: twisted pairs, copper wires, coaxial cable, air ...

Nature of information transmitted: voice, video, data ...

Description of the signal to be transmitted: analogue, digital transmission, analogue/digital conversion, voice codec.

Coding of the signal, PCM, line codes (NRZ, unipolar, bipolar, Manchester encoding...).

Modulation used (QPSK, PSK, QAM, FSK, PSK, ASK). Amplitude, phase, frequency modulation.

Transmission and reception of the signal. Demodulation. Decoding.

Error recovery and correction. Error correction codes (linear, cyclic, BCH, convolutional codes). Channel codes. Signal repetition (ARQ).

Description of the network: star, mesh, ring network.

In a wireless communication network, the radio link, called air interface, between the divers network components is described.

Different mobile systems exist. For example: cordless telephony is a short range system.

The mobile telephony has evolved toward cellular telecommunication systems for voice, narrowband or broadband data transmission.

The physical channel, channel access procedures and multiple access are the lower levels of the transmission system linking users and are the object of these groups. The higher levels control the flow of messages between the network components and allow the building up of a communication and are the subject of H04W in general.

The signals transmitted on the air interface and the apparatuses therefore are described.

The frequency band or time interval allocated is separated in physical wireless channels.

Definition of the physical and logical channels, mapping of the logical channels on the physical channels. Logical channels for traffic of voice or data. Logical channels for control: dedicated control channels, broadcast channels, paging channels, access grant logical channels, random access channels, pilot channels, synchronisation channels ... Frequencies, time slots used, number of bits, format, overhead bits, preamble, guard periods ...

Emission: digitization, source coding, interleaving, ciphering, burst formatting, modulation. BPSK, QAM, hierarchical modulation.

Transmission: path loss, multipath fading, noise, interference, error and error correction (equalisation, error correction codes, interleaving ...).

Reception: source decoding, channel decoding, desinterleaving, deciphering, burst formatting, demodulation.

H04B 7/2612 takes precedence.

Relays are used for linking a user equipment with a base station.

Relays for lightening dark zones. Use of relays in tunnels, in buildings, in closed environments.

Roadway communication systems.

Fixed relay, mobile relay.

Relays for cell extension.

Multiplicity of relays.

Relay selection.

Cooperative relays.

Multihop communication.

Use of multiple antennas. Antenna characteristics, antenna patterns, spacing of antennas.

Relay functionality and design. Half-duplex, full duplex repeater. TDD (Time Division Duplex), frequency change, frequency selective repeaters, amplify and forward, decode and forward repeaters. Loop-back interference cancellation. Signal delay. Link with the base station, link with a user equipment. Protocols implemented in the relay.

Allocation of a physical layer transmission capacity.

Transport channels for carrying the logical channels.

Channel access control mechanisms.

Error recovery, ARQ (Automatic Repeat Request).

Multiplexing/demultiplexing techniques such as: random access protocols (ALOHA, CSMA; CSMA/CD), fixed assignment protocols (TDMA, FDMA, CDMA, SDMA), demand assignment protocols (polling, reservation protocols (centralized), token passing protocols (decentralized)).

H04B 7/2615 - H04B 7/2643 take precedence.

OFDM (Orthogonal Frequency Multiplexing).

FDD (Frequency Division Duplex).

H04B 7/2615 takes precedence.

Using a common frequency.

Single frequency network.

A network of stations broadcasting on a single frequency for example.

For DVB-T (Digital Video Broadcasting Terrestrial), DVB-H (handheld), DVB-SH (satellite handheld), DTMB (Digital Terrestrial Media Broadcasting) , DAB (Digital Audio Broadcasting), mediaflo (forward link only).

Repeaters synchronized, adaptive equalization.

Use of OFDM (Orthogonal Frequency Division Modulation), COFDM (Coded Orthogonal Frequency Division Modulation; FEC convolutional coding, time and frequency interleaving).

Divers types of spread spectrum systems:

Codes used:

Transceiver:

H04B 7/2618 takes precedence.

Transmission of information on a plurality of parallel channels.

Protocols such as WCDMA (Wideband CDMA), HSPA (High Speed Packet Access).

TDD (Time Division Duplex).

Superframes, frames, time slots.

Formats used for the frames and the time slots. Description of the burst, the information in the time slot.

Guard bands to avoid overlapping of the signals.

Preamble, training, equalisation, synchronisation, start/stop bits.

Uplink, downlink frame.

H04B 7/2615, H04B 7/2618 take precedence.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

Group used for consultation only. Documents are classified in H04W 56/00.

H04B 10/00 deals with the physical layer of an optical communication system, i.e. dealing with the physical properties of the optical data signal, e.g., power, distortion, optical-electrical and electric-optical conversion of data.

H04J 14/00, H04J 14/05 and H04J 14/07 deal with the optical multiplexing layer, e.g. dealing with the optical signals as channels necessary for data transfer, e.g. routing, allocation, add-dropping, WDM networks, WDM protection.

Optical switching is covered by H04Q 11/0001.

Light guide arrangements as components or modules per se are classified in G02B 6/00, e.g. modules based on light guides for coupling, splitting, mixing, switching and dispersion compensation

Lasers and fibre amplifiers per se are classified in H01S and H01S 3/067

Optical devices per se for changing the optical properties of the signals based on a change in refractive index, e.g. modulators are classified in G02F.

If appropriate, multiple classes for different technical features in the same document should be assigned

Optical - Non-optical transmission systems

Non-optical transmission systems, falling within the scope of this group, are only classified in group H04B 10/90.

Subject matter wherein a corrective action is taken to return an inoperative or malfunctioning optical communication system or its component to a satisfactory operating condition.

Subject matter wherein the recovery is provided by a predetermined protection path in parallel with the working path that provides protection when the working path has a failure.

Subject matter wherein data signals are detoured in a reverse path through the network to avoid the malfunctioning component.

Subject matter including a provision for alternate routing around the malfunctioning component.

Subject matter including means for monitoring, measurement or testing for evaluating an operational condition of an optical communication system or its components.

Subject matter wherein at least one communication parameter is determined by information from a signal reflected from a location in the communication network.

Subject matter wherein the operational condition of an optical communication network or its component is tested or evaluated using an external stimulus signal while the system is not in operation.

Subject matter wherein the operational condition of an optical communication network or its component is tested or evaluated signal while the system is in operation.

Subject matter wherein at least one communication parameter is determined by information from a control signal provided in addition to the data signal. The additional signal can for example be modulated on the data signal or placed on a separate wavelength.

Subject matter wherein at least one communication parameter is determined by information derived from a measurement of the data signal, e.g. measurement of system performance parameters, e.g. OSNR, quality factor, dispersion value, power.

Subject matter wherein a signal-carrying optical beam is propagated such that the beam is transmitted through air or a vacuum and not spatially confined in any optical component or medium.

Subject matter wherein the optical beam is transmitted in a straight line to the receiver across longer distances outdoors, e.g. between buildings.

Subject matter wherein one central station is communicating wirelessly with a plurality of terminal stations. Even if the document focuses on one such connection, but it is clear from the description and drawings it is for a network, the document should be classified here.

Subject matter wherein the optical beam is propagated between nearby apparatuses or elements within an indoor space, directly or via diffuse communication.

Subject-matter wherein two devices are communicating only one-way, e.g. remote controllers.

Subject matter wherein one central station is communicating wirelessly with a plurality of terminal stations. Even if the document focuses on one such connection, but it is clear from the description and drawings it is for a network, the document should be classified here.

Subject matter wherein the signal-carrying optical beam includes or consists of light having a wavelength in the visible light spectrum, e.g. a modulated lighting device or a modulated overhead light.

Subject matter wherein the optical beam is propagated to or from an Earth-orbiting object.

Subject matter including one or more transparent elongated structures (e.g., rods, fibers, or pipes) which are used to transmit light waves from one point to another within the confines of their outer surface by means of internal reflections or modal transmission.

Subject matter comprises means for correcting or reducing distortion induced by (1) scattering in a light beam as it travels along the fiber or (2) overlapping of a light signal on one wavelength onto different wavelengths because of reflected rays and different refractive indices of the optical fiber material.

Subject matter comprising means for correcting or reducing distortion that is caused by the broadening of the signal as it travels the length of the fiber.

Subject matter comprising means for correcting or reducing distortion caused by chromatic dispersion using a fiber Bragg grating.

Subject matter wherein a correction fibre of specified length and amount of dispersion is used to compensate for chromatic dispersion.

Subject matter wherein over the whole fibre span a combination of different fibres are used to compensate for the dispersion of the span (does not cover a combination of fibres within a device)

Subject-matter wherein dispersion is compensated through mid-span spectrum inversion.

Subject matter comprising means for correcting or reducing distortion caused by the interaction of the signal with molecules in the fiber.

Subject matter comprising means for correcting or reducing distortion caused by variations in the optical properties of the fiber, e.g. due to the Kerr effect.

Subject matter comprising means for compensating for Self-phase modulation. SPM is caused by the Kerr effect which produces a variation in the refractive index of the fibre. This variation in refractive index will produce a phase shift in the pulse, leading to a change of the pulse's frequency spectrum.

Subject matter comprising means for compensating for Cross-phase modulation. XFM is caused by the Kerr effect which produces a variation in the refractive index of the fibre. This leads to one wavelength of light potentially affecting the phase of another wavelength of light.

Subject matter comprising means for compensating for Four-wave mixing. FWM is an intermodulation phenomenon in optical systems; when three wavelengths interact in a nonlinear medium, they give rise to a fourth wavelength.

Subject matter which comprises means for correcting or reducing distortion caused by modal dispersion where two different polarizations of light in a waveguide, which normally travel at the same speed, travel at different speeds due to random imperfections and asymmetries, causing random spreading of optical pulses.

RF-over-Fiber architecture, wherein a data-carrying RF (Radio Frequency) signal with a high frequency is imposed on a lightwave signal before being transported over the optical link. Wireless signals are optically distributed to base stations directly at high frequencies and converted from the optical to the electrical domain at the base stations before being amplified and radiated by an antenna.

RF-over-Fiber systems used specially for CATV or video distribution

Subject matter comprising systems using more than one mode for transmission using multimode fibres.

Subject matter wherein the light source in a first station is used to transmit an optical data signal to at least a second station and the second station modulates the received light to transmit an optical data signal to the first station. The at least second station does not comprise a local light source.

Subject matter wherein an optical communication system is comprised of a specific arrangement of interconnections.

Subject matter wherein an optical data distribution system contains a common node connected to one end of each of three or more branches and the other end of which is connected to each member of a local area network multiplex system to permit optical information flow between all of the members.

Subject matter wherein the local area network consists of a series of stations connected to each other and the last station is connected to the first station.

Subject matter wherein multiple optical stations are interconnected via a network of fiber optics in a bus configuration to enable transmission and reception between the stations.

Subject matter including apparatus for receiving a light wave signal and reradiating the signal at a same or different carrier frequency.

Note. The recreating or retransmitting signal is usually at a higher power level or in a desired direction.

Note. The information content of the transmitted signal is not changed with respect to that of the received signal.

Subject matter in which the optical data signal is regenerated without conversion into the electrical domain. Feedback or control signals may be converted from optical to electrical.

Subject matter in which the regeneration leads to a constant signal power level.

Subject matter wherein the power control takes place in a wavelength division multiplexing [WDM] system

Subject matter in which compensation is provided if the power of the signal changes rapidly due to changes in system parameters.

Subject matter in which the regeneration is provided using a single device that retransmits both upstream and downstream signals. The single device may contain different devices that interact with each other. A single fibre is used for upstream and downstream signals, the regeneration device can however comprise separate amplifiers for upstream and downstream signals.

Subject matter in which the shape and/or timing of the signal is processed prior to regeneration, e.g. 3R amplifiers.

Subject matter wherein an optical transmitter and a receiver are at a common location for transmission and reception of separate optical signals in such a manner that an optical signal is transmitted using some of the same equipment used for the reception of another optical signal. The optical transmitter and receiver are usually confined to a common housing in a transceiver and termed "a station".

Simultaneously operating transmitter and receiver elements that are completely separated physically are excluded from this subclass.

Subject matter wherein a same diode element is used both to transmit or receive signals depending on how it is biased.

Subject matter including an opto-electric circuit for converting an information signal into a modulated optical signal suitable for propagation through or along a transmission medium. The opto-electric circuit includes, for example, opto-electronic light sources such as LEDs, laser diode, incandescent bulbs, an optical modulator and other elements associated with fiber optic or infrared transmission system required to communicate an information signal from one location to another via an optical beam.

Subject matter comprising details of a process in which the optical energy is transformed into pulses having a particular characteristic before information signal coding or modulation is applied to the optical energy.

Subject matter comprising details of a process in which information signal is coded into beams of optical energy by use of a carrier wave.

Subject matter in which modulation is produced by modulating a carrier light wave by a series of digital pulses and varying a non-amplitude attribute of the pulses (e.g., position, width) to represent information in the optical beam.

Subject matter in which the polarization of the carrier light wave is controlled to represent information

Subject matter in which modulation is produced by varying the amplitude of a carrier light wave as a function of the information signal.

Subject matter in which angle modulation is produced by proportionally varying the instantaneous phase angle of a sine wave carrier with the instantaneous value of an amplitude of a modulating signal, or by causing the instantaneous frequency of a sine wave carrier to depart from a carrier frequency an amount that is proportional to the instantaneous value of a modulating signal.

Subject matter in which the modulation is produced by creating discrete variations of the phase or frequency of the optical signal.

Subject matter comprising details of regulating the energy level output from the transmitting laser or light emitter.

Subject matter comprising details of regulating the wavelength output from the transmitting laser or light emitter. Regulating the wavelength output may include wavelength tuning or wavelength stabilization.

Subject matter wherein at least one output of the opto-electric circuit is modified to be an approximately linear function of its inputs. (techniques for making the output of the transmitter into a linear output)

Subject matter including particular details of varying the output of at least one laser diode element using another element outside of the laser diode to provide the optically transmitted signal.

Subject matter including an opto-electric circuit for retrieving information from a modulated optical signal propagated through or along a transmission medium.

Subject matter wherein a received wave is combined with a locally generated wave to produce one or more beat frequency signals at the output for detection of the transmitted information signal.

A receiver that demodulates the received signal by mixing it with a local oscillator signal synchronized in frequency and phase to the carrier of the received signal.

A receiver that demodulates the received signal by mixing it with a local oscillator signal having a different frequency than the carrier of the received signal.

Subject matter in which the data signal is directly converted from optical to electrical without the use of an oscillator.

Subject matter in which the detection of the signal is enhanced by an optical arrangement in the receiver that is provided in addition to the photodetection means.

Subject matter in which the detection of the signal is enhanced by an electrical arrangement within the receiver that is provided in addition to the photodetection means.

Subject matter wherein characteristics of single photons are varied to represent respective bits of data and these photons are transmitted and/or received in a communication system to convey an information-bearing message.

Optical aspects relating to specific applications of optical communication not provided for in any of the previous subgroups, e.g. optical power feeding, optical transmission through water or rotary joints,.