| US 7,489,623 B2 | ||
| Control modulation in multipoint-to-point communication using orthogonal frequency division multiplexing | ||
| Michael J. Geile, Loveland, Ohio (US) | ||
| Assigned to ADC Telecommunications Inc., Eden Prairie, Minn. (US) | ||
| Filed on Jun. 14, 2007, as Appl. No. 11/763,188. | ||
| Application 11/420851 is a division of application No. 09/903273, filed on Jul. 11, 2001, granted, now 7,069,577, filed on Jun. 27, 2006. | ||
| Application 09/397443 is a division of application No. 08/673002, filed on Jun. 28, 1996, granted, now 6,334,219, filed on Dec. 25, 2001. | ||
| Application 11/763188 is a continuation of application No. 11/420851, filed on May 30, 2006. | ||
| Application 09/903273 is a continuation of application No. 09/397443, filed on Sep. 15, 1999, granted, now 6,279,158, filed on Aug. 21, 2001. | ||
| Application 08/673002 is a continuation in part of application No. 08/650408, filed on May 20, 1996, abandoned. | ||
| Application 08/650408 is a continuation in part of application No. 08/457295, filed on Jun. 01, 1995, abandoned. | ||
| Application 08/457295 is a continuation in part of application No. 08/457317, filed on Jun. 01, 1995, abandoned. | ||
| Application 08/457317 is a continuation in part of application No. 08/384659, filed on Feb. 06, 1995, abandoned. | ||
| Prior Publication US 2007/0223363 A1, Sep. 27, 2007 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. H04J 11/00 (2006.01); H04Q 7/00 (2006.01) | ||
| U.S. Cl. 370—208 [370/328; 370/335; 370/342] | 7 Claims |
| 1. A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprising: a plurality of
remote units; a host unit that includes a demodulator; wherein each of the remote units transmits an upstream OFDM signal
using a multiple access scheme to the host unit demodulator using at least one of a plurality of orthogonal tones within an
OFDM waveform;
wherein the host unit receives the upstream OFDM signals from a plurality of the remote units, the tones of the upstream signals
being substantially orthogonal when received at the host unit;
wherein portions of upstream OFDM signals from at least two of the remote units arrive at the host unit at the same time;
wherein the host unit demodulator demodulates said portions; wherein the host unit sends an adjustment signal to at least
one of the remote units instructing the at least one remote unit to adjust the timing of transmissions from the remote unit
to improve orthogonality of the OFDM waveform received at the host unit;
wherein control data is sent between the host unit and at least one remote unit using a first modulation scheme on at least
one orthogonal tone within the OFDM communication system;
wherein payload data is sent between the host unit and the at least one remote unit using a second modulation scheme on at
least one orthogonal tone within the OFDM communication system;
wherein the first modulation scheme is different than the second modulation scheme; and
wherein the first modulation scheme is a form of phase shift keying and the second modulation scheme is a form of quadrature
amplitude modulation (QAM).
|