Patent ID: 7684379
Filing Date: 2010-03-23
Classification: H04L

Abstract:
1. An orthogonal frequency division multiple access (OFDMA) system comprising: a base station; and a plurality of subscriber stations in signal communication with the base station, each subscriber station having a unique uplink frequency offset, wherein each subscriber station compensates for its own unique uplink frequency offset prior to transmitting compensated data to the base station, constructs an uplink frame comprising the compensated data, and transmits the uplink frame to the base station as a substantially real-valued signal, wherein the base station receives uplink frames from the plurality of subscriber stations, each uplink frame comprising data compensated for the unique uplink frequency offset of the transmitting subscriber station, respectively, compensates for the uplink frame by an intermediate frequency offset obtained by averaging the unique uplink frequency offsets of the uplink frames transmitted from the subscriber stations, respectively, and wherein each subscriber station compensates for its own unique uplink frequency offset relative to the intermediate frequency offset by compensating the phase of its uplink signal prior to transmitting the uplink frame to the base station.