Patent ID: 7852954

Claim:
A method of receiving channel information at a base station in an OFDM (orthogonal frequency division multiplexing) or OFDMA (orthogonal frequency division multiple access) wireless communications system, the method comprising: transmitting, by the base station, an information element (IE) to a mobile subscriber station, the IE comprising instruction information and a feedback type, wherein the instruction information indicates a signal measurement region selected among a data region allocated to the mobile subscriber station, a preamble region, and a midamble region within a data frame, and wherein the feedback type indicates a type of the channel information to be received from the mobile subscriber station; transmitting, by the base station, the data frame to the mobile subscriber station, wherein the data frame comprises the data region allocated to the mobile subscriber station, the preamble region and the midamble region; and receiving, by the base station, the channel information from the mobile subscriber station, the channel information estimated by the mobile subscriber station using signals transmitted on the indicated signal measurement region in accordance with the feedback type, wherein, when a partial band of the preamble region or the midamble region is selected as the signal measurement region, the instruction information comprises a first field indicating a lowest subchannel index of the partial band and a second field indicating a number of subchannels of the partial band.