Patent ID: 7680027

Claim:
In a collaborative Multiple Input Multiple Output (MIMO) communication system having a Base Transceiver Station (BTS) and a plurality of Mobile Stations (MSs), the BTS having a plurality of receive antennas and each MS having a transmit antenna, a method for estimating channel of at least one MS, the method comprising: receiving signal from a transmit antenna of a first MS and a transmit antenna of a second MS at the BTS, wherein a signal comprises a plurality of tiles, each tile comprises a plurality of pilot sub-carriers and a plurality of data sub-carriers corresponding to at least one of the first MS and the second MS; computing conjugate products for each of the first MS and the second MS using signals received at each of the plurality of receiver antennas of the BTS, wherein a conjugate product is computed for the plurality of pilot sub-carriers in a tile of a signal received at each receiver antenna of the BTS; determining an average over the plurality of receiver antennas and plurality of tiles of the plurality of conjugate products for each of the first MS and the second MS; dividing a phase determined based on the average of the plurality of conjugate products for each of the first MS and the second MS into a first phase and a second phase for each of the first MS and the second MS; determining a channel estimate for each tile in the signal for the first MS and the second MS at each receiver antenna of the BTS, wherein a channel estimate corresponding to a MS for a tile at a receiver antenna of the BTS is determined based on the phase and a plurality of pilot sub-carriers corresponding to the MS in the tile; and performing predefined computations on the channel estimate of each tile of the first MS and the second MS at each receiver antenna of the BTS using the corresponding first phase and the corresponding second phase; wherein the predefined computations performed comprise; generating a combined phase for each pilot sub-carrier and each data sub-carrier in the tile by weighting the first phase and the second phase; applying the combined phase corresponding to each pilot sub-carrier and each data sub-carrier in the tile to the channel estimate determined for the tile.