Methods for opportunistic multi-user beamforming in collaborative MIMO-SDMA

摘要

A system and method for opportunistically designing collaborative beamforming vectors is disclosed for a wireless multiple input, multiple output (MIMO) space division multiple access (SDMA) communication system by sequentially designing beamforming vectors for ranked channels in order to exploit the instantaneous channel conditions to improve per user average SNR performance. Each subscriber station independently transmits information to a base station that allows the base station to determine beamforming vectors for each subscriber station by ranking the subscriber stations by channel strength. Using sequential nullspace methods, the ranked channel matrices are then used to select the channel matrix H_i for the best subscriber station, to design the w_i, v_i for the best subscriber station as the left and right singular vectors of the MIMO channel matrix H_i, to transform the remaining channels and to continue the process until beamforming vectors are designed for all channels.