A practical transmit beamforming strategy for closed-loop MIMO communication

A new beamforming strategy is proposed for multiuser systems with N transmit antennas at the transmitter and M ? N single antenna receivers. The proposed scheme remarkably improves on the classical spatial division multiple access, and achieves the same data rates as spatial multiplexing for all users but with significantly superior performance/diversity gain. When compared with the Bell labs layered spacetime system, the symbol rate is the same and the performance is much superior because of the presence of diversity gain. In addition, unlike the Bell labs layered spacetime system, the receivers do not need to know each other's vector channels. Finally, the proposed algorithm is based on dirty-paper coding, but does not require much complexity and is implementable. Copyright (c) 2011 John Wiley & Sons, Ltd.