Date Added: May 2012
Optimal transmitter beamforming with per-antenna power constraints has been a long outstanding problem. In this paper, The authors derive the necessary and sufficient conditions for optimal single-stream and multi-stream transmitter beamforming with per-antenna power constraints. They also develop iterative algorithms for single-stream and multi-stream transmitter beamforming, and prove the algorithms converge to the optimal solutions. Multiple antenna technology has been a major component in modern mobile communication since the pioneering work by Foschini and Gans. The optimal transmission strategy, given the knowledge of channel station information at the transmitter and with total power constraint, is shown to be a "Water-filling" strategy along the transmitter side singular vectors of the channel matrix .