Distributed Beamforming with Limited Feedback in Regenerative Cooperative Networks

This paper investigates beamforming with limited feedback in regenerative cooperative networks where relays demodulate and forward the received symbols .We propose an optimal beamforming vector maximizing the received signal-to-noise (SNR) at the destination and derive an upper bound on performance for limited feedback scheme. Given the fixed number of feedback bits, the gap in performance between beamforming with quantized and perfect channel state information (CSI) at high SNRs is proved to be constant. The results indicate that this scheme is very attractive in terms of performance-complexity tradeoff.