Relay Network Beamforming and Power Control Using Maximization of Mutual Information

In this paper, distributed beamforming and power control are considered for amplify-and-forward wireless relay networks with single antenna nodes. The optimal relay weights are designed by maximizing the mutual information in the case of perfect channel state information, individual node power constraints and the existence of a direct link between the source and destination nodes. In our approach, the source node transmits up to two precoded independent information streams as opposed to several previously proposed techniques in which a single symbol is always transmitted. Our solution to the relay power control given the power allocation at the source node is obtained analytically with linear complexity. Simulations show that the proposed method outperforms the previously proposed techniques in terms of mutual information, outage probability and bit error rate.