Optimal power allocation for amplify-and-forward relay networks via conic programming

Relay power allocation has been shown to provide substantial performance gain in wireless relay channels when perfect global channel state information (CSI) is available. In this paper, we show that by using a class of conic optimization theory, we can solve the relay power allocation problem for amplify-andforward (AF) relay networks in a straightforward manner. The problem formulation is such that the achievable rate with perfect global CSI is maximized under both the aggregate and individual relay power constraints for coherent and noncoherent AF relay networks. Numerical results quantify the performance gain using the optimal relay power allocation for both the coherent and noncoherent AF relay networks.