Efficient algorithm for optimal power allocation in OFDM transmission with relaying

In this paper we consider an OFDM (orthogonal frequency division multiplexing) transmission scheme with a relay, working in decode-and-forward (DF) mode. Assuming perfect CSI (channel state information) the paper investigates the power allocation problem for rate maximization of the scheme with individual power constraints at the source and at the relay. The theoretical analysis provides a deep understanding of the structure of the solution. Based on this, an efficient iterative algorithm is proposed that exhibits a quicker convergence than classical methods. In addition, it enables to solve the convergence issues observed in some situations.