On the Optimal Power Control of Parallel OFDM Relaying Networks

We investigate the power allocation problem for dual-hop parallel OFDM relaying networks where an aggregate power constraint is imposed on all of the amplify-and-forward relays. Based on Y. Zhao et al´s recent work, we first formulate the problem to how to optimally allocate the total power among all subcarriers such that the system instantaneous information rate is maximized, then we decompose it into a group of subproblems which can be solved with Lagrange multiplier method. Considering the prohibitive complexity to calculate the optimal solution, we further propose a low-complexity iterative algorithm to construct a suboptimal solution which converges very quickly. The simulation results show the performance gap between suboptimal and the optimal solutions is negligible.