Dual Decomposition Based Power Allocation for Downlink OFDM Non-Coherent Cooperative Transmission System

In this paper, we study the subchannel power allocation problem to maximize the total throughput of the downlink orthogonal frequency division multiplexing (OFDM) multiple access points (APs) systems with non-coherent cooperative transmission. Although the problem has been claimed as a non-convex optimization problem, we prove that the duality gap between the original problem and its dual optimization problem is nearly zero when the number of subchannel is large, which implies solving the problem in the dual domain. Then, the problem is solved with the standard Lagrange dual decomposition method with an acceptable deviation. In addition, in order to reduce the complexity of the dual decomposition based method, we propose a suboptimal low-complexity algorithm, at a minor cost of the total throughput. Numerical results are also given to verify the proposed schemes.