A joint resource allocation algorithm for cooperative communications

The OFDM based cooperative communication system attracts wide attention due to its ability of improving the overall system performance. We study the joint allocation mechanism of wireless resources in cooperative two-hop multi-relay OFDM systems, with the combination of relay nodes, power and subcarriers. We firstly formulate the power allocation problem for a given subcarrier pairing assignment. Using Lagrange multiplier method, we solve the optimal power allocation problem, and present a practical power allocation algorithm (OPA). Then, an iterative resource allocation algorithm is developed based on the Hungarian Algorithm and the proposed OPA. The goal aims at maximizing the system transmission rate subject to total subcarrier power constraint at relay nodes, which adopt the amplify-and-forward (AF) scheme. Simulation experiments indicate that the algorithm is the optimal solution to this problem compared with the fixed resource allocation algorithms.