Joint Subcarrier Pairing, Relay Selection and Power Allocation in OFDM Relay Systems

In this paper, joint optimization of subcarrier pairing, relay selection and power allocation is formulated through a capacity maximization problem in orthogonal frequency division multiplexing (OFDM) relay systems, with fairness considerations and individual power constraint on each node. Because achieving the optimal solution is computationally demanding, which is resulted from the excessive possibilities of joint resource allocation, we propose a sub-optimal allocation method. The proposed scheme decouples the allocation procedures into two steps, which reduces the complexity significantly by avoiding the search for all possible subcarrier pairs. Moreover, simulation results reveal the effectiveness of the proposed algorithm in both Amplify-and-Forward (AF) and Decode-and-Forward (DF) relay systems.