Sum-Rate Maximization of Multi-User OFDMA Two-way Relay Networks under Sub-Carrier Pairing and Fairness Constraints

In this paper, we invoke sub-carrier pairing based sum-rate maximization problem in wireless cooperative networks. Two-way relaying (TWR) with amplify-and-forward (AF) protocol is considered in multi-user, multi-carrier environment over two-hop with single fixed relay station (FRS), in which direct link between source and destination is not available. We formulate to maximize the overall sumrate and individual sum-rate achieved by users subject to sub-carrier pairing and data rate fairness. The joint optimization of resources turn the problem to be combinatorial having NP-hard solution due to its utmost computational complexity. Firstly, we propose an optimal solution and then a lowcomplexity resource allocation scheme based on “Hungarian Algorithm” is presented. Finally, the simulation results of performance evaluation describe the effectiveness of sub-carrier pairing for sumrate maximization.