Sum Rate Balancing for OFDM-Based Cognitive Two-Way Relaying

In this paper, we study a cognitive two-way relay network in which orthogonal frequency division multiplexing (OFDM) technique is adopted within the secondary system and a pair of secondary source nodes communicate with each other through a relay node by using amplify-and-forward two-way relaying strategy. We propose an optimal power allocation scheme to maximize the smaller data rate of the secondary users while satisfying both individual node power and aggregation interference constraints. We decompose the optimization problem into two subproblems and solve them by using dual decomposition approach. Furthermore, we propose a distributed power allocation algorithm. Finally, numerical simulations and comparisons are presented to illustrate the performance of the proposed scheme.