Resource allocation in OFDM-based cooperative cognitive radio networks with two-way amplify-and-forward relay

In this paper, we investigate the subcarrier allocation and power adjustment to maximize the sum data rate of the secondary users with limited interference to the primary users in OFDM-based cooperative cognitive networks. A fixed common relay is introduced to forward the data of the secondary users by adopting two-way amplify-and forward (AF) relay. By categorizing the subcarriers into 2 classes, the idle subcarriers and the busy subcarriers, we analyze the resource allocation problem for them and propose a resource allocation scheme which limits the power interferences caused to primary user and maximizes the sum data rate of the secondary users. The simulation results show that the proposed scheme can significantly increase the sum data rate.