Cooperative Relay with Power Control in Cognitive Radio Networks

In cognitive radio networks (CRNs), secondary users (SUs) can share the spectrum with the primary users (PUs) as long as the quality of service (QoS) of the primary system is guaranteed. The heterogeneity of spectrum availability among SUs has brought significant challenge for efficient spectrum allocation in CRNs. Cooperative relay scheme exploits relay nodes to improve link throughput, by allowing spectrum-abundant nodes to help the spectrum-short ones. In this paper, we investigate the problem of cooperative relay scheme in CRNs together with adaptive relay selection and power control (PC). To maximize the throughput of the cognitive system, one best relay will be selected and besides, optimal power allocation is performed, so that the throughput of the cognitive system under the QoS requirement of the primary system is maximized. Simulation results show the effectiveness of the proposed scheme.