Optimal Full-Duplex Cooperative Spectrum Sensing in Asynchronous Cognitive Networks

Spectrum sensing and sharing are challenging task in asynchronous cognitive networks (CNs), where there is no synchronization between primary and secondary users (PUs and SUs). In this paper, we propose combination of cooperative spectrum sensing and full-duplex communication for improving quality and throughput of both primary and secondary users in asynchronous CNs. More specifically, we have studied two types of full-duplex schemes, namely full-duplex receive-sense (FDr) and full-duplex sense (FDs). FDr allows SUs to transmit and receive data simultaneously whereas in FDs the SUs continuously sense the channel during transmission time. The average throughput is derived for secondary and primary users under both schemes and for different levels of residual self-interference (SI). We demonstrate the respective trade-offs and obtain the optimal scheme based on cooperative full-duplex spectrum sensing.