Performance analysis of cognitive relay sharing systems with bidirectional primary transmissions under Nakagami-m fading

Abstract

This study investigates the performance of a cognitive relay sharing system (CRSS) wherein two primary users (PUs) exchange the information bidirectionally. The overall transmission in CRSS takes place using an amplify-and-forward-based multiple access broadcast protocol. Herein, besides assisting the transmission of secondary users, the relay also provides an aid for the bidirectional communication between PUs. In addition, the secondary system employs an opportunistic user scheduling with multiple destinations to further ameliorate the performance of secondary network. Here, by considering Nakagami-m fading channels, the authors derive novel closed-form expressions of outage probability (OP) and average error probability for both primary and secondary systems. Based on the derived expressions of OP, the authors also quantify the average system throughput. With bidirectional primary communications, the proposed CRSS offers higher spectral efficiency and incentivises the secondary communication through multiuser diversity. Finally, numerical and simulation results are provided for the validation of the theoretical analysis. © The Institution of Engineering and Technology.