Cooperative Selection Diversity in Wireless Multiuser Relay Networks

This paper advocates the performance of wireless multiuser relay networks (MRNs) equipped with a single amplify-and-forward (AaF) relay. For such networks, we focus on opportunistic scheduling, in which the destination with the highest instantaneous end-to-end signal-to-noise ratio (SNR) is scheduled for transmission. The scheduled destination can receive either directly from the source or indirectly through the relay, based on cooperative selection diversity (CSD). Assuming Rayleigh fading channels, we first derive a new expression for the cumulative distribution function (CDF) of the received instantaneous end-to-end SNR. Then, relying on this statistical result, we present new exact expressions for the outage probability and symbol error rate (SER), both of which are obtained in closed-form. Furthermore, we derive simple yet valuable closed-form asymptotic expressions for the outage probability and SER in the high SNR regime. Our results explicitly reveal the impacts of CSD and opportunistic scheduling on the diversity order and array gain. Numerical results are presented to validate the analysis.