Outage Performance of Cognitive Relay Networks with Best Relay Selection in Nakagami-m Channels

This paper investigates the outage performance of a cognitive relay network considering best relay selection in Nakagami-m fading environment. The secondary user is allowed to use the spectrum when it meets the interference constraints predefined by primary user. Due to deep fading, cognitive source is unable to communicate directly with cognitive destination. As such, multiple relays are ready to deliver the signal from the cognitive source to cognitive destination. We select a single best relay and the selected relay uses decode-and-forward protocol. Specifically, we derive the exact outage probability expression, which provides an efficient means to evaluate the effects of several parameters. Finally, numerical simulation results are presented, which validate the correctness of the analytical analysis.