Asymptotic performance of amplify‐and‐forward cooperative diversity networks with the N th best relay over Rician fading channels

This paper analyzes and derives the asymptotic symbol error rate expression of amplify‐and‐forward cooperative communications with the N th best relay over independent and non‐identical Rician fading channels. Rician fading takes the line‐of‐sight effects into account and often exists in microcellular mobile and wireless mesh networks. In practice, the N th best relay is selected when the best relay is unavailable because of fairness and load balancing issues. Performance analysis reveals that the diversity gain of the N th best‐relay scheme equals R – N +2, while the best relay and all‐participate schemes achieve the diversity gain of R +1, where R is the number of relays. Simulation and numerical evaluation show the tightness of the asymptotic symbol error rate expression and the accuracy of our theoretical analysis. Copyright © 2012 John Wiley & Sons, Ltd.