Study of statistical channel knowledge-based cooperative relay selection

Statistical channel knowledge-based cooperative relay selection in amplify-and-forward cooperative relay networks was studied.Firstly,it was proved that pre-selecting a single relay is better than selecting all relays in terms of the outage probability when the signal-to-noise ratio(SNR) is below a threshold.Based on this,a cooperative relay selection scheme was proposed and proved to be optimal.Secondly,an optimal cooperative relay selection scheme combined with a power allocation scheme was given.Finally,a sub-optimal scheme was proposed to reduce the complexity.Simulation results show that the performance of the sub-optimal scheme is nearly the same as that of the optimal scheme.