Abstract:Cooperative diversity with multi-relay provides dramatic gains in slow fading wireless environments. In terms of average Symbol-Error Rate(SER) at the destination, the performances of multi-relay cooperative transmission with Maximal Ratio Combining(MRC) detection and opportunistic relaying with multi-node listening were analyzed, one relay retransmitting in Amplify-and-Forward(AF) networks under independent Rayleigh slow fading channels. The closed-form expressions of SER for M-PSK and M-QAM modulations are also derived based on Moment Generating Function(MGF). Monte Carlo simulation results show that all the SER formulas proposed are tight bounds particularly at medium and high SNR. Moreover, it can be seen that the opportunistic relaying, whose diversity gains are proportional to the number of cooperative listening nodes, and performs better in SER than multi-relay cooperation using MRC detection algorithm.