On the performance of selection cooperation with equal gain combining

In this study, the performances of selection cooperation are investigated in a scenario based on decode-and-forward and where equal gain combining (EGC) technique is adopted at the destination. Assuming that the channels suffer from independent non-identical Rayleigh fading, we first derive the cumulative distribution function, probability density function and moment generating function for the total instantaneous signal-to-noise ratio (SNR) at the destination after EGC. Then, these statistical functions are used to derive closed-form expressions for average SNR output, outage probability and average symbol error rate (SER) of selection cooperation. The results hold for arbitrary number of relays and refer to multiple-phase shift keying (M-PSK) modulations. Finally, simulations are carried out to verify the correctness of our theoretical analysis. A random network model is introduced to investigate the effect of relay number and path loss exponent on outage probability and average SER. In addition, based on this random network, the comparison between the performance of selection cooperation with EGC and that of selection cooperation with maximal ratio combining are performed.