Full CSI selection combining for multi-relay cooperative diversity systems

In this paper, a cooperative diversity system having a source, multiple relays, and a destination is considered. Conventional selection combining schemes failed to include the effect of source-to-relay channels in the error analysis of cooperative diversity systems; hence its performance is not optimum. In this paper, we have proposed a full channel state information (CSI) selection combining which effectively utilizes the CSI of all channels in the error analysis; thereby giving optimum performance. The end-to-end symbol error probability (SEP) of a full CSI selection combining scheme for such a system, with decode and forward relaying and binary phase-shift keying in a flat Rayleigh fading environment, is derived in closed form. This scheme has been compared with conventional selection combining scheme. Results show that proposed scheme offers a substantial signal-to-noise ratio gain over conventional selection combining.