Performance analysis of Switched Selection Combining with MPSK signaling for cooperative diversity systems

Cooperative diversity has been proved to be a technique which achieves higher data rate and throughput. We consider a single-relay cooperative diversity system employing decode and forward (DF) protocol. In this work, we present a new diversity combining technique which we call it as “Switched Selection Combining”, in which we combine the ideas of switched diversity and selection combining. In this technique, first, destination compares the instantaneous signal to noise ratio (SNR) of source-to-destination link with a threshold, if it is above threshold, the destination selects source-to-destination link else the destination compares the instantaneous SNR of source-to-destination link with relay-to-destination link and chooses whichever is higher. We derive the exact end-to-end symbol error probability of Switched Selection Combining with M-ary phase-shift keying (MPSK) for a flat Rayleigh fading. Results show that the Switched Selection Combining outperforms the conventional selection combining and the direct communication between the source and destination.