Performance analysis of switched-selection combining for cooperative diversity systems

We consider a cooperative diversity system that consisting of a source, a relay and a destination. The source transmits its data to the destination as well as through relay with the help of decode and forward technique. We propose a new diversity combining technique which we call it as a “switched-selection combining”, in which, we choose the signal from source-to-destination link if instantaneous signal to noise-ratio (SNR) of source-to-destination is above certain threshold, and suppose, if instantaneous SNR of source-to-destination link is below the threshold then we apply selection combining for source-to-destination and relay-to-destination links. In this paper, we derive, in closed form, the end-to-end symbol error probability of this technique with binary phase-shift keying 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.