Performance Analysis of Generalized Selection Combining for Decode-and-Forward Cooperative-Diversity Networks

We consider adaptive decode-and-forward (DF) cooperative-diversity system where a source node communicates with a destination node directly and indirectly (through multiple relays). In this paper, we analyze the system where N multiple relays that have the strongest signal strength at the destination are selected out of M relays and forward their received data from the source node to the destination node. We derive closed-form expressions for the average symbol error probability, the outage probability and the average channel capacity. In particular, closed-form expression for the moment generating function of the SNR at the destination node is determined. Then, we find a closed-form expression for the probability density function (PDF) of the total SNR at the destination. This PDF is used to derive the closed-form expressions of the performance metrics. Simulation results are also given to verify the analytical results.

I. Introduction

Cooperative-diversity networks technology is a promising solution for the high data-rate coverage required in future wireless communications systems [1]. In regular cooperative-diversity networks, in addition to the direct link all relays participates in sending the source signal to the destination. Then, the destination combines all received signals from the indirect links and the direct link using Maximum Ratio Combining (MRC) technique.