Performance of Cooperative Diversity Systems in Non-Gaussian Environments

Cooperative diversity (CD) systems have received significant attention recently as a distributed means of exploiting the inherent spatial diversity of wireless networks. In this paper, we consider a CD system where a source transmits to a destination via multiple single--hop amplify and forward (AF) relays. In particular, we provide a mathematical framework for the asymptotic analysis of this system in general non--Gaussian noise and interference for high signal--to--noise ratios (SNRs). Assuming independent Rayleigh fading for all links in the network, we obtain simple and elegant closed--form expressions for the asymptotic symbol error rate (SER) and bit error rate (BER) valid for arbitrary linear modulation formats, arbitrary numbers of relays, and arbitrary non--Gaussian noise and interference with finite moments. Furthermore, exploiting the derived analytical results, we introduce a new relay selection criterion for non--Gaussian environments. Simulation results confirm our analysis and illustrate that, in non--Gaussian noise, the proposed relay selection criterion can lead to large performance gains compared to the conventional relay selection criterion which was optimized for Gaussian noise.