Performance Analysis of Multi-branch Dual-hop Non-regenerative Fixed Gain Relay Systems in Nakagami-m Channels

In this paper, we analyze the performance of a multi-branch dual-hop fixed gain relay system with maximal ratio combiner (MRC) at the destination operating over independent Nakagami-m fading channels. We first derive the probability density function (PDF) of the signal to noise ratio (SNR) of the relay branch, from which the exact closed form expressions for the moments of MRC´s output SNR are obtained. The average end-to-end SNR and the outage probability of the considered system is evaluated using moments based approach. Furthermore, assuming the independence among the relay branches, we also derive the closed form moment generating function (MGF) of the end-to-end SNR. The average bit error probability for several modulation schemes is numerically evaluated. Simulation results are pre.sented to verify the analytical results.