Performance of Fixed Gain Relaying Systems over MIMO Fading Rayleigh Channels

This paper aims to analyze and evaluate the performance of fixed gain amplify-and-forward (AF) cooperative diversity multiple-input multiple-output (MIMO) relay systems over flat fading Rayleigh channels. Diversity is achieved through using orthogonal space-time block coding technique (OSTBC) at the transmitter. OSTBC is used to encode a BPSK modulated signal before being transmitted through the channel. At the destination, signals are combined using a Maximal Ratio Combiner (MRC) and detected using a Maximum-Likelihood (ML) detector. The system is evaluated in terms of capacity and BER using different power allocation techniques. The performance of studied system has been compared with single-input single-output (SISO) system, AF SISO, and conventional MIMO systems. MATLAB simulation results have shown that using AF cooperative diversity technique with MIMO systems enhances the MIMO BER performance. Further, the results have been shown that using optimal power allocation in AF MIMO relaying systems enhances the BER and capacity.