Performance Analysis of DF Cooperative Diversity System with OSTBC over spatially correlated Nakagami-m Fading Channels

In this paper, we investigate the performance of cooperative decode-and-forward multiple-input multiple-output relaying system with orthogonal space-time block code transmissions over spatially correlated Nakagami-m fading channels for integer values of m. We consider both the opportunistic-maximal ratio combining and -maximal ratio combining receivers at destination. For the former one, we give the closed-form expression for cumulative distribution function of the instantaneous endto- end signal-to-noise ratio (SNR), relying on which the exact analytical and asymptotic expressions are also derived for outage probability and symbol error rate; while for the latter one, the closed-form expressions are derived for the exact and asymptotic bit error rate (BER) of binary phase shift keying signals, and the optimal value of that minimizes the BER is also provided by using Newton's method. It is shown that opportunistic-maximal ratio combining outperforms -maximal ratio combining, since the former one takes the relay decoding results into account. For -maximal ratio combining, the optimal decreases with the increase of SNR and spatial correlation, since increasing the SNR and spatial correlation could increase the confidence of sourcedestination link and decrease the confidence of source-relay link respectively.