Performance analysis of opportunistic decode-and-forward relaying over Nakagami-m fading channels

In this paper, we investigate the symbol-error-rate (SER) performance of opportunistic decode-and-forward (DF) relaying with selection combining receiver and maximal ratio combining receiver at the destination, respectively, at arbitrary signal-to-noise ratios (SNRs) and number of available relays, over Nakagami-m fading channels. Both the case of adaptive relay and fixed-gain relay are considered. We first derive the expressions of SER for different cases using the statistical characteristic of the SNR. Then, the theoretical analyses are validated by Monte Carlo simulations. Both the theoretical analysis and simulations show that, irrespective on the metric analyzed, maximal ratio combining always yields higher performance than selection combining, and fixed-gain relay always outperforms the one of adaptive relay.