Dual-hop AF relaying systems in mixed nakagami-m and Rician links

New, exact closed-form expressions for the probability density function (PDF) and the cumulative distribution function (CDF) are derived for the instantaneous received end-to-end signal-to-noise ratio (SNR) of dual-hop amplify-and-forward (AF) relaying systems operating over mixed Nakagami-m and Rician fading links. The expressions are used to obtain exact integral solutions for the ergodic capacity and the average symbol error probability as well as an exact closed-form solution for the outage probability of dual-hop AF systems operating over mixed links. The results obtained represent the first exact results for the cases of composite Nakagami-m/Rician fading links. The exact performance metrics are compared to performance bounds in the literature, and it is shown that the performance bounds are not tight for medium ranges of SNR. The effects of fading parameters on the system performance are studied. It is shown that the limiting slopes of the average error probability and outage probability curves are not affected by the fading parameters, however, SNR gains are achieved by increasing the fading parameter. Moreover, it is shown also that an increase in the Rician parameter, K, results in a notable SNR gain in the system performance, while an increase in the Nakagami-m parameter, m, has diminishing returns and gives negligible improvement in the system performance in some instances.