On the error rate analysis of dual-hop relaying over composite fading channels using mixture gamma distribution

In this paper, we present the end-to-end performance of a dual-hop amplify-and-forward (AF) relaying system over independent nonidentical (non-i.i.d) composite Nakagami-lognormal (NL) fading channels by using mixture gamma (MG) distribution. Novel closedform expressions for the probability density function (PDF) and the moment-generation function (MGF) of the end-to-end signal-tonoise ratio (SNR) are derived. Moreover, the average error rate and the diversity order are found based on the above new expressions, respectively. These expressions are more simple and accuracy than the previous ones obtained by using generalized-K (KG) distribution. Finally, numerical and simulation results are shown to verify the accuracy of the analytical results. These results show that it is more precise to approximate the composite NL distribution by using the MG distribution than using the KG distribution in the performance analysis of cooperative relaying systems.