Performance analysis of cooperative diversity with relay selection over non-identically distributed links

A performance analysis for cooperative diversity systems with best relay selection over Rayleigh fading channels is presented. The authors obtain analytical expressions for the probability density function (PDF), cumulative density function (CDF) and the moment generating function (MGF) of end-to-end signal-to-noise ratio (SNR) of the system under study for independent and non-identically distributed (i.ni.d.) fading links. Using these expressions the authors derive lower bound closed-form expressions for the average symbol error rate (SER), the outage probability, and an upper bound closed-form expression for the average channel capacity. Using numerical evaluation of the mathematical expressions, system performances of different cases are evaluated and compared for both non-identically and identically distributed links showing the impact of the relay selection in cooperative communication systems.