Exact MGF-Based Performance Analysis of Dual-Hop AF-Relayed Optical Wireless Communication Systems

In this paper, we analyze the subcarrier intensity modulation-based-relayed optical wireless communication system in the presence of various channel impairments such as turbulence, path loss and pointing errors. The relay follows an amplify and forward relaying protocol and the optical links are modeled assuming independent but not necessarily identically distributed (i.n.i.d) gamma-gamma fading statistics. We derive the novel analytical expressions for the moment generating function and cumulative distribution function of the equivalent end-to-end signal to noise ratio (SNR) at the destination and utilize these results to obtain the exact analytical expressions for outage probability and average symbol error rate for M-ary phase shift keying and M-ary quadrature amplitude modulation constellations, respectively. The results are obtained in terms of special function such as generalized bivariate Meijer's G-function and to get insight further, we present asymptotic analysis at high SNR values to find the effect of various parameters on the system performance.