On the Performance Analysis of Cooperative Non-Regenerative Relay Systems over Generalized Fading Channels

In this article, we present three novel moment generating function (MGF) based approaches for performance evaluation of multi-hop, multi-relay cooperative amplify-and-forward (CAF) networks over a myriad of stochastic channel models. Method I is based on a recursive expansion of the MGF of effective SNR for a 2-hop CAF relay network developed in [15]. The second method is also similar to Method I except that it requires the exact MGF of the end-to-end SNR for a 2-hop relay network. Method III involves the split of a multi-hop route path into two sections, evaluating the MGF of the "weakest link" in each section, and then finding the MGF of end-to-end SNR using the result in [15] for a 2-hop CAF network. We show that all the above mentioned methods closely approximate the 'exact' MGF and yield performance comparable to existing bounds. Unlike the existing methods (which are restrictive to specific fading channels), our proposed solutions is quite general and can be applied to a wide range of fading environments while dramatically reducing the computational complexity of average symbol error rate (ASER) for multi-hop multi-branch CAF relay networks. Moreover, our final solutions for the MGF of end-to-end SNR are expressed in closed-form for first two methods, and in terms of a single integral for Method III. The accuracies of our approximations have been validated with "exact" formulas that are available for specific wireless fading environments and via Monte Carlo computer simulations.