MRC and selection combining in dual-hop AF systems with Rician fading

Maximum ratio combining (MRC) and selection combining (SC) are studied for multi-branch dual-hop amplify-and-forward relaying systems. Expressions for the statistical metrics, such as the probability density function, cumulative distribution function and the moment generating function are obtained for systems operating over independent but non-identically distributed Rician fading links. Such systems can be used to model heterogeneous indoor environments where a number of relay nodes are available for line-of-sight cooperative communications. Performance metrics, such as the average error probabilities and outage probabilities, are evaluated for the systems under study to investigate the effects of the link fading parameters as well as the number of available relays on system performance. It is shown that, while the diversity order of such combining systems does not depend on the line-of-sight parameter, it is proportional to the number of available relays, for MRC systems as well as for SC systems.