Theoretical Diversity Improvement in GSC ( , ) Receiver With Nonidentical Fading Statistics

The study on generalized selection combining (GSC) ( , ) diversity systems that adaptively combines a subset of paths with the highest instantaneous signal-to-noise ratios (SNRs) out of available diversity paths has both theoretical and practical importance in the design of low-complexity receiver structures for cellular wideband code-division multiple access, indoor millimeter-wave, and ultra-wideband communications. This paper presents a novel mathematical framework to tackle the problem at hand by deriving a single integral expression for the moment generating function (MGF) of the GSC ( , ) output SNR when the resolvable multipaths are independent with nonidentical fading statistics. The MGF is then used to unify the performance evaluation of a broad range of digital modulation/detection schemes in practical wireless channels.