Unified analysis of generalized selection diversity with normalized threshold test per branch

The ability to capture significant amount of transmitted signal energy present in the resolvable multipaths using only a modest number of RAKE fingers (correlators) is an important receiver design consideration for ultra-wideband (UWB) and wideband CDMA communication systems. This, however, is achieved at the expense of RAKE receiver performance. Motivated by this need, several suboptimal hybrid receiver structures have been proposed in the literature. The study on generalized selection diversity combining with normalized threshold test per branch (T - GSC(μ,L)) is also important from a theoretical standpoint because this model encapsulates both the traditional selection diversity and maximal-ratio combining (coherent detection) or post-detection equal-gain combining (noncoherent detection) schemes as limiting cases. However, mathematical analysis for T - GSC(μ,L) has been limited to i.i.d. Rayleigh fading channels. This paper derives simple to evaluate formulas for the moment generating function (mgf) of T - GSC(μ,L) output SNR with L resolvable multipaths. In addition to providing new results for many cases that heretofore has resisted solution in a simple form, our approach also allows some of the previously obtained results to be simplified both analytically and computationally.