Unified performance analysis of hybrid-selection/equal-gain combining

Hybrid-selection/equal-gain combining (HS/EGC) is a new diversity format in which a subset of branches with the largest signal-to-noise ratios are selected and combined per EGC rule. It provides a performance close to the hybrid-selection/maximum-ratio combining, and yet with a lower implementation complexity, and thus may be regarded as a promising candidate diversity format for multipath channels or multiple-antenna systems. In this paper, to enable HS/EGC diversity for nonconstant modulus modulation formats, we propose the relevant HS/EGC receiver structure and decision variable. By deriving the moment-generating function expression for the HS/EGC output signal amplitude and with the help of Parseval's theorem, we develop a general analytical framework to evaluate the error and outage probabilities of predetection HS/EGC for a large class of modulation formats and versatile system and channel parameters. Simulation results verify the validity and accuracy of our analysis. Some insightful findings on the effect of the system and channel parameters are provided.