An MGF-based performance analysis of generalized selection combining over Rayleigh fading channels

Using the notion of the "spacing" between ordered exponential random variab les, a performance analysis of the generalized selection combining (GSC) di versity scheme over Rayleigh fading channels is presented and compared with that of the conventional maximal-ratio combining and selection combining s chemes. Starting with the moment generating function of the GSC output sign al-to-noise ratio (SNR), we derive closed-form expressions for the average combined SNR, outage probability, and average error probability of a wide v ariety of modulation schemes operating over independently, identically dist ributed (i.i.d.) diversity paths. Because of their simple form, these expre ssions readily allow numerical evaluation for cases of practical interest. The results are also extended to the case of non-i.i.d. diversity paths.