Performance analysis for MRC and postdetection EGC over generalized gamma fading channels

In this paper, we provide a unified analysis of average symbol error probability (SEP) for a diversity system over generalized gamma fading channels, which is a generalization of Rayleigh, Nakagami, and Ricean fading channels. We consider independent generalized gamma fading on the diversity branches and derive different closed-form expressions of the average SEP for a general class of M-ary modulation schemes (including MPSK, MQAM, BFSK, and MSK) with maximal-ratio combining (MRC) and for M-ary orthogonal FSK with postdetection equal-gain combining (EGC). The results apply to the situations where some branches are Nakagami faded and the others are Ricean faded. Furthermore, the results are applied to obtain closed-form expressions of the average SEP for the cases of arbitrarily correlated and not necessarily identically distributed Nakagami and Ricean faded branches with the help of virtual branch technique by Win et al. Our approach provides a canonical structure for the average SEP as a weighted sum of elementary closed-form expressions, which are the closed-form expressions for the average SEP of a diversity system in independent and identically distributed (i.i.d.) Nakagami fading environments.