Contour Integral Representation for Generalized Marcum-Q Function and Its Application to Unified Analysis of Dual-Branch Selection Diversity over Correlated Nakagami-m Fading Channels

Using a circular contour integral representation for the generalized Marcum-Q function, Qm(a, b ) , we derive a new closed-form formula for the moment generating function (MGF) of the output signal power of a dual-diversity selection combiner (SC) in bivariate Nakagami-m fading with positive integer fading severity index. This result involve% only elementary functions and holds for any value of the ratio a / b in Qm(a, b ) . As an aside, we show that previous trigonometric integral representations for Qm(a, b) can be obtained directly from this contour integral. The MGF is used to unify the evaluation of average error performance and outage performance of a dual-branch SC for coherent, differentially coherent and noncoherent communications systems.