Moment Generating Functions of Generalized Wireless Fading Channels and Applications in Wireless Communication Theory

In this paper, new exact and approximate moment generating functions (MGF) expression for generalized fading models are derived. Specifically, we consider the η-λ-μ, α-μ, α-η-μ, α-κ-μ, α-κ-μ, and α-λ-η-μ generalized fading distributions to derive approximate MGF expressions. The new expressions are very accurate and, in contrast to earlier results in the literature, avoid any complicated special functions, e.g. the Meijer-G and Fox H-functions. As such, the new MGF expressions allow easier and more efficient analytical manipulations, which also apply for their special cases such as the Rayleigh, Rice, and Nakagami-m fading. As an illustrative application, the average bit error rates for each of the fading models are evaluated using the new derived MGF expressions. The accuracy of the analytical results by using the numerically computed results as a basis of comparison as well as published results from the literature.

I. Introduction

Wireless systems are inevitably subjected to different signal propagation impairments, such as the additive Gaussian noise, multipath fading, and shadowing, that predominantly degrade the wireless system performance that is mainly characterized by the bit error rates and ergodic channel capacity [1] [2].