Sum of Nonidentical Squared $\kappa {-} \mu$ Variates and Applications in the Performance Analysis of Diversity Receivers

In this paper, a generalized Laguerre polynomial expansion for the probability density function and the cumulative distribution function of the sum of independent nonidentically distributed squared κ-μ random variables is proposed. Based on these statistical results, we investigate the performance of maximal-ratio-combining diversity techniques operating over κ-μ fading channels with arbitrary fading parameters. Our newly derived formulas are mathematically tractable and include as special cases several results available in the technical literature, namely, those of Rice and Nakagami-m fading channels. The proposed analysis is substantiated by numerically evaluated results compared with Monte Carlo simulations.