FGM Copula based Analysis of Coverage Region for Wireless Three-User Multiple Access Channel with Correlated Channel Coefficients

Analyzing the constructive or destructive effects of the dependence of wireless communication channel coefficients on the coverage region (one of fundamental wireless performances) is of practical importance. Using Copula functions is one of the methods for modeling the dependence between interdependent random variables (RVs). In this paper, a wireless multiple-access fading channel (MAC) with independent sources and a coherent receiver is evaluated, where, the channel fading coefficients are assumed to be dependent on each other. Then, an exact expression for the coverage region is achieved using the Farlie-Gumbel-Morgenstern (FGM) Copula, and, it is proved that the negative dependence of the channel coefficients on each other has a constructive effect on the coverage region; that is, it expands the coverage region, but the positive dependency has a destructive effect on the coverage region. We present numerical illustrations to demonstrate the efficiency of the analytical results, validating our theoretical findings.