From both practical and theoretical viewpoints, performance analysis of communication systems using information-theoretic results is very important. In this study, first, we obtain a general achievable rate for a two-user wireless multiple access channel (MAC) with specially correlated sources as a more general version for continuous alphabet MACs, by extending the known discrete alphabet results to the wireless continuous alphabet version. Next, the impact of wireless channel coefficients correlation on the performance metrics using Copula theory, as the most convenient way for describing the dependence between several variables, is investigated. By applying the Farlie-Gumbel-Morgenstern (FGM) Copula function, we obtain closed-form expressions for the outage probability (OP) under positive/negative dependence conditions. It is shown that the fading correlation improves the OP for a negative dependence structure. Specifically, whenever the dependence structure tends to negative values, the OP decreases and the efficiency of the channel increases. Finally, the efficiency of the analytical results is illustrated numerically.