Error probability for M-ary modulation in correlated Nakagami channels using maximal ratio combining

We derive the symbol error probability for coherent detection of several types of M-ary modulation schemes using maximal ratio combining with an arbitrary number of diversity branches. We consider correlated Nakagami fading channels, where the instantaneous signal-to-noise ratios of the diversity branches are not necessarily independent or identically distributed. The proposed problem is made analytically tractable by transforming the correlated physical diversity branches into independent “virtual branches”