Analysis of H-S/MRC in correlated Nakagami fading

We present an analysis of a hybrid selection/maximal-ratio combining (H-S/MRC) diversity system over an evenly correlated slow frequency-nonselective Nakagami fading channel. In this system, the L branches with the largest instantaneous signal-to-noise ratio (SNR) out of N available branches are selected and combined using maximal-ratio combining. From the joint characteristic function (c.f.) of the instantaneous branch SNR, we obtain an expression for the c.f. of the combiner output SNR as a series of elementary c.f.´s. The expression can be conveniently used to obtain the symbol error probability of coherent detection of different M-ary modulation schemes.