Performance Analysis of Adaptive MQAM in Correlated Rayleigh Fading Channels

Closed-form solutions for the correlated Rayleigh fading channel capacity under L-branch Maximum Ratio Combining (MRC) diversity reception are obtained in this paper. The performance of constant-power adaptive M-ary Quadrature Amplitude Modulation (MQAM) schemes over correlated Rayleigh channels under MRC diversity reception is investigated. Closed-form expressions for spectral efficiency of adaptive MQAM assuming perfect channel estimation and negligible time delay are derived. Numerical results that illustrate the effect of correlation and antenna configurations on the correlated Rayleigh fading capacity and spectral efficiency of adaptive MQAM are also presented.