Envelope Correlation Coefficient for Logarithmic Diversity Receivers Revisited

The analysis of the envelope correlation coefficient for logarithmic diversity receivers, given by de Neumann (de Neumann, 1989) for one Rayleigh fading branch in isotropic scattering environments (two independent real Gaussian branches), is extended in this letter to the general case where a maximum ratio combiner (MRC) operates on M ges 1 independent Rayleigh fading branches, with the same temporal correlation coefficient, in nonisotropic scattering environments. The derived exact closed-form expressions include the results by B. de Neumann in 1989 as special cases. In addition, when M is not so small, theoretical analysis and Monte Carlo simulations show that the envelope correlation coefficient can be accurately approximated by the squared amplitude of the channel correlation coefficient.