A tight upper bound on the average mutual information in correlated rayleigh fading MIMO channels

We derive a tight upper bound on the average mutual information in Rayleigh distributed channels with spatial Correlation among antenna elements in transmitter and receiver arrays. The derivation of the upper bound is based on calculation of expected values of elementary symmetric functions of complex Gaussian matrix quadratic forms. It can be used for arbitrary SNR, arbitrary number of antenna elements and arbitrary spatial Correlation matrix that can be presented as a Kronecker product of transmitter and receiver correlation matrices. Using the upper bound it is simple to evaluate how the mutual information depends on correlation among elements in transmitter and receiver arrays.