Power and complex envelope correlation for modeling measured indoor MIMO channels: a beamforming evaluation

The multivariate complex normal distribution is often employed as a tractable and convenient model for MIMO wireless systems. Several models may result, depending on how the covariance matrix is specified, i.e. power or complex envelope correlation and full or separable (Kronecker) correlation. This paper investigates the differences of the various models by applying a joint transmit/receive beamformer to recent wideband MIMO radio channel measurements at 5.2 GHz. It is found that the Kronecker model, especially for power correlation, significantly alters the joint beamformer spectrum. A multipath clustering model is applied whose parameters are estimated directly from the measured data. The clustering model is able to match capacity pdfs, and resulting simulated joint beamformer spectra look more realistic than those generated with conventional separable correlation functions.