Validity of the Kronecker Model for MIMO Correlated Channels

The goal of this paper is to investigate the validity of the Kronecker model for MIMO correlated channels. First, mathematical and equivalent propagation conditions of validity are detailed. In a second part, we address several areas where the Kronecker model is not valid. We also review the one-ring model and experimental results dealing with the validation of the Kronecker model. Based on these scarce results, the preliminary conclusion is that the Kronecker model might not be valid for arrays larger than 2times2 when antenna correlations are high across both receive and transmit arrays. The paradox is that the Kronecker model has been developed and is being widely used to account for correlation. This is in strong contrast with the popular belief that the Kronecker model is valid in many indoor and outdoor cases