The Geometry-Based Statistical Modeling of MIMO Mobile-to-Mobile Channels Revisited

In this paper, we discuss a problem in the formulation of geometry-based statistical models for multiple-input multi-ple-output (MIMO) mobile-to-mobile (M2M) fading channels that have been proposed under the plane wave propagation (PWP) assumption. The problem is caused by an oversimplification of the PWP model in the characterization of the channel complex envelope (CCE). This modeling imprecision has led to impose an unnecessary restriction on the size of the antenna arrays to warrant the mathematical tractability of the geometrical PWP channel models. The results presented in previous papers for relevant channel statistics, such as the space-time cross-correlation function (ST-CCF), are not invalidated if the problem is corrected. On the contrary, a thorough description of the physical process of PWP reduces the number of approximations required to obtain such results, extending in consequence their validity to a wider range of propagation scenarios.