Spatial-temporal-frequency decomposition for 3D MIMO microcellular environments

A three-dimensional (3D) model is proposed for multiple-input multiple-output (MIMO) microcell Rayleigh fading channels with an ample number of scatterers. We assume appropriate probability density functions (pdf) for relevant physical parameters of the complex scattering media. The impact of these parameters are discussed using the expression of the correlation function (CF) between each of the two sub-channels of the MIMO channel. The CF is decomposable into several components that describe spatial, temporal, and frequency characteristics of the MIMO communication system. Such a decomposition allows easier investigation and gives a better understanding of the full potential of MIMO wireless communications. The describing components do not always have closed-form expressions. Therefore, closed-form expressions are obtained for some special cases. In practice, a linear convex combination of the expressions from these cases can approximate almost any model of microcellular environments. The proposed model is a generalization of several existing models including the Jake's/Clark model.