Modeling and Characterization of MIMO Mobile-to-Mobile Communication Channels Using Elliptical Scattering Geometry

In this paper, we develop a two-dimensional (2-D) elliptical geometrical scattering model for multiple-input multiple-output (MIMO) mobile-to-mobile (M2M) communication channels. The elliptical geometry is supposed to be an appropriate approach to model streets and canyons in M2M communication environment. We assume that both mobile stations (MSs) are located at the centers of ellipses and are surrounded by uniformly distributed scatterers present on the elliptical loci. The equal spacing between two consecutive scatterers on the elliptical loci forces the angle-of-arrival (AoA) or angle-of-departure (AoD) distribution at either of the MSs to be non-isotropic. We provide an empirical model for such a non-isotropic AoA and compare its results with the numerical curves of the elliptical geometry which results in excellent agreement. Utilizing the non-isotropic AoA and the proposed geometrical model, we derive closed-form expressions for the marginal and joint correlation function of the channel coefficients. We provide various plots to analyze the correlation among the diffused components of M2M MIMO communication link. Furthermore, a comparison of the correlation curves obtained from the mathematical expression of the proposed model is carried out with the existing results in the literature. In order to validate the proposed model, the elliptical geometrical shape is transformed into circular one. The resulting comparative analysis verifies that the circular geometrical models are the special cases of our proposed model.