Radio channel models for MIMO antenna systems based on ellipsoidal scattering

For multiple-input, multiple-output (MIMO) antenna systems, it is necessary to evaluate performance under realistic propagation channels that include spatial correlation and dispersion. Models developed for this purpose must have enough flexibility to handle different antenna configurations and propagation scenarios. In this paper, the recently proposed 3GPP spatial channel model is extended to three-dimensional scattering using ellipsoidal sub-regions to model time dispersion. We further develop an analytical formulation of the space-time correlation function, allowing traditional methods to generate correlated fading realizations. We show that the 3D model reduces correlation compared to 2D propagation, and evaluate correlation properties for different antenna orientations, showing that averaging over random receive antenna orientations both reduces correlation and its dependence on the base to mobile distance.