A three-dimensional wideband propagation model for the study of base station antenna arrays with application to LMCS

Abstract

A model is proposed herein to simulate wideband correlated diversity channel from the point of view of the base station. It is assumed that scattering activity is limited to a local area around the subscriber and possibly additional secondary scattering areas, each being of local extent. Simulation is possible by generating correlated random variates obeying a complex Gaussian law to represent an instance of the impulse response at each antenna element. A mathematical definition of the correlation existing between discrete channel coefficients is provided as a function of separation in space (lag) and separation in frequency. Thus, the channel correlation between antenna elements is characterized by a lag-frequency correlation function in a three-dimensional (cylinder of scatterers) propagation scenario. The mathematical formulation incorporates the effect of arbitrary antenna patterns at the base and at the subscriber station. Simulation proceeds by dividing the band of interest into a number of frequency bins (each smaller than the coherence bandwidth) leading to the construction of a discrete lag-frequency matrix of channel coefficients. Since the model is not concerned with temporal channel variations, it is appropriate for Monte-Carlo simulations for calculations such as outage probability, system capacity, etc.