Modeling of the correlation coefficients of a receive antenna array in a MIMO multipath channel

In this paper we propose a ray-tracing method for modeling the correlation of the received signals by two or more antennas operating in a multipath environment. Assuming that the maximum excess delay in the channel is known, we create an elliptical region surrounding both the transmitter and receiver antennas. A number of scatterers are randomly distributed in this region. They scatter the incoming waves spherically. Considering a Rayleigh amplitude and uniform phase for the waves scattered by each scatterer and computing their superposition in each receive antenna, we have determined the amplitude and phase of the received signals and used this signals to obtain joint pdf (probability distribution function) of the received signals. This model has the advantage of being applicable for any configuration of antennas. Furthermore, the joint pdf of the received wave amplitudes, independent of the shape of the receiver array, can be calculated and used to produce correlation coefficient and also higher-order statistics.