The impact of polarized MIMO channels in vehicular based communications

Abstract

Measurements of orthogonally polarized MIMO channels were conducted in downtown Ottawa with dual-polarized receive array elements positioned along the sides of a measurement vehicle. The measured channel data are used to analyze characteristics of the polarized channel including the angular distribution of received power, diversity, correlation and cross-polarization discrimination. It is shown that if spatially separated antennas are replaced with dual-polarized elements the cross-polarization discrimination results in a performance loss that is partially compensated for by improved cross-polar correlation characteristics. Further, it is observed that the locations of the array elements at the mobile has a significant impact on the channel characteristics measured. In areas where the received signal energy is highly directional, the orientation of the vehicle with respect to the location of the transmitter often results in channels with characteristics which are significantly different from one side of the mobile to the other. This is further influenced by the presence (or lack thereof) of buildings, which can act as reflective signal sources for elements of the array shadowed by the vehicle.