Macro-Cellular MIMO with Dual Polarized base Station Antennas and Different Spacing

We present a theoretical analysis of the joint effect of azimuth spread, base station antenna spacing, and environment cross-polar discrimination on the capacity of a 4 x 4 MIMO system using dual polarized antennas. The results indicate that a spatial separation of 3 wavelengths is sufficient for near-optimal MIMO operation. We also present analysis of channel measurements from urban Stockholm which shows that two dual polarized base station antennas with a spacing of only 1.12 wavelengths at 1747 MHz increases the capacity by 50% compared to a single dual polarized antenna.