Impact of Rician fading on the orthogonality of dual-polarized macrocellular channels

The paper examines the impact of Rician fading on the orthogonality of dual-polarized MIMO channels in a measured urban macrocellular scenario. The measurements confirm the previous finding that the Rician k-factors of the cross-polarized channels are strongly correlated to those of the co-polarized channels. However, the Rician k-factors do not in general give direct indications on the orthogonality of dual-polarized channels. Our results show that, in the presence of strong Rician fading, the co- and cross-polarization ratios largely determine the channel orthogonality. In particular, good channel orthogonality is achieved when the co- and cross-polarization ratios are close to 1 and very small, respectively. Nevertheless, more than 70% of the measured route achieves better channel orthogonality than the average performance of the reference IID Rayleigh channel, indicating that efficient multi-stream MIMO communication can be achieved in the measured scenario.