Impact of Rician fading and cross-polarization ratio on the orthogonality of dual- polarized wireless 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 crosspolarized channels are strongly correlated to those of the copolarized channels. However, the Rician K-factors do not in general give direct indications on the orthogonality of dualpolarized channels. Our results show that, in the presence of strong Rician fading, the coand cross-polarization ratios largely determine the channel orthogonality. In particular, good channel orthogonality is achieved when the coand 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.