A geometric polarization rotation model for the 3-D spatial channel model

It is common to use channel models such as the 3GPP spatial channel model (SCM), the WINNER model or ray tracing to evaluate multiple-antenna multiple-user techniques in wireless communications. Cross-polarized antennas can enhance the channel rank and thus the throughput of such systems especially in case of a line-of-sight (LOS) connection. This requires an exact model of the polarization characteristics. To increase the accuracy of the existing channel models, we propose a new method that predicts the polarization state of a microwave link based on findings in the field of optics. We verified the method by cross-polarized multiple-input-multiple-output (MIMO) measurements at 2.6 GHz with 16 transmitters and ten receivers in an urban macrocell environment under strong LOS conditions in downtown Berlin, Germany. Comparisons of simulation and measurement results show that the coefficients of the polarized LOS channel can be predicted very well by the new method. Measured capacities at 10-dB signal-to-noise ratio (SNR) were in between 14.2 and 19.1 b/s/Hz-values that can be predicted by the channel model with more than 90% accuracy. This increase in modeling accuracy is an important feature for many applications such as heterogeneous networks, space-to-ground satellite communications, and cooperative communications.