Analysis of Millimeter-Wave Polarization Diverse MIMO Capacity

Abstract

Millimeter-waves offer the possibility of wide bandwidth and consequently high data rate for wireless communications. For both uni- and dual-polarized systems, signals sent over a link may suffer severe degradation due to antenna misalignment. Link robustness may be enhanced by the use of mutual orthogonality in three dimensions. In the general case of a Rician fading channel the inclusion of a third orthogonal dipole may provide a useful additional degree of freedom and allow high capacity communication in any unit vector direction. Multiple-input multiple-output polarization diversity offers a way of improving signal reception without the limitations associated with spatial diversity. It additionally allows for polarization-time block coding at the transmitter and maximal ratio combining at the receiver. We develop a novel Rician fading channel model for a millimeter-wave tri-orthogonal half-wave dipole transmitter and receiver employing polarization diversity. Our simulation extends analysis into a three-dimensional field of view representation fully exploiting individual channel paths. Capacity is observed to be more robust than that of a dual-polarized system over the majority of a field of view.