Dual-Polarized Massive MIMO Systems Under Multi-Cell Pilot Contamination

This paper considers a multi-cell network with base stations (BSs) equipped with large dual-polarized antenna arrays. We derive closed-form expressions of network performance in terms of user signal-to-interference-and-noise ratio both with perfect channel state information and in the presence of pilot contamination. In general, a dual-polarized system enjoys the reduction in pilot contamination and multiuser interference due to orthogonal polarizations, while the available BS array dimension is reduced in each polarized direction compared with a monopole antenna setup. The derived results, however, reveal that the performance of a dual polarization system can be optimized by properly setting receive antenna polarizations, and fortunately, the optimal performance behaves identically to that of a monopole-antenna one in massive MIMO. We finally verify the observations by numerical simulations.