Dual-Polarized FDD Massive MIMO: A Comprehensive Framework

We propose a comprehensive scheme for realizing massive multiple-input multiple-output (MIMO) system with dual-polarized antennas in frequency division duplexing (FDD) mode. Dual-polarized arrays are commonly employed due to the favorable property that, principle, they can double number of channel spatial degrees freedom less-than-proportional increase array size. However, processing MIMO is demanding high dimension and lack Uplink-Downlink (UL-DL) reciprocity FDD In particular, difficulty arises common training DL precoding multi-user setup. To address this, we develop unified framework consisting three steps: (1) covariance estimation efficiently estimate UL from noisy pilots; (2) UL-DL transformation method that obtains estimated covariance, eliminating need via pilot transmission; (3) joint method, which enables BS effective channels given any protocol-specific use them interference-free beamforming data transmission. Through extensive simulations, show our applicable variety communication scenarios terms antennas, dimensions, angular scattering properties. Unlike trend literature, do xmlns:xlink="http://www.w3.org/1999/xlink">not make strong structural assumptions about wireless (such as sparsity), ensuring general treatment problem.