Finite-Alphabet Beamforming for Multi-Antenna Wideband Systems

Finite-alphabet beamforming for multi-antenna wideband systems is provided. The combination of massive multi-user multiple-input multiple-output (MU-MIMO) technology and millimeter-wave (mmWave) communication enables unprecedentedly high data rates for radio frequency (RF) communications. In such systems, beamforming must be performed at extremely high rates over hundreds of antennas. For example, spatial equalization applies beamforming in the uplink to mitigate interference among user equipment (UEs) at a base station (BS). Finite-alphabet equalization provides a new paradigm that restricts the entries of a spatial equalization matrix to low-resolution numbers, enabling high-throughput, low-power, and low-cost equalization hardware. Similarly, precoding applies beamforming in the downlink to maximize the reception of a signal transmitted from a BS to a large UE. Finite-alphabet precoding can be applied in the downlink to similarly improve power and cost in precoding hardware