Fast Beam Training in mmWave Multiuser MIMO Systems with Finite-Bit Phase Shifters

Hybrid analog/digital precoding has been widely utilized in millimeter wave multiple-input multiple-output (MIMO) systems to relieve the severe power consumption of gigasample/s mixed-signal devices. With conventional exhaustive beam searching, however, the beams formed by large antenna arrays can lead to a large time overhead at beam training stage. In this paper, we propose a novel multiuser downlink beam training algorithm to estimate the angle of arrival (AoA) and the angle of departure (AoD) between the base station(BS) and the mobile stations (MSs). The proposed algorithm realizes much reduction of beam training overhead and releases more time resources for users' data transmission.