Near-Field Beamforming for MU-MIMO Millimeter Wave Communication System

Employing a large number of antennas in conjunction with the exploitation of higher frequencies is a promising solution for improving the rate of future wireless systems. The use of large antenna arrays with high transmission frequencies results in the devices operating in the near-field region of the large-scale antenna arrays. This paper studies near-field beamforming for a multi-user multiple-input multiple-output (MU-MIMO) millimeter wave (mmWave) communication system. We exploit the distance discrimination potentials of the near-field beamforming to facilitate an efficient de-ployment of high-rate multi-user downlink MIMO mmWave systems. To this end, we study the performance of the near-field beamforming using several precoding schemes. Our numerical results demonstrate a significant performance improvement due to the capability of the near-field beamforming to support reliable communications even for devices that are located at the same angular direction which corresponds to the “worst case” situation.