A Study on the Basics Processes of Massive MIMO

Massive Multiple Input Multiple Output (MIMO) is a key technique used in 5G mobile communication systems; it aims to efficiently increase the spectral efficiency of the communication systems. Massive MIMO is a MIMO system with a massive number of antennas in the base station, it uses its large number of antennas to efficiently transmit and receive the signals between the base stations and the user equipment and maximize the spectral efficiency of the system. Massive MIMO is mainly composed of three important processes: channel estimation, uplink transmission (receive beamforming), and downlink transmission (transmit beamforming). Based on the effective channel estimation methods, the base station can process the signal to make efficient transmit and receive beamforming and provide good transmission and reception quality, which is measured by the spectral efficiency of the system. Many references present the basics of massive MIMO processes, including channel estimation, transmit beamforming and receive beamforming. This paper aims to present a cleared and concluded study on these basics massive MIMO processes. It presents different channel estimation methods and evaluates its performance based on the normalized mean square error. It also presents different receive and transmit beamforming techniques and evaluates its performance based on spectral efficiency.