Massive MIMO (large-scale antenna technology, also known as Large Scale MIMO) is a key technology for improving system capacity and spectrum utilization in 5th generation mobile communication (5G). It was first proposed by researchers at Bell Laboratories in the United States, and studies have shown that when the number of base station antennas in a cell tends to infinity, the negative effects of additive Gaussian white noise and Rayleigh fading can be ignored, and the data transmission rate can be greatly improved.
Understood from two perspectives:
(1) Number of antennas
Traditional TDD networks typically have 2, 4, or 8 antennas, while Massive MIMO refers to the number of channels reaching 64/128/256.
(2) Dimension of signal coverage
Traditional MIMO is referred to as 2D-MIMO, for example, with 8 antennas, the actual signal coverage is limited to horizontal movement only, and vertical movement is fixed, the signal is like a plane emitted outwards, while Massive MIMO, is the vertical dimension of the space introduced in the horizontal dimension of the signal coverage for utilization, the radiation pattern is an electromagnetic beam. Therefore, Massive MIMO is also called 3D-MIMO.