Massive MIMO, also known as Large- Scale Antenna System or Very Large MIMO, is a multi- antenna system that has antenna arrays of 128 to 1,024 active antenna elements at each base station. In contrast, classic MIMO uses antenna arrays of 2, 3, 4, or 8 antennas at the transmit and receive ends.
Massive MIMO is of particular interest for 5th GenerationNew Radio(5GNR) mobile communications technology and for high-bit-rate WLANs because it bundles transmit power, thereby increasing energy efficiency and data throughput. This is due to the fact that Massive MIMO uses spatial multiplexing and uses multi-user beamforming( MUBF) to target transmit power to individual mobile devices. Multi-user beamforming increases range and reduces interference between radio cells. In addition, separate transmission links to multiple mobile devices can be established simultaneously in the same frequency range. In addition, there is less scattering of the transmission power, which helps to increase efficiency.
Thanks to the large number of antennas, even smaller room segments are covered by the radio technology. Massive MIMO was developed for Time Division Duplex( TDD), but can also be used in Frequency Division Duplex( FDD).