Multi-user MIMO

Wireless communications technology using MIMO for multiple users Multi-user MIMO (MU-MIMO) is a family of multiple-input and multiple-output (MIMO) techniques in which a wireless communication system communicates with multiple users at the same time by using the spatial dimension of the radio channel. In a typical MU-MIMO system, a base station, access point, or other multi-antenna device transmits to, or receives from, several user devices over the same time-frequency resources. MU-MIMO extends single-user MIMO (SU-MIMO), where one multi-antenna transmitter communicates with one multi-antenna receiver. It is closely related to space-division multiple access (SDMA), because users are separated by their spatial channel characteristics rather than only by time, frequency, or code resources. MU-MIMO is used in cellular networks and wireless LAN systems, and is related to techniques such as massive MIMO, coordinated multipoint transmission and reception (CoMP), and cooperative MIMO. Overview In SU-MIMO, the antennas used for spatial multiplexing usually belong to one transmitter and one receiver. In MU-MIMO, the spatial streams may be assigned to different users. This can increase syst