What is MU-MIMO?

MU-MIMO (multi-user, multiple input, multiple output) is a wireless technology that allows a single access point to simultaneously communicate with multiple devices to improve overall efficiency. MU-MIMO was introduced as the part of the Wi-Fi 5 (802.11ac) Wave 2 standard but support was limited to downlink connections only. Due to this adoption of this technology was very low. With the launch of the Wi-Fi 6 (802.11ax) protocol, MU-MIMO started supporting uplink connections as well which led to a much higher level of adoption. Currently, MU-MIMO works only within the 5 GHz Wi-Fi band.

SU-MIMO vs MU-MIMO

The main difference between SU-MIMO (Single User MIMO) and MU-MIMO is that SU-MIMO allows only a pair of wireless devices to simultaneously send or receive multiple data streams. While MU-MIMO allows multiple wireless devices to simultaneously receive the multiple data streams. So in SU-MIMO an access point communicates with only one device at a time.

In MU-MIMO, the router divides the available bandwidth into separate, individual streams that share the connection equally. MU-MIMO routers are available in 2x2, 3x3 or 4x4 variations, which refer to the number of streams (two, three or four) that are created by the router. Every access point or router has a certain fixed number of streams it supports.

MU-MIMO uses beamforming to direct signals toward the intended wireless device(s) instead of randomly in all directions. And hence is more efficient resulting in better the Wi-Fi ranges, speeds and network throughput.