What is MU-MIMO?
Definition
MU-MIMO, multi-user multiple input multiple output, lets a single access point send data to several devices at the same time rather than one after another. It uses multiple antennas to create separate spatial streams. It has been standard since WiFi 5 and matters most in high-density venues.
MU-MIMO explained
Without MU-MIMO, an access point serves clients in turn, and every device waits for its slot of airtime. With it, the AP shapes independent spatial streams towards different devices, so several receive data in the same moment. The gain is capacity rather than peak speed for any one device.
The feature has grown with each generation. 802.11ac (WiFi 5) introduced MU-MIMO for downlink traffic only. WiFi 6 (802.11ax) added uplink MU-MIMO and supports up to eight simultaneous spatial streams. Uplink matters in places like stadiums, where fans upload video and photos at the same time and would otherwise queue for airtime.
MU-MIMO works alongside OFDMA, the other WiFi 6 capacity feature, which divides a channel into smaller resource units so many low-traffic devices share one transmission. Both need support on the access point and on the client device, so the benefit grows as a venue’s visitors upgrade their phones and laptops, not only when the venue upgrades its APs.
Guides on MU-MIMO
- Technical guideOFDMA explained: how WiFi 6 handles dense environments
- Technical guide802.11ac (WiFi 5): a technical deep dive
- Technical guideWiFi 6 vs WiFi 5: does it solve channel interference?
Where it fits
- Pillar guideGuest WiFi guide
- Purple productSupported network hardware
- Free toolAccess point calculator
Related terms
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