Multi-User MIMO (MU-MIMO)
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Multi-User MIMO (MU-MIMO)
- An 802.11 AP was only able to communicate with one device at a time.
- When an AP made a transmission, it was addressed to a single client device.
- With 802.11ac, it is possible to communicate with up to four devices simultaneously.
- 802.11ac provides a solution by allowing an AP to communicate with up to four clients simultaneously.
- The goal of MU-MIMO is to use as many spatial streams as possible, whether the transmission is with one client using four spatial streams or with four clients using one spatial stream each.
- Due to the advanced signal processing that is required, MU-MIMO is only supported for downstream transmission from an AP to multiple clients.
- With CSMA/ CA technology, slower devices affect the overall performance of the network for all devices. With MU-MIMO, the AP can transmit to up to four devices simultaneously. Instead of four 433 Mbps single-stream devices splitting the transmission, MU-MIMO allows multiple downstream transmissions to occur simultaneously, theoretically providing up to four simultaneous 433 Mbps communications. This can only occur if the devices are spatially separated, since beamforming will not work properly if two devices are near each other.
Reference:
Coleman, David D.,Westcott, David A. CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106 Wiley.
Coleman, David D.,Westcott, David A. CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106 Wiley.
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