MU-OFDMA vs MU-MIMO-Difference between MU-OFDMA and MU-MIMO
This page compares MU-OFDMA vs MU-MIMO and mentions difference between MU-OFDMA and MU-MIMO in WLAN 802.11ax.
Introduction:
MU-MIMO is used to increase overall capacity by transmitting multiple streams simultaneously.
MU-OFDMA does not increase capacity but it uses it more efficiently by allocating subcarriers
to users based on their needs. Both MU-MIMO and MU-OFDMA complement each other.
MU-OFDMA in 802.11ax
Image Courtesy: Aerohive Networks
• OFDMA is multi-user version of OFDM used in 802.11a/g/n/ac.
• It allows multiple client devices (i.e. users) with varying BW to use wifi network
simultaneously.
• OFDMA divides wifi channel into small frequency allocations known as RUs (Resource Units).
• AP communicates with individually assigned clients simultaneously due to their unique allocations of RUs.
• The figure-1 depicts MU-OFDMA in which channel bandwidth is divided into number
of channels. Each of these channels can be used by multiple clients at different time instants unlike
previous wifi standards.
• Refer MU-OFDMA basics >>.
MU-MIMO in 802.11ax
• As shown MU-MIMO uses different spatial streams for communication between multiple client devices.
• It uses beamforming technique to provide unique connection with desired clients.
• Minimum RU size to use MU-MIMO in 802.11ax is 106 subcarriers or higher.
• IEEE 802.11ax technology uses both MU-MIMO and MU-OFDMA together.
OFDMA offers multiuser access by dividing single channel into multiple subcarriers.
MU-MIMO offers multiuser access by using different spatial streams.
Image Courtesy: Aerohive Networks
• MU-MIMO is ideal for very low client density and high BW applications in which large packets are
used for transmission.
• Refer MU-MIMO basics >>.
Difference between MU-OFDMA and MU-MIMO
Following table mentions difference between MU-OFDMA and MU-MIMO.
| Features | MU-OFDMA | MU-MIMO |
|---|---|---|
| Full form | Multi User Orthogonal Frequency Division Multiple Access | Multi User Multiple Input Multiple Output |
| Function | MU-OFDMA offers multi-user access by division of channel. | MU-MIMO offers multi-user access by using different spatial streams. |
| efficiency/capacity | Increased efficiency | Increased capacity |
| Latency/Data rate | Reduced latency | Higher data rates per user |
| Applications | Ideal for low bandwidth applications | Ideal for high bandwidth applications |
| Packet size | Best with small size packets | Best with large size packets |
Also refer difference between MU-MIMO and OFDMA >>.
WLAN 802.11n, 802.11ac and 802.11ax related links
advantages and disadvantages of 802.11ac
advantages and disadvantages of 802.11ax
Difference between 802.11ac Wave1 and Wave2
Difference between 802.11n,11ac,11ad
WLAN 802.11ac tutorial
WLAN 802.11ac frame structure
WLAN 802.11ac Physical Layer
WLAN 802.11ac tutorial
WLAN 802.11ax tutorial
802.11ac MAC Layer
802.11ax basics
WLAN 11a,11b,11n,11ac frame structures
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