MU-MIMO: Advantages and Disadvantages

This page covers the advantages and disadvantages of MU-MIMO, along with its fundamental concepts. It highlights the benefits and drawbacks of MU-MIMO technology.

What is MU-MIMO?

Introduction:

MU-MIMO (Multi-User Multiple-Input Multiple-Output) was introduced in the WLAN 802.11ac WiFi standard. It leverages different spatial streams for different users to utilize MIMO technology for multiple users simultaneously. It’s also implemented in the latest WiFi 6 standard (IEEE 802.11ax).

With MU-MIMO, smart TVs, consoles, PCs, smartphones, and tablets can all experience faster internet speeds, potentially three times faster, compared to sequential access.

Image Courtesy: Aerohive Networks

In WiFi 6, MU-MIMO is combined with MU-OFDMA to enhance spectral efficiency and support a greater number of users.

The figure above illustrates the MU-MIMO concept. MU-MIMO uses beamforming to establish efficient connections with desired WiFi clients. IEEE 802.11ac utilizes 2x2 MU-MIMO configurations, while 802.11ax employs 8x8 MU-MIMO configurations.

Benefits or Advantages of MU-MIMO

The following are the key benefits and advantages of MU-MIMO:

• Increased Capacity: MU-MIMO increases the overall capacity of a WiFi router by utilizing multiple streams simultaneously.
• Simultaneous MIMO for Multiple Users: More than one user can leverage MIMO concurrently. This means WiFi is available to multiple devices at once and at the same speed.
• Coverage Improvement: It offers immediate coverage improvements for existing 802.11ac and other legacy WiFi client devices.
• Higher Data Rates: MU-MIMO helps in achieving higher data rates per user.
• Optimized for Large Packets: It’s best suited for large-size WiFi packets.
• Ideal for Low Client Devices and High Bandwidth Applications: Works well with numerous client devices and applications demanding higher bandwidth.
• Improved Latency and Power Consumption: Improves latency and reduces power consumption for clients in increasingly crowded home networks.

Drawbacks or Disadvantages of MU-MIMO

The following are the drawbacks and disadvantages of MU-MIMO:

• Precise Beamforming Required: It requires highly precise beamforming.
• Interference Management: There is interference between terminals that must be handled by complex algorithms at the receiver to recover data bits.
• Prior Resource Allocation: It necessitates prior resource allocation to the terminals.
• Hardware Complexity: The MU-MIMO system is more complex in terms of hardware compared to SU-MIMO due to the use of multiple antennas.
• Higher Cost: It’s more expensive due to the use of advanced DSP (Digital Signal Processing) in the MU-MIMO system.