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One of the features you will often see advertised when comparing routers is MU-MIMO technology, but what is it exactly and how does it benefit your home network?
MU-MIMO Wi-Fi is a wireless technology used to better support networks where multiple users and their devices are trying to access a wireless network at the same time. It allows a router to break up the available bandwidth into individual streams that share a portion of the bandwidth evenly.
What is MIMO and SU-MIMO Wi-Fi?
MIMO stands for “Multiple-Input, Multiple-Output” and refers to the way in which bandwidth is broken up into smaller chunks and then pushed out to individual devices by a router.
SU-MIMO, which stands for “Single User, Multiple-Input, Multiple-Output”, is the technology many modern routers will use.
Using these routers means that only one device is able to receive data at any given time. If you were to have two members of the household try and stream online video at exactly the same time, the SU-MIMO router would give one of the devices priority over the other.
The lesser priority device would need to wait until the priority devices had started receiving some data before it could begin.
To better understand how SU-MIMO works, think of a school cafeteria.
There is a single lunch lady that is only able to serve one student at the time. The students stand in a queue and wait their turn to be served their lunch. The second in line student will need to wait until the student at the front has been served as they are considered the lunch lady’s priority.
This delay is often not even noticeable though. Despite only being able to transmit data to one device at a time, SU-MIMO routers act very quickly. To you and I, it would appear as if the device receives a constant stream of data.
Even though SU-SIMO routers are quick, it was found that congestion can still occur when multiple devices are queued up waiting for some bandwidth from the router.
This is where MU-MIMO comes in.
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What is MU-MIMO Wi-Fi?
MU-MIMO (Multiple User, Multiple-Input, Multiple-Output) is a more advanced MIMO technology in which the router is able to break up the available bandwidth into individual streams that share a portion of the bandwidth evenly, regardless of the device it is sending data to.
MU-MIMO enabled routers come in three different types: 2×2, 3×3 and 4×4.
These numbers refer to the number of streams they can create for each device on your home network.
Going back to our school cafeteria analogy, instead of just a single lunch lady who can only serve one student at a time, there are now two, three, or even four lunch ladies who are simultaneously able to serve the students their lunch.
This reduces the time in which students have to wait to be served, and therefore how long multiple devices have to wait to receive data from the router.
The main benefit of using MU-MIMO Wi-Fi is that the router can maintain a constant signal to multiple devices. The bandwidth is evenly distributed to each device to not compromise the speed in which each device receives data at any time.
MU-MIMO sounds great, but there are a few rules regarding the use of it that are worth keeping in mind.
Firstly, the streams are spatial. This means that if two devices are within close proximity to each other, they will have to share the same stream and therefore, the stream’s share of the bandwidth.
Secondly, MU-MIMO only works for downlink connections.
This is great for those who want the fastest possible speeds for their online gaming sessions, or are streaming high-quality video from the Internet, but less useful should you be uploading a video to YouTube, for example.
How Does MU-MIMO Wi-Fi Work?
To understand how MU-MIMO Wi-Fi works, let’s first talk briefly about transmit beamforming (TxBF).
Unlike regular MIMO which sends a different stream of bandwidth on each antenna, transmit beamforming sends the same stream but across multiple antennas. The timing is deliberately offset to increase its range.
MU-MIMO takes this one step further by adding even more antennas into the mix.
A router can control the phased antenna pattern and decide where the signal is at its strongest and at its weakest.
The additional antennas and knowledge of the relative position of all of your devices allow the router to create a phased pattern to communicate with multiple devices at the same time, both simultaneously and independently.
Unlike MIMO and SU-MIMO, a router is able to transmit a Wi-Fi signal to multiple devices at the same time thanks to MU-MIMO technology.
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Are There Any Drawbacks to MU-MIMO Wi-Fi?
No device or technology is perfect, so you won’t be surprised to hear me tell you that MU-MIMO WI-Fi doesn’t come without its drawbacks.
The one big drawback is that to get the most out of MU-MIMO, both the router and the device itself must be fully MU-MIMO compatible in order to communicate with each other.
MU-MIMO routers are currently only able to broadcast over the more modern 802.11ac wireless standard; a signal which many devices are unable to decode and work with yet, unfortunately.
Also, MU-MIMO does work best with stationary Wi-Fi devices, so if you walk around your home streaming an online video on your smartphone, you won’t be getting the full benefit of MU-MIMO even if your smartphone does support it.
As a result, your router may even limit your smartphone’s connection to it by using SU-MIMO instead. This is so the moving connection doesn’t negatively impact the stronger MU-MIMO connections given to static devices.
Do You Need MU-MIMO Wi-Fi?
As we all know, modern homes have an ever-increasing number of devices that are constantly connected to a Wi-Fi network.
Even though some of your devices will not support MU-MIMO, you can still benefit from having a router that supports MU-MIMO thanks to their ability to better handle multiple devices being connected to it at any one time.
I would recommend considering a MU-MIMO router should you have 8 or more devices connected to your home Wi-Fi.
MU-MIMO is a wireless technology used to better support networks where multiple people and their devices are trying to access a wireless network at the same time.
This technology allows a router to break up the available bandwidth into individual streams that share a portion of the bandwidth evenly, regardless of the device it is sending data to.
The result is each device not having to wait in turn to receive a share of the bandwidth as MU-MIMO can provide a signal to multiple devices simultaneously.
The caveat being the streams are spatial, so devices that are in close proximity to each other will have to share the same stream and with that, the stream’s share of the bandwidth.
Also, MU-MIMO only works for downlink connections, so content creators uploading large video files to YouTube will not benefit from it as much compared to those who are online gaming, for example.
The big drawback with MU-MIMO is that both the router and the device itself must support MU-MIMO in order to take full advantage of it. Even today, not all routers and devices support this wireless technology.
That being said, I would still recommend a MU-MIMO supported router for any home network that has 8 or more devices connected via Wi-Fi for their ability to better handle multiple connections at the same time.