Wireless networking is at the heart of so many things in the modern world, and if you need to maintain a reliable wireless network, then you need the right tools for the job.
That can involve a lot of research, but you can narrow things down quickly when you know more about how wireless communication works. These days, MIMO is the most common technique for wireless communication, and when you know what it’s doing and how to compare different types of MIMO, you can browse equipment and find what you need a lot faster.
With that in mind, here’s a quick crash course on MIMO.
What Is MIMO?
Before jumping into SU and MU MIMO, it’s probably best to start with a breakdown of MIMO. It stands for “multiple input multiple output,” and it’s a radio communication concept that has shaped WiFi as we know it today.
The gist of the idea is that with MIMO, a single radio channel can handle communications from multiple devices. In the context of WiFi, MIMO is the method that allows a single router to manage communications for a number of wireless devices. When you have multiple phones, smart TVs, and other devices, all on a single home network, MIMO is at play.
That might lead you to assume that MIMO allows for simultaneous communication between the devices on that single channel, but that’s where things get more interesting, and to explain that, we have to break down SU and MU MIMO.
SU-MIMO is single user MIMO. This very simply means that an antenna using SU-MIMO can only communicate with one device at a time. That might sound very limiting, but with smart routing, SU-MIMO can enable many devices to connect on one channel, even if they aren’t broadcasting simultaneously.
In fact, your home router likely uses SU-MIMO. It has been a standard in WiFi for many years.
The simple fact is that the single aspect of SU-MIMO isn’t all that limiting when you have very fast networking devices. Even if a router is managing traffic for one client at a time, each broadcast is short enough that the experience can feel seamless even while a number of devices are connected on a single channel.
You can almost think of it like an auction. There is only one auctioneer managing communications with a room full of people. It feels fast and seamless because the auctioneer can manage each individual communication so quickly.
Expanding Networking With MU-MIMO
MU-MIMO is multi user MIMO. As you might have guessed, the major difference here is that the networking device can simultaneously broadcast to multiple users on the same channel. This small change extends into major performance differences, and as a result, MU-MIMO has higher ceilings for throughput and total network capacity.
Using the auction example, if SU-MIMO is one auctioneer, then MU-MIMO is an auction app that allows everyone to view items and place bids simultaneously. The scale is much broader, and that translates into performance very quickly.
Choosing Between the Two
The comparisons make more sense when we look at raw numbers and some common applications for each type of communication.
The most prolific example of these two communication methods is with 4G and 5G cellular. 4G was built on SU-MIMO while 5G utilizes MU-MIMO. As a result, 5G access points can handle up to 16 times as many users at the same throughput. Or, 5G can provide data rates up to 100 times as fast as 4G, partly because of this one technological difference.
In general, MU-MIMO networks are faster and handle many more users. Looking at a few common use cases, we can see that in a broader context.
SU-MIMO is still ideal for many small office and home networks. It’s plenty fast and can handle the involved devices just fine, and SU-MIMO hardware is typically less expensive.
MU-MIMO really starts to shine when you add a lot more users or need much faster wireless communication. Enterprise wireless and campus wireless are great examples. A hospital, airport, or stadium wifi network will have thousands of simultaneous users, and MU-MIMO is much better equipped to handle that kind of work.
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