IPIQ: MIMO

Difficulty level:  • • •
By Lindsay Bull, technical writer

Wi-Fi… your customers want it, but they just don’t understand it. They want it to magically perform feats that simply aren’t possible—stream to every device in the house simultaneously without slowing speeds and get the kids to wash the dishes…

Lucky for you, you’re on the Luxul blog, where we solve the world’s problems and teach you about networking. We can’t promise that just by reading this post you’ll be able to appease your clients’ unrealistic Wi-Fi expectations, but we can help you better understand the technology that will offer them the closest thing.

When Wi-Fi first busted onto the scene, people were simply excited by the prospect of being able to use the internet without a wired connection. But in perfect homo sapien form, their expectations grew, and technology had to evolve. Initially, clients had to share a single data stream or connection from their wireless routers:

The client would make a request:

Then the router would answer the request:

Though this technology was a big deal, each client had to wait for its turn to communicate with the router, and streams of data could only be sent one at a time with limited throughput. The difference in speed between wired and wireless connections was significant.

As you can imagine, users wanted more! Their expectations were fulfilled by a leap in technology known as MIMO—multiple input, multiple output. MIMO still required clients to take turns communicating with the router but now enabled multiple spatial streams to be sent to a single client, as long as the client also supported MIMO. In other words, MIMO allowed better throughput to a single device:

This drastically sped up wireless and improved the user experience enormously.

Now-a-days, streaming video and music has become so accessible and popular that users have come to expect an increase in speed and bandwidth from their routers. Thus, the introduction of MU-MIMO, or multi user multiple input, multiple output. With the introduction of MU-MIMO, the previous version gained a new prefix, now being referred to as SU-MIMO, or single user multiple input, multiple output.

With MU-MIMO, clients no longer have to take turns communicating with the router, as the router is capable of communicating with multiple compatible clients (this is where ‘multi user’ comes in) at once.

Several clients make a request, and simultaneously, the router answers each of those requests:

Of course, even with MU-MIMO, you still don’t have infinite wireless bandwidth. Too much bandwidth usage (like streaming on too many devices at once) can still slow down the speed of a user’s Wi-Fi, which is why it’s important you understand the limitations of technology—so you can set proper expectations with your customers upon installation of their systems.

We may still not be able to offer your clients help getting their kids to wash the dishes, but we can certainly assist in an uninterrupted experience watching their favorite streaming service as a family after dinner.

Lindsay Bull