Snake oil that only exists to take your money seems to be everywhere in the tech world
from $1,000 HDMI cables to heat sinks for your hard drives, I mean, come on.
And our Wi-Fi equipment is often no exception as manufacturers keep finding ways to make our routers
and access points seem more powerful than they actually are.
With one of the biggest culprits being how they've implemented a technology
called multi-user, multi-input, multi-output,
or MU MIMO, Mu MIMO.
So what exactly is it supposed to do and why does it suck?
To answer, we had a conversation with our good friend Joel Crane
and we'd like to thank him for his input. Thanks Joel, love you.
Now to understand this, we're gonna have to go all the way back to the early days of Wi-Fi
where our routers and gadgets each had just one antenna on them.
They're basically just rocks. So let's say your router sent out a signal.
To do this, the same signal blasted outwards in many directions and because of this,
the different waves carrying this same signal would bounce around the room and arrive at your laptop
or Nintendo DS or whatever at different times.
Kind of like when you hear an echo in a large warehouse like this one.
Now these signals arriving at different times caused undesirable interference.
So a solution was introduced with the 802.11N standard in 2009
called multi-input multi-output or MIMO.
We've heard of that before. The simplest way to think about it is that both the client and the router
would each have two antennas and two radios.
This would allow the client to recombine these waves that arrived at different times
into one much cleaner wave for better range and reliability.
A solution called Maximal Radio Combining or MRC.
Additionally, the multiple radios also meant that the router could also put different data
on each stream to transmit information more quickly
in a technique called Spatial Multiplexing.
Sounds like a wrestling move. For a two radio access point,
you could pick either MRC or Spatial Multiplexing
depending on whether you needed to prioritize speed or range.
However, if you had three antennas, you could actually use both at the same time
using two antennas for MRC and a third for Spatial Multiplexing
or all three for one technique or the other
depending on your needs. It was so great. Now all this actually worked pretty well
and resulted in significant speed and reliability improvements.
However, the powers that be asked, hey, what if we use these different antennas
to talk to different devices all at the same time?
With that, multi-user or MU MIMO was born.
But unlike standard MIMO, also called single user MIMO,
MU MIMO simply does not work as advertised.
Let me explain. The stated advantage of MU MIMO is that the messages being sent out from the router
will arrive at all your devices at the same time, which is theoretically faster than waiting around
for the router to talk to one device at a time, which is how traditional Wi-Fi works.
However, for the messages to arrive at the same time,
they need to be the same size. Something that very, very rarely happens
since the different devices on your network are asking for different data,
meaning that one device is going to be waiting to finish receiving a message after the others are complete,
largely nullifying any advantage. Now on top of that, making the router deal
with timing signals to all those different devices at once creates management overhead,
adding latency and further cutting into any time savings.
So the issue is while MU MIMO technology does work,
technically, you're simply not going to see any real world advantage from it.
In fact, many common clients don't even bother supporting MU MIMO, including many higher end ones.
So the bottom line is this, don't prioritize MU MIMO support
when buying your next router. You're better off looking for things that actually matter,
build quality, customizable settings, and an aesthetic that makes your living room
look like an evil layer so that you can impress your friends at your next house party.
If you want them to be scared, I guess. All right, thanks for watching, guys.
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