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What are the WLAN benefits of 802.11ac vs. 802.11n?

In analyzing wireless 802.11ac versus 802.11n, our expert says the advantages of 802.11ac are many, but the engineering has to be spot on.

The IEEE's new 802.11ac wireless LAN standard is designed to offer better access point capability, speed, throughput...

and roaming than its predecessor 802.11n.

When looking at the benefits of 802.11ac compared with 802.11n, theoretically, both Wi-Fi standards top out at controlling 256 devices, but the primary difference is that the ac standard starts looking a lot more like conventional cellular, so you have all sorts of capabilities with things like beam steering and multi-in, multi-out. With the right kind of architecture, it may be possible to significantly improve the throughput to each connected device and have the capacity to avoid conflicts between devices. Essentially, 802.11ac uses beam steering, new capabilities for access points to talk to each other and some other things to drastically improve the user experience over 802.11n.

With the right kind of architecture, in theory, 802.11ac could go up to a gigabit to a particular device. With that, you can actually exceed most Ethernet types of installations in terms of speed. But in practice, that's never going to happen. Still, it should take care of some of the more substantial issues that people have with Wi-Fi now.

An example of what 802.11ac can improve is the notion of roaming around a Wi-Fi enabled campus. When it comes to weighing the benefits of 802.11ac, you can actually have handoffs between access points. The quality of experience can be a lot higher. On top of that, because the throughput can be increased, assuming you have a device with an 802.11ac transceiver in it, you can do serious content distribution using 802.11ac.

Engineering your 802.11ac network

In enterprises, 802.11ac adoption is going slowly because not many things talk 802.11ac yet.

In enterprises, 802.11ac adoption is going slowly because not many things talk 802.11ac yet. It's the same thing we had with 802.11n adoption. You have to wait for devices to actually have 802.11ac transceivers in them. Then they have to have something to talk to.

Right now, the only ac-enabled devices I know of are some laptops that have a transceiver that talks 802.11ac. But the virtue of 802.11 is that everything is backwards compatible, so you may have an ac transceiver, but it's probably talking 802.11n most of the time. When it can talk 802.11ac, it can talk everything else.

When we compare the benefits of 802.11ac, it usually seems that 802.11ac probably will do a better job for you, and there are a number of reasons why you would want to do it.

But you don't get something for nothing. You have to pay attention to your architecture and what you want to do with it. The price of admission is that you can't just take out all of your old access points and plug in an 802.11ac replacement. You have to do serious thinking about where you want to put the new access points. You never want to flash-cut anything. You probably have a phased-in approach with replacing 802.11n access points with 802.11ac access points. Qualitatively there's more you have to pay attention to.

If you can't do a quality job on this, you should hire the expertise to come in and do a site survey and figure out where to put the access points. That applies even more to ac because we're talking about a fundamentally more complex environment. You could take out all your 802.11n routers and plug in 802.11ac routers and it would work, but only about as well as your 802.11n infrastructure.

Reaching the speed limit

The speed benefits of 802.11ac include a higher throughput than the 300 megabits promised by the older of the two standards. So, if you have ac, it's more likely you'll be able to deliver on the promise of 802.11. You might go faster than that. For the most part, 802.11n doesn't run at the speeds it promises. We all adopted 802.11n because we thought it would be qualitatively better in terms of speed. Mostly it isn't because in terms of the devices you can actually support, and given the normal communications you have, you're running at a lot less than that. So, if you have 802.11ac that can do beamforming on the antennas, and it can know where you are -- and it's using a much higher, denser encoding scheme -- you may suddenly get the experience you expected with 802.11n.

Next Steps

Wired network backs up 802.11ac standard

Uncovering 802.11ac security considerations

802.11ac prompts changes in WLAN architecture

This was last published in November 2015

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