802.11ac: The Fifth Generation of Wi-Fi Technology

May 17, 2012 - 2 Comments

802.11ac: The Fifth Generation of Wi-Fi Technology

In the last few months, there have been a lot of written on the emerging 802.11ac standard. This next generation of Wi-Fi promises to be very exciting since 802.11ac will address some critical pain points faced by users of 802.11n today – more bandwidth and more simultaneous users.  To help explain the technology, we put together a new Fundamentals video.  You’ll learn about new features such as:

  • Operating in the 5GHz band
  • Wider channels (80MHz & 160MHz) which means more capacity in the band
  • Increased modulation with 256 QAM (Quadrature Amplitude Modulation), providing a significant increase in throughput over 802.11n which has 64 QAM
  • Downlink Multi-User MIMO which allows an AP to transmit to multiple clients simultaneously
  • Up to 8 Spatial streams which doubles the number of spatial streams used in 802.11n

Cisco, along with several other vendors is leading the definition of 802.11ac through the IEEE standards body with the expectation to have the standard ratified by the end of 2013. In the meantime there is a lot of activity around the specification centered on a number of items such as wrapping the specification, interoperability and Wi-Fi Alliance certification which is targeted for early 2013.

Consumer devices will be the first to market access points with some vendors having already announced product availability.  It is expected that the availability of enterprise access points will lag behind by a few months. Of course, what will drive the use of 802.11ac will be the availability of devices such as laptops, smartphones and tablets that support the standard. Don’t initially expect the advertised Gbps screaming throughput with these devices.  Many of these devices will only be 1×1 MIMO but much like 802.11n, other devices could follow up with 2×2 or maybe 3×3.

The more important fact is these devices can operate exclusively on the 5GHz band. This is important for a few reasons: One being that the 2.4GHz band is crowded, real crowded. I was recently at Interop in Las Vegas where on the show floor you could find roughly 750 radios operating on one of the three non-overlapping channels of the 2.4GHz band. This might not be a typical scenario in your network but it still highlights the overuse of this unlicensed band. Some of this can also be attributed to the fact that a lot of these devices do not support dual bands (2.4 & 5GHz) and do not have the option of operating on the 5GHz band. The second point is that the 5GHz band has a lot more channels available. Unlike the 2.4GHz, which depending on which country you reside, could have 11 to 13 available channels. However, the non-overlapping channels are limited to 3 or 4 (depending on your region). The 5GHz band has 21 or 24 channels (depending region of the world you live) which should be more than enough for things like channel bonding.

When 802.11ac consumer products become commonplace, especially the laptops, tablets and smartphones, more people will want to use these devices in their work place. That’s right. Bring Your Own Devices (BYOD) will drive the use of 802.11ac into your enterprise network. So if you are an enterprise network manager pondering what you would do with 802.11ac; besides the potential for a lot more bandwidth for HD video streaming, large imaging transfers, etc., another driver will be BYOD. With the growth consumer devices, one can expect that pressure may mount to support your employees’ new shiny tablet that has 802.11ac in your enterprise network.

However, we are not there yet. It is important to keep in mind that with all of exciting features that 802.11ac will bring, 802.11n is still essential to Enterprise Networks and the mobile revolution in general

We have seen an increased demand on wireless networks which can be attributed to the explosion of video consumption and via BYOD, the growing number of wireless devices being used. However, 802.11n is still your best bet to meet these demands for bandwidth and coverage on enterprise wireless networks with 802.11ac addressing the ever increasing bandwidth demands of future networks.

So with the help of our good friends at TechWise TV, here is a primer on what 802.11ac is all about. And while you are learning about 802.11ac, look for the thinly veiled reference to a Mel Brooks movie somewhere in the video.  Enjoy!


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  1. Nice and simple explanation of next-generation WiFi within optimal environment.

  2. Sounds like the next generation of wi-fi technologies is taking a big leap forward. I can’t exactly get my head around it yet but the video was very interesting.