802.11ac: the Future of Wi-Fi

What’s better than a fast, reliable Wi-Fi network? With 802.11ac, the latest IEEE standard (approved January 2014), Wi-Fi just got better. Exponentially better. With ‘Gigabit Wi-Fi,’ your network can stream HD video to multiple clients simultaneously, as well as perform rapid synchronization and backup of large data files.

As with the move from 802.11 to 802.11g, the change from 802.11n to ac is marked by significantly enhanced data encoding at the same frequency and power levels, so you are getting more for basically the same. Instead of being limited to 300 or 600 Mbps as you were on 802.11, with the 5 GHz band you’re able to do a Gigabit or better.

802.11ac is cleaner, faster, and has more available channels. Operating solely on the 5 GHz band, ac eliminates the problematic 2.4 GHz band and offers 20 channels (up from just three). When you build a network and put several cells together to cover large areas, you don’t have to worry about the cells interfering with each other. With 20 cells, you have the ability to place more cells closer together, which gives you density and the ability to give users significantly more bandwidth, improving the speed of their connection. Additional improvements over the older 802.11n include:

  • Wider RF bandwidth – up from 40MHz to a mandatory 80 MHz (160 MHz optional) channel bandwidth for stations
  • High density modulation – up from 64 to 256 QAM (Quadrature Amplitude Modulation)
  • More MIMO (Multiple-Input and Multiple-Output) spatial streams – up from four to eight
  • Downlink multi-user MIMO – up to four simultaneous clients

Essentially, the move to ac means you’re much more likely to get connected and stay connected at higher speeds.

The new standard supports using multiple transmitters and receivers to a single client at the same time. Whereas with 802.11n you could have multiple channels talking to a single client by using multiple transmitters, with ac you can have wide channels to multiple clients at the same time, which is perfect for multicasting HD video.

The best environments for the new standard are so-called “green field” environments, which are areas that currently don’t have wireless coverage. There’s not a lot of downside to putting in a new ac system as almost all relatively new clients will support 5 GHz, with one caveat – if you have devices that only work in 2.4 GHz, then you still need Access Points (APs) that are capable of both bands. At the moment, that’s not a problem, but 2.4 is becoming anathema, so primary data and all of your development is going to be done in the 5 GHz band. So, in addition to purchasing new APs that support the new band (or both), endpoints, like the bar code readers and scanners we see in warehouses, will have to be upgraded eventually as well.

To determine your return on investment with new wireless networking equipment, you must consider the business benefit of the services ac enables, like streaming video, that haven’t been used much in the past. Also, you can do away with static wired connections unless you need dedicated Gigabit speeds. Even voice is relatively low bandwidth, so most users don’t need wired connections.

A wireless site survey is an invaluable tool that helps discover coverage gaps and determine AP placement. Any new installations should be done with ac, but the change over may be deployed in phases. As legacy APs are replaced by ac-compliant APs, you need to complete a site survey to make sure you’re not affecting the coverage areas since APs need to be closer together to provide coverage on the 5 GHz band.

Upgrading is a true no-brainer. The old 802.11n will be gradually phased out over the next few years and is expected to be totally displaced by 2018. The new standard has been adopted by consumer endpoints – both Apple and Samsung now include the standard in their handhelds. While it’s workable not to implement ac immediately, you need to be planning for the change in the long term.

Thang Pham | Network Practice Director
Effram Barrett | Solutions Architect
Jeff Collins | Senior Consultant

Leave a Reply

Your email address will not be published. Required fields are marked *