Michael Finneran
Michael F. Finneran, is President of dBrn Associates, Inc., a full service advisory firm specializing in wireless and mobility; services...
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Michael Finneran | October 09, 2012 |


Wi-Fi Riding High at Interop

Wi-Fi Riding High at Interop A new round of access point refreshes is on the way, along with other developments supporting higher-bandwidth, multimedia-capable wireless LANs.

A new round of access point refreshes is on the way, along with other developments supporting higher-bandwidth, multimedia-capable wireless LANs.

Interop New York wrapped up last week and once again Craig Mathias of Farpoint Group put together an excellent string of sessions on wireless and mobility. I hit just about every one of them (including my own workshop on BYOD, Mobile Policy and Mobile Security), and while strategies for addressing the shift to user-owned devices clearly topped the list of issues, there was also a lot of talk about developments in Wi-Fi.

I've tracked the Wi-Fi market since its inception, but over the past few years it has been rather "boring". Everyone has moved to coordinated implementations (either with a controller or controllerless architecture) and we continue the conversion from legacy 802.11 a/b/g to 802.11n, but for the most part, Wi-Fi had become about as exciting as Cat 6 cable.

One session at the show that stood out was "Wi-Fi: Gigabit Performance (and a lot more!)" moderated by Edgar Figueroa, CEO of the Wi-Fi Alliance. On the panel were Mark Hamilton, Chief Architect for Wireless Products at SpectraLink (currently a division of Polycom); Sean Coffey, Director, Standards and Business Development for Realtek and a member of the the 802.11ac committee; and Mark Grodzinksy, VP of Marketing, Wilocity.

As the title indicated, this was going to be about the new higher-speed radio standards, 802.11ac and ad, but it was also a tour through some of the other big developments in Wi-Fi:

Voice-Enterprise Certification: Mark Hamilton of SpectraLink talked about the Voice-Enterprise certification, which is only fitting given that his company manufactures a line of voice over Wi-Fi handsets. SpectraLink's handsets are resold by many of the IP-PBX manufacturers, and Mr. Hamilton has been active in many of the Alliance's committees on voice over Wi-Fi certification programs.

The objective of the Voice-Enterprise certification program is to certify devices that can provide enterprise-grade voice call quality with full WPA2 security mechanisms. The certification bundles together a number of the voice standards for Wi-Fi including Wi-Fi Multimedia quality of service (802.11e), fast secure roaming (802.11r), and WMM admission control. With the drive to move more real time voice and video onto cost-effective Wi-Fi networks, we will be looking for the UC&C vendors to be getting on board with this one.

IEEE 802.11ac: You can see that the 802.11 committees have been active, as they have now had to go to two-letter suffixes (aa, ab, ac, ad, etc.) to identify their standards. IEEE 802.11ac will be the next major upgrade in the radio link from 802.11n and will deliver data rates into the gigabit range. Sean Coffey of Realtek talked about the 802.11ac standard that will operate exclusively in the 5-GHz band and can support data rates from 6.5 Mbps to 866.7 Mbps on a single stream, using a number of tricks first seen in 802.11n. Where 802.11n supports 20-MHz and 40-MHz channels, 802.11ac has 20-MHz , 40-MHz, 80-MHz, and 160-MHz implementations; without going into the finer points of Shannon's Law, bigger channels means more potential bits per second.

Along with the bigger channels, 802.11ac also uses a more efficient coding system to pack more bits onto each cycle of radio spectrum. Like 802.11n, it uses OFDM signal encoding, but where 802.11n tops out at 64-QAM (6-bits per symbol), 802.11ac goes to 256-QAM (8-bits per symbol); in each case some of those bits are used for forward error correction, so you don't get the full impact (though you do get better error performance).

Another enhancement is in the multiple input-multiple output (MIMO) implementation. MIMO is used in both 802.11n and ac, and allows the transmitter to send multiple simultaneous data streams over the air; each 802.11ac stream has a maximum data rate of 866.7 Mbps. Where 802.11n can send up to 4-streams (most existing products use a max of two or three), 802.11ac can go to 8-streams for a total maximum data rate of 6.934 Gbps; by the way, 802.11n has a maximum data rate of 600 Mbps, so we're looking at a better than 10x increase in capacity.

Multiple data streams calls for multiple radios, which in turn calls for more power. To conserve battery, highly portable devices like smartphones generally use a single stream, but now that stream could carry a raw data rate of 866.7 Mbps; actual throughput rates should be roughly half of that.

One last trick in 802.11ac is the incorporation of multi-user MIMO. With 802.11n's use of MIMO, all the streams are used to communicate between the access point and a single device. Multi-user MIMO means the different MIMO streams could be directed to different users. This could be a real plus in an environment where the access point has multiple radios but the devices are single stream. In effect, the access point could now be communicating with multiple users simultaneously, greatly increasing total network throughput.

Chipsets for 802.11ac are already going into production and we expect to see products rolling out early next year, and 802.11ac sales could catch up with 802.11n devices by 2015. So get ready for another access point refresh, everyone!

Next Page: More new standards


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