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
IEEE 802.11ad: Most of the talk has been about 802.11ac, as it will serve the same applications as 802.11a/b/g and n. The 802.11ad standard is a high-speed radio link that will work in the 60-GHz band; about the only other thing we find in that band now is the Wireless HD standard. The 60-GHz band is lightly used primarily because the signal loss is so high relative to 2.4 GHz, 5 GHz, and the frequencies we use for cellular. However there is roughly 7 to 9 GHz available in the 60 GHz band throughout most of the world; by comparison, the 5 GHz band has around 0.5 GHz.
As Mark Grodzinksy of Wilocity laid it out, the story with 802.11ad is that you go real fast, but you don't go real far. The industry doesn't have near as much experience at building 60-GHz products, so the initial implementations will use relatively simple modulation schemes and no MIMO. However, you can use a 2-GHz channel and support data rates up to around 7 Gbps; Mr. Grodzinksy pointed out that you can do uncompressed 1080p HD video in around 3 Gbps. As time goes on and more bandwidth-efficient techniques are brought to bear, the data rate could potentially go to 25 Gbps.
One technique they are using to compensate for signal loss is directional antennas that can focus the radio beam into a 6-degree angle rather than the 360-degree omnidirectional antennas typically found in Wi-Fi devices. Even with that, we are looking at in-room applications like wireless HDMI. A 6-degree beam means that you may have to aim the devices at one another, though there is an option to incorporate beamforming so the two devices could "find each other" and aim the beam automatically. Besides connecting home entertainment systems, the other key application identified was connecting computer peripherals wirelessly.
Standards for 802.11ad are at a much earlier stage than 802.11ac, so there is no clear picture as to when commercial products might appear on the market.
Passpoint: The other Wi-Fi development that got a brief mention was Passpoint. Based on the Alliance's Hotspot 2.0 specification, Passpoint will allow cellular devices to automatically discover and connect to Wi-Fi networks and will automatically configure WPA2 security protections without user intervention. In essence, Passpoint could provide a standard way for mobile operators to offload cellular data traffic to Wi-Fi. Carriers like AT&T are already doing that, but through their own proprietary mechanisms.
The idea of Wi-Fi offloading came up in a number of other sessions, and was pushed by Bob Friday, CTO for Cisco's wireless group. The different operators have different attitudes about where Wi-Fi will fit in their networks, but a standard mechanism for supporting secure hand-offs between the two environments can only be a plus.
All in all, there's a lot happening on the Wi-Fi front. Ruckus Wireless has just filed for an IPO and companies like Aerohive and Meraki are making good headway on their controllerless and cloud-based controller offerings. Industry stalwart Aruba Networks recently announced its own controllerless offering as well.
While much of our industry is tripping over its feet trying to develop plans for multi-vendor interoperability, the Wi-Fi Alliance continues to do a superb job at making the pieces work together and driving the Wi-Fi industry forward.
