White Spaces Wireless: A Chat With The Wi-Fi Alliance

The list of groups who applaud the FCC's recent decision to allow new wireless connectivity in the frequencies between TV channels includes biggies like Microsoft, xG Technology and the Wi-Fi Alliance. Given the Obama administration's goals of getting all Americans connected, the FCC's ruling probably wasn't much of surprise to most people. "Super Wi-Fi" (or "White-Fi"-- let's hope that one doesn't stick) as it is being nicknamed, will bring obvious advantages to the current 802.11-based Wi-Fi landscape, but there are just as many questions regarding what "new" Wi-Fi will look like. To gain perspective, I talked with Wi-Fi Alliance's Technical Director Greg Ennis for his take on what's to come on the heels of the FCC's ruling. Given Ennis' long history as a contributor to the development of early 802.11 and tenure at the Wi-Fi Alliance that dates to the organization's inception, I couldn't have spoken to a better resource.

For those who don't know, the Wi-Fi Alliance is as much the author of the white-hot success of wireless networking as anyone. By providing interoperability testing and certification under the ubiquitous "Wi-Fi Certified" logo, the Alliance has catalyzed the growth of wireless networking by ensuring wireless clients and infrastructure solutions all play by the same rules. They have brought great piece of mind and order to an industry that could have otherwise turned into the technical Wild West. The standard for wireless in the new spectrum will be 802.11af when ratified (not to be confused with 802.3af  Power over Ethernet standard). I grilled Ennis on a number of points regarding the 802.11af working group as the Alliance sees it, and came away educated.

Badman: Exactly what frequencies are opened up for wireless use in the new white spaces?
Ennis: The answer is dependent on your location. White spaces in Syracuse will be different from white spaces in Spokane, for example. The technology will have to use geolocation technology to query the FCC's databases to ensure that spectrum truly is "white" (unused) before it is used in a given area. And rural regions will tend to have more available spectrum than urban environments.

Badman: When do we expect ratification of 802.11af?
Ennis: The IEEE speculates ratification will come in December of 2011, but there's much to be figured out regarding modulation techniques and data rates, so it wouldn't be surprising if the date slipped.

Badman: What will be the actual advantages of 802.11af?
Ennis: Because 802.11af will use lower frequencies--measured in megahertz as opposed to gigahertz in the current .11a/g/n world--longer ranges are inherently possible, along with better building penetration. The newly available spectrum will have almost no "clutter" in it, and as clients move out of current 2.4 and 5 GHz spaces into the new spectrum, those left in the legacy spaces will have less contention.Badman: What about speeds?
Ennis: It's too early to really say. But we can expect usable data rates at distances that are unheard of with current 802.11-based wireless.

Badman: Is MIMO (Multiple Input Multiple Output antenna technology) a given?
Ennis: Not necessarily, but again, it's too early to tell. MIMO plays on multipath to enhance reception. In rural areas, for example, multipath may not be a factor.

Badman: Nothing really changes with wireless security, right?
Ennis: Not likely. 802.11af is an evolution of what we have today, not a wholesale change.

Badman: Combination chipsets in client devices are expected at some point- right? Like 802.11n/af?
Ennis: Yes. And just like with earlier and current 802.11 standards, the Wi-Fi alliance will develop interoperability criteria for testing and certification to make sure it all plays well- both on the client and infrastructure sides.

Given that the Wi-Fi Alliance's efforts largely parallel the IEEE's, I would personally expect to see something akin to the "11n Draft 2.0" step hit the market for 802.11af before full standards ratification, given the declared hunger for product in the white space frequencies. As Ennis mentioned, though, a lot regarding "Super Wi-Fi" remains to be seen.