White-space: Is super WiFi just a dream?

Lynnette Luna


This week I'm taking a deeper look into the white-space market--that industry that has been so overly hyped for the last three years.

As the FCC moves along to finally put the technical pieces into place since officially approving the use of white-space spectrum back in September, I can't help but wonder when, if ever, this market will show significant growth outside of connectivity for more rural markets.

The promise has been that white space could usher in WiFi on steroids since white-space is those slivers of 700 MHz spectrum freed by the transition of TV channels from analog to digital. Therefore it has better propagation than today's WiFi.

But it's unlikely, even by incorporating the usual broadband tricks such as MIMO technology, that white-space spectrum will provide the meaningful speed and capacity that we see today. There are fewer TV white space channels available in urban areas, where demand for high-speed, WiFi-like services will be highest. White space devices must use geolocation data from databases to determine what frequencies to use, thereby preventing interference with TV broadcasts and other signals. But with heavy use of the spectrum in big markets such as Los Angeles and New York, very few channels will be available for use at a given time.

Moreover, the TV band is divided into 6-megahertz channels, which will severely limit white-space data speeds. In comparison, 802.11n systems take advantage of 20 megahertz to 40 megahertz of spectrum and offer data speeds of about 65 Mbps.

Some vendors may find they can bond channels together for more capacity, but given the interference and requirements that white-space devices move from channel to channel, that might not be an answer for the high-speed data services that consumers are now accustomed to.

As such, we aren't hearing WiFi vendors talking about the potential of white space. There are a lot of technical issues to work through. Meanwhile, the primary worries in the wireless broadband space--at least in urban areas--are speed and capacity. And 802.11n is filling that niche rather nicely at this point, and is poised to play an even larger role with operators when it comes to data offloading. Many mobile applications actually work better on today's WiFi networks.

So where does that put the white-space market? For one, rural broadband providers are clamoring for it given its potential to reach hard-to-access areas. Moreover, there appears to be much opportunity in mid-sized cities when it comes to city applications and smart grid. But it's hardly a mass market that will attract a host of WiFi players, especially given the technical challenges associated with it.

However, one can look back at the WiFi market in its early years and conclude that wasn't going to be much of a market either. And while the FCC wants to see white space as a key enabler to bringing broadband to the masses, it also sees this market as a litmus test for a new way the FCC would like to see spectrum in the future controlled--via databases.

Check out my special feature on the white-space market here.--Lynnette