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White space spectrum: What it is, and what it isn’t

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The Washington Post stumbled this week when it published this front-page piece documenting how the Federal Communications Commission hopes to build a footprint of “super Wi-Fi networks across the nation” that would enable users to make calls or surf the web via unlicensed spectrum without paying cell phone bills. The plan is backed by major players such as Google and Microsoft, according to the story, while the traditional cellular industry – carriers, gear vendors and the like – is fighting the proposal tooth and nail.

The story attracted attention because it included several important inaccuracies: DSLReports notes that the debate over what to do with those airwaves has been occurring for nearly a decade, and Ars Technica points out that the FCC doesn’t have any desire to actually build or manage the networks itself. But it succeeded in drawing attention to “white space” spectrum –airwaves that fall between the frequencies reserved for TV broadcasters that have gone largely unused as those broadcasters moved to digital. And it illustrated just how much confusion continues to surround unlicensed spectrum.

A brief history

The idea of using white spaces for mobile data traffic – which some have dubbed “Super Wi-Fi” – first surfaced about eight years ago. The FCC approved the first device in 2011 and the world’s first commercial white spaces network came online in North Carolina last year. White space airwaves are included in the spectrum allocation that Congress mandated last year, which encourages TV broadcasters to sell back unused or underused spectrum during an “incentive auction” in an effort to maximize usage. The FCC will in turn auction off most of the recovered airwaves, but it hopes to “free up a significant amount of unlicensed spectrum for Wi-Fi-like uses,” FCC Chairman Julius Genachowski wrote in a prepared statement last fall.

There are some things to like about white space spectrum: In addition to its abundance (assuming TV broadcasters will hand it over), the 600 MHz to 700 MHz range can travel long distances and easily pass through walls and other barriers – making it superior to Wi-Fi for some use cases. But it’s far slower than traditional Wi-Fi, with download speeds “up to” 22 Mbps and upload speeds maxing out around 6 Mbps. Those connection speeds are sure to be vary drastically in the real world, though, particularly if they’re being maintained by a hodgepodge of service providers hoping to leverage the unlicensed airwaves. And while those speeds may rival 4G LTE, no white space-based network would be truly mobile – it couldn’t provide the seamless handoffs we enjoy every day on cellular networks.

Very valuable, but very limited

Instead of a replacement for cellular service and traditional Wi-Fi, then, white space spectrum is likely to be a complementary source of mobile broadband – at least for the next few years. It appears to be a great solution for rural areas where cable broadband isn’t available and 4G (or even 3G) networks have yet to come online. And it could be ideal for short- to mid-range machine-to-machine applications, like water level sensors, energy-usage monitors or video cameras.

In the longer term, though, white space spectrum could be a valuable tool for carriers. It could be the next step in the evolution toward next-generation technologies and services such as LTE SON (self-organizing networks), which promises to help operators deploy and maintain their networks. It could support an entry-level freemium service, handling no-frills services for carriers looking to upsell customers to more sophisticated offerings. (Google is tinkering with such a model with its Fiber offering in Kansas City.) And it might be ideal for offloading low-data traffic such as SMS during peak scenarios such as at big sporting events and concerts.

Connectivity isn’t free, and white space spectrum simply isn’t going to support offerings that threaten the lifeblood of entrenched mobile carriers – not in the U.S., at least. Rather than fighting the proposed unlicensed spectrum, then, operators should be considering new business models and finding ways to embrace it.