Tech - US;Wireless at warp speed

How much would you pay for unlimited access to Wi-Fi hotspots that stretched for miles instead of a few hundred feet, provided unbroken connections even deep inside buildings, and offered broadband speeds ten times faster than today's wimpy connections found in coffee shops, hotel lobbies, airport lounges and homes?

How about nothing, or next to nothing? That could be on the cards within a couple of years, thanks to a decision taken recently by America's Federal Communications Commission (FCC).

After four years of deliberations—and staunch opposition from television broadcasters, makers and users of wireless microphones, and mobile-phone companies—the federal regulators voted unanimously on November 4 to allow a new generation of wireless gizmos to access the internet using the empty airwaves 'white spaces' between television's channels 2 to 51.

The FCC could have auctioned off those frequencies—it raised $19.6 billion in March 2008 by auctioning blocks of frequencies above 700 megahertz that will be vacated when television switches from analog to digital broadcasting—but to its credit it opted to make them freely available.

The decision is a huge win for public-interest groups and tech firms like Google, Microsoft and Intel, who believe the white-space transmission could bring broadband to poorly served parts of the country.

They see it as America's last chance to build a 'third pipe' capable of providing much-needed competition to today's broadband duopoly controlled by the phone and cable companies. As a bonus, white space could also provide improved communications for fire-fighters, police forces, ambulance crews and other emergency responders.

Competition and community services aside, the FCC has other reasons for making the white-space frequencies free for public use. It hopes to replicate the wave of innovation that swept the wireless world a decade ago with the introduction of unlicensed Wi-Fi devices using frequencies in the public 2.4-gigahertz band.

Before Wi-Fi came on the scene, the 2.4-gigahertz band was considered good for little more than cordless phones, microwave ovens and garage openers. In 2008 almost 300 million

Wi-Fi-enabled devices will be sold; that number is expected to rise to a billion by 2012. Over the past decade, the industry servicing the sector has grown from nothing to become a $30-billion-a-year business.

White space could be even bigger. The frequencies involved were chosen for television back in the 1950s for good reason: they travel long distances, are hardly affected by the weather, carry lots of data, and penetrate deep into the nooks and crannies of buildings. No surprise proponents have dubbed them 'Wi-Fi on steroids'.

Once the changeover from analog to digital broadcasting is complete, the television networks will no longer need the white spaces between analog channels to prevent interference from noise and other transmissions. Apart from digital broadcasts being far less vulnerable to interference, there's now plenty of frequency-hopping technology around for detecting digital broadcasts and avoiding them.

That hasn't stopped television broadcasters from claiming interference will remain a problem if unlicensed devices are allowed to operate in the same part of the spectrum. They point to trials carried out by the FCC in the summer of 2007 with a pair of preliminary devices designed to operate in the television band's white spaces. The results were spotty, with one of the devices unable to detect the presence of digital television signals reliably.

But the broadcasters are being less than sincere. For instance, in busy television markets like Los Angeles, the vacant slices of white-space spectrum account for a third of the airwaves used by broadcasters; in rural areas, they occupy anything up to three-quarters of the spectrum allocated to television. Broadcasters had hoped to annex this valuable resource abutting their channels and use it to sell additional information services.

They are well aware, too, that the trials they say proved white-space devices impaired their broadcasts were flawed, and were subsequently repeated successfully. Microsoft (a member of the White Spaces Coalition along with Google, Dell, HP, Intel, Philips, Samsung and Earthlink) demonstrated the scanner in the device that caused the problem was damaged. In follow-up trials, a backup prototype worked perfectly, detecting even the faintest of digital transmissions with 100% reliability.

The FCC later concluded that the prototypes proved interference could be eliminated by using spectrum-sensing and geolocation to detect any television transmissions in their vicinity. Whenever a television signal was detected, the white-space device would automatically switch off until out of range.

As far as the FCC was concerned, there was therefore no valid reason why broadcasters should be allowed to keep their unused, but extremely valuable, white space.

To put television viewers at ease, the FCC has made it clear that white-space devices—whether mobile phones, laptops, game consoles, music players or other appliances with internet connections—will be required to operate on no more than four watts of broadcasting power. They will also be restricted to channels 21 to 51, where there are fewer television stations.

For good measure, the geolocation circuitry built into a white-space device will determine precisely where it is, and then interrogate a database containing the locations of all the television transmitters in the area. The device will be prevented from transmitting until given an 'all clear' by the database.

Google has proposed that white-space devices be blocked from broadcasting in channels 36 to 38 to protect both wireless microphones operating in that frequency, as well as channel 37, which is used for telemetry in medicine and radio astronomy.

Apart from consumers, the biggest beneficiary from the FCC's decision to open the white-space spectrum for unlicensed use has to be Google. Recall it was Google that started the bidding in March for the highly prized block of 700-megahertz frequencies occupied by analog television's channels 52 to 69.

In the process, Google persuaded the FCC to attach 'open-access' conditions to the block. Whoever finally won the auction would then have to allow phones supplied by others to work unhindered on its network. In other words, users would no longer be restricted to the carrier's proprietary services, but would be free to roam the internet—and, naturally enough, use Google's search engines, maps and other advertising-supported services.

Having achieved its objective, Google then backed out of the bidding, leaving it to Verizon to cough up $9.4 billion and AT&T $6.6 billion for various 700-megahertz licenses. Now Google gets arguably an even more valuable bit of spectrum real estate effectively for nothing.

Building a network of white-space transmitters would then be a small price for Google to pay for gaining much the same kind of market dominance in mobile search and services as it has long established on the desktop.

© The Economist Newspaper Limited 2008