The spectrum released by TV’s switch to digital broadcasting will soon be put to good use. In some places, this “white space” of unused frequencies separating working channels amounted to as much as 70% of the total bandwidth available for television broadcasting. Mobile-phone operators and other would-be users of wireless spectrum have long lusted after television’s empty airwaves. In America, after two years of wrangling, the Federal Communications Commission (FCC) in Washington, DC, has finally given the go-ahead for white-space frequencies to be put to use.
In 2008 the FCC voted to reallocate the various segments of white space and unused channels between 54MHz and 806MHz (channels two to 69), which would no longer be needed when the last of the country’s analogue television transmitters switched to digital broadcasting in June 2009. Unlike analogue transmissions, digital signals do not “bleed” into one another and can therefore be packed closer together. As a consequence, television broadcasters now need little more than half the spectrum they hogged before switching to digital. That has not stopped them fighting tooth and claw to hang on to their unused white space. Most had grand plans for using such frequencies to sell information services to the public.
It was not to be. Instead, the FCC has used the switch to digital as an opportunity to liberate huge swathes of bandwidth for others to use. The most valuable frequencies of all, those in the 700MHz band (channels 52-69), have been auctioned off to mobile-phone operators. Between them, Verizon, AT&T and others paid nearly $20 billion to clinch this prime spectrum. The reason these channels are so valuable—and why they were chosen for terrestrial television in the first place—is that their signals travel for miles, can carry a lot of information, are unaffected by weather and foliage, and go through walls to penetrate all the nooks and crannies within the bowels of buildings.
The white space freed up below 700MHz is to be made available for unlicensed use by the public. By doing this, the FCC hopes to trigger another wireless revolution—one potentially bigger than the wave of innovation unleashed a decade or so ago when Wi-Fi, Bluetooth and other wireless technologies embraced the unlicensed 2.4GHz band previously reserved for microwave ovens, baby alarms and remote openers for garage doors.
The difference this time is that the frequencies being released will allow much higher data rates.
Enthusiasts talk about white-space devices offering a “third pipe” for access to the internet, to rival cable and telephone broadband. Others see them providing an alternative to mobile phones. When wireless zones cover entire university campuses rather than mere coffee shops, anyone with a smartphone running Skype or something similar would be free of usage charges and operators’ restrictions.
White-space consumer products could then hit the retail market by late 2012.
Read more at The Economist
