Google has begun testing a new database that would allow unlicensed TV broadcast spectrum to be used for wireless broadband and shared among many users.
The new database will keep track of the TV broadcast frequencies in use so that wireless broadband devices can take advantage of the unlicensed space on the spectrum, also called "white space."
Google is one of several companies that has built such a database, and it is the latest one to enter into the Federal Communications Commission's 45-day testing phase. Spectrum Bridge and Telcordia completed their trials, and there are another 10 companies, including Microsoft, which are working on similar databases.
The FCC unanimously agreed in November 2008 to open up this spectrum for unlicensed use. Experts say there could be between 300MHz to 400MHz of unused spectrum across the U.S. This white space could be used on an unlicensed basis to deliver wireless broadband services.
In 2010, the FCC approved new rules for using unlicensed white space, which included using databases to check for clear frequencies and ensure that devices do not interfere with existing broadcast TV license holders. These databases would contain information supplied by the FCC.
Two white space database trials with the FCC have been concluded already, which means in theory users could start accessing white space whenever they like. However, no white space devices yet exist. What's more, it likely will take a service provider to come up with a viable offering to make white space useful to the masses.
Wireless service providers, which typically license space on the spectrum for millions of dollars, have complained that there is not enough available spectrum to keep up with market demand for data services.
"There is available spectrum out there, but it can be hard to find if you don't know where to look," wrote Google Access Strategy team member Alan Norman in a blog post discussing the database trial. "One way we're trying to help researchers and other stakeholders identify available spectrum is through dynamic spectrum sharing."
According to Norman, a database that tracks available spectrum is an integral part of the process.
Solving the 'spectrum crunch'The FCC has been working to free up wireless spectrum, which it can auction to providers, but it also has been looking at making more unlicensed use possible. Hoping that it could spur innovation, policy makers point to the success of Wi-Fi as a reason why the government should set some spectrum aside for unlicensed use.
Still, the wireless industry and TV broadcasters have resisted the idea of unlicensed use. In general, broadcasters have complained that allowing others to use white space, which is so close to the spectrum they occupy, could cause interference.
Wireless carriers have protested that they want more spectrum that is auctioned and not shared among many users. The FCC is in the process of formulating rules for a new auction that would allow TV broadcasters to give up spectrum they aren't using and auction it to wireless broadband providers. The FCC has proposed making a portion of this spectrum available for unlicensed use. Wireless operators and some congressional leaders argue that white space should be allocated for licensed use as much as possible.
What Google and others developing this database technology hope to show is that it is possible to share white space without creating interference. If that is the case, it could free up a lot of spectrum.
Google's trial will allow TV broadcasters, cable, wireless microphone users, and licensed spectrum holders to test and provide feedback on the database. The trial site also will allow anyone to find out how much TV white space is available at any location.
"The completion of the trial will bring us all one step closer to freeing up more spectrum," Norman wrote, "which, in turn, will help the industry bring new wireless technologies to market and enable people to get wireless Internet access when and where they need it."