A small town in rural Virginia has become the first community to receive broadband Internet connectivity via a wireless network operating on spectrum between active TV channels — known as TV white spaces — in what many officials hope becomes a unlicensed model for broadband access in the future.
Using an experimental license obtained from the Spectrum Bridge has designed and deployed a TV white-spaces network in Claudville, Va., a town of about 1,000 residents that had been unable to convince a carrier to offer broadband service in the community. The effort also was supported by Dell and Microsoft, which donated computing equipment and software for the project.,
During a press conference yesterday announcing the white-spaces network, U.S. Rep. Rick Boucher (D-Va.) — chairman of the House subcommittee on communications, technology and the Internet — called the deployment a “milestone” in rural broadband deployment.
“It is our hope that this will demonstrate definitely that white spaces can work,” Boucher said.
Spectrum Bridge CEO Richard Licursi called the Claudville deployment “a dawn of a new era in wireless communications,” noting that the project was “very inexpensive.” The company’s total cost for the project was about $40,000, with a large portion of the money being used to cover employees’ travel expenses to Claudville, he said.
The equipment cost for the Claudville network was less than $5,000, said Rick Rotondo, vice president of marketing for Spectrum Bridge. The company used a prototype white-spaces radio from Koos Technical Services, but the other TV-band components were not hard to find.
“One of the neat things aboutis that frequency and radio domain is very well understood, as you can imagine — , cables, splitters, propagation models, it’s just very well understood,” Rotondo said in an interview. “So it was fairly easy for us to get all the ancillary equipment and engineering together to design a network that would work in that type of terrain and tree cover.
“Guess what our receive antenna is? It’s a TV antenna … and it’s a specific antenna designed specifically for the VHF frequencies we’re operating in — and it’s pretty cheap. High gain, pretty cheap, you can get them anywhere — there’s a lot of advantages.”
Other white-spaces advantages include the fact that the spectrum below 700 MHz has excellent propagation characteristics, Rotondo said. Many of Spectrum Bridge’s founders were part of MeshNetworks, which built mesh networks in the 2.4 GHz unlicensed band before the company was sold to Motorola, and recalled that it was “not unusual” to deploy 40 to 60 network nodes to cover a square mile, he said.
“My guess is, given the terrain and tree cover in Claudville, that number would have much higher [if 2.4 GHz mesh technology was used],” Rotondo said. “In Claudville [using white-spaces spectrum], we have one transmitter that’s covering pretty close to 8 square miles reliably, and it’s non-line of sight. We’re getting phenomenally reliable and consistent connectivity. Those frequencies are just rock solid.”
Rotondo said a key to the network was the existence of Spectrum Bridge’s white-spaces database, which indicates which spectrum in the TV band are unused by television broadcasters for a geographic region. This information is given to the white-spaces radio, which leverages the white-spaces spectrum to provide wireless broadband access.
In deploying the Claudville network, Spectrum Bridge learned a great deal about some unique characteristics of white-spaces deployment, Rotondo said. For instance, while there was never a problem with the Claudville network interfering with a TV broadcast, but there was some unexpected TV interference to the Claudville network, he said.
“Claudville is mountainous, and the signal from that TV transmitter was stronger than expected,” Rotondo said. “It wasn’t strong enough to actually be received and be decoded by TVs there — we asked folks, and they could never get that channel—but it was enough that it caused a noise floor, so we just moved to a different channel.”
The FCC has created draft rules for the use of white-spaces spectrum. Rotondo said there is hope that the agency would release final rules either late this year or early in 2010. Companies like Dell, Microsoft and Google have helped lead the lobbying effort to dedicate the white-spaces spectrum for unlicensed use.