fixed wirelessA bi-partisan coalition of 43 Congressional representatives is asking the FCC to reserve at least three TV white space channels in the 600 MHz band to support rural broadband deployments.

“We believe that the television white spaces (TVWS) have strong potential to revolutionize broadband internet accessibility in rural areas,” wrote the coalition in a letter to the FCC. The coalition was led by Republican Congressman Kevin Cramer of North Dakota but also included some Democratic representatives, including Anna Eshoo, the former ranking Democratic member of the House Energy and Commerce Subcommittee on Communications and Technology.

The three channels referenced would include the duplex gap between 652-663 MHz, Channel 37 (608-614 MHz) and an additional vacant channel in the post-auction broadcast TV band (54-608 MHz), the letter stated. The channels would be reserved for unlicensed use.

If the idea of reserving three channels below 700 MHz for rural broadband sounds familiar, it may be because that’s what Microsoft has asked for to support the company’s plan to spur the deployment of TV white spaces technology to unserved rural areas.

The 600 MHz band initially was licensed to television broadcasters but a portion of that band will now be repurposed for wireless use. A recent auction gave broadcasters the option of voluntarily relinquishing spectrum and sharing the auction proceeds with the government.

TV White Space Channels
Cramer noted in a press release that TV white spaces technology has been shown to be “a viable and cost-effective way to make access to broadband available in extremely remote areas where there isn’t a Wi-Fi connection readily available due to buildings, hilly or mountainous terrain or general lack of population.” The observation about “buildings, hilly or mountainous terrain” references the excellent propagation characteristics of spectrum in the 600 MHz band that eliminate the need for a line of sight between the customer and the service provider’s base station.

According to the coalition letter, TVWS spectrum can support connectivity over distances as great as nine miles, which is in line with what WISPs deploying the technology have reported.

For several years, wireless internet service providers (WISPs) have been deploying service on an unlicensed basis using TV broadcast spectrum in rural areas where that spectrum is not in use by broadcasters. A key enabler was the development of spectrum sharing technology built into TV white spaces equipment and designed to track where spectrum is vacant and therefore available for unlicensed use.

The FCC previously ruled that the 600 MHz duplex gap and Channel 37 would be available post-auction on an unlicensed basis and supported by spectrum sharing technology. The commission also adopted a notice of proposed rulemaking that would reserve an additional 6 MHz channel in each broadcast market for unlicensed use. That proposal has not been finalized, but the Congressional letter spearheaded by Cramer asks the FCC to finalize it.

Fixed broadband wireless technology has been getting a lot of attention lately and claims have been made about the ability of some other spectrum bands and other wireless technologies to support non-line of sight communications.

The question is whether those other bands and technologies will be practical for the sort of limited-scale deployments in rural areas that are the focus of the Cramer letter.

Image courtesy of flickr user Stefano Brivio.