Reclaiming the Vast Wasteland: The Engineering Case
Policy Paper
Oct. 18, 2005
On May 13, 2004, the Federal Communications Commission approved a Notice of Proposed Rulemaking (NPRM) proposing to allow a new generation of wireless devices to utilize vacant television channel frequencies in each market. This so-called TV band “white space” consists of frequencies that are allocated for television broadcasting but are not actually in use in a given area. The FCC’s proposed rulemaking is pending but currently inactive.
The proposed rules are intended to make way for technologies that utilize unlicensed spectrum, such as Wi-Fi, to utilize the prime TV band spectrum to offer wireless broadband services. Wi-Fi technology has become very popular at higher frequencies, and has had a positive impact on the growth of broadband services. However, the bands used for Wi-Fi do not have appropriate radio propagation characteristics to serve low population densities. Lowerfrequency spectrum, such as that used for TV broadcasting, is capable of traveling longer distances at a given power level, and can better penetrate obstacles such as buildings and trees.
The FCC’s proposal would promote both spectrum efficiency and wireless broadband deployment. The TV band has been called a “vast wasteland” of underutilized spectrum. Even after the completion of the DTV transition – and the reallocation of TV channels 52-to-69 – an average of only seven full-power DTV stations will be operating on channels 2-to-51 in the nation’s 210 local TV markets. Only a fraction of the 294 MHz of prime spectrum allocated to DTV services will actually be utilized in most markets.
Thus, the proposed use of “white space” TV channels could have a particularly great impact on the growth of information services in rural areas, where such empty channels are readily available. In urban areas, where less “white space” is available, this spectrum would also be useful because of the great demand for wireless broadband services and because of the ability of the TV band spectrum to penetrate buildings and objects within buildings better than the higher bands.
The FCC was clear in this NPRM that any devices certified to operate in the TV white spaces would be required to use new “smart radio” technology that would not interfere with television reception. Nevertheless, the National Association of Broadcasters (NAB) and other broadcast industry representatives, in comments filed at the FCC and in communications with Congress, have objected to the FCC’s proposal, claiming that unlicensed devices operating on vacant channels in the TV band would cause harmful interference to television broadcasts and other uses of licensed TV band channels.
This Issue Brief responds to the broadcast industry’s allegations, addressing each of the industry’s concerns about interference. The paper concludes that interference-free unlicensed use of the white space is practical with today’s technology. While some of the issues raised here are novel, the FCC as an "expert agency" should be able to handle them as it handles other cutting-edge spectrum problems. Indeed, the FCC is required by statute to avoid harmful interference with licensed TV broadcasts – and its NPRM describes several different ways to protect the dwindling number of over-the-air TV viewers from interference.
For the complete document, please see the attached PDF version below.