INTRODUCTION
These reply comments are being filed by a coalition of the New America Foundation and other entities (NAF et al.) listed on the cover page. These entities include nonprofits, corporations, and professors of engineering, and they have joined in urging the Commission to complete positive action in its proposals in this proceeding. These entities have explicitly reserved the right to file reply comments individually. These coalition comments only concern issues on which the above entities were able to reach consensus.
Increasing use of TV broadcast spectrum in a way that protects existing users will also further the Commission's goal of using spectrum more efficiently. The spectrum is an exceedingly valuable resource and increasing its utilization will contribute to economic growth in both FCC-regulated industries and throughout the rest of the economy. The proposals in the Notice basically are valid as will be shown below. Some legitimate concerns about the specific proposals have been raised in the comments and New America et al. address those concerns in these Reply Comments and show how modifications of the original proposals could eliminate concerns about interference.
While some would like to portray this Notice as an unprecedented step to use unproven technology, it actually builds on precedents in FCC action, commercial products, and military R&D. Cordless telephones have used dynamic frequency selection for about a decade to improve spectrum use and minimize interference. The Commission has already authorized software-defined radio and in an ongoing rulemaking is considering improving the security of the software. The Commission has already authorized a software-defined radio developed by one of the members of this coalition. The Commission proposed in its Notice three different techniques that could be used to enable unlicensed use in TV band "white space": geolocation/GPS with comparison to database of licensed facilities, listen-before-talk systems that look TV signals before selecting a free channel, and systems using local beacons that identify free channels.
Geolocation technology using GPS is already widespread and has been recognized by the Commission in the E-911 context. Other geolocation technologies with better indoor coverage are under development. Fail-safe applications of such geolocation technology can be implemented in a straightforward way that would allow unlicensed transmitters to turn on only if they are in "white space" where they cannot cause interference. Ironically, the limiting factor of such systems may be the present accuracy and timeliness of the Commission's publicly available databases. This problem can and should be resolved independent of this proceeding.
The Notice proposes that portable unlicensed devices could detect and avoid TV signals by having a detection system much more sensitive than normal receivers.1 It is a basic technical fact that it is much easier to detect a signal than to demodulate. A detection system can accumulate signals for a long time before it makes a decision about whether a specific type of signal is present. By contrast, a normal receiver must decide what signal is present very quickly, which in the case of DTV is about 20,000,000 decisions/second.2 Several commentors have said that it is possible to have a TV signal detector that is more sensitive than a TV receiver by simply using a very narrow bandwidth. Other commentors have pointed to "cyclostationary" or "feature" detector technology, featured at a Commission Tutorial on February 12, 2003, which is even more sensitive than the narrow filter approach. Thus technology is available to reliably detect weak TV signals and prevent interference.
The final enabling mechanism in the notice was the use of a beacon signal to signal what TV channels are available. The proposal in the Notice did not specify adequately that the range of the beacon signal had to be comparable to the validity of its contents since "white space" is location dependent. New America et al. suggest below a clarification that eliminates this concern.
NAF et al. are organizing these reply comments to focus initially on the points raised in the Joint Comments of The Association for Maximum Service Television, Inc. and the National Association of Broadcasters (MSTV/NAB) filed November 30, 2004. MSTV/NAB represent a large number of entities concerned about the proposals in this proceeding and their comments cover more issues than other commentors who were opposed to the proposals. After the points raised by MSTV/NAB are discussed, NAF et al. will address points raised in other comments. In each case the Commission can adequately address each raised issue with either the proposed rules in the Notice or straightforward modifications of the proposed rules in the Notice.
The coalition members all agree that making additional unlicensed spectrum available in lower bands is very important to the development of the information society in the US and in removing barriers to broadband in rural areas. Additional alternatives to broadband service, such as proposed in this docket, will also spur competition, innovation, and decreased costs in the provision of broadband services.
To view the full comments, please see the PDF file linked below.
