From all indications, FCC 04-113 is stalled, and it will be a difficult task to get it moving again in Chairman Kevin Martin's new FCC given the intense negative response to the idea by the Television Broadcasters (as I predicted).
One "everything else" element was a short-lived weblog devoted to the subject called Wireless Unleashed authored by four of my favorite people.)
There are now indications that Intel, Cisco, and Microsoft and other large companies are pushing hard to get FCC 04-113 moving again. An indication of the strange bedfellows this work is spawning is that excerpts from a private email mailing list called TVWHITESPACE have leaked out onto a mailing list run by the Wireless Internet Service Providers Association (WISPA), for which the corporate interests of Intel, Cisco, and Microsoft would otherwise have little in common. The "heat" in Congress over the repeatedly-stalled conversion to Digital Television Broadcasting, and the resulting "full" conversion of TV channels 52-69 to commercial and public safety communications use is causing related attention on license-exempt sharing of (remaining) Television Broadcast Channels after the conversion to digital broadcasting is complete.
The New America Foundation has published a number of commendable briefs and white papers on the complex subjects of US Spectrum Policy. Its latest (PDF Link) is:
Issue Brief # 17 October 2005
Reclaiming the Vast Wasteland
WHY UNLICENSED USE OF THE WHITE SPACE IN THE TV BANDS WILL NOT CAUSE INTERFERENCE TO DTV VIEWERS
By Michael J. Marcus, Paul Kolodzy and Andrew Lippman
It's nine pages of good reading, and I recommend it. The authors, the first two whom I've met, and know by professional reputation, and have enormous respect for their technical capabilities, do a good job of knocking over the Television Broadcast industry's straw men objections to the "very idea!!!" of license-exempt communications use of unused Broadcast Television channels.
While I understand the authors' intent in discussing all three methods of insuring non-interference with Television Broadcasting - Listen Before Talk, Geolocation/Database, and Local Beacon... in the real world only Listen Before Talk is the least bit viable... and I think that with a careful reading will most readers will agree. With the amount of Digital Signal Processing that can be inexpensively included in a new type of radio for license-exempt communications use of vacant Television Broadcast channels, it's completely viable that such a system could reliably exclude Television Broadcast channels that are actually in use for Television Broadcasting in a given area from being used for license-exempt communications. The complexities of embedding GPS receivers and a related database are fraught with peril and ultimately unworkable. This is particularly poignant when you factor in that it is all-but-certain that analog television broadcasting will have ceased by the end of the decade, and that over-the-air television broadcasting is used by, at best, 15% (and declining) of the television-viewing public.
(end of discussion of New America publication)
* My article, retitled to Wireless Smart Radio, Heavy Lobbying Would Bring Wireless ISP Band and poorly edited, appeared in Boardwatch Magazine Online - then at URL http://www.ispworld.com/boardwatchonline/2002/jan02/technology-wireless.htm. Boardwatch is no more, and Light Reading, the subsequent owner of boardwatch.com removed all the former content, but fortunately this article, at least, is available on the wonderful Internet Archives.
In a sense of Deja Vu... only in the last few months have Wireless ISPs actually begun to rally to this cause, though nowhere near the unified front that I recommended they would need to assume.
Note that my proposal/article, I "start" at Channel 14, since all the Digital Television conversion proposals at the time stated that as part of the transition, Television Broadcast Channels 2-13 would also be surrendered because their spectrum is far more valuable for communications use. Unlike Channels 14 and up, Channels 2-13 are not continuously located in the UHF band. Apparently the Television Broadcasters were able to maneuver themselves into retaining Channels 2-13.
I've subsequently learned that Channels 14-20 are used in some urban areas for public safety two-way radio communications. Such usage would be much more difficult to detect than television broadcasting, so unless the Smart Radio can be made "smart enough" to detect such usage, I may remove Channels 14-20 from consideration for license-exempt sharing. In my research at the time that Channels 52-59 would also be reallocated into the "Lower 700 MHz Band". My last mea culpa is that Channel 37, while allocated, is reserved for Radio Astronomy nationwide and thus no transmissions of any kind are allowed there. So, now my math on the available spectrum is Channels 21-51, minus Channel 37, equals 29 channels, for a total of 174 MHz of Television Broadcasting Spectrum - 512-608 MHz and 614-698 MHz, that is potentially available for license-exempt communications use. That's an incredible amount of spectrum, especially given that most... and often all of that will be available in rural areas where the propagation characteristics of this spectrum will be the most useful.
Below is the text of that article, as it appeared in Boardwatch Magazine Online, January, 2002.
Technology
Wireless Smart Radio, Heavy Lobbying Would Bring Wireless ISP Band
Operating in the 2.4 GHz band can be a difficult challenge for many ISPs because of interference issues. An oft-mentioned "cure" for such problems is reserved spectrum for wireless ISP (WISP) use. The technology is there, the obstacles are political. Broadcast lobbying forces, such as the National Association of Broadcasters, in Washington would fight the proposal, and it would take a united effort by service providers to push it to fruition.
The idea of a WISP band has merit and is achievable, especially in the context of local ISPs providing a cost-effective service to address the digital divide issue in non-metropolitan areas. The basic idea is to share, strictly on a non-interference basis, unused television broadcasting channels 14 to 59.
Channels 14 to 59 are the 470-746 MHz range and contain 276 MHz of contiguous spectrum reserved for television broadcasting. (Channels 2 to 13 and channels 60 to 69 are already slated for reallocation.) In contrast, the 2.4 GHz band is only 83.5 MHz.
Such a sharing scheme would only be possible with the emergence of a new type of radio - a smart radio. A WISP smart radio (WSR) is programmed to survey the 470-746 MHz spectrum. On any television channel where transmissions are heard, that channel is automatically "locked out" from being used by the radio.
A smart radio can make such a decision (whether or not there is a potential interference problem on a channel) in milliseconds, versus humans making the same decision in weeks, months or years.
One of the prime reasons for trying to make use of 470-746 MHz is that it has good penetration characteristics (trees don't stop signals at this frequency). Reasonable transmission power levels at 470-746 MHz are possible, with reasonable safety. A maximum power limit of 10 watts should be ample.
The technology to build a WSR certainly exists. Frequency Hopping Spread Spectrum (FHSS) modulation seems most applicable to WSR, as it can simply "hop over" television broadcast channels that are in use. I further propose that WSR be designed as a consortium, and standardization between manufacturers would insure interoperability and drive down costs.
Generating Revenue and Acceptance
There is a very real expectation that any new use of spectrum must generate some income for the government. A revenue generating approach that seems applicable to WSR is for a one-time "spectrum tax" applied to the final purchase price of each WSR.
The more use made of spectrum (the more units sold), the more government revenue generated. The expense is directly proportional to use, and the expense is incurred only after the additional business is generated.
The main obstacle in developing WSR is not technical. Television broadcasters and their industry organization, the National Association of Broadcasters (NAB; www.nab.org), are powerful forces in Washington, D.C. Any non-broadcasting use of television broadcasting spectrum will be fiercely resisted.
Wireless ISPs could overcome this obstacle with effective representation in Washington, D.C. To accomplish this, the WSR will require time, sustained effort, financial support and experienced lawyers. The Wireless Communications Association International (WCA; www.wcai.org) fulfills many of those requirements, and is an established, effective presence in Washington, D.C., representing wireless broadband service providers and equipment manufacturers.
The WCA certainly doesn't currently have budget to tackle a project as ambitious as WSR, nor the mandate. But if there were a groundswell of wireless ISPs joining WCA, then it could happen. If you are interested is joining the grass-roots effort, contact the WCA and find out how you can contribute.
One last suggestion is for manufacturers to build in the capability for WSR to work at 420-450 MHz with some reasonable substitution of components, with instructions on such a modification available only upon presentation of a valid amateur radio license. I, and my fellow 682,218 U.S. amateur radio operators, would greatly appreciate it.
(end of January, 2002 Boardwatch Magazine article)
By Steve Stroh
This article is Copyright © 2005 by Steve Stroh. Excerpts and links are expressly permitted (and encouraged.)
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