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FCC Considers Expanding Unlicensed Spectrum
Syntari writes "Reuters is reporting that the US Federal Communications Commission has begun to seek comment (the first step in promulgating regulations) "on whether unlicensed devices, like wireless home networks for Internet service, could operate on television broadcast airwaves in areas where they are not being used or at times when the spectrum lay fallow". The news release by the FCC itself, in MS-Word format, is online.
This is pretty big, as these things go - especially since television spectrum, being of a wavelength that easily penetrates walls and is not overly affected by rain or snow, is ideal for wireless services. Should any slashdotter actually want to submit a comment (gasp! could it be?), read this first (FCC's rules on electronic comment submission), and then go here."
more on this topic here: http://www.fcc.gov/Speeches/Abernathy/2002/spkqa21 8.pdf
FCC BEGINS INQUIRY REGARDING ADDITIONAL
SPECTRUM FOR UNLICENSED DEVICES
As part of the ongoing effort to promote efficient use of spectrum, the FCC today asked for public comment on the possibility of permitting unlicensed transmitters to operate in additional frequency bands. Such changes could allow the development of new and innovative types of unlicensed devices. This inquiry examines new and creative ways to utilize the spectrum resource more efficiently by considering new spectral frontiers for unlicensed use.
In a Notice of Inquiry approved today, the Commission stated that the current rules for unlicensed transmitters have been a tremendous success. A wide variety of devices have been developed and introduced under those rules for consumer and business use, including cordless telephones, home security systems, electronic toys, anti-pilfering and inventory control systems, and computer wireless local area networks. The success of those rules shows that there could be significant benefits to the economy, businesses and consumers in making additional spectrum available for unlicensed transmitters. Unlicensed transmitters may be operated under the provisions of Part 15 of the Commission's Rules. Part 15 transmitters generally operate on frequencies shared with authorized services at relatively low power, levels and must operate on a non-interference basis.
The Notice seeks comments on whether unlicensed operations should be permitted in additional frequency bands. Specifically, it seeks comments on the feasibility of allowing unlicensed devices to operate in the TV broadcast spectrum and locations and times when spectrum is not being used. It also seeks comment on the feasibility of permitting unlicensed devices to operate in other bands, such as the 3650-3700 MHz band, at power levels higher than other unlicensed transmitters with only the minimal technical requirements necessary to prevent interference to licensed services.
The Commission noted that there have been significant advances in technology that may make it feasible to design new types of unlicensed devices that are able to share spectrum in the TV bands without causing interference to licensed services operating in those bands. Advances in computer technology make it possible to design equipment that could monitor the spectrum to detect frequencies already in use and ensure that transmissions only occur on open frequencies. The low cost of GPS equipment could allow a device to determine its location and use information from a database to determine whether there are any licensed operations in its vicinity. Equipment can be designed that is frequency agile, with the capability of changing frequency as needed to avoid interference to licensed users.
Action by the Commission December 11, 2002 by Notice of Inquiry (FCC 02-328). Chairman Powell, Commissioners Abernathy and Copps, with Commissioner Martin approving in part and dissenting in part, Commissioner Adelstein not participating and Chairman Powell, Commissioners Abernathy, Copps and Martin issuing separate statements.
OET Docket No. 02-380
- FCC -
Office of Engineering & Technology Contact: Hugh L. Van Tuyl (202) 418-7506
If they open up these frequencies now, doesn't this mean that these areas are never going to get tv signals over the air ?
No, the advent of DTV [2] assures that this will happen. The FCC, NAB, and networks seem to be pushing DTV on us - a lot of people I know don't want it (it means being forced to buy new TV sets, digital-rights management, etc). But the FCC's clear on the matter; we're going to have DTV (eventually[2]) - DTV uses a different set of frequencies so within a relatively short amount of time, all the standard television frequencies we use now will become quiet and unused.
And, if these frequencies aren't being used now, doesn't this imply that the utility of e.g. wireless is somewhat diminished in these areas, if only because it seems likely that there aren't that many people there ??
That depends on what type of wireless system this is talking about - and I just don't know. Short range, say; between houses or you and your neighbors house, no problem. Long range - sure, your comment has merit to some extent, but remember that most TV frequencies are taken up. This is due to interference, signal propagation, and other things that prevent two tv stations on adjacent channels from being anywhere near each other. The same problem would plague high-powered/long-range wireless services.
footnotes:
[1] - DTV includes such services as HDTV
[2] - the date's been pushed back from (i think) 2004 to 2007, and probably will be pushed back again.
"The low cost of GPS equipment could allow a device to determine its location and use information from a database to determine whether there are any licensed operations in its vicinity. Equipment can be designed that is frequency agile, with the capability of changing frequency as needed to avoid interference to licensed users."
This means the devices will include the additional expense of a GPS chip and some way to contact the database to check if the location is safe for the frequency it wants, but this is certainly affordable. Heck, you can get a $130 phone from Sprint PCS that does all that (GPS and data network over 1xRTT). So, worst case, these devices will cost as much as a wireless NIC and a cell phone at the start. It is also possible that the database could be stored locally on the device (since TV stations don't move too often) with an expiration date, and need to be reloaded via a cable at some point or the device quits.
But cost aside, the problems you mention are addressed already in the proposal.
If you change the last three characters of the URL to pdf, you will see the pdf version, likewise with txt. I'm not sure why the story submitter chose to link to the word version.
Every official release from the FCC is in all three formats.
-Alison
How about trying PDF or text if you don't want the word version. In this case, the story submitter messed up, not the FCC.
-Alison
and carry LESS information than 2.4Ghz the amount of information you are able to carry in a frequency channel is DIRECTLY coupled with the frequency and width of the channel you use. in the 50MHZ range where channels 2 and 3 reside you CANNOT transmit very much without using alot of the spectrum with a wide channel. I.E. you are using tons of frequencies to transmit the same information that is able to be transmitted on a few in the higher frequencies. and to do this you need Gobs more power.
Huh? The bandwidth required is not dependent on frequency. A television channel takes 6MHz no matter where you put it in the spectrum... 50MHz, 400MHz, 1.2GHz, etc.
The power required for an equivalent coverage area varies, yes, but the bandwidth required does not. If you modulate a 10MHz carrier with a television signal, you'll suck up 6MHz of space.
I think this is a common misconception because of the way the spectrum is currently laid out. The reason that high-bandwidth items are higher in frequency is simply that they were developed later in history than other uses. Therefore, they got higher frequencies because those below it were allocated and didn't provide enough available space for that particular purpose.
If you could find a 25MHz chunk of bandwidth at any frequency you could run 802.11 stuff. Your power requirements would vary, of course, and your antenna would change size (and perhaps shape).
It's not magical. we use 2.4ghz because at low powers and small channel widths we can spew lots of information... as your frequency goes down the wider you need to be and the more powerful you need to be.
That is just wrong. We use 2.4GHz because that's where the available spectrum is, not because there's something magical about 2.4GHz itself.
The only thing special about higher frequencies versus lower ones is propogation concerns (higher frequencies tend to go less distance with an equivalent power output) and antenna design.
The bandwidth required does not change.
All opinions presented here aren't mine.