what do white spaces devices have to protect

A Notice of Proposed Rulemaking proposing greater coverage areas for unlicensed “white space” devices operating in the TV bands was adopted at the FCC’s open meeting last week and released earlier this week.   We have written about these white space devices before (see, for instance, our articles here and here).  These devices operate at relatively low powers in unused portions of the TV bands.  They are designed to offer wireless services, including broadband.  Advocates of these operations see them as an inexpensive way to offer broadband services to underserved areas, including parts of rural America.

The concern of course with these devices is that if their use is not managed correctly, their operations could interfere with existing TV operators (including LPTVs, TV translators, broadcast auxiliary services, and wireless microphones).  Thus far, operations have been limited to power levels of 10 watts or less from antenna heights that did not exceed 250 meters height above average terrain.  The advocates for these devices, including Microsoft, have argued that these low power levels make it difficult to serve rural areas given their small coverage area.  NAB, on behalf of broadcasters, and advocates for wireless microphone operators, have urged caution in any increase in the coverage of these operations if they could possibly cause interference to existing users of the spectrum.  After significant discussion and compromise between the NAB and Microsoft, the NPRM adopted last week tries to strike a balance between these positions.
Continue Reading FCC Adopts Notice of Proposed Rulemaking Looking to Allow Higher Power and Greater Height for Unlicensed White Space Devices Operating in the TV Bands

The FCC this week released the details of its "White Spaces" decision, authorizing the use of both fixed and mobile unlicensed devices within the television spectrum.  In theory, these devices are supposed to be able to sense the existence of television signals so that they can operate on other frequencies and avoid creating interference.  However, as an extra safety measure, the FCC has also required that these devices connect at least once a day with a database of all other protected users of the television spectrum and, by used of geo-location technology, determine what other users are in the area where the "TVBD" (television band device) is being used and operate on frequencies which protect those other users.  Our firm has prepared a memo outlining the full decision.  The Davis Wright Tremaine memo can be found here.  When one reviews the full text of the FCC decision, it becomes pretty clear that we should not look for such devices anytime soon.

While the Commission’s order actually discussed in some detail the question of whether these devices should be permitted to operate before the end of the digital television conversion in February 2009, given the issues that still need to be resolved, this discussion really appears to be an academic one.  First, devices that meet all of the FCC requirements have to be designed and built, and type-accepted by the FCC labs.  In a recent article by Shelly Palmer in his well regarded blog on television issues, he suggests that many engineers are convinced that these devices simply will not work.  When one reviews the FCC requirements, one can see why that might be the case.


Continue Reading Details of White Spaces Decision Released – Don’t Look for Them Soon as There is Lots to Do Before Any Devices Will Be Introduced