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The Register: ‘White Space Fillers are Hospital System Killers’
5/2/2008

In researching this week’s RF Report, I came across an article by Bill Ray titled “White space fillers are hospital systems killers” on The Register Web site warning that white space devices could disrupt medical telemetry systems that haven’t moved to Channel 37. Hospitals and medical facilities are allowed to use Channel 37, unlike broadcasters that can’t because of its significance for radio astronomy. (See “The Last Empty Channel” by Andrew Dart on the TV Technology Web site).

The Register articles quotes Tim Kottak, engineering general manager for GE Healthcare. “If a new white space application that’s operating thousands of times more powerfully came online, either in the hospital or outside the hospital, it could very well directly interfere with the telemetry system and prevent patient monitoring," he told the paper. The article says he wants the FCC to block off Channels 36 and 38 and, “just to be sure,” to block off Channels 33 to 35 for a year or so as many legacy systems operate in Channel 34.

Google has proposed removing broadcasters from UHF Channels 36 and 38 to allow use of that spectrum for wireless microphones and other users white space devices would displace. It isn’t clear from the article if GE Healthcare was asking broadcasters to vacate the channels or if only white space devices would be prohibited from using the channels. Channel 36 is currently used in many markets by TV stations, including NBC’s KNBC-DT in Los Angeles and Telemundo’s WNJU-DT in New York. GE owns both NBC and Telemundo, so it is unlikely that their plan is the same as Google’s, which would remove broadcasters from Channels 36 and 38.

There is a potential partial solution to the problem of white space devices interfering with medical facility devices. As a condition of their construction permit, broadcasters are required to notify all medical facilities in their coverage area before beginning or modifying their DTV facilities. Perhaps white space device users should be required to notify medical facilities (and possibly theaters, churches, sports facilities, and nuclear power plants—all of which now use TV “white space") nearby before being assigned a code to unlock their white space device. To prevent a user from taking his white space device to a location where it might interfere with a medical facility, a new code would have to be required when the device was moved outside the original coordination area.

Of course, if a white space user has to go through that exercise, a requirement to license or register the device (as is now required for 3650 MHz wireless links) and assignment of specific channels to the device might become more attractive, although hospitals would also have to register the channels used by their medical devices for such a requirement to be effective.
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