By Cindy Atoji
May 13, 2008 | Next year, when broadcasters make the switch from analog to digital broadcasting, some wireless frequencies will be up for grabs. Tech giants like Google and Microsoft are lobbying to have to have these so-called “white spaces” used for next-generation consumer devices. But hospitals using remote patient monitoring could be negatively impacted, says Tim Kottak, engineering manager for System and Wireless in GE Healthcare.
“If a new white space application that’s operating thousands of times more powerfully than those in a hospital or outside the hospital, came online, it could interfere with the telemetry system and prevent patient monitoring,” says Kottak.
Last week, filings urged federal regulators to put a buffer zone around the spectrum used for medical telemetry (also called WMTS or Wireless Medical Telemetry Service, which operates on Channel 37), an encouraging development for hospitals. Kottak says these filings ask that certain channels be off-limits and would require device operators to alert medical institutions before deployment.
As the time for digital conversion nears—February 2009—the debate over the unused airwaves continues, as well as its potential impact on health care, especially if, for example, heart or blood oxygen monitors operating on radio frequency are disrupted. Kottak discussed the white space controversy to Digital HealthCare & Productivity, as well as other wireless challenges for hospitals.
DHP: The FCC (Federal Communications Commission) is expected to make a decision this summer on how the white spaces can be used. What do hospitals need to know, especially those with older systems that might not using the protected band?
Kottak: Number one, that there is a limited timetable for legacy telemetry devices that are not designed for WMTS. The FCC has set aside Channel 37 of the broadcast TV band as a protected area for exclusive use of medical telemetry devices, but some older systems are still operating outside that band. These systems can cost millions of dollars to upgrade, and health care facilities will need to identify and address the source of interference or replace equipment with newer, protected Channel 37 installations. These legacy systems often use Channels 33-35, and we’re advocating to the FCC to give the healthcare industry another year, until February 2010 to make the conversion and get out of these spectrums before they’re used.
DHP: What about medical centers that are already on the protected band?
Kottak: After an incident at Baylor Medical Center in Dallas when interference disrupted patient monitoring, the FCC cordoned off a spectrum—Channel 37—for wireless medical telemetry. One of the challenges is that with white spaces possibly being freed up for other uses, there will be the risk of interference again. So obviously if there was a really strong signal on Channel 38, for example, it could take out part of Channel 37 and render patient monitoring interference.
Some of these devices may be thousands of time more powerful than what’s in a hospital. The patient-worn devices in a hospital are very low-power and they don’t have to transmit for miles. We’re advocating certain guidelines to the FCC and to the industry to avoid that risk. The recommendation is that adjacent Channels 36 and 38, should be guard bands, to provide adequate protection for Channel 37, and also that certain power levels cannot be exceeded that would bleed over into Channel 37.
The legislation has not been solidified, and there is an opportunity to weigh on this. We’re not talking about a big part of spectrum that we’re asking to be set forth and guard banded—there are hundreds of megahertz of unlicensed spectrum available for voice, data, and video use.
DHP: How are medical telemetry systems currently regulated, to ensure there is no interference with broadband cable or other wireless technologies?
Kottak: The FCC authorizes ASHE (the American Society of Healthcare Engineering) part of AHA (American Hospital Association), as a neutral body to educate hospitals on the purpose of WMTS and to be the frequency coordinator for WMTS. What typically happens is a hospital will purchase a telemetry system, register it with ASHE, and ASHE has a public database of who is using spectrums. If there is a case where hospitals are right next to each other and are worried about competing use of that spectrum, the ASHE would be the arbitrator and intervene to work out a resolution. TV broadcasters today have to notify hospitals if they are testing or bringing a new TV station online. So if there is a nearby TV station, hospitals would have notice and could take steps if needed for extra filtering for Channel 37.
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