You've probably heard that television broadcasts are transitioning from analog to digital in February 2009. Digital channels uses less power and less bandwidth, so there's no need for what are called geographical guard bands. For example, in a city that has TV channel 19, the station may also license channels 18 or 20, which are practically unused, to prevent broadcasting interference. After Feb 2009, each TV station will only use one frequency channel. This means spectrum will be freed up for other uses such as consumer products with Internet capabilities.

Currently, within the television band channels is spectrum set aside for medical devices. In 2000, the Federal Communications Commission, FCC, designated 6 MHz of spectrum, or one full television channel, channel 37, for the Wireless Medical Telemetry Service, WMTS. Hospitals use this dedicated spectrum for telemetry, patient-monitoring devices used to monitor ECG and other vital signs. The wireless devices let patients get mobile by walking to labs or X-ray rooms while still under watch of the hospital staff.

The FCC decided to dedicate channel 37 to WMTS after an incident at Baylor University Medical Center, Dallas, where a television station came on line and disrupted patient monitoring. It took the hospital over 24 hours to figure out the cause while patient lives were at risk.

Now the FCC is considering unlicensed use of these TV white spaces, or freed spectrum. Unlicensed use means that anybody meeting the FCC's rules for that spectrum can use it, for example, laptops that operate wirelessly in Wifi hotspots.

The FCC released a “Notice of Proposed Rulemaking” for the regulation, which includes draft guidelines on which industry may comment. The agency takes those comments and makes changes as needed, and the notice becomes a regulation.

The agency does not plan to change the WMTS designation but medical-device industry leaders are stepping up to make further recommendations to the FCC proposal. According to Tim Kottak, Engineering General Manager of Systems and Wireless at GE Healthcare, the first suggestion is to establish channels 36 and 38 as guard bands, with technical limits on spurious emission, or signal power transmitted outside of the intended channel. This ensures new unlicensed devices don't interfere with much lower power WMTS devices operating on a protected, licensed basis in channel 37.

A second recommendation, according to Kottak, concerns older devices that were designed before WMTS was established that still operate in TV white spaces, typically channels 33 to 35. When WMTS was established, the FCC stated that hospitals could continue using these legacy products indefinitely. Because most hospitals are not aware of the potential impact of new white space devices directly interfering with legacy telemetry products, GE Healthcare is also recommending a one year extension (to Feb. 2010) before new white space devices could operate in channels 33 to 35. With this extension, hospitals will have more time to transition these legacy systems to new equipment that operates within WMTS. This will minimize the risk to patient safety.

Another point of note is the relatively small amount of spectrum in discussion. There is hundreds of megahertz of spectrum currently available for unlicensed use for consumer products, so these recommendations to the FCC are fairly reasonable in the interest of patient safety.

The FCC is expected to make a ruling by summer of 2008. A group called the White Spaces Coalition, which includes companies like Google, Dell, Microsoft, and Intel, is lobbying the FCC to open these white spaces to consumer products, and they are aware of WMTS and the need for the dedicated channels. Should they get the right to make consumer devices, they understand those products have to be safe and effective in and out of the hospital.