08.16.2007 11:08 AM
Originally featured on BroadcastEngineering.com
Group of CE makers files comments opposing spectrum-sensing white space devices
Some of the world’s largest consumer electronics manufacturers jointly filed comments with the FCC Aug. 15 opposing any commission decision allowing the use of unlicensed personal and portable devices that rely on spectrum-sensing technology to avoid interfering with television stations and wireless mics.
In the filing, LG Electronics, Panasonic Corp. of North America, Samsung Electronics and Hitachi Home Electronics contend that interference from such unlicensed devices “could derail the DTV transition,” slated for Feb. 17, 2009.
The companies urged the commission “to exercise caution” in allowing the use of devices that could prevent “reliable reception of digital television signals or the use of digital cable-ready sets.” On July 31, the commission’s Office of Engineering & Technology released two reports detailing the results of FCC Laboratory testing of prototype white space devices that at best, in the worlds of one report, turned in “mixed” results. Microsoft, one of the companies submitting a prototype for FCC testing to evaluate whether or not it’s possible to detect the presence of a DTV signal or wireless mic transmission on specific frequencies and automatically select an unused frequency in the TV band for operation, subsequently filed ex parte comments with the commission saying its device failed because of a “broken” component.
It was no surprise that Microsoft claimed its device was “broken” because receivers are especially vulnerable when they operate “in weak signal conditions” that “the FCC has found to occur in up to 84 percent of a station’s coverage area,” the joint filing said. Devices that use spectrum sensing “will fail to detect these weak signals in most situations.”
“In light of the results of its recent studies, the Commission should not authorize devices that rely solely on spectrum sensing, but instead should move forward with its more developed proposal concerning fixed devices that use a geolocation/database approach to interference avoidance,” the joint Aug. 15 filing said.