White spaces debate continues after testing
Aug 24, 2008 8:00 AM
The FCC’s Office of Engineering and Technology (OET) tested prototype white space devices in two high-RF environments last week: a Broadway theater and at a preseason NFL game. The agency did not offer a formal publication of results, which were witnessed by interested parties on both sides of the debate. The devices tested were submitted to the FCC by Philips Electronics and the Institute for Infocomm Research (I2R) in Singapore.
The debate has ramped up steadily over the past few years and has reached a fever pitch in recent months as the February 2009 deadline date for broadcaster to switch to digital program delivery approaches. The testing was designed to determine whether or not the devices could accurately sense both DTV signals and wireless microphone signals. Successfully doing so would protect both incumbent bandwidth users by, theoretically, instructing the device to switch to an open channel, thus preventing interference. Predictably, an outcome supporting their view was claimed by both supporters and opponents of using unlicensed white space devices in the unused portion of the TV spectrum.
One attendee, Mark Brunner, Shure’s director of industry relations, summarized the test results of the two prototypes: “They had problems in opposite directions,” he said. “The Philips device indicated that the channels were already occupied prior to the mics being turned on. Turning on the mics essentially made no change in the display. On the other hand, the I2R device’s initial sweep indicated that the channels were open. Then when the mics were turned on, it would not detect them. In almost all test locations, both devices showed no change between the mics being on or off.”
But Ed Thomas, a former FCC chief engineer and now a policy adviser to the White Spaces Coalition, said the tests were successful. “I think they went very well,” Thomas said. “The bottom line on this thing is that there was nothing unexpected from our perspective. The Philips device reached a decision in every case that wouldn’t interfere with wireless mics, and in no case did it say a channel was vacant when a device was on it.”
Meanwhile, as the contestants in this battle await the FCC’s interpretation and next steps, the political side of the battle continued to escalate. Eight members of the U.S. Congress signed a letter to FCC Chairman Kevin Martin in support of using white spaces for broadband Internet, while Google announced a YouTube-based grassroots campaign to drum up support for unlicensed airwave usage, which it has now dubbed “WiFi 2.0.”
For more information, visit www.fcc.gov/oet.
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