'White Spaces' Issue Remains murky


FCC tests of prototype wireless radios that would use unoccupied parts of the broadcast spectrum—the so-called “white spaces”—without requiring an FCC license to operate on broadcast channels, were an increased source of debate last week. While some broadcasters and theater owners opposed their use, technology companies like Microsoft and Google backed the new devices.

The FCC evaluated the devices at a sports-production test during the Washington Redskins-Buffalo Bills preseason NFL game on Aug. 9, and a theater production of Phantom of the Opera last week at the Majestic Theater in New York.

Sports leagues, microphone manufacturers and theater owners have lobbied aggressively against the proposed “unlicensed devices” because they believe they will cause interference to existing operations.

The tests were designed to gauge the performance of spectrum analyzers in two prototype devices, one developed by Philips and the other by Singapore's Institute for Infocomm Research (I²R). The devices are supposed to be sensitive enough to identify the operation of both existing UHF broadcast channels and wireless microphones, and thus not transmit in channels where they would cause interference to existing signals.

The FCC hasn't formally disclosed results. But proponents and opponents have both proclaimed victory.

According to Mark Brunner, a spokesman for wireless microphone manufacturer Shure who attended both events, the field tests didn't show the prototype devices to be very accurate in sensing the operation of wireless mics in a live environment. The Philips device indicated that all channels were occupied, even when they weren't, while the I²R unit didn't sense any wireless mics and proclaimed all channels to be available. “They had problems in opposite directions,” Brunner says.

But Ed Thomas, a former FCC chief engineer who is now a policy adviser to the White Spaces Coalition—which counts Google, Microsoft, Dell and others as members—says the tests were successful: “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 said a channel was vacant when a device was on it.”

Motorola wasn't involved in the most recent tests, but thinks it has a solution to the interference issue by transmitting a “beacon” that unlicensed devices would detect that could be referenced against a “geolocation database” of existing spectrum users. It hopes to give a demonstration to the FCC this week.

For more detailed accounts of the white-space tests and debates, go to www.broadcastingcable.com.