FCC Extends White Spaces Testing

Broadcasters say wireless devices garble DTV signals
Author:
Publish date:

Broadcasters said last week that wireless devices are interfering with the DTV spectrum in lab tests, while backers of the devices counter that the tests aren't conclusive.

Nonetheless, the FCC said last week it will extend those lab tests—which were to have ended—before it takes the devices out into the field. At stake, say broadcasters, could be the fate of the DTV transition.

The devices are intended to simulate laptops and “smart radios,” which are meant to sniff out available spectrum to broadcast on and which the FCC wants to be able to share the spectrum band with digital TV stations.

Broadcasters don't oppose licensed devices using the band because they can be monitored and controlled. But they fear unlicensed devices will interfere with TV signals and wireless mics used for sports broadcasts and other programming, with little the FCC can do once they are allowed to share the band.

According to David Donovan, president of MSTV, which says it has been monitoring the tests, the Microsoft device and two Philips devices in what is the second round of lab testing have had trouble sensing wireless microphone signals. In addition, he says, they don't appear to be sensing DTV signals properly, finding that all the channels are occupied, so-called “false positives,” when they are not, even when tested in a chamber that is supposed to prevent any RF (radio frequency) signals from being received.

“Once again these devices appear to have fundamental problems,” Donovan told B&C. “Last year they said the device was broken. Earlier this year it was a power source. Now the device fails and senses signals that are not even there, and fails to sense signals that are present.”

Good outcome

“I think the FCC's time would be better spent doing technical work on the DTV transition rather than trying to push technology that simply does not work in the lab, let alone in the real world,” Donovan adds.

“Our sense is that the FCC is getting the test results it needs from the devices it is testing to set final rules allowing the use of the white spaces,” said Microsoft spokeswoman Ginny Terzano.

Brian Peters, a spokesman for the Wireless Innovation Alliance, a computer industry-backed group that includes Microsoft, Google, Dell, and HP, agreed.

He said that his understanding of the test is that there was something wrong with the chamber or the testing procedure, rather than the devices, and that it was addressed by the engineers.

“Instead of mischaracterizing the FCC analysis, they should actually recognize that this is not a pass/fail proposition,” Peters said. “In our view, every piece of information is another step toward completing analysis and moving forward toward final rules. So, the broadcasters can call them failures, but there is no such thing as a failure at this point. This is an analysis, it is not a certification pass/fail.”

Bad outcome

The first strike, opponents of the unlicensed devices argue, was in the FCC's first round of testing. The prototype devices sense out open frequencies to use, but broadcasters said they don't do that well enough to prevent interference with digital-TV signals. The FCC's first round of testing appeared to bear out that fear, though proponents of the devices blamed it on equipment that wasn't working correctly.

The second “strike” was last month, when Microsoft withdrew one of the devices it was testing. Microsoft called it a problem with a power supply, rather than the device's ability to sense signals.

Broadcasters saw it differently. “By failing two out of two tests at the FCC,” NAB spokesman Dennis Wharton said at the time, “Microsoft and the Wireless Innovation Alliance have demonstrated that unlicensed devices are not ready for primetime.”

FCC commissioners have been generally supportive of allowing the devices, with the caveat that they not interfere with DTV signals as broadcasters prepare analog operations.

But broadcasters got a boost in their fight from Rep. Jerrold Nadler (D-N.Y.), recently wrote an op-ed in The New York Times urging the FCC to move cautiously and warning that the devices “could disrupt the new digital-TV signals that government and industry have spent so much time and money to promote.”

FCC spokesman Robert Kenny said he could not comment on how any device fared in the test, but said testing them remains a priority for the commission. He also couldn't say how long the lab tests would be extended. There will be field trials after that, he said, with a schedule ultimately posted on the commission's Website.

Related