The National Association of Broadcasters is raising objections to a Federal Communications Commission report suggesting that unlicensed wireless devices could operate in vacant slices of the white-space spectrum without causing interference to adjacent TV channels.

The NAB said the executive summary released by the FCC's Office of Engineering and Technology is actually contradicted by the report's key findings.

"It would appear that the FCC is misinterpreting the actual data collected by their own engineers," said NAB Executive Vice President Dennis Wharton. "Any reasonable analysis of the OET report would conclude that unlicensed devices that rely solely on spectrum sensing threaten the viability of clear television reception."

Not So Fast

The FCC is expected to consider approving white-space devices at the next meeting of the five commissioners on Nov. 4. The move would be a victory for Google cofounder Larry Page, who recently told members of the Wireless Innovation Alliance that he hoped the FCC would act before the results of the November elections were in. "We can show real leadership in the world in a way that matters to everybody," Page said.

However, the trade association representing the nation's broadcasters wants the FCC to seek public comments on its report before it decides to move forward. "With the transition to digital television looming and tens of millions of TV viewers at risk, the stakes are too high for this proposal to be rammed through without thoughtful deliberation," Wharton said.

The NAB said the test results documented in the report clearly show that the spectrum-sensing technique used by the white-space devices that were tested is clearly not reliable. For example, the report said Microsoft's prototype sample device "began to malfunction and eventually ceased to operate, necessitating the abandonment of further measurement utilizing this device."

And with respect to the prototype devices that the FCC tested in the field, the NAB said their ability to properly sense the presence of television signals fluctuated wildly. Two devices also failed to detect occupied channels with complete reliability, the trade association said.

No Big Deal

Page remains skeptical about the NAB's objections. "If you look at all the people who are all arguing against this, they all directly benefit, against the public good, in this area," he said.

Broadcast TV stations typically transmit using 100,000 watts of power, he noted. Given that the power output of white-space devices is minuscule by comparison, "worrying about interference is just crazy," Page said.

The prototypes that the FCC has tested so far are being "treated like a device that's available for general release" to the public, Page commented. Once the FCC grants approval, Page explained, "hundreds of millions of dollars will be invested" to ensure that interference absolutely won't be a problem.

Under Google's recommended design approach, no white-space device would be able to transmit without first receiving permission based on reference to a TV-station database that would identify the specific areas where interference remains a concern. Google's Geode geolocation technology would help white-space devices keep track of precisely where they are at any given moment.

"It's not a big deal to know where you are -- even with a mobile device," Page said. "So we can remove the issue entirely by saying we are not going to broadcast in areas where we know there are TV stations."