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FCC is overlooking interference as it considers band plan options, says NAB

The primary issue facing the FCC as it develops a post-incentive-auction band plan is “the real-world problem” of co- and adjacent-channel interference, NAB told the agency in comments filed last week.

In comments, filed in response to a public notice issued May 17 by the agency’s Wireless Telecommunications Bureau, NAB said the commission has “failed altogether to acknowledge” that serious engineering concerns must be addressed before moving forward.

“The band plan options introduced in the Notice skirt this issue (co- and adjacent-channel interference) entirely, evidently favoring academic economic flexibility over real-world engineering,” NAB said.

At the heart of NAB’s concern is that the Wireless Bureau’s does not adopt the “down from 51” approach which is “overwhelmingly” favored as an alternative to the notice’s “split” band plan. According to NAB, “…the Notice asserts that the ‘Down from 51’ approach ‘limit[s] the amount of market variation that can be achieved,” or put differently, constrains the Commission’s ability to ‘offer[] varying amounts of spectrum in different geographic locations, depending on the spectrum available.’”

Thus, what is driving the band plan proposals in the notice is “a nearly singular desire to permit the repurposing of different amounts of spectrum in different markets,” the comments said.

The association acknowledged the agency’s interest in looking for ways to permit intermittent market variability, the comments said, but to do so, requires the commission to “first grapple with the serious engineering challenges” that will be faced.

NAB said it and others have raised concerns with the agency about broadcasters and wireless carriers operating on the same and adjacent channels in neighboring markets. Not adequately addressing co- and adjacent-channel interference concerns could undermine the success of the incentive auction, it said.

NAB pointed to Auction 73 as an example of the deleterious effect of failing to resolve interference issues reducing auction proceeds. In the instance of Auction 73, “the 700MHz A block sold for only about 40 percent of the amount the B block did in the same auction,” it said.

According to NAB, the notice and the Notice of Proposed Rulemaking in this proceeding “scarcely acknowledge that separation distances — indeed, quite large ones — will be needed to mitigate inherent interference between broadcasts and wireless carriers operating on the same or adjacent channels.”

The problems are compounded by other factors, NAB said. The likelihood that 5MHz blocks will be used rather than the 6MHz blocks used for TV channels and that Economic Areas rather than Designated Market Areas will likely be used as geographic building blocks, dramatically magnifies the interference issue, NAB said.

Achieving Congress’s goals of more spectrum for mobile broadband and more revenue for the government can only be achieved by a nationwide band play, which “is the only proven way to eliminate widespread harmful interference.”