The US court of appeals ruled against the National Association of Broadcasters (NAB), which had challenged “key elements” of the Federal Communications Commission’s (FCC) framework for its spectrum incentive auction, set to take place in the first quarter of next year.

“Petitioners argued that certain Commission decisions announced in the orders conflict with the Spectrum Act or are otherwise arbitrary and capricious. We deny the petitions for review and sustain the Commission’s orders,” wrote Circuit Judge Sri Srinivasan.

The sale is unusual in that the regulator is buying back spectrum from TV broadcasters, and then selling it to the mobile industry, which is trying to keep up with capacity demands.

Low-band airwaves, such as the 600MHz spectrum on offer via the incentive auction, are coveted by the mobile industry. They provide wider coverage than higher frequencies, as well as deeper in-building penetration.

NAB and Sinclair Broadcast Group, however, were worried about the impact the auction would have on TV stations and on the methodology used to predict local coverage areas and the population served.

FCC Chairman, Tom Wheeler, was “gratified that the court agrees with the commission’s balanced, market-based approach to freeing up more valuable spectrum for innovative wireless broadband services,” adding that the decision will help the commission “proceed apace toward a successful auction”.

Executive vice president of communications at NAB, Dennis Wharton, said “we’re disappointed with the ruling, which we believe fails to hold the FCC to the letter of the law passed by Congress,” adding that “NAB’s focus has been on preserving a robust local television service that is the envy of the world.”

Back in March, NAB president and CEO Gordon Smith told Mobile World Live that massive returns from the $44.9 billion AWS-3 auction had made broadcasters more willing to participate in a sell-off of their own frequencies but also stressed that regulators need to safeguard spectrum for the broadcasters.

In April, the FCC said it was on course for the auction and Wheeler told the NAB Show in Las Vegas the agency would begin accepting applications in autumn 2015, ahead of the 2016 contest.

Among operators, AT&T has shown the most enthusiasm for the 600MHz frequencies. T-Mobile US and Dish have also said they would take part in the contest.