As the FCC’s incentive auction of 600 MHz spectrum passes the finish line, carriers are pushing hard to get their hands on those airwaves as quickly as they can.

The assignment phase of auction closed today, wrapping up an auction that started more than a year ago. Bidders committed more than $19.63 billion for TV broadcasters’ airwaves during the auction, and proceeds from the assignment phase—in which winning participants bid on exactly which blocks of spectrum they want in each market they won—provided an additional $136 million.

The FCC won’t release the names of winning bidders for roughly two more weeks, when the agency's so-called “quiet period” ends. But operators are already urging the agency to stick to the 39-month repacking plan it has allotted to reshuffle TV broadcasters’ airwaves for wireless use to avoid interference problems as the spectrum is redeployed.

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The National Association of Broadcasters recently asked the FCC to reconsider its timeline, calling it a “flawed” schedule (PDF) that doesn’t give ample time to move to new channels. The 39-month timeframe “essentially seems to reflect the hope” that the transition will occur perfectly, the NAB said, adhering to an “arbitrary and unfounded” deadline rather than a realistic schedule.

The Competitive Carriers Association struck back this week in its own FCC filing, however, describing the NAB’s claims as “a regurgitated challenge” to the proposed deadline.

“The record in this proceeding demonstrates a real and significant need for expeditious clearing of 600 MHz spectrum for wireless broadband services,” CCA said in the filing. “Introducing delay and uncertainty will have an adverse impact on deployment of rural broadband services, jobs, education, healthcare, and the ability of the United States to compete in a global economy.”

The battle between broadcasters and wireless carriers to free up the 600 MHz spectrum for wireless use has been raging for at least as long as the auction has unfolded. T-Mobile, which hopes to put some of those airwaves to use as soon as late this year, filed a 29-page document with the agency last June claiming the schedule gives broadcasters plenty of time to move off the spectrum onto other bands.

But whether the FCC reconsiders its proposed timeframe—and whether broadcasters will be able to comply—remains unclear.