AT&T is clearly still a little annoyed that the Federal Communications Commission thwarted its bid to acquire T-Mobile.

During a Thursday earnings call, AT&T chief Randall Stephenson talked up the need for more spectrum, but said the carrier is at a loss for how to proceed because of the rather arbitrary way in which the FCC handles the issue.

Specifically, Stephenson called out the FCC for applying its "spectrum screen" standards differently when evaluating the T-Mobile deal and when considering the (now-approved) Qualcomm spectrum transfer.

"We don't know what spectrum caps are going to apply with one transaction to the next," Stephenson said. "The first issue is not identifying [available] spectrum, but what the rules are."

In a statement, an FCC spokesman said the AT&T/T-Mobile deal was "unprecedented on many levels." Ultimately, however, the FCC and Justice Department concluded it was not in the public's interest. "Those conclusions surely disappointed AT&T executives, but they followed directly from the facts and the law," the spokesman said.

While spectrum might seem like a rather boring topic to the average consumer, its availability might eventually have an impact on how well your mobile devices work. At this point, the wireless carriers have enough spectrum to keep their networks running, but they argue that with more and more people picking up smartphones and other data-hungry devices like tablets, that bandwidth is running low. As a result, companies with excess bandwidth - like Qualcomm - have been selling it off to the highest bidder.

In determining whether to improve spectrum deals, the FCC evaluates the companies' current holdings to see if a transfer would result in anti-competitive holdings. Until 2003, the FCC consulted a broad "spectrum cap," but it eliminated that process in exchange for a "spectrum screen" that evaluates deals on a case-by-case basis.

Stephenson argued today, however, that the "spectrum screen" is arbitrary and leaves companies like AT&T in the dark as to whether their spectrum deals will gain FCC approval.

"Our biggest issue is figuring out what we're allowed to do," he said. "We don't know how much spectrum we're allowed to hold."

The issue is not a new one, however, and FCC chairman Julius Genachowski discussed it in a December letter to House Energy and Commerce chairman Fred Upton about the failed AT&T, T-Mobile deal.

"The Commission developed an initial spectrum screen during its review in 2004 of the Cingular/AT&T Wireless transaction to identify or 'trigger' specific markets for further competitive evaluation," Genachowski wrote. "It has no actionable effect; it is merely a tool used to narrow the Commission's focus on markets where there may be a higher level of concern. The screen is triggered when a transaction would aggregate more than approximately one third of the spectrum suitable for the service at issue (e.g., mobile broadband) in a particular market in the hands of one entity."

In approving the AT&T-Qualcomm spectrum transfer, the FCC said that "relatively few" markets were triggered for further analysis.

In the Qualcomm order, the FCC acknowledged that some companies have urged a review of the spectrum screen, but said it has no plans to change the process at this time.

"While we are not revisiting the spectrum screen for the purposes of evaluating this particular transaction, we anticipate that as we consider the input market for spectrum in future transactions, revisions to the screen may be necessary," the FCC said.

The FCC spokesman today, meanwhile, pointed out that the FCC has approved more than 150 commercial mobile transaction applications in the past year and more than 300 in the past two years, "facts [that] were completely ignored in the [AT&T] conference call," he said.

The CEO Who Cried Spectrum?
Stephenson, meanwhile, is just the latest wireless carrier CEO to ask for more spectrum. AT&T's network can currently support the planned rollout of its 4G LTE network, but "utilization rates are running hot," he said.

In this "capacity-constrained environment," tiered data plans, increased prices, and throttling are "logical and necessary steps" to manage usage, Stephenson said.

The LTE rollout will give AT&T a 30-40 percent "lift in network efficiency, but LTE is "not the silver bullet in terms of capacity planning," he said.

As a result, AT&T is pushing for open spectrum auctions as soon as possible. The "beauty" of the T-Mobile deal, Stephenson said, was the extra spectrum it brought with it; (critics argued that AT&T should've spent the $39 billion on the spectrum it needed, not T-Mobile).

Ideally, Stephenson said, AT&T would acquire more spectrum in the lower 700 MHz band. In 2008, AT&T scored 227 700 MHz licenses for $6.6 billion.

The FCC and AT&T have not been best of friends lately. After the FCC recommended that the AT&T/T-Mobile deal be considered by an administrative law judge - which effectively killed its chances of approval - AT&T pulled the deal from the FCC and later killed it altogether. Before doing so, however, AT&T lashed out and argued in a blog post that the FCC's staff report about the merger was biased and hypocritical.

The FCC responded simply that it was "deeply concerned" by AT&T's statements.

As part of the failed T-Mobile deal, meanwhile, AT&T must transfer some of its spectrum to T-Mobile. For more, see How AT&T's Spectrum Transfer Will Help T-Mobile Customers.

Rival Verizon recently snapped up $3.6 billion worth of spectrum from Comcast, Time Warner Cable, and Bright House Networks, which also includes a deal to sell each others' products and services.

When asked about the Verizon deal today, Stephenson said it was "interesting," but declined to comment on the specifics. He did say, however, that AT&T will "be watching very closely" as to whether the FCC approves the deal or not, which will "give us some clarity" about the spectrum screens.

Also check out AT&T Gets a Qualcomm Consolation Prize.

Editor's Note: This story was updated at 4:45pm Eastern with comment from the FCC.