A federal judge granted a request by AT&T, T-Mobile and the Justice Department to a cancel a trial over whether a proposed merger between the two wireless giants violates antitrust law, giving AT&T one month to decide if it wants to drop the deal altogether.

"We are actively considering whether and how to revise our current transaction to achieve the necessary regulatory approvals so that we can deliver the capacity enhancements and improved customer service that can only be derived from combining our two companies' wireless assets," AT&T said in a statement Monday.

The deal needs approval from the Justice Department and the Federal Communications Commission.

The Justice Department sued to block the deal in August.

The FCC wrote last month that the deal was not in the best interests of consumers because cell phone service prices would go up if just three major carriers were left on the market. That promoted AT&T to withdraw from the FCC approval process to first focus on the antitrust trial, which was scheduled to begin in February.

But the Justice Department said Friday that the case was not real unless FCC approval was also being sought.

A status hearing in the case is now scheduled for Jan. 18, meaning that AT&T must advise the judge of its plans by Jan. 12.

If the deal falls through, Dish Network's CEO told Bloomberg the company would be interested in partnering with T-Mobile as Dish plans to rolls out its own national wireless network.

The Washington Post recently described how the playbook successfully used by AT&T lobbyists countless times backfired during this proposed merger.