NEW YORK – The collapse of AT&T’s $39 billion bid for T-Mobile USA leaves the second-largest U.S. mobile carrier with few attractive strategic options as it seeks to challenge market leader Verizon Wireless.

To accommodate data-usage growth, AT&T argued it needed the airwaves the T-Mobile USA purchase would have brought.

With that option now unavailable, AT&T can either seek to buy spectrum from another company, wait for the government to auction more frequencies or try to squeeze more capacity out of its current airwaves. Each option is time-consuming, expensive and risky, said Colby Synesael, a Cowen & Co. analyst in New York.

“Without this deal, it is going to be difficult for AT&T,” Synesael said. “There’s no clear solution.”

Already criticized for dropped calls and network coverage, AT&T will face more constrained capacity than Verizon Wireless, Synesael said. That may hurt customer growth at a time when carriers are seeking to sign up lucrative smartphone and tablet subscribers who will generate revenue for years to come. Earlier this year, AT&T lost U.S. exclusivity to the Apple iPhone.

While AT&T focused on winning regulatory approval for the takeover, rivals negotiated their own airwave deals. That means several spectrum assets that would have still been available for AT&T to purchase earlier this year are now off the market.

AT&T abandoned the T-Mobile deal last Monday after a nine-month campaign that underestimated opposition from regulators. The Justice Department sued to block the deal in August, saying it would reduce competition. The purchase of T-Mobile from parent Deutsche Telekom would have vaulted Dallas-based AT&T past Verizon Wireless as the biggest U.S. mobile carrier.

Spectrum is a term used for airwaves, licensed by the government, that carry wireless voice and data signals. Governments often sell unused or repurposed frequencies to the highest bidder, and companies also trade them.

Still, AT&T can’t rely on the federal government auctioning new wireless spectrum soon. While lawmakers are working on legislation that would allow carriers to bid on airwaves currently held by television broadcasters, no timing for such a sale has been set.

That leaves AT&T seeking spectrum holders willing to sell. However, any such attempts became more difficult in the past few weeks because purchases by rivals reduced the amount available.

On Dec. 1, wholesale wireless-service provider and spectrum-owner Clearwire secured its ties with partner Sprint Nextel through a financing and network-sharing agreement. Sprint, the No. 3 carrier, reserved rights to bid for Clearwire’s spectrum if other offers were made.

That move was followed by Verizon Wireless’s $3.6 billion deal to acquire airwaves held mostly by Comcast and Time Warner Cable, something Synesael called “a real coup.”

AT&T may now seek to buy Dish Network, a satellite-TV provider that owns spectrum, Stifel Nicolaus said last week. Dish said this month it isn’t interested in selling its airwaves and that it may partner with T-Mobile if AT&T’s bid fails.