AT&T announced on Friday plans to buy mobile carrier Leap Wireless in a deal worth at least $4 billion. If the deal is closed, the acquisition will boost the nation’s No. 2 wireless provider to better compete in the mature market of low-cost prepaid service.

AT&T said it was paying $15 a share, around 1.2 billion, and would assume the smaller carrier’s $2.8 billion in debt. It will acquire the five million customers now using Leap. The deal also includes Leap’s wireless properties, its licenses, network assets, and retail stores and subscribers.

“The result will be increased competition, better device choices, improved customer care and a significantly enhanced mobile internet experience for customers seeking low-cost prepaid wireless plans,” a company statement said.

AT&T said it will keep the Cricket brand name, and expand Cricket’s presence to additional US cities. Moreover, the telecom giant plans to use Leap's spectrum in furthering its development of AT&T's 4G LTE network.

The acquisition includes spectrum covering 137 million people and is largely complementary to AT&T's existing holdings, according to AFP. The statement said owners of 29.8 percent of Leap’s outstanding shares have approved the plan, which is subject to regulatory approval.

In 2011, AT&T tried to buy T-Mobile but dropped the plan after regulatory opposition, the AFP reported.