AT&T is phasing out 2G.

AT&T says the move to phase out 2G is part of its efforts to improve network performance and address the need for additional spectrum capacity. Above, an AT&T store in New York. (CX Matiash / Associated Press)

AT&T plans to phase out its 2G service to support more advanced mobile Internet services on its 3G and 4G networks, the company said in a regulatory filing Friday.

The company said it expected to fully discontinue the service by the end of 2016. It said it would manage the process consistent with previous network upgrades and would "work proactively" to transition customers on a market-by-market basis from GSM and Edge networks (referred to as 2G) to more advanced 3G and 4G.

As of June 30, about 12% of AT&T's postpaid customers were using 2G handsets, the company said.

AT&T said the move was part of its ongoing efforts to improve network performance and address the need for additional spectrum capacity.

The company also said more than one-third of its postpaid smartphone subscribers use a 4G-capable device. The "substantial increases" in the demand for wireless service in the U.S. is causing AT&T to face "significant spectrum and capacity constraints on its wireless network in certain markets," it said.

"We expect such constraints to increase and expand to additional markets in the coming years," the company said. "While we are continuing to invest significant capital in expanding our network capacity, our capacity constraints could affect the quality of existing voice and data services and our ability to launch new, advanced wireless broadband services, unless we are able to obtain more spectrum."

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