AT&T Inc and T-Mobile USA plan to file paperwork about their planned merger with the Federal Communications Commission next week.

We plan to file our public interest statement at the FCC around April 21, AT&T's Michael Balmoris said in an email on Thursday.

AT&T's $39 billion bid to buy Deutsche Telekom AG's T-Mobile USA will also be reviewed by the Justice Department to ensure it does not violate antitrust law. The request for the Justice Department review was filed last Friday.

The FCC will review the proposed deal to ensure it is in the public interest.

The review process could easily take a year.

The deal would concentrate 80 percent of U.S. wireless contract customers in just two companies -- AT&T/T-Mobile and Verizon Wireless, a joint venture of Verizon Communications and Vodafone Group Plc.

AT&T, currently the No. 2 U.S. mobile carrier behind Verizon, has said the merger will spur innovation and economic growth by improving quality and expanding wireless service to 95 percent of Americans.

(Reporting by Diane Bartz; Editing by Tim Dobbyn)

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