KDDI Corp., the nation's No. 2 mobile carrier, officially announced Monday that it has agreed to sell its PHS business to the Carlyle Group, a U.S. private equity fund, for 220 billion yen.

The personal handy-phone system is one of the wireless communications systems that has been developed in Japan. Building the necessary infrastructure for PHS operations is cheaper than building the required infrastructure for regular cell phone systems.

KDDI will now concentrate its resources on its mainstay au mobile services as part of an offensive targeting industry titan NTT DoCoMo Inc.