The U.S. Federal Communications Commission (FCC) on Friday approved Japanese company SoftBank's 21. 6 billion-dollar deal to acquire Sprint Nextel, the third-largest U.S. wireless provider.

The FCC also approved Sprint's 3.7 billion-dollar bid to buy the remaining outstanding shares of U.S. wireless provider Clearwire and take full control of the company.

"After thorough review, the Commission has found that the proposed SoftBank-Sprint-Clearwire transactions would serve the public interest," FCC's Acting Chairwoman Mignon Clyburn said in a statement.

"The increased investment in Sprint's and Clearwire's networks is likely to accelerate deployment of mobile broadband services and enhance competition in the mobile marketplace, promoting customer choice, innovation and lower prices," she added.

This decision completed all Federal government reviews of SoftBank's merger with Sprint and allowed SoftBank to take a 78 percent stake in Sprint, paving the way for the Japanese company to explore the U.S. telecom market and compete with U.S. rivals such as AT&T and Verizon.

Sprint, Clearwire and SoftBank expect the transactions to close in early July 2013, according to Sprint.