Clearwire, a leading U.S. wireless broadband provider, on Thursday announced its plans to build a test-bed mobile network in Silicon Valley using WiMAX, a fourth-generation (4G) wireless communication technology.

The so-called WiMAX Innovation Network will initially cover an area of more than 20 square miles (52 square kilometers) in Silicon Valley for software developers to try out new applications, said Clearwire, which is headquartered in Kirkland in the U.S. state of Washington.

The network will bring 4G wireless service to campuses of some of the world's leading technology companies including Google and Intel.

Service is expected to be available to developers by late summer this year ahead of Clearwire's planned launching of commercial 4G service in the San Francisco Bay Area in 2010.

"The WiMAX Innovation Network will provide some of the world's most talented developers with a live test environment in which to build broadband services Service will be provided free to a limited number of qualified developers for one year, the company declared.

In addition to the San Francisco Bay Area, Clearwire said it expects to launch its 4G mobile Internet service covering up to 120 million people in more than 80 U.S. cities in 2010.