Clearwire is extending its reach outside U.S. borders through an agreement with WiMAX operators UQ Communications of Japan (UQ) and Yota of Russia. The agreement will ultimately allow the three carriers to provide international WiMAX roaming capability.

"With over 500 WiMAX deployments under way in about 145 countries, the existence of a roaming framework – helping to connect operators as well as WiMAX customers – is vital to advanced cross-market cooperation," said Barry West, president of Clearwire International, in a statement.

The agreement came in the form of a memorandum of understanding signed by Clearwire subsidiary Clearwire Communications LLC. The memorandum outlines a collaboration between Clearwire, UQ and Yota to support international roaming and device interoperability between the carriers' respective WiMAX networks.

Clearwire is also working to ensure roaming interoperability with four other carriers in its Global Alliance Partner Program. YTL Communications of Malaysia, wi-tribe of Pakistan, Vee Telecom of Taiwan and Global Mobile of Taiwan are working to make sure roaming on their WiMAX networks works upon commercial deployment.

UQ and Yota will also work with Clearwire's Global Alliance Partner Program members and other WiMAX operators to ensure that seamless roaming occurs in an increasing number of countries. When necessary, the collaboration will use guidelines created by the WiMAX Forum to handle roaming guidelines, specifications and templates.

"The mobile WiMAX position in the telecom market is currently so strong, that operators are taking action to organize a civilized roaming environment," said Dennis Sverdlov, CEO of Yota, in a statement. "The trilateral MOU, signed by the leading global WiMAX operators, is evidence of that. We are committed to making telecom services easy to use for our clients, and this MOU was signed with their interests in mind."