China Mobile, the world's largest mobile operator, and US service provider Clearwire will later this month conduct joint interoperability testing (IOT) for TD-LTE devices. “The labs will allow for the evaluation and qualification of commercial TD-LTE devices simultaneously in the US, China, and other promising markets, using common testing methodology, equipment, and infrastructure,” notes a statement. Clearwire plans to conduct its TD-LTE testing in the US cities of Phoenix and Herndon. China Mobile's testing will be carried out in Beijing and other TD-LTE trial cities. The joint test platforms will be open for device IOT by key participants in “early 2012.” Both China Mobile and Clearwire are moving from less prolific earlier network technologies (TD-SCDMA and WiMAX, respectively) to the globally recognised 4G standard, LTE, using unpaired TDD spectrum.