China Mobile, the world's largest wireless operator in terms of subscribers, has forged a pact with US broadband carrier Clearwire Corp to advance the development of devices based on time-division long-term evolution (TD-LTE) technology, the high-speed 4G standard backed by the mainland. The collaboration marks a coup for China Mobile, which has championed the international adoption of TD-LTE as a viable 4G system for current 3G mobile network operators. Wider TD-LTE coverage would enable global roaming services for subscribers on networks that adopt this standard. With increased data use by consumers on smartphones and media tablets, roaming provides carriers with a high level of revenue. 'The co-operation with Clearwire will leverage economies of scale in the two largest markets in the world to speed up the development of TD-LTE devices,' China Mobile chairman Wang Jianzhou said yesterday. Wang said in May that China Mobile's discussions with Apple had included the potential design and release of a new iPhone that supports the TD-LTE standard next year, when the mainland operator was expected to launch commercial 4G services. The Beijing-based company, which had 621.85 million subscribers at the end of July, agreed to work jointly with Clearwire to hasten the availability of TD-LTE chipsets and devices by next year. Details of this venture were not provided. The two companies will also collaborate on enabling worldwide data roaming among networks based on TD-LTE and the parallel 4G standard called frequency division duplexing LTE, along with 3G and 2G networks. 'We anticipate the widest variety and most cost-effective high-performance devices - modems, routers, smartphones and tablets to provide end-users with affordable, advanced mobile broadband services,' Wang (pictured) said. China Mobile, which runs a nationwide 3G network based on the mainland-backed standard called time division synchronous code division multiple access, started large-scale domestic TD-LTE tests on the 2.5-gigahertz spectrum band in seven major cities late last year. The company said there were 32 TD-LTE trials worldwide as of June this year that used prototype 4G devices and commercially available TD-LTE network infrastructure. It recently helped Clearwire conduct extensive TD-LTE network trials in the US that achieved mobile internet download speeds of more than 120 megabits per second, faster than the average download speeds of 3Mbps to 6Mbps on the US firm's existing 4G network based on WiMAX technology. 'We expect to launch a next-generation LTE network that will offer more capacity than any other 4G network in the US,' said John Stanton, executive chairman of Clearwire. 'By working with China Mobile, we fully expect to benefit from a device eco-system that aims to support billions of potential users worldwide.' Clearwire's WiMAX service, available in 70 US markets with more than 130 million customers, is resold by partner 4G providers such as Sprint, Comcast, Time Warner Cable and Locus Telecommunications. Clearwire's own branded 4G service, Clear, had 7.65 million subscribers as of June. Clearwire announced last month its intention to add TD-LTE infrastructure on its mobile broadband network. The company operates on the same 2.5GHz frequency band preferred for TD-LTE deployment.