Clearwire exceeded 10 million subscribers in the fourth quarter but still needs to raise more money to build its planned LTE network, a task that could be funded in part by an upcoming US$300 million stock offering.

Clearwire will test its LTE network in two U.S. cities and China Mobile will build test networks in select Chinese cities early this year to foster development of a global ecosystem for the version of the technology they will be using.

Clearwire's big payday on Tuesday, when it raised US$734 million through a stock offering and a new investment by majority owner Sprint Nextel, helped the WiMax carrier but didn't seal the deal on its planned LTE network.

Clearwire plans to raise as much as $345 million in stock transactions to help fund its LTE (Long Term Evolution) network deployment and other activities.

At least one of the cable operators that struck a wireless spectrum deal with Verizon on Friday now plans to stop reselling WiMax mobile service from Clearwire.

Sprint Nextel may help finance Clearwire's LTE network and keep offering WiMax service through 2015 under a set of agreements worth as much as US$1.6 billion that the companies laid out on Thursday.

WiMax carrier Clearwire has stopped selling postpaid service plans and dual-mode 3G-WiMax client devices, two moves that make it less of a competitor to its main wholesale customer, Sprint Nextel.

Cooperation between Sprint Nextel and Clearwire on LTE should help to bring two versions of that technology together, leading to increased device choices and roaming opportunities for subscribers in developed markets.