Clearwire Corp. has started to fill in details of its planned LTE TDD buildout, most likely in conjunction with longtime 4G partner Sprint Nextel Inc.
Clearwire has been testing Long Term Evolution Time Division Duplex (LTE TDD) -- also called TD-LTE -- in Phoenix for more than a year. CEO Erik Prusch said on the company's earnings call Tuesday that the operator now has more than 800 of the LTE TDD sites ready to be connected to Sprint's core network.
The operator is planning to have 2,000 sites up by June 2013 and 5,000 sites by the end of the year. The full buildout calls for 8,000 of the faster 4G sites to be deployed.
Clearwire CFO Hope Cochran said that "up to $250 million" of the capex for the build will come from vendor financing. Clearwire has named Huawei Technologies Co. Ltd and Samsung Corp. as its LTE TDD suppliers.
"Early tests of our LTE sites have produced peak downlink speeds of 60Mbit/s," CEO Prusch noted. He pointed out that this was on an unloaded network and commercial speeds will be different, but added that because of the nature of LTE TDD the operator will be able to boost download speeds further.
Clearwire has also been testing 2.5GHz TD LTE devices at the test site in Phoenix with China Mobile Ltd. The Chinese giant has made no secret of its ambition to make TD LTE a global 4G standard with roaming in the 2.3GHz to 2.7GHz range at its core.
Would-be Sprint suitorSoftBank Mobile Corp. already has LTE TDD smartphones on its network in the 2.5GHz range.
"We can tweak those phones to work on our network," noted Clearwire CTO John Saw. He added, however, that the difficulty is that the voice fall-back capability in the phones runs on GSM. Sprint's voice calls currently run over the CDMA network.
The site numbers suggest a more focused network than Clearwire's current WiMAX offering. CTO Saw said that Clearwire has about 15,000 cell sites up and running now.
Why this matters
Clearwire wouldn't comment on the proposed $2.2 billion Sprint buyout on the earnings call. Nonetheless, the company's LTE TDD deployments are plainly ready to link this new network to Sprint's 3G and 4G upgrades. The focused LTE TDD build, meanwhile, appears to dovetail neatly with the Sprint concept of adding this fast, video-friendly 4G capacity in big cities to cope with growing demand.