Clearwire has announced plans to test Test both FDD LTE and TDD LTE in US. In addition Clearwire  will test multiple coexistence scenarios between LTE and WiMAX as well. The tests will be conducted in the fall and throughout early 2011 in Phoenix, Arizona.

Clearwire plans to conduct the tests in collaboration with Huawei Technologies. Clearwire will also be testing LTE on Samsung Electronics' common base station platform which it currently uses for its mobile WiMAX deployments.

To conduct FDD LTE (Frequency Division Duplex) tests, Clearwire intends to use 40 MHz of spectrum, paired in 20 MHz contiguous channels, of its 2.5 GHz spectrum. Clearwire expects to confirm the capability to produce real-world download speeds that range from 20-70 Mbps. 

 To test TDD LTE (Time Division Duplex) Clearwire will use a 20 MHz configuration, which is twice the channel size currently used in its 4G WiMAX deployments.

Clearwire will also test WiMAX co-existence with both FDD LTE and TDD LTE to confirm the flexibility of its network and spectrum strength to simultaneously support a wide-range of devices across its all-IP network.

"Clearwire's unmatched spectrum and all-IP network make us the only service provider in the U.S. able to conduct tests of this nature and on this scale," said Dr. John Saw, Clearwire's chief technology officer, according to company statement.

"As we have consistently stated, we remain technology agnostic, but WiMAX provides us with unique advantages to meet the needs of our customers today. Ultimately, consumers don't care about technical acronyms, but they do care about quality and affordable Internet services that work where and when they want, and that's what we're focused on delivering. Part of our technical due diligence at Clearwire is to be prepared to leverage a number of possible opportunities as we future-proof our network, and that's the goal of these tests," he added.

The company also restated its commitment to use WiMAX technology for its current 4G build plan. Since the company expects that a significant number of LTE devices will be available in coming years, Clearwire is conducting technical trials to determine how it could potentially add LTE technology to coexist with WiMAX.