For some time, Clearwire has been conducting tests of various LTE implementations, at one point calling the test results (with speeds up to 120 Mbps) "mind blowing." As such, it's not too surprising to see Clearwire today finally make their love of LTE official, issuing a press statement confirming that the company will be adding "LTE Advanced-ready" technology to its 4G network. The company says they'll initially be running LTE Time Division Duplex (TDD) LTE and Mobile WiMax services simultaneously.

According to Clearwire, the initial deployment of LTE will unsurprisingly target "densely populated, urban areas of Clearwire's existing 4G markets," but the company didn't offer launch specifics in terms of a time frame or specific cities. While a sizable chunk of network components overlap, the company says they'll need to upgrade base stations and a number of core network elements to make the shift.

"In addition, the 2.5 GHz spectrum band in which we operate is widely allocated worldwide for 4G deployments, enabling a potentially robust, cost effective and global ecosystem that could serve billions of devices," Clearwire CTO John Saw said in a statement. Saw took a not-so-veiled shot at LightSquared, adding that "...since we currently support millions of customers in the 2.5 GHz band, we know that our LTE network won't present harmful interference issues with GPS or other sensitive spectrum bands."

While the LightSquared jab is amusing considering Clearwire, Sprint and LightSquared will soon likely find themselves part of an intimate LTE love triangle (assuming Sprint doesn't just buy Clearwire's collapsed assets), Clearwire has their own problems to overcome with LTE. For one, their 2.5 GHz spectrum has shown coverage issues when it comes to building penetration. The company, which was already facing questions about funding its Mobile WiMax expansion, will also need to find the cash for this architecture shift. CEO John Stanton today estimated the cost of the shift at around $600 million, which in CEO parlance likely means several billion additional dollars Clearwire doesn't have.