Does LTE require a special modem from WiMAX or just a firmware upgrade? Sprint has talks of starting LTE data, but for now all their 4g phones support WiMAX.

I am considering starting a sprint unlimited contract with the EVO 3D phone. 

The phone supports WiMAX 4g, on a snapdragon msm8660 processor. I'm wondering if this phone will be able to support LTE if sprint does release it, or does LTE require a special modem?
The HTC Evo does not contain any LTE hardware, so it wont work