[Nrsolis]

That's not necessarily true. There is little difference between WiMAX and LTE on all of the hard parts: antenna configuration, transceivers, and amplifiers. Even the modulation scheme is the same: OFDM. Sprint started installing firmware-upgradable base stations a little while ago and I strongly suspect that the process for converting from WiMAX to LTE is governed by staff time limitations than outright technical debt.

[indiekid]

Unfortunately LTE-based devices on Sprint still won't be backwards compatible with the converted WiMAX towers as they only output in 2.3 GHz, 2.5 GHz and 3.5 GHz bands. The iPhone 5 specifically maxes out at a 2.1GHz band.

[Nrsolis]

Oh ya, the user terminals out there are going to have to be replaced wholesale. My only point was that Sprint is going to be able to convert to LTE a lot quicker than people expect. Building up a user base is another issue entirely.