But network transitions of that sort can be messy in the interim, as the operator has to continue to support existing users and devices that operate on the older platform, while adding new users to the next-generation platform. If Sprint intends to shift to LTE on its fully-owned spectrum, that means adding LTE to the network now running CDMA.
Clearwire has other options, as it can light a separate LTE network alongside its existing WiMAX network.
In an interim period, while lots of users continue to use CDMA gear, Sprint would likely introduce new devices that support both CDMA and LTE. There are some cost considerations, but it is an approach mobile operators and suppliers are quite familiar with.
That move would need to be made at some point even as Sprint continues to use Clearwire facilities, as the CDMA network itself will have to be entirely replaced at some point by a 4G solution.