I recently saw a reddit post for a new CDMA2000 base station project, which has previously been impossible to achieve on an SDR. I had my doubts at first, but it turns out to be legit! The software is known as 1xBTS, and can be found at 1xbts.org
Been working on this project for a while and finally released it. Time to unpack your old CDMA phones.
1xBTS is everything you need to run a full CDMA network (from RF to all core components). It's still a WIP but you can already do a lot (voice calls, SIP -> PSTN gateway, SMS, and basic packet data).
You'll need a LimeSDR, USRP B2xx, or bladeRF to try it out.
Site: https://1xbts.org