- Get USRP N (not USRP 2), if you want to have access to variety of
daughter boards, available for USRPs. Though it's quite expensive,
especially if you add a GPSDO to it.
- Get USRP B200, if you want a small single-channel device. Though
you _may_ have issue if you start playing with handover, as it doesn't
have GPS or a stable enough reference clock.