From the standpoint of custom phonesat implementations there is a significant software automation-set for phone design with virtual and hardware in the loop simulation. You can change the frequency, the modulation, the codes, the operation modes (act not just as a client but as a peer to peer or even as a base station), bandwidth, etc. Modern phones use direct convert digital to and from RF. Meaning there are no limitations other than a top frequency of the converters used.
This means that new designs using latest components can be rapidly used and designed and built in less than 6 months.