Software Defined Radio is opening up many new possibilities for amateur digital modes. One family of technologies that interests me is cellular. 2G GSM voice/sms and 2.5G GPRS data has been proven to work with OpenBTS on a USRP SDR using licensed cellular bands. Can this technology be used by amateurs? Could an amateur cellular network be deployed sometime in the future?
Note: I know that there are many small practical considerations to doing this. Cellular technologies are heavily patented, but patents on many older GSM technologies have recently expired. Also, some deployment tweaks will be needed to adhere to amateur regulations, such as disabling encryption. Answers should focus on the fundamentals of amateurs using cellular technologies via sdr and not these small hangups.