We now have a working GSM base station using free software; with OpenBTS you can turn the Universal Software Radio Peripheral into your own GSM base station.
However, all available mobile phones, even the 'open' linux-based phones, have closed, proprietary code running on the baseband processors.
We need to have a fully software-defined radio solution to this problem using free software.
At the moment the target hardware is the USRP2. Later on, we can worry about the size of the USRP2. It isn't going to fit in your pocket!
First we need to have a working software stack.
To contact AJ Potter: ajpotter AT sdrphone.org