OpenBTS is an amazing project to build a GSM base station using open source software and hardware. It uses Asterisk as the back end, and can work with standard GSM handsets. The RF side is handled using the open hardware Universal Software Radio Peripheral, a software defined radio that be programmed to transmit and receive on GSM frequencies.
OpenBTS has been created by David Burgess and Harvind Samra, with lot of contributions from Raffi Sevlian.
Here is a photo of the equipment used at some recent field trials at Burning Man:
With this technology you can build your own small scale GSM network, using commodity handsets. This would be very nice for Village Telco type applications, and would have big range advantages over Wifi technology. Getting a license for spectrum is the challenge I guess.
Great to see some open technology in this area, and quite amazing that a small team can build their own GSM base station! Fantastic work guys….