Osmocom (Open Source Mobile Communication) is a collection of Free Software / Open Source Software projects in the area of mobile communications.Our member projects implement a variety of public and private communications systems, ranging from GSM/GPRS mobile telephony to TETRA private mobile radio, DECT cordless telephony, GMR satellite telephony and many others.The goal of those implementations is to provide free software implementations available in source code, which we believe are key aspectsto encourage research, innovation and experimentation on widespread communications systemsto help interested engineers and students with practical insight into systems they normally only read about in booksto ensure that technical and implementation details of such vital communications systems are known outside the small group of manufacturers

http://openbsc.osmocom.org/trac/wiki/OsmocomOverview