The Osmocom project is an umbrella project regarding Open source mobile communications. This includes software and tools implementing a variety of mobile communication standards, including GSM, DECT, TETRA and others.
The most well-known examples are
- the network-side GSM and 3G implementations originally known as OpenBSC (but now including BTS, PCU, BSC, MSC, HLR, PCU, SGSN, GGSN)
- the phone-side GSM implementation OsmocomBB
- the RTL-SDR project to use DVB-T receivers as general purpose software defined radio receivers.
Osmocom exists since late 2008 and is a classic, enthusiast-driven open source community project.