Date: November 2021
Amount: €249,424

Open Source Mobile Communications (Osmocom) is an umbrella project, fiscally sponsored by the Deutscher Amateur Radio Club (DARC), that hosts, develops, and maintains  mobile communications and SDR open source projects, with a main focus on cellular telephony systems. Osmocom identified a gap between the last decade of very promising open source developments in cellular technology and the requirements of being able to use this in the context of amateur radio. This grant will be used to develop software that will allow the use of GSM/GPRS technology on amateur radio bands by:

1. Implementing a SDR PHY that can be plugged beneath the existing OsmocomBB code to allow its use on general-purpose SDR hardware such as the LimeSDR or USRP series of radios.
2. Adding basic support for packet-switched GPRS services to OsmocomBB.

Osmocom developers will utilize their long-term experience developing open source software for mobile communications to carry out the project. Any developments made within this project are developed as part of existing Free/Open Source Software (FOSS) projects, published under licenses recognized by the FSF Free Software Definition and the OSI Open Source Definition. The entire development process happens in the Osmocom community, using publicly accessible resources such as redmine issue tracker, gerrit code review platform, mailing lists, IRC channel, etc. Once completed, the work within this project will pave the way to a potential subsequent development of 8PSK based EGRPS/EDGE in order to significantly increase the achievable packet data rates within the same narrow-band channel.

Learn more at https://osmocom.org/.

Update

The Osmocom team successfully delivered on the grant objectives, opening 2G GSM and 2.5G GPRS cellular technology to amateur radio experimentation for the first time. The first major milestone was the implementation of an SDR physical layer for OsmocomBB, replacing the proprietary baseband chips that previously locked mobile stations to commercial frequencies. This upgrade allows GSM networks to operate on any frequency using commodity Software Defined Radio (SDR) hardware such as USRP and LimeSDR platforms. The team demonstrated the capability by running a GSM network in the 2.4 GHz WiFi band with successful voice calls and SMS messaging. A complete GPRS protocol stack, libosmo-gprs, was also developed from scratch, implementing all the necessary layers for packet data services on the mobile station side. GPRS attach, PDP context establishment, and bidirectional IP data exchange have all been demonstrated on non-commercial frequencies. The work establishes a foundation for future development of 2.75G EDGE/EGPRS support to achieve higher data rates within the same narrow-band channels.