Welcome to SDR PHY for OsmocomBB project


OsmocomBB project provides almost free software GSM mobile station implementation, from Layer 2 to Layer 3. The last non-free parts are: layer 1 and low level signal processing that are implemented in a non-free DSP software which is inside of the hardware platform that OsmocomBB is currently based on (mainly reverse engineered Calypso based mobile phones).

The SDR PHY for OsmocomBB aims to replace these non-free parts through use Software Defined Radio devices and by creating missing software part for tasks such as scheduling, voice encoding/decoding, channel encoding/decoding, burst modulation/demodulation and controlling SDR hardware. In order to achieve this goal the SDR PHY for OsmocomBB brings together OsmocomBB and gr-gsm projects, where the role of gr-gsm is to provide GSM bursts transmission and reception with everything starting from channel coding/decoding being done in OsmocomBB.

Having support for general purpose SDR hardware has additional advantage of not being locked to a single and already obsolete hardware platform. Adding support for a new well documented SDR platform is significantly easier than reverse-engineering mobile phone's hardware and software. This could sustain OsmocomBB project's life even in the absence of hacked mobile phones it is able to run on.

A comparison of Calypso based and SDR based approaches can be found on SDR PHY vs Calypso subpage.


Project status

Known limitations (not implemented):

Work in progress:

  • Docker scripts (Dockerfiles)
  • GAPK based audio back-end
  • TCH/H implementation
  • Frequency Hopping

Future plans:

  • Extend supported hardware list (Soapy?)
  • PC/SC physical SIM interface
  • AMR (Adaptive Multi-Rate)


The project has support of NLnet Foundation


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