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fixeria, 05/24/2020 01:39 PM


OsmoBTS is a software implementation of a GSM BTS.

It implements the follwing protocols/interfaces:
  • LAPDm (GSM 04.06)
  • RTP
  • A-bis/IP in IPA multiplex
  • OML (GSM TS 12.21)
  • RSL (GSM TS 08.58)

OsmoBTS is building up on work done previosuly for OpenBSC (e.g. RSL, OML, RTP) and OsmocomBB (e.g. LAPDm). The Abis/IP protocol staking is inspired by ip.access A-bis/IP, sometimes called IPA multiplex.

OsmoBTS in the Osmocom architecture

OsmoBTS in a GSM + GPRS/EDGE network using OsmoNITB

OsmoBTS in a GSM + GPRS/EDGE network using OsmoBSC and OsmoMSC

Backends / Hardware support

OsmoBTS is modular and has support for multiple back-ends. A back-end talks to a specific L1/PHY implementation of the respective BTS hardware. Based on this architecture, it should be relatively easy to add a new back-end to support so-far unsupported GSM PHY/L1 and associated hardware.

So far OsmoBTS has been integrated with several different L1/PHY and hardware systems. The backends are:
  • osmo-bts-sysmo
  • osmo-bts-sysmo-remote
  • osmo-bts-trx
    • Wideband SDR transceiver hardware supported by OpenBTS transceiver or OsmoTRX PHY layer software, including the UmTRX, the USRP family, etc.
    • Multiple indoor and outdoor fairwaves BTSs, like UmDESK and UmSITE
  • osmo-bts-litecell15
  • osmo-bts-octphy
  • osmo-bts-bb
    • A pretty crazy experimental BTS hardware based on two OsmocomBB phones had originally been supported, but needs to be re-integrated with core code changes.

Binary Packages

Osmocom provides binary packages for several flavors of Debian and Ubuntu GNU/Linux on a variety of architectures (i586, x86_64, armhf, armv7l). Unless you are a software developer interested in developing on Osmocom, it is recommended you use those packages instead of building from source.

For more details see Binary_Packages


GPRS support

In the GSM architecture, the BTS is an element in the circuit-switched domain only.

For packet-switched support, OsmoBTS provides a socket interface towards OsmoPCU. This adds GPRS and EDGE support to it.

Source code

The source code is available from (module osmo-bts).

Public read-only access is available via

git clone git://

You can browse it via cgit:

Test Suite

We have a TTCN-3 test suite for OsmoBTS as part of our Titan_TTCN3_Testsuites

Authors / Credits

OsmoBTS was originally developed in 2011 by Andreas Eversberg and Harald Welte.

Today it is mostly maintained by Harald Welte and his team at sysmocom.

Commercial Support

Commercial support as well as development, system integration and training services for this project are available from sysmocom

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Updated by fixeria over 3 years ago · 29 revisions

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