Osmocom (open source mobile communications) is an

open-source software Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Op ...

project that implements multiple mobile communication standards, including

GSM The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such ...

DECT Digital enhanced cordless telecommunications (Digital European cordless telecommunications), usually known by the acronym DECT, is a standard primarily used for creating cordless telephone systems. It originated in Europe, where it is the common ...

TETRA Terrestrial Trunked Radio (TETRA; formerly known as Trans-European Trunked Radio), a European standard for a trunked radio system, is a professional mobile radio and two-way transceiver specification. TETRA was specifically designed for use by go ...

and others.

History and usage

In 2008

Harald Welte Harald Welte, also known as LaForge, is a German programmer. Welte is the founder of the free software project Osmocom and was formerly involved in the netfilter/iptables and Openmoko projects. He is a member of the Chaos Computer Club. Bi ...

and Dieter Spaar experimented with a

base transceiver station A base transceiver station (BTS) is a piece of equipment that facilitates wireless communication between user equipment (UE) and a network. UEs are devices like mobile phones (handsets), WLL phones, computers with wireless Internet connectivity, o ...

from

Siemens Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad. The principal divisions of the corporation are ''Industry'', '' ...

that was end-of-life and implemented the BSC side of the A-bis protocol, which eventually turned into OpenBSC. After attracting more interest, support for other BTS models was added. The first release of the OpenBSC project took place at the 25th

Chaos Communication Congress The Chaos Communication Congress is an annual conference organized by the Chaos Computer Club. The congress features a variety of lectures and workshops on technical and political issues related to security, cryptography, privacy and online ...

held in December 2008. In the following years, the software has been used at various hacker cons such as the Chaos Communication Congress, Chaos Communication Camp and

Electromagnetic Field An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by (stationary or moving) electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical c ...

to provide a

cellular network A cellular network or mobile network is a communication network where the link to and from end nodes is wireless. The network is distributed over land areas called "cells", each served by at least one fixed-location transceiver (typically thre ...

. In 2010, a telephone-side implementation of the GSM stack was developed, named OsmocomBB. Together with OpenBSC, these projects became part of the new Osmocom umbrella project. The Sysmocom GmbH company was founded by Welte and Holger Freyther in 2011 to provide commercial support. Since 2018 Osmocom software and Sysmocom hardware has been used in

Villa Talea de Castro Villa Talea de Castro is a town and municipality in Oaxaca in south-western Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the Un ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

to provide a cellular network to around 3500 people. Osmocom software has been used in research projects.

Projects

OpenBSC

OpenBSC was a project to develop a

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

implementation of

protocol stack and elements. It runs on Linux and requires an E1 interface (ISDN Primary Rate Interface, via mISDN). It is written in C and licensed using the GPL (≥v2) license. The first version implemented the GSM specification 21.12 and 08.5x, and worked for a specific Base Transceiver Station (Siemens BS11 MicroBTS). OpenBSC implemented several MSC components, including the A-bis protocol (the protocol between the

BTS BTS (), also known as the Bangtan Boys, is a South Korean boy band formed in 2010 and debuting in 2013 under Big Hit Entertainment. The septet—consisting of members Jin, Suga, J-Hope, RM, Jimin, V, and Jungkook—co-writes and co-produ ...

and the

BSC A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University ...

), AUC, HLR, VLR (both using SQL tables), and a

SMS Short Message/Messaging Service, commonly abbreviated as SMS, is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile devices exchange short text ...

Switching Center. OpenBSC can be accessed using

telnet Telnet is an application protocol used on the Internet or local area network to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. User data is interspersed in-band with Telnet control i ...

. OpenBSC supported the following BTS devices: * Siemens BS11 (microBTS) (E1 Primary Rate interface) * ip.access nano BTS (PoE-interface) OpenBSC is now considered legacy and the features have been split into different projects: OsmoBSC, OsmoMSC and OsmoHLR.

SDR

rtl-sdr Software-defined radio (SDR) is a radio communication system where components that have been traditionally implemented in analog hardware (e.g. mixers, filters, amplifiers, modulators/ demodulators, detectors, etc.) are instead implemented by m ...

was discovered by Steve Markgraf, who also created osmo-fl2k for radio transmissions. These projects deprecated the use of OsmoSDR.

OsmoTETRA

The OsmoTETRA project implements the TETRA protocol. Osmo-tetra implements the lower layer of the protocol. Some conducted research revealed that some government traffic is not properly secured.

OsmocomBB

OsmocomBB is a free firmware for the

baseband processor A baseband processor (also known as baseband radio processor, BP, or BBP) is a device (a chip or part of a chip) in a network interface controller that manages all the radio functions (all functions that require an antenna); however, this term i ...

of mobile phones which handles the encoding and radio communication of both voice and data. OsmocomBB is the only existing free implementation of baseband firmware, excluding failed projects like TSM30 from

THC Tetrahydrocannabinol (THC) is the principal psychoactive constituent of cannabis and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) describes multiple isomers, the term ''THC' ...

and MadOS. Motorola C123 OsmocomBB

OsmocomBB implements the GSM

protocol stack The protocol stack or network stack is an implementation of a computer networking protocol suite or protocol family. Some of these terms are used interchangeably but strictly speaking, the ''suite'' is the definition of the communication protoco ...

's three lowest

OSI OSI may refer to: Places * Osijek Airport (IATA code: OSI), an airport in Croatia * Ősi, a village in Veszprém county, Hungary * Oši, an archaeological site in Semigallia, Latvia * Osi, a village in Ido-Osi, Ekiti State, Nigeria * Osi, Ekiti ...

Layers of the client side GSM protocol and

device driver In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and ot ...

s. The protocol layers forming the kernel exists on the baseband processor, typically consisting of an

ARM In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...

processor and a

digital signal processor A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio si ...

It has support for the Calypso chipset produced by

Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...

Karsten Nohl Karsten Nohl (born 11 August 1981) is a German cryptography expert and hacker. His areas of research include GSM, Global System for Mobile Communications (GSM) security, radio-frequency identification (RFID) security, and privacy protection. Lif ...

has extented OsmocomBB to be able to detect IMSI catchers.

References

External links

Official website
{{Mobile telecommunications standards Free_software Free communication software Software using the GPL license Telecommunications