GEO-Mobile Radio Interface

GEO -Mobile Radio Interface (GMR ) is a standard for satellite telephony by the European Telecommunications Standards Institute (ETSI ).

There are defined two parallel existing standards, GMR -1 ( ETSI TS 101 376) and GMR -2 ( ETSI TS 101 377).

GMR -1

GMR -1 is used in the services of the operator Thuraya Telecommunications, SkyTerra Communications, TerreStar Networks and ICO Global Communications. It leans heavily on GSM. The transmission protocol differs only in the lowest three OSI layers, for GmPRS only on the bottom two. Further, specialized features include terminal - to-terminal calls, and the so-called "High Penetration Alerting " (HPA, such as " call signaling with high penetration" ). The end-to -end calls are directly sent from the satellite to the remote site, without having to be routed through the network, and again via the satellite must. The High Penetration Alerting allows a notification of an incoming call even in confined spaces, whereas the calls can be made only in the open. An audio codec is used AMBE and encryption has its own, likely from A5 / 2 derived algorithm 2012 has broken. The system integrates tightly with GPS. GMR -1 also includes a packet-based service, called GmPRS (analogous to GPRS).

The OsmocomGMR project developed a free protocol stack for GMR -1.

Swell

  • Sylvain Munaut: Introducing Osmo - GMR. Building a sniffer for the GMR satphones. In: 28c3. Berlin December 29, 2011 ( http://events.ccc.de/congress/2011/Fahrplan/events/4688.de.html ).
  • Telephony
  • Satellite technology
  • Cryptologic standard
Satellite phone Multi-Band Excitation
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