GEO-Mobile Radio Interface (GEO stands for
Geostationary Earth Orbit), better known as GMR, is an
ETSI
The European Telecommunications Standards Institute (ETSI) is an independent, not-for-profit, standardization organization in the field of information and communications. ETSI supports the development and testing of global technical standard ...
standard for
satellite phone
A satellite telephone, satellite phone or satphone is a type of mobile phone that connects to other phones or the telephone network by radio through orbiting satellites instead of terrestrial cell sites, as cellphones do. The advantage of a sa ...
s. The GMR standard is derived from the
3GPP-family terrestrial digital cellular standards and supports access to GSM/UMTS core networks. It is used by
ACeS
ACeS (PT Asia Cellular Satellite) was a regional satellite telecommunications company based in Jakarta, Indonesia. It offered GSM-like satellite telephony services to Asian market. The coverage area included Indonesia, Malaysia, Thailand, Phili ...
,
ICO,
Inmarsat,
SkyTerra SkyTerra (SKYT), formerly Mobile Satellite Ventures (MSV or MSVLP), was a Reston, Virginia company that developed telecommunications systems that integrate satellite and terrestrial radio communication technologies into one system. In March 2010, ...
,
TerreStar and
Thuraya.
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There are two widely deployed variants of GMR, both heavily modeled after GSM
* GMR-1: The first version of the standard and that has evolved over time into 3 different revisions:
** GMR-1: The basic circuit switched model, more or less corresponding to what GSM Phase 2 is, and using exactly the same core network infrastructure.
** GmPRS: Adding support for packet data. The equivalent of GPRS in the GSM world. Still connected to a 'Gb' style core network.
** GMR-1 3G: Adds support for some new channel types, but the most important changes are in the core network, adding interoperability with UMTS core network components. Contrary to the classic cell network where UMTS and GSM have a radically different air-interface, GMR-1 3G is still very similar to GMR-1 on the Layer 1 side.
* GMR-2: Which is not an evolution of GMR-1 but rather a concurrent standard that has been developed by another group of companies.
GMR-1 is the technology used by Thuraya. GMR-1 3G is the technology used for TerreStar and SkyTerra.
GMR-2 is used by Inmarsat iSatPhonePro.
GMR was developed by TIA and ETSI.
Air Interface Ciphers
Versions of standard and cipher used:["Don’t trust satellite phones"]
* GMR-2 - GEO mobile radio 2 (InmarSat iSatPhonePro). Based on byte operations and 2 S-Boxes from DES.
References
External links
CreonicETSIETSI Publications Download AreaDon’t trust satellite phones – The GMR-1 and GMR-2 ciphers have been broken
Satellite telephony
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