What is MSS Mobile Satellite Service

Technical details of Mobile Satellite Service (MSS):

1. Definition:
   • MSS, or mobile-satellite radiocommunication service, is a specialized form of wireless communication that utilizes satellites to provide connectivity to mobile devices. It serves as a crucial communication link in areas where terrestrial cellular networks are not available, such as remote regions or locations affected by natural disasters.
2. Key Characteristics:
   • Radiocommunication Service: MSS involves communication between mobile earth stations (such as satellite phones) and one or more space stations (satellites) .
   • Feeder Links: It may also include feeder links, which are necessary for the operation of the service .
   • Frequency Band: Most commercial voice and some data mobile satellite services operate in the L-band spectrum, which spans between 1.5 GHz and 2.5 GHz. The upper portion of this band is often referred to as the S-band .
   • Satellite Constellations:
     • Low Earth Orbit (LEO) Satellites: Systems like Iridium (with 66 satellites) and Globalstar (with 48 satellites) use constellations of LEO satellites for MSS .
     • Geostationary Satellites: Inmarsat and Thuraya operate geostationary satellites (4 for Inmarsat and 2 for Thuraya) for their L-band services. These services are similar but not interoperable, and most terminals can use only one of the two services .
     • Other Systems: Other MSS systems include MSV / MSAT / LightSquared / Ligado (serving North America) and China’s upcoming S-band satellite phone using the Tiantong-1 geostationary satellite .
3. Legacy Services: Inmarsat maintains some legacy L-band services on its previous-generation satellites, although they are gradually being phased out in favor of newer services .
   • Ka-band Services: Inmarsat also operates a fleet of three Ka-band satellites (known as the Inmarsat 5 constellation), providing high-speed mobile satellite data services called Global Express .
   • Other Inoperative Systems: Systems like Ico / Pendrell, TerreStar, and Ellipso are currently inoperative .
4. Machine-to-Machine (M2M) Communication:
   • MSS plays a crucial role in machine-to-machine (M2M) communication:
     • Orbcomm: Orbcomm provides data-only M2M services using a constellation of LEO satellites in the VHF band and partners with Inmarsat for M2M services in the L-band .
     • Iridium: Iridium offers low-bandwidth modes often used for M2M applications .
     • Inmarsat BGAN M2M: Inmarsat provides an M2M version of BGAN (Broadband Global Area Network) called BGAN M2M .

MSS bridges communication gaps in areas where traditional cellular networks cannot reach, making it essential for global connectivity, emergency response, and remote operations.