Mobile satellite services (MSS) are collections or networks of satellites that are expressly configured for the provision of wireless communications, such as cell phones and portable wireless phones. The use of these communications satellites has greatly increased the level of efficiency with many types of audio services, especially international calling. By making use of strategic placement of each satellite, it is possible to create a network that will allow for clear signaling around the globe, even in conditions that once made placing a call impossible.
The use of mobile satellite services is not unlike that of using a conventional cellular telephone link. However, because the repeaters are not located on land but in the atmosphere above the planet, the level of interference is generally understood to be lower. The process of MSS involves making use of satellites that are positioned in orbits that are considered low earth and medium earth in nature.
This allows for the most efficient use of transmissions from one part of the network to the other, until the point of origin and the point of termination are linked. When necessary, the mobile satellite services network will link with land based cellular networks, usually as part of accessing switches in the local calling areas. Using this system, it is possible to link any two wireless systems into communication, regardless of where they are located around the world.
One of the easiest ways to understand how mobile satellite services work is to consider the use of telephones within commercial airliners. Generally, telephony services are handled by linking with land based cellular carriers as the airliner crosses over land that is included in the territory for a given service provider. However, when traveling over oceans and countries with less developed cellular networks, mobile satellite services would make it possible for passengers to continue using the onboard phones to make contacts with phone subscribers anywhere, regardless of the location of the subscriber. By establishing a link between the airliner and a satellite, the signal can then be forwarded through the MSS network, eventually transfer to a land-based relay, and be routed to the point of termination.
