Satellite communications networks

The evolution of satellite communication systems over the past two decades from simple point-to-point links with unique subcarrier-defined paths between points to today´s multipoint, satellite-switched, multi-satellite networks tying together hundreds of earth stations, and transmitting voice and data increasingly in the time domain is considered. Examples of the methods used to manage network resources efficiently through terrestrial control and monitoring of information flow together with on-board switching are given. These examples are choosen mostly from the INTELSAT experience which will soon include a sixth generation of space segment. The paper concludes with a discussion of the future directions of satellite network development made possible by the technology being planned for NASA´s Advanced Communications Technology Satellite. This design anticipates the needs of both high-volume trunking and thin-route service.