The group-modem for the direct-multicasting satellite communications system

摘要

The Internet has become a global medium for communication, entertainment, and e-commerce. And there is increasing demand to deliver multimedia contents, such as audio and video data, from web sites to many customers simultaneously. The size of data to be delivered and the number of transmission points has been increasing recently. In this context satellite communication is thought to be effective network and communication infrastructure because it covers large area and easily provides high-speed service with great many reception points. The direct-multicasting satellite communications system had previously proposed to achieve a full mesh type satellite network economically, and the group-modem (multi-carrier multi-rate modem), the efficient channel assignment control program, and highly reliable multicasting program have been developed for it. This paper presents the architecture of the group-modem (multi-carrier multi-rate modem) that is used for direct-multicasting satellite communications system as a key technology of it.