Interactive channel for multimedia satellite networks

Multimedia, including Internet traffic, can currently be multiplexed within the DVB/MPEG-2 formats and delivered direct to home users. Traditionally a slow terrestrial telephone link between the user and Internet service prov ider is used to request data. A direct return channel system will facilitat e users' high-bit-rate bidirectional communication via satellite. The retur n link could be used for the fast Internet access or large data exchanges t hat will be necessary in a multimedia world. The satellite system not only removes the need for wires but also increases transfer speeds. Satellite in teractive terminals can establish network connections via satellite and a g round-based hub. The DVB/MPEG-2 format carries up to 45Mb/s in the forward link, and a multifrequency time-division multiple access scheme allows up t o 2Mbitis in the return direction. The return channel of the interactive ch annel for multimedia satellite networks underwent final standardization by ETSI in early 2000. This article reviews the system concept of a typical im plementation. The key features of the return channel air interface, from tr ansmission parameter to login procedure, are explained. In general, Interne t packets are expected to be carried via DVB/MPEG-2 in the forward directio n and via ATM in the return direction. The IP transportation techniques are described.