ATM multiplex method for multimedia satellite communication system

NTT has developed an asymmetrical multimedia computer network, combining satellite and terrestrial circuits. This system provides interactive communications between customer PCs and servers. The forward signals (from servers to customers) are transmitted by satellite circuits, the transmission rate is approximately 30 Mbit/s in each transponder, and the backward signals (from customers to servers) are transmitted by narrow band terrestrial circuits. This paper proposes two types of multiplex methods for the satellite circuit, one is the ATM multiplex method and the other is the MPEG multiplex method. The ATM multiplex method transfers different kinds of multimedia data such as IP packets and MPEG signals on ATM cells. We have obtained the IP packets transmission performances over ATM cells through experiments using the N-STAR satellite since the middle of 1996. The MPEG multiplex method can be used to transmit MPEG2 high-quality data as the innovative digital satellite broadcast systems. The hardware of MPEG2 decoding units is becoming economical as digital satellite broadcasts become popular. This multiplex method enables the transmission of ATM cells on the MPEG transport stream. The proposed multiplex methods are applied according to the customers requests for their applications.