NETWORKING OVER THE IBIS SYSTEM Sergio Chacón (1) , José Luis Casas (1) , Asís Cal (1) , Rafael Rey (1) , Josep Prat (1) , Javier de la Plaza (1) , Gilles Monzat (2) , Patrice Carrere (2) , Carlos Miguel Nieto (3) , Fco. Javier Ruiz Piñar (3) (1) ALCATEL ESPACIO, C/ Einstein 7, 28760 Tres Cantos (Spain), sergio.chacon@space.alcatel.es (2) ALCATEL SPACE INDUSTRIES 5, rue Noël-Pons 92737 Nannterre Cedex (France) gilles.monzat@space.alcatel.fr (3) ETSIT Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain), cmn@dit.upm.es ABSTRACT The Integrated Broadcast Interaction System is implemented with a fully regenerative On-Board Processor (Alcatel 9343) designed to provide direct (distributed) DVB-RCS[1] (Digital Video Broadcasting Return Channel Satellite) compliant satellite access for individual digital video broadcasters, Internet Service Providers, and multimedia users. This paper presents the mechanisms which make it possible to support connectionless services over a connection oriented satellite network as well as provide QoS support. I. INTRODUCTION IBIS integrates two existing satellite transmission standards: DVB-RCS and DVB-S [2] (Digital Video Broadcasting Satellite). Both of which are used in transparent satellites without any regeneration on board. IBIS combines these two standards into a single regenerative multi-spot satellite system allowing for full cross-connectivity between the different uplink and downlink beams. UPLINK COVERAGE #2 DOWNLINK COVERAGE #1 DVB-RCS UPLINK UPLINK COVERAGE #1 DOWNLINK COVERAGE #2 FDMA TDMA A9343 DVB-S DOWNLINK #1 DVB-S DOWNLINK #2 DVB-S DOWNLINK #N Figure 1: IBIS System Concept The Uplink will be compliant with the DVB-RCS standard. This fact will allow users to use standard RCST (Return Channel Satellite Terminal) stations, which will be widespread and relatively inexpensive in the future thanks to the standardization effort of terminal manufacturers and broadcast satellite operators. Individual users and broadcasters will be able to access the satellite on any of several uplink coverage footprints illuminated by the satellite, using multiple frequencies, within a TDMA frame, and at several transmission rates (multiple-rate MF-TDMA or Multiple Frequency Time Division Multiple Access). The Downlink will be fully compliant with the DVB-S Standard, including all the possible convolutional rates [3]. This will allow users to take advantage of the economies of scale and the performance of standard commercial DVB-S receivers, which are widespread across Europe today. A key feature of the system will be the capacity to route data on any of the uplink coverage footprints on to any combination of downlink coverage footprints; the system will implement full cross-connectivity between uplink and downlink footprints. In order to accomplish all this, contributions from all DVB-RCS compliant uplink users must be demultiplexed, demodulated, and decoded and then switched and re-multiplexed into the DVB-S compliant downlink data streams as required by users. On board switching and multiplexing will take place in accordance with a dynamic multiplexer table. Each downlink has associated with it a multiplexing table. It will be possible to reconfigure this table very quickly through a regenerative signaling channel allowing very fast circuit switching at packet level on- board. In case of emergency the standard Telecommand (TM/TC) channel will be used to configure the payload. II. THE IBIS NETWORKING MODEL The Communication Model as is defined in the DVB- RCS Standard is shown in Figure 2. The Broadcast Channel is defined as a unidirectional channel from the Service Provider to the User, while the Interaction Channel is defined as a bi-directional channel used to exchange information between the Service Provider and the User or between Users.