Research — Project Overview

Overview of the ATM—Sat Project

The project ATM-Sat provides methods for a new ATM-based communication technology for Low Earth Orbit (LEO) satellite systems. This is a technically challenging and strategically important R&D task having in mind that the Integrated German Space Program estimates a market volume of US-$ 60 billion for the satellite communications market in the year 2000. Just for satellite multimedia services, Merril Lynch expects a market of US-$ 38 billion in the year 2007.

For these multimedia communications—with fixed, portable, and mobile endsystems—the project ATM-Sat aims to develop the concept of an ATM satellite system. In order to be seamlessly integrated into the environment of terrestrial ATM-based multimedia networks, the future LEO (Low Earth Orbit) satellite networks for multimedia have to adopt the ATM (Asynchronous Transfer Mode) transmission scheme and to implement ATM switches on board the satellites.

However, compared to communication in fixed networks, satellite communication is characterised by special constraints (limited bandwidth, delay, transmission errors, dynamic network topology) requiring the development of a new ATM-based communication technology. In ATM-Sat, satellite-oriented ATM-based transmission schemes and protocols will be specified and verified in a demonstrator, made available by Bosch Telecom.

ATM-Sat is a cooperation of DLR (Institute for Communication Technology and Institute of Radio Frequency Technology, both in Oberpfaffenhofen), Fraunhofer Fokus (Institute for Open Communications Systems, Berlin), and TeSat GmbH (former Bosch SatCom/Telecom) (Dept. Engineering, Systems Technologies, Backnang). All partners have distinguished themselves within their areas by leading various communication projects.

• The main goals of the ATM-Sat project are summarized as follows:
  ATM-Sat will develop the system concept as well as the network and protocol architecture of an ATM-based LEO satellite system for fixed, portable, and mobile multimedia communication. This will serve as a reference system for further scientific work in the project;
• In the ATM-Sat project suitable application scenarios and services for satellite multimedia communication will be identified;
• The ATM-Sat project will develop new protocols for multiple access, specify them in SDL, and implemented them as prototype;
• ATM-Sat will provide a reference solution for the combined routing and dimensioning of the ISL network valid for a global multiservice traffic flow scenario;
• In the ATM-Sat project a new Connection Admission Control algorithm together with an adjusted Carrier Assignment Strategy will be developed, specified in SDL, and implemented in the simulator;
• ATM-Sat will study the impact of satellite-based ATM networks onto the TCP/IP protocol suite and will propose optimised solutions for the support of existing and future Internet applications;
• ATM-Sat will design a specific payload with on-board ATM switching and on-board management functions to be used for LEO satellites;
• ATM-Sat will develop the technology of active intelligent antennas for broadband satellite communications in the Ka- or V-band, respectively;
• Finally, ATM-Sat will modify an available multimedia switch demonstrator and use it to verify and demonstrate key switching and management functions defined in the project.