KOPERNIKUS - National Space Research Program

A novel architecture for a satellite access controller was elaborated which enables to support different services such as fast Internet access, ISDN and isochronous services via satellite. The hardware functions for the air interface and the real-time operating system have been defined. To use the satellite capacity efficiently, detailed investigations of the optimum transmission units in a cell-based multiplexing system were carried out. Based on the results, the system requirements were determined. Measurements of throughput over the satellite using different operating systems for the end-user and optimisations of the TCP/IP parameters (in particular the window size) were made. Using simulation novel forward-error correction techniques (e.g. Turbo codes) have been investigated for their applications in a satellite environment.