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MEDIS — Multimedia Demonstration in Space

Overview The goal of the MEDIS project is a technology demonstration of several key technologies for multimedia satellite services including Ka-Band links, optical intersatellite links, ATM switching technology, a small bus platform and others.

The part of Fraunhofer Fokus is the specification and realisation of experiments showing the feasability of multimedia communication over this platform. Fokus concentrated on the lower layers of the communication stack from the physical layer up to the transport layer.

Test scenarios have been specified in several steps: verification of link characteristics, end-to-end measurements and hand-over. The link verification step aims at measuring the characteristics of the links (ground-satellite, satellite-ground, satellite-satellite) that influence higher level protocols (AAL5, IP, TCP, ...). Among the characteristics are bit error rate, error distribution, delay, delay jitter, cell mis-insertion rate and others. These characteristics are measured on the ATM layer.

The end-to-end measurement step measures the performance of some critical protocols like AAL5, IP, TCP, NTP and others and compares the theoretical performance as expected on basis of the link characteristics with the measured performance. The interesting point in these measurements is the time variance of the link characteristics and how the different protocols are able to cope with this (the satellites are MEO's).

The next step is the testing of handovers from one satellite to another one. Whether this is possible or not depends on the actual parameters of the Ka-band channel and the ground station antennas, so at this point it is not clear whether this will be possible or not.

One outcome of the work in this project is the follow-up activity ATM-Collumbus

Workshops The projects has undergone the usual PDR. No public workshops were held.
Publications All project documentation is project internal.
Developments List project related developments here
Partners Astrium Bremen
Astrium Ottobrunn
Tesat GmBH (former Bosch SatCom)


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