Fade countermeasures at Ka band: Direct Inter-establishment Communications Experiment (DICE)

In the 20/30 GHz bands the fading of a satellite channel can be severe due to precipitation. In the DICE project a fade countermeasure system is realised using spread spectrum techniques. An adaptive remultiplexer has been developed which varies the spreading ratio depending on the monitored channel quality. The transmitted bandwidth remains constant as the data rate varies according to the fading depth. The fade countermeasure system is applied in a multi-point video conferencing trial over the 20/30 GHz communications payload of ESA´s OLYMPUS satellite. The DICE system interconnects up to four sites and offers continuous-presence video, audio and computer data facilities. The video conferencing system is based on small satellite earth stations with 1.5 m antennas and easily transportable units (rollabouts) for the video, audio and graphics facilities