A Prototype Adaptive Fade Countermeasure System for TDMA Operation at Ka Band

Ka band, the 20/30 GHz frequency band for satellite communications, has gained much interest in recent times. It is well suited for applications with small sized earth stations. The major disadvantage of Ka band, however, is its sensitivity to rain fading. Several satellite experiments are being carried out at the moment studying so called adaptive fade countermeasures, the purpose of which is to improve link quality in presence of rain. In this paper, the design and early laboratory experiments of a prototype fade countermeasure system implemented on a TDMA controller are described. This system is used for an experiment carried out by German PTT, Swiss PTT and DLR to investigate the significance of adaptive fade countermeasures for the availabilty of a Ka band satellite link. First results show, that an effective improvement of the link is possible with simple fade countermeasures.