Fade prediction and control systems

The growing utilisation of high frequencies (Ka band) has made very important the use of one or more fade countermeasures (UPPC, site diversity, frequency diversity, adaptive coding, etc.) to overcome rain fading avoiding the need to over-dimension the systems. Fade countermeasures could provide better performance if supported by a control system that is able to predict the dynamic characteristics of rain fading in the instant in which the attenuation crosses a certain threshold. Such a system would allow one to avoid over-compensation or false alarms as well as to optimise the available resources in the case of multilevel compensation, with an efficiency as great as the prediction accuracy. After the description of the main techniques for real time measurement of the attenuation, a hypothesis of a new control system with the relevant algorithm is presented. This system bases the prediction of the dynamic characteristics of fading on the observation of some initial parameters