Modeling Ka-band scintillation as a fractal process

摘要

We propose a model that describes the signal fading process due tonscintillation in the presence of rain. We analyzed a data set of uplinkn(30 GHz) and downlink (20 GHz) attenuation values averaged over 1 snintervals. The data are samples relative to ten significant events, forna total of 180 000 s recorded at the Spino d'Adda (North of Italy)nstation using the Olympus satellite. Our analysis is based on the factnthat the plot of attenuation versus time recalls the behavior of anself-similar process. We then make various considerations, and propose,na fractional Brownian motion model for the scintillation process. Wendescribe the model in detail, with pictures showing the apparentnself-similarity of the measured data. We then show that the Hurstnparameter of the process is a simple function of the rain fade. Wendescribe a method for producing random data that interpolate thenmeasured samples, while preserving some of their interesting statisticalnproperties. This method can be used for simulating fade countermeasurensystems. As a possible application of the model, we show how to optimizenfade measurement times for fade countermeasure systems