A New Rain Attenuation Prediction Model for the Earth-Space Links

In the Earth-space link communication system design, rain attenuation must be considered, especially with a frequency above 10 GHz. Therefore, a reliable rain attenuation prediction model is necessary for the design of these systems. Recently, two anomalous behaviors have been reported in existing rain attenuation prediction models. First, predicted rain attenuation results from many models vary nonmonotonically with elevation angles. Second, the rain attenuation predicted by the ITU-R model varies nonmonotonically with a percentage of time or rain rate in low latitudes (between 36° S and 36° N) and low elevation angles (below 25°). To tackle these problems and improve the prediction accuracy, a new rain attenuation model is developed based on the exponential rain cell profile, and a concept of rain rate adjustment factor is proposed. Evaluating performance by utilizing the Recommendation ITU-R P.311-15, the new model provides better prediction results than other existing models. Moreover, the anomalous behaviors are also improved in this model.