Model for the prediction of the differential rain attenuation between a terrestrial line-of-sight radio relay system and a low-angle satellite path based on the two-dimensional lognormal distribution

摘要

The main propagation effect on interference of a terrestrial line-of-sight radio relay system from a low-angle satellite path is the differential rain attenuation. In the present paper, a predictive method for the differential rain attenuation statistics is proposed which is based on a modified model convective raincell structure by taking into account the conventional limits of the raincell size. The assumption that the point rainfall statistics follows a lognormal form is also adopted. The results of the predictive procedure are applied to a particular problem of terrestrial line-of-sight system interference from a low-angle broadcasting satellite service in the 22.5 – 23 GHz band. The sensitivity of the various parameters affecting the differential attenuation is also examined. As a general remark, the conditional differential rain probability is found to be significantly dependent upon the rainfall characteristics of the climatic zone and the parameters of the spatial rainfall structure. Finally, a comparison of the present predictive procedure with a semiempirical developed model is treated and gives a quite reasonable agreement.