Study on rain attenuation considering rainfall-intensity dependent spatial correlation characteristics

For the link budget of a wireless access system that uses a frequency higher than the quasi-millimeter-wave band, we calculate the required rain attenuation margin that satisfies the required quality level based on the cumulative distribution of the rain attenuation. To reflect the nonuniformity of the rainfall in a wireless transmission line, the spatial correlation characteristics of the rainfall intensity should be considered because the cumulative distribution of the rain attenuation is derived from the rain rate distribution. On the other hand, the spatial correlation has a tendency to be dependent on the rainfall intensity. However, there is no method for predicting the rain attenuation distribution that considers this tendency. The distance characteristics of the rainfall spatial correlation are analyzed based on the rainfall data of a high-resolution meteorological radar in addition to the rainfall data obtained through the Automated Meteorological Data Acquisition System (AMeDAS) administered by the Japanese meteorological agency, which is often used to analyze the rain rate distribution. The dependency on the rainfall intensity is confirmed by this study. As a result of reflecting this characteristic in a typical link budget, and the rain attenuation margin is approximately 4.6 dB less than one of the existing methods.