A Study on the Rain Attenuation Characteristics Using Multiple Ku-Band Satellite Signals in Relation to Rain Area Motion

Characteristics of rain attenuation statistics for the Ku-band satellite signals are investigated among the three earth stations at Osaka Electro-Communication University (OECU, Neyagawa, Osaka), NTT Yokosuka R&D Center (Yokosuka, Kanagawa), and satellite base station (Matsuyama, Ehime), respectively, from April 2022 to March 2023. The time difference of the attenuation occurrence among these stations is well explained by the motion of rain fronts and extratropical cyclones obtained from the weather charts. Rain attenuation characteristics such as duration time are shown to be largely affected by the speed of the rain area motion around each station. The scale of rain cells inferred from duration time and rain area speed is found to be increased up to around 10 km for the 5 dB attenuation according to the rainfall rate at each rainfall event. The time delayed diversity effects are also examined using the attenuation data observed at 1 min interval. The results are converted to the site diversity effects with the distance up to about 10 km by the rain area motion around each station. A novel method is thus proposed to estimate the site diversity effects from the 1 min attenuation data observed at only one station during at least one year. The joint time percentages agree fairly well with the ITU-R recommendations up to about 10 km distance at the original time percentages of more than 0.05%.