Beacon-measured Fade Slopes and Disdrometer Derivations with Variable Integration Time

Ultra-high throughput satellites (UHTS) operating at high frequencies provide large bandwidths but are severely impaired by atmospheric phenomena on the Earth–space path. Reliable short-term forecasts of channel characteristics can be used for fade mitigation techniques (FMT) such as adaptive coding and modulation (ACM) and site diversity. Numerical weather prediction (NWP) models are available on a global scale as a basis for such forecasts. Rain is the strongest effect, with the rain rate being highly variable in time. This study discusses which rain rate integration time and thus NWP forecast step is suitable for forecasting satellite channel characteristics. The rain attenuation is obtained from disdrometer measurements for various integration times and the resulting fade slope statistics are compared with beacon measurements and the model in the ITU-R P.1623 [1]. It is shown that NWP models with forecast steps of 5 minutes or less are interesting for such purpose.