A RAIN ATTENUATION TIME SERIES MODEL FOR MUOS

Rain attenuation is the predominant signal impairment on satellite-earth communications above 10 GHz [1] [2]. The impact can be described as deep slowly-varying amplitude fades where signal phase is "significantly less affected"[3]. For the purpose of real-time hardware testing of Ka fade compensation algorithms on the Mobile User Objective System (MUOS), a rain attenuation time series model is developed. The model is based on the ONERA/CNES Spectral Model [4]. Gaussian white noise is filtered/accumulated and then shaped using an asymmetric non-linearity based on the ITU-R P.618-8 complementary cumulative distribution function (CCDF) [5]. A resulting realization for a heavy rain fade on the harshest weather MUOS Ka link is presented. The CCDF and fade slope of the generated time series realization are computed and shown to be consistent with the ITU CCDF data. The time series is implemented in the MUOS Ka Link Effect Simulator (Ka-LES) using real-time file playback. The requirements on the hardware simulator are shown to be sufficient for testing the MUOS satellite prior to launch.