Simulation of satellite systems operating at Ka-band and above using experimental time series of tropospheric attenuation

Rain causes the most significant propagation loss to satellite communication systems operating above 10 GHz. However, at the higher frequencies, heavy rain is not the only propagation factor likely to degrade system performance. Gases, cloud and light rain, factors that are normally neglected in the lower frequency bands, can significantly limit the performance of an Earth-space system operating at Ka-band and above. This paper presents a series of event-based analyses that quantify the levels of attenuation at ITALSAT beacon signals caused by the presence of rain and cloud. The significance of the observed attenuation levels in the design and performance of a hypothetical VSAT system is evaluated. Severe atmospheric attenuation is the most significant obstacle to the design of high-availability VSAT systems at V-band frequencies. Our study has shown that affordable power margins are not sufficient to alleviate the effects of rain on these systems. We demonstrated a possible solution where the system is dimensioned to cope with cloud attenuation and variable data rates are employed against rain attenuation. However, delay-sensitive real-time services (e.g. video transmission) may not be suited to this mitigation technique.