Unavailability due to rain of VSAT networks operating in Ka and Ku bands in Brazil

Abstract

SUMMARYThe unavailability due to rain of VSAT star networks operating on Ku and Ka bands in Brazil is analysed in this paper. A large number of simulations performed over the Earth-space links resulting from combinations of four (real and hypothetical) satellites with six Brazilian Earth stations provide a good characterization of the rain unavailability in tropical and equatorial regions subject to heavy rainfall and thunderstorms. The simulations also compare the influence on the estimated unavailability of the use of two different ITU-R rain attenuation models and two values (calculated and measured) for the rainfall rate exceeded during 10 À2 % of the time, the climatic parameter in the models, in addition to the link polarization employed. The results obtained point to VSAT star networks as a practical solution to provide telecommunications services to remote communities.

Unavailability due to rain of VSAT networks operating in Ka and Ku bands in Brazil

“…Since the probability of simultaneous occurrence of rainfall events on both (up and down) links is considered negligible, the total unavailability will be the sum of these values for each link: From the margins defined above and the values of rainfall rate R 0:01 for each link, the probabilities on the right-hand side of expression (1) were estimated using the two ITU-R models for rain attenuation [1,2]. Typical values obtained for M u and M d ranged, respectively, from 7 to 22 dB and from 9 to 25 dB [6].…”