Analysis and design of gateway diversity systems for Very High Throughput Satellites (VHTS)

Resumen

Currently, it is estimated that the traffic demand through satellites will be 1 Tbps by 2020 and it will be satisfied thanks to a new generation of satellites named Very High Throughput Satellites (VHTS). In order to satisfy this demand, the use of higher frequency bands such as Q/V band is necessary due to their greater bandwidth. However, the use of high frequency bands entails severe effect of rain attenuation in satellite communications. To prevent from rain fade, ground stations make use of gateway diversity systems which consist of the separation and spatial
decorrelation between gateways. The creation of gateway diversity is possible thanks to the use of differential rain attenuation statistics which are extracted from Rec. ITU-R P-1815-1. In addition, when a rain event takes place, these smart systems distribute ideally the bandwidth between gateways in order to maintain operationally the system. To do this, the use of the rain
attenuation time series obtained from Rec. ITU-R P.1853-1 is crucial to know the dynamics of the channel and to study the transfer events of bandwidth between gateways.
In this project, a tool which implements the use of differential rain attenuation statistics for
designing gateway diversity systems is presented. This document describes its implementation through the explanation of its structure and functioning. Afterwards, results from real systems cases of study are presented where the purpose is to analyze and study the variation of
differential rain attenuation statistics according to parameters such as geographic location or frequency among others. The studies are carried out through the observation of outage probability contours and the discussion of the importance of changes on the contours due to the influence of some interest parameters.
Along with the design tool, a tool that permits analyze the transfer events of bandwidth produced in gateway diversity systems is included. This is reached thanks to the use of rain attenuation time series whose extraction procedure and their use to get the switch events are
described in this document. Justified results from studies are also presented where the aim is to observe how the switch events vary with the modification of geographic location and antenna‟s size. From the results from both tools, conclusions about factors to be taken into account in the establishment of gateway diversity have been drawn.
Finally, together with these tools and their results, the writing of a paper about the design of gateway diversity for VHTS and some results that summarize some of the main ideas from these documents is included. This paper has been accepted in the XXXIII Simposium Nacional de la
Unión Científica Internacional de Radio, URSI 2018.