Novel dimensioning method for high-throughput satellites: forward link

Abstract

This work presents a detailed study of the forward link of a high-throughput satellite and proposes a novel methodology for the dimensioning of broadband communication satellites, based on the optimization of the capacity and/or the cost per capacity unit. The optimization process combines the characteristics (gain and interference) of the satellite antenna(e) with propagation effects, for a given set of technical and commercial parameters. The approach uses a spacecraft architecture implementing multibeam coverage based on frequency reuse, using a fixed payload power and targeting given user terminals. The methodology can be applied to any beam distribution, payload power distribution, or variable beam sizes, as these parameters are recalculated each time in the optimization process due to their impact on the interference environment or the available power for each beam. In this work, the method has been tested on single-feed-per-beam systems with a uniform power distribution. Among the input criteria, one can list the percentage of covered service area and the service availability. The proposed methodology is adaptable to any kind of service area and frequency band. A digital video broadcasting satellite second-generation air interface with adaptive coding and modulation is used as a reference. The method employs iterative link-budget calculations (including carrier-to-interference ratio and propagation attenuations) and provides the highest capacity or the best cost per capacity unit, for a fixed size of the antennae and a pragmatic feed design. The method is combined with the calculation of the channel capacity in order to be able to evaluate the difference between the theoretical performance and a realistic system.