Non-homogeneous gain state optimization for transponding satellite communications

Abstract

Recent advances in the design of transponding communications satellites the ability to switch transponder sub-bands among multiple up-link and down-link antennas. This feature increases the flexibility of traffic routing and improves spectral re-use characteristics. A side benefit of such a new system is the capability of applying different transponder gains to carriers in different sub-channels within a given transponder. Recently, techniques have been developed for analyzing link supportability and the transponder loading with these non-homogeneous gain states. However, these new analysis techniques require that the gains be known a-priori. to complement these analysis techniques a method is needed for selecting the best gains to be used in each sub-channel. This paper presents such a method for selecting transponder gains. We define the constraining equations, which ensure that each link can be supported, and propose a optimization metric that maximizes the overall supportability. We the suggest an optimization approach that can be sued to select the gains for each sub-channel and the overall transponder operating point. The approach described includes a means of selecting the starting point for the optimization. A numerical example is provided.