Recent advances in the design of transponding communications satellites provide the ability to switch transponder sub-bands among multiple up-link and down-link antennas.This feature increases the flexibility of trafic 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 stares. 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 an optimization metric that maximizes the overall supportability. We then suggest an optimization approach that can be used 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.
Several multi-aperture multiple beam antenna (MA-MBA) designs have been proposed for future military communications satellites to satisfy demands for increased nulling resolution against jammers. However, overall network performance can be severely degraded because of spurious nulls that are associated with MA-MBA antennas. In this paper, we propose and analyze a nulling algorithm that improves overall network performance by reducing potential performance degradation caused by MA-MBA antenna spurious nulls while providing high jamming resolution. This algorithm also provides wide area coverage for network users near a jamner in support of tactical scenarios. We show that optimized beam weights are a function of individual user optimum beam weights along with proper phase rotation for each beam. Computer simulated results are then provided illustrating p e r j o m c e of this proposed technique versus another nulling algorithm developed for Defense Satellite Communication System (DSCS) Super High Frequency (SHF) satellites.
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