Tap-Weight Computer for Satellite Interference Cancellation
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Solution Overview
Problem
In satellite communications, cross-satellite and cross-polarization interference pose challenges due to increased satellite density, leading to signal interference that diminishes information transmission efficiency, and existing methods to separate signals reduce the amount of information that can be transmitted.
Innovation Solution
A system utilizing a Tap-Weight Computer (TWC) to calculate Tap-Weight Vectors (TWVs) for adaptive filters, which weight and subtract interfering signals from received signals, effectively reducing interference by using multiple adaptive filters with relatively short TWVs to simplify calculations and improve interference cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If satellite spacing is decreased to increase satellite density, then the number of satellites increases, but cross-satellite interference increases
Solution Approach 1:
The patent converts the harmful interfering signals from adjacent satellites into useful information by using them as inputs to adaptive filters. The interference signals are processed through tap-weight computers that calculate optimal weighting factors, and the filtered interference is then subtracted from the desired signal, transforming the harmful interference into a benefit by enabling its cancellation and improving overall system capacity
Solution Approach 2:
The patent introduces adaptive filter modules with tap-weight computers as intermediary components between the interfering satellite signals and the desired signal. These intermediaries process the interference signals through tapped delay lines and weight calculations, generating filtered versions that are then subtracted from the composite signal, effectively mediating the interference problem
2Object-affected harmful factors
If antenna beam-width is increased to reduce cross-satellite interference, then interference decreases, but antenna gain decreases
Solution Approach 1:
The patent replaces the mechanical approach of adjusting antenna beam-width with a signal processing approach. Instead of physically changing antenna characteristics to reduce interference, the system uses electronic signal processing through adaptive filters and tap-weight computers to cancel interference, thereby maintaining high antenna gain while eliminating the need for beam-width adjustment
3Object-affected harmful factors
If signal separation methods are used to reduce interference, then cross-polarization interference decreases, but information transmission efficiency decreases
Solution Approach 1:
The patent converts the harmful cross-polarization interference into a beneficial element by using it as an input to the adaptive filter. The interference signal from the orthogonal polarization is processed through the tap-weight computer and subtracted from the composite signal, transforming what was previously harmful interference into a useful component that enables cancellation and allows more efficient use of available frequencies
Data Source
AI summary
A method and apparatus in which a Tap-Weight Computer (TWC) calculates a Tap-Weight Vector (TWV). The TWV is coupled to a register in each of a plurality of adaptive filter modules. Each such adaptive filter module includes several adaptive filters that each include a tapped delay line. The input to the tapped delay line of each such adaptive filter is one of a plurality of potential interfering signals. The TWV controls the weighting of the outputs from the taps off the delay line. The weighted outputs from each tapped delay line are then subtracted from a received signal which potentially includes interference from the potential interfering signals. The TWC is multiplexed to each of the plurality of adaptive filters so that each adaptive filter is loaded with a TWV calculated by the TWC to reduce the amount of interference contributed by a particular potential interfering signal coupled to an input to that particular adaptive filter. In one embodiment, a plurality of such adaptive filter modules share the same TWC.