Satellite Transmitter With Variable Superframe Lengths for Signal Security
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Solution Overview
Problem
Existing satellite communication systems are vulnerable to adversaries who can retrieve the spreading or scrambling sequences used in transmission, leading to potential jamming, eavesdropping, or spoofing, especially when adversaries have higher SNR with large antennas.
Innovation Solution
A transmission system that varies the distance between superframe preambles unpredictably by using a generator to determine different superframe lengths and incorporates scrambling and spreading mechanisms to obscure the communication waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed superframe structure with regular preambles is used, then synchronization and waveform acquisition are simplified, but the system becomes vulnerable to adversaries who can retrieve spreading sequences through pattern recognition and averaging
Solution Approach 1:
The patent applies dynamics by making the superframe structure variable rather than fixed. Specifically, the distance between superframe preambles is varied within a range defined by minimum and maximum superframe lengths. This dynamic variation prevents adversaries from using fixed pattern recognition and averaging techniques to retrieve spreading sequences, while still maintaining synchronization through the periodic presence of preambles at variable intervals.
Solution Approach 2:
The patent changes the parameter of superframe length to enhance security. By varying the superframe length between minimum and maximum values, the system alters the temporal structure of preambles in a way that disrupts adversary attempts to retrieve spreading sequences through correlation and averaging, while ensuring that preambles remain present at predictable enough intervals for legitimate receivers to acquire synchronization.
2Reliability
If the distance between superframe preambles is varied, then adversaries cannot easily retrieve spreading sequences, but synchronization and waveform acquisition become more challenging
Solution Approach 1:
The patent applies partial action by varying the superframe length within a controlled range rather than completely randomly. The variation is constrained by minimum and maximum superframe lengths, ensuring that preambles appear frequently enough for legitimate receivers to acquire synchronization through correlation, while still providing sufficient variability to prevent adversary pattern recognition and sequence retrieval.
3Ease of operation
If fixed frame lengths are used for all superframes, then system operation is simplified, but security against eavesdropping and jamming is reduced
Solution Approach 1:
The patent applies dynamics by transitioning from fixed frame lengths to variable superframe lengths. The system maintains operational simplicity through structured constraints (minimum and maximum lengths) while achieving security through the variability that prevents adversaries from using fixed-pattern correlation and averaging techniques to retrieve spreading sequences.
Data Source
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AI summary
The present invention relates to a transmission system arranged for generating data traffic to be transmitted in a satellite communication system. The transmission system comprises : - encoding and modulation means for encoding and mapping a plurality of baseband frames of information bits, each baseband frame associated with a modulation and coding type, to a plurality of frames of encoded and modulated symbols, - generator means to generate one or more values to determine a superframe length, - framing means arranged for inserting synchronization symbols and preambles into frames of the plurality of frames of encoded and modulated symbols, so obtaining a plurality of superframes, each preamble indicating the start of a superframe, - spreading means arranged to receive the plurality of superframes (or a version thereof), and to spread each symbol in the plurality of superframes with a spreading sequence to a chip sequence, so obtaining a plurality of spread superframes, wherein the generated one or more values determine for a current superframe a frame length different from the frame length of the preceding superframe.