Satellite Communication Transmitter With Matched Synchronization Symbols
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Solution Overview
Problem
Existing satellite communication systems are vulnerable to eavesdropping and exploitation of frame structures, particularly in the presence of higher order constellations, as synchronization symbols and pilots can be easily detected, allowing adversaries to determine the frame structure, operational SNR, and exploit the waveform.
Innovation Solution
The system employs a transmission method where synchronization symbols are expanded to the same constellation as the payload symbols, using the same modulation order, and optionally applies scrambling with a cryptographic module to obscure the frame structure, while maintaining efficient modulation orders to prevent adversaries from detecting the frame structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If synchronization symbols are inserted into frames using a lower modulation order (e.g., QPSK) than the payload symbols (e.g., 64-APSK), then frame structure detection and waveform acquisition are facilitated, but the frame structure becomes detectable by eavesdroppers, compromising transmission security
Solution Approach 1:
The patent applies local quality by making the synchronization symbols locally indistinguishable from payload symbols through expansion to the same constellation. The synchronization symbols are expanded from a lower modulation order (e.g., QPSK) to the same modulation order as the payload (e.g., 64-APSK), making them locally identical in appearance to an eavesdropper, thus preventing frame structure detection while maintaining their synchronization function through correlation-based detection at the receiver
Solution Approach 2:
The patent introduces an intermediary transformation process that expands synchronization symbols from a lower modulation order to the same modulation order as payload symbols. This expansion acts as a mediator that preserves the synchronization function while hiding the frame structure from eavesdroppers, allowing waveform acquisition through correlation detection without revealing the frame structure
2Productivity
If higher order constellations are used for payload transmission, then spectral efficiency is improved, but the frame structure becomes more vulnerable to detection and exploitation by adversaries
Solution Approach 1:
The patent applies local quality by making the synchronization symbols locally indistinguishable from payload symbols through expansion to the same constellation. The synchronization symbols are expanded from a lower modulation order (e.g., QPSK) to the same modulation order as the payload (e.g., 64-APSK), making them locally identical in appearance to an eavesdropper, thus preventing frame structure detection while maintaining their synchronization function through correlation-based detection at the receiver
Solution Approach 2:
The patent applies parameter changes by transforming the modulation order parameter of synchronization symbols from a lower value (e.g., QPSK) to match the payload modulation order (e.g., 64-APSK). This parameter change ensures that synchronization symbols have the same statistical properties as payload symbols, making frame structure detection through modulation order analysis ineffective while preserving spectral efficiency
Data Source
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AI summary
The present invention relates to a transmission system arranged for generating data traffic to be transmitted. The transmission system comprises : - encoding and modulation means for encoding and mapping a plurality of frames whereby in each frame a set of information bits of the data traffic is encapsulated, each frame being associated with a first modulation order and a coding rate, to a plurality of frames of encoded and modulated symbols, - physical layer framing means arranged for inserting synchronization symbols taken from a second modulation order into at least one frame of encoded and modulated symbols of said plurality, so obtaining a plurality of physical layer frames. The transmission system is characterized by comprising expansion means to replace, if the second modulation order is smaller than the first modulation order, at least a subset of the synchronization symbols inserted by the physical layer framing means by symbols from the same constellation as the modulated symbols in the frames of encoded and modulated symbols.