Waveform Generation for Low Probability of Intercept Communications
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Solution Overview
Problem
Existing communication systems with cyclostationary features are vulnerable to interception and detection, particularly in changing noise and interference environments, as radiometric methods yield suboptimal performance in detecting and identifying spread-spectrum signals.
Innovation Solution
A wireless communication system using waveforms devoid of cyclostationary signatures, generated through Gram-Schmidt Orthogonalization of band-limited Gaussian-distributed seed waveforms, to enhance Low Probability of Intercept (LPI), Low Probability of Detection (LPD), and Low Probability of Exploitation (LPE) properties, with synchronized transmitters and receivers to maintain orthonormal functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cyclostationary waveforms are used for communication, then the communication system achieves reliable signal transmission and detection, but the system becomes vulnerable to interception and detection by radiometric methods
Solution Approach 1:
The patent extracts and eliminates the cyclostationary features from the communication waveform. By removing the periodic structure and deterministic characteristics that enable radiometric detection, the system achieves LPI/LPD/LPE properties while maintaining reliable communication through alternative waveform designs that lack these detectable features
Solution Approach 2:
The patent changes the fundamental parameters of the communication waveform by transitioning from cyclostationary signals with periodic structure to waveforms with random or aperiodic characteristics. This parameter change eliminates the spectral correlation features that radiometric detectors rely upon, thereby reducing detectability while preserving communication functionality
2Object-affected harmful factors
If spread-spectrum techniques are employed to improve covertness, then the signal becomes more resistant to detection, but the performance of radiometric detection methods deteriorates to suboptimum levels
Solution Approach 1:
The patent merges spread-spectrum techniques with the elimination of cyclostationary features to create a hybrid approach. By combining direct-sequence spread spectrum with frequency-hopping and removing periodic structure, the system achieves enhanced covertness that causes radiometric detectors to perform at suboptimum levels, as the merged techniques create a signal that lacks the stable spectral features required for effective radiometric analysis
3Object-affected harmful factors
If frequency-hopping and direct-sequence spread spectrum are combined in pseudo-random bursts, then the signal energy becomes insufficient for radiometric detection thresholds, but the communication system achieves low probability of intercept and detection
Solution Approach 1:
The patent uses periodic action in the form of time-hopping burst transmission combined with frequency-hopping. By transmitting in pseudo-random bursts rather than continuously, and by constantly changing frequencies within each burst, the system prevents radiometric detectors from integrating energy over a stable frequency over time, thereby keeping signal energy below detection thresholds while maintaining effective communication through synchronized receivers
Data Source
AI summary
Systems and/or methods are disclosed for generating a waveform that comprises a plurality of elements by using a Fourier transform and/or an inverse Fourier transform. The waveform that comprises the plurality of elements may be transmitted by transmitting, sequentially in time, the plurality of elements. In some embodiments, the Fourier transform and/or inverse Fourier transform comprises a Fast Fourier Transform and/or Inverse Fast Fourier Transform and the waveform that comprises the plurality of elements may be transmitted by using, sequentially in time, the plurality of elements to modulate a single carrier frequency.