Coarse Synchronization for Chaotic Waveforms

Solution Overview

Problem

Current low probability of detection (LPD) and low probability of exploitation (LPE) communications face challenges in waveform detection and synchronization, particularly in hostile environments, where advanced detectors can identify signals due to energy, waveform feature, or signal rate detection, and synchronization difficulties arise from complex waveforms and channel distortions.

Innovation Solution

A wideband chaotic waveform with a rateless design, operated below the signal-to-noise ratio (SNR) wall, using coherent and non-coherent processing techniques for efficient coarse synchronization, and creating coherence domains to handle maximum uncompensated Doppler values, enabling accurate and real-time synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If energy detection is used to detect signals, then detection capability is improved, but signal-to-noise ratio requirements worsen (requiring higher SNR for reliable detection)

Engineering Contradiction:

Improvesignal detection capabilityVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Difficulty of detecting and measuringVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by performing coarse synchronization before fine synchronization. The coarse synchronization stage pre-processes the signal by estimating initial time and frequency offsets, which prepares the signal for more efficient fine synchronization. This preliminary step reduces the overall detection complexity and improves detection capability while managing SNR requirements more effectively.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the synchronization process into two distinct stages: coarse synchronization and fine synchronization. Coarse synchronization handles large time and frequency offsets using lower computational complexity methods, while fine synchronization refines these estimates with higher precision techniques. This segmentation allows each stage to be optimized independently, improving overall detection capability without excessively increasing SNR requirements.

Inventive Principle:

Principle #1Segmentation

2Reliability

If waveform synchronization is performed with complex waveforms and channel distortions, then communication reliability is improved, but synchronization difficulty worsens

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidsynchronization difficulty

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by performing coarse synchronization before fine synchronization. The coarse synchronization stage pre-processes the signal by estimating initial time and frequency offsets, which prepares the signal for more efficient fine synchronization. This preliminary step reduces the overall detection complexity and improves detection capability while managing SNR requirements more effectively.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the synchronization process into two distinct stages: coarse synchronization and fine synchronization. Coarse synchronization handles large time and frequency offsets using lower computational complexity methods, while fine synchronization refines these estimates with higher precision techniques. This segmentation allows each stage to be optimized independently, improving overall detection capability without excessively increasing SNR requirements.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If advanced detectors with long integration time are used, then detection accuracy is improved, but probability of detection worsens (detection becomes inevitable)

Engineering Contradiction:

Improvedetection accuracyVSAvoidprobability of detection

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing coarse synchronization before fine synchronization. The coarse synchronization stage pre-processes the signal by estimating initial time and frequency offsets, which prepares the signal for more efficient fine synchronization. This preliminary step reduces the overall detection complexity and improves detection capability while managing SNR requirements more effectively.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the synchronization process into two distinct stages: coarse synchronization and fine synchronization. Coarse synchronization handles large time and frequency offsets using lower computational complexity methods, while fine synchronization refines these estimates with higher precision techniques. This segmentation allows each stage to be optimized independently, improving overall detection capability without excessively increasing SNR requirements.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11652680B1Waveform independent coarse synchronization method

Publication Date: 2023.05.16 BAE SYSTEMS INFORMATION ANDELECTRONIC SYSTEMS INTEGRATION INC

AI summary

A wideband chaotic waveform that is rateless in that it may be modulated at virtually any rate and has a minimum of features introduced into the waveform. Further, the waveform provided may be operated below a signal to noise ratio wall to further enhance the LPD and LPE aspects, thereof. Additionally, the present disclosure may provide a mix of coherent and non-coherent processing techniques applied to signal samples to efficiently achieve coarse synchronization with a waveform that is faster, more efficient and more accurate than using time domain signal correlators alone.