Chaotic Spreading Sequences for Drift Correction
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Solution Overview
Problem
Current chaos-based communications systems suffer from low throughput due to analog chaos generator drift and non-coherent waveform limitations, which require frequent synchronization and compromise data rate.
Innovation Solution
The system generates orthogonal or statistically orthogonal chaotic spreading sequences using polynomial equations and residue number system arithmetic, allowing for concurrent transmission over a common RF frequency band with static or temporally offset sequences to correct drift without compromising throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If analog chaos generator circuits are used to generate chaotic signals, then chaotic properties are achieved, but drift occurs over time requiring frequent synchronization
Solution Approach 1:
The patent replaces analog chaos generator circuits with digital chaos generator circuits. This substitution eliminates the drift problem inherent in analog circuits while maintaining chaotic signal properties. The digital implementation uses polynomial equations and residue number system arithmetic to generate chaotic sequences that are stable over time without requiring frequent synchronization.
Solution Approach 2:
The patent changes the fundamental parameter of chaos generation from analog continuous signals to digital discrete sequences. By using polynomial equations with specific parameters (coefficients, initial conditions) and residue number system arithmetic, the system achieves stable chaotic behavior without the drift characteristic of analog circuits.
2Measurement precision
If state information is frequently exchanged between transmitter and receiver for synchronization, then synchronization accuracy is improved, but throughput decreases
Solution Approach 1:
The digital chaos generator at the receiver automatically generates the same chaotic sequence as the transmitter using identical polynomial equations and initial conditions. This self-synchronization mechanism eliminates the need for frequent state information exchange, allowing the system to maintain synchronization while maximizing throughput.
3Device complexity
If multiple pseudo-random number generators are used to generate chaotic-like sequences, then sequence complexity increases, but true chaotic properties are not achieved
Solution Approach 1:
The patent replaces pseudo-random number generator algorithms with actual digital chaos generator circuits based on polynomial equations. This substitution provides true chaotic properties through deterministic chaos theory while maintaining sequence complexity through the use of multiple polynomial equations and residue number system arithmetic.
Data Source
AI summary
Systems and methods for code-division multiplex communications. The methods involve forming orthogonal or statistically orthogonal chaotic spreading sequences (CSC1,1, CSCD,1), each comprising a different chaotic sequence. The methods also involve generating an offset chaotic spreading sequence (CSC1,2, CSC1,3, . . . , CSC1,K(1), CSCD,2, . . . , CSCD,K(D)) which is the same as a first one of the orthogonal or statistically orthogonal chaotic spreading sequences, but temporally offset. Spread spectrum communications signals (SSCs) are each respectively generated using one of the orthogonal or statistically orthogonal chaotic spreading sequences. Another SSC is generated using the offset chaotic spreading sequence. The SSCs are concurrently transmitted over a common RF frequency band.