Digital Chaos Generator for Synchronized Spread Spectrum Access
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Solution Overview
Problem
Current chaos-based communications systems suffer from low throughput due to analog chaos generator drift, leading to synchronization challenges and reduced data transmission efficiency, while non-coherent systems compromise on throughput and error rates.
Innovation Solution
A permission-based multiple access communications system using digitally generated chaotic sequences and orthogonal spreading codes to create a protected data communication signal with a constant power envelope, allowing for synchronized data transmission without extreme throughput compromise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If analog chaos generator circuits are used, then chaotic signals with random-like properties are generated, but drift occurs over time causing synchronization loss and reduced throughput
Solution Approach 1:
The patent replaces analog chaos generator circuits with a digital chaos generator implemented as a finite state machine. This substitution eliminates the drift problem inherent in analog circuits while maintaining the chaotic signal properties needed for secure communications. The digital implementation uses discrete state transitions defined by mathematical equations rather than continuous analog processes, providing stable long-term synchronization.
Solution Approach 2:
The patent changes the fundamental parameter of chaos generation from continuous analog voltage levels to discrete digital states. By using a finite state machine with defined state transition equations, the system achieves parameter stability that prevents drift while maintaining the necessary chaotic characteristics for spread spectrum communications and user synchronization.
2Reliability
If state information is exchanged frequently between transmitter and receiver, then synchronization is maintained, but throughput is reduced due to the overhead of synchronization exchanges
Solution Approach 1:
The digital chaos generator is designed to be self-synchronizing through its finite state machine architecture. The receiver independently generates the same chaotic sequence by replicating the transmitter's state transition equations and initial conditions, eliminating the need for frequent state information exchanges. The system serves its own synchronization needs through deterministic state evolution rather than external coordination.
Solution Approach 2:
The system performs preliminary synchronization by establishing initial conditions and state parameters before data transmission begins. Once synchronized, the deterministic nature of the digital chaos generator maintains alignment without requiring continuous adjustment, allowing data transmission to proceed at full throughput without interruption for synchronization exchanges.
3Device complexity
If multiple pseudo-random number generators are used to generate chaotic-like sequences, then sequence complexity increases, but the sequences retain pseudo-random artifacts and lack true chaotic properties
Solution Approach 1:
The patent replaces multiple pseudo-random number generators with a single digital chaos generator based on a finite state machine. This substitution produces genuine chaotic sequences with deterministic yet unpredictable properties, eliminating the cyclostationary artifacts inherent in pseudo-random generation. The finite state machine implements true chaotic behavior through nonlinear state transitions rather than linear congruential methods.
Data Source
AI summary
Systems (100) and methods (400) for selectively controlling access to multiple data streams which are communicated using a shared frequency spectrum and shared spreading codes. The methods involve generating a first product signal (FPS) by spreading first symbols of a first amplitude modulated (AM) signal using a first spreading code (SC). The methods also involve generating a second product signal (SPS) by spreading second symbols of a complimentary AM signal using a second SC. The FPS (124) and SPS 126 are combined to form a protected data communication signal (PDCS) including first data recoverable by a receiver (106). A global data communication signal (GDCS) is combined with PDCS (128) to form an output signal (140) having a spread spectrum format. The GDCS is generated using a digital modulation process and includes second data recoverable by a plurality of receivers (106, 108).