Waveform Design Hopping for Secure Spread Spectrum
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Solution Overview
Problem
Current spread spectrum communication systems face challenges in enhancing security without inordinately increasing bandwidth usage and are vulnerable to interception if an unauthorized party gains access to the transmitter or receiver, particularly in secure DSS systems.
Innovation Solution
The method involves using a series of unique waveform designs with composite spreading codes, generated by combining constituent code segments through different combinatorial logic, and changing various waveform parameters like code length, timing, and modulation, to create a hopping sequence that minimizes autocorrelation and cross-correlation peaks, thereby enhancing security and reducing the likelihood of detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple unique waveform designs with composite spreading codes are used in a hopping sequence, then security against interception is improved, but device complexity increases
Solution Approach 1:
The spreading code is divided into multiple constituent code segments that can be independently selected and combined. Each waveform design uses a unique combination of these segments, allowing security enhancement through code diversity while managing complexity through modular code construction.
Solution Approach 2:
The system dynamically switches between multiple waveform designs according to a hopping sequence. The waveform parameters including code length, timing, and modulation are changed over time, providing security through temporal variation while using field programmable gate arrays to manage the dynamic reconfiguration efficiently.
2Object-affected harmful factors
If waveform parameters such as code length, timing, and modulation are changed to create unique waveform designs, then the probability of detection is reduced, but manufacturing precision requirements increase
Solution Approach 1:
Multiple waveform designs are created by varying key parameters including code length, timing characteristics, and modulation schemes. Each waveform design uses a unique combination of constituent code segments with different parameter sets, reducing detectability through parameter diversity while using standardized field programmable gate arrays to maintain manufacturing precision.
3Quantity of substance
If field programmable gate arrays are used to generate and store multiple spreading codes, then bandwidth usage is minimized, but device complexity increases
Solution Approach 1:
Field programmable gate arrays are used to universally generate and store multiple spreading codes, replacing the need for separate dedicated hardware for each code. The FPGA can be reconfigured to generate different waveform designs and composite spreading codes, providing multi-functionality that minimizes bandwidth usage while consolidating complexity into a single reconfigurable device.
Data Source
AI summary
A method of transmitting a spread spectrum signal in a single communication session between a transmitter and a receiver, stores a series of N unique waveform designs and a hopping sequence in a transmitter memory. A signal is transmitted to a receiver according to the hopping sequence using the plurality of N unique waveform designs. Preferably, each waveform design is characterized by a unique composite spreading code that is formed by at least some of a plurality of constituent code segments. Alternatively or additionally, the waveform designs may differ by any one or more of code length, symbol or chip timing or phase, frame or burst structure, chip offset, modulation, error control coding, encryption scheme, or scrambling code. A transmitter and receiver are also disclosed, as is the concept of appending chips between symbols to expand the universe of unique spreading codes without incurring an increase in processing gain.