RF Sampling Spread Spectrum Sequences for Secure Adaptive Links

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Solution Overview

Problem

Existing spread spectrum communication systems rely on predefined pseudorandom sequences that can be intercepted and are not adaptable to changing radio frequency environments, compromising security and flexibility.

Innovation Solution

Devices dynamically generate spreading sequences based on reciprocal channel characteristics using RF sampling, ensuring sequences are known only to communicating devices and adaptable to bandwidth and environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If predefined pseudorandom sequences are used for spread spectrum communication, then system implementation is simple and straightforward, but security is compromised because sequences can be intercepted and are not adaptable to changing radio frequency environments

Engineering Contradiction:
ImprovesecurityVSAvoidsequence generation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic sequence generation where the spreading sequences are not fixed but are generated in real-time based on reciprocal channel measurements between transmitting and receiving devices. This dynamic approach ensures that sequences adapt to changing radio frequency environments and cannot be easily intercepted or predicted, directly resolving the security vulnerability of predefined sequences while maintaining reasonable system complexity through the use of standard channel estimation techniques.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses the natural reciprocal characteristics of radio channels to generate sequences autonomously at each device without requiring external key distribution infrastructure. Each device independently generates sequences based on its own channel measurements, eliminating the need for complex centralized key management systems while achieving high security through the uniqueness of each device's channel characteristics.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If predefined pseudorandom sequences are used, then device complexity is low, but adaptability to changing radio frequency environments and bandwidth conditions is poor

Engineering Contradiction:
Improveadaptability to bandwidth and environmental conditionsVSAvoidsequence generation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameter of sequence generation from static predefined values to dynamic values derived from channel characteristics. By using channel impulse response measurements and their statistical properties (such as phase differences and correlation values) as the basis for sequence generation, the system automatically adapts to varying bandwidth conditions and environmental factors without requiring complex additional processing or multiple predefined sequence sets.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If sequences are generated based on reciprocal channel characteristics, then security is enhanced and sequences are unknown to eavesdroppers, but the system requires RF sampling and processing infrastructure

Engineering Contradiction:
Improvesecurity against eavesdroppersVSAvoidRF sampling and processing requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent leverages the universal functionality of existing RF sampling and channel estimation infrastructure to achieve secure sequence generation. The same hardware and software components used for standard channel characterization and equalization are repurposed to generate secure spreading sequences, eliminating the need for separate dedicated security infrastructure while maintaining strong security guarantees through the use of physically unclonable channel characteristics.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3516798B1Sequence generation for spread spectrum from RF sampling
Publication Date: 2026.03.25 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3516798B1 patent drawingFigure 1A~1B
  • EP3516798B1 patent drawingFigure 2
  • EP3516798B1 patent drawingFigure 3

AI summary

A method for generating spread spectrum spreading sequences in communicating devices. A first device receives a first sequence of one or more radio frequency (RF) signals from a second device, sends a second sequence of one or more RF signals to the second device, samples the first sequence of one or more RF signals, generates sampling results, and generates a spreading sequence based on the sampling results. The second device receives the second sequence and creates an identical spreading sequence using an identical process to create sampling results and generate the sequence. The spreading sequence may be used by the first and second devices for spread spectrum communications with each other. Gain for spread spectrum communications may be dynamically varied based on available bandwidth by varying the number of RF signals and sampling rate.