Antenna Signal Phase Deviation Pattern Matrix Authentication

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Solution Overview

Problem

Intrinsic phase-deviations in radio transmitters due to manufacturing variations lead to security risks, as these deviations can be used for device tracking and impersonation attacks, compromising authentication and privacy in wireless communication systems.

Innovation Solution

Introducing arbitrary phase-deviations in addition to intrinsic ones, creating a composite signature that does not disrupt receiver operation, allowing for device authentication while making impersonation attacks more difficult by changing the signature over time and using a pseudo-randomization key for pattern generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If intrinsic phase-deviations are used for device authentication, then device identification is enabled, but security is compromised due to susceptibility to impersonation attacks

Engineering Contradiction:
Improvedevice authentication accuracyVSAvoidsecurity risks from impersonation attacks
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically modifying the phase-deviation parameters over time through a pattern matrix that changes with each transmitted frame. The pattern matrix contains phase rotation values that are applied to modulation symbols, transforming the static intrinsic phase deviations into dynamic composite signatures that change with each transmission frame, thereby preventing impersonation attacks while maintaining authentication capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the phase deviation pattern time-varying through the pattern matrix that changes with each frame transmission. The pattern matrix is updated based on a counter, creating a dynamic signature that evolves over time. This dynamic behavior ensures that even if an attacker captures signals, they cannot use them for impersonation since the signature changes continuously

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If frequency-specific phase-deviations are introduced to authenticate devices, then device tracking becomes possible, but the system becomes vulnerable to security attacks

Engineering Contradiction:
Improvedevice tracking capabilityVSAvoidsecurity vulnerabilities
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful frequency-specific phase deviations into a beneficial security feature by systematically introducing controlled phase rotations through the pattern matrix. The phase rotation values in the pattern matrix are designed to counteract and mask the intrinsic phase deviations, transforming them from identifiable fingerprints into obscured signals that maintain authentication capability while preventing tracking and impersonation attacks

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If arbitrary phase-deviations are added to intrinsic phase-deviations, then impersonation attacks become more difficult, but receiver compatibility may be affected

Engineering Contradiction:
Improveimpersonation attack resistanceVSAvoidreceiver compatibility
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback mechanisms where the receiver is provided with the pattern matrix or information about the phase rotation values applied by the transmitter. This feedback allows the receiver to compensate for the arbitrary phase deviations introduced by the pattern matrix, maintaining compatibility while enabling the enhanced security features. The receiver uses the feedback information to correctly interpret the modulated symbols despite the additional phase variations

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3945701A1Transmitting data via antenna signals having arbitrary phase-deviations
Publication Date: 2022.02.02 TECH UNIV DARMSTADT
  • EP3945701A1 patent drawingFigure 1
  • EP3945701A1 patent drawingFigure 2(i)~2(iii)
  • EP3945701A1 patent drawingFigure 3

AI summary

Generating an antenna signal (390) for transmitting data is adapted to apply frequency division multiplexing over subcarriers. A symbol unit (120) obtains logical code symbols (311, 312, 313) and derives modulation symbols (321, 322, 323) with subcarrier-specific values for an in-phase component (I) and for a quadrature component (Q). A baseband processor unit (160) performs baseband processing to the modulation symbols (321, 322, 323) to generate the antenna signal (390). A pattern unit (150) obtains a pattern matrix (340) with phase rotation values (dl, d2, d3) that indicate arbitrary phase-deviations per subcarrier and applies the phase rotation values to the modulation symbols (321, 322, 323) so that baseband processing (460) is performed with modified modulation symbols (351, 352, 353).