Vehicle UWB Receiver Layout for Relay Attack-Resistant Keyless Entry

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Solution Overview

Problem

Existing keyless entry systems using low-frequency (LF) and high-frequency (HF) radio waves are vulnerable to relay station attacks, compromising their security, necessitating an improved authentication method for vehicle ID transmitters.

Innovation Solution

A communication system employing ultra-wideband (UWB) technology with two spaced-apart UWB receivers and antennas on a vehicle, which evaluates the transit time difference of UWB signals received by each antenna to authenticate the ID transmitter, ensuring secure vehicle function release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If LF or HF radio communication is used for keyless entry, then communication range and ease of operation are improved, but security against relay station attacks deteriorates

Engineering Contradiction:
Improvekeyless entry operationVSAvoidsecurity against relay station attacks
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the fundamental parameter of radio communication frequency from traditional LF/HF bands to UWB (Ultra-Wideband) frequency range. This parameter change enables both improved security through accurate distance determination capabilities and maintains ease of operation for keyless entry functions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the traditional cryptographic authentication mechanism with a physics-based distance verification mechanism. Instead of relying solely on encrypted data exchange, the system uses measured propagation times of UWB signals to physically verify the location of the ID transmitter, making relay station attacks detectable

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If LF or HF radio communication is used for authentication, then communication simplicity is improved, but vulnerability to signal forwarding attacks increases

Engineering Contradiction:
Improveauthentication system complexityVSAvoidsignal forwarding attacks
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where the vehicle authentication system receives propagation time measurements from multiple UWB receivers, compares these measurements against expected values for legitimate user positions, and uses this feedback to accept or reject authentication attempts. This closed-loop verification actively detects and prevents signal forwarding attacks

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple UWB receivers are deployed at different positions, then authentication accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvedistance determination accuracyVSAvoidnumber of UWB receivers
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the authentication function across multiple UWB receivers positioned at different locations on the vehicle. Each receiver independently measures propagation times, and these segmented measurements are combined through evaluation logic to achieve high-precision three-dimensional location determination of the ID transmitter

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The UWB receiver system is designed to perform multiple functions: distance determination, location verification, and authentication decision-making. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall device complexity despite using multiple receivers

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

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The UWB-based authentication system significantly enhances security by accurately determining the ID transmitter's location and authenticity, reducing the likelihood of signal manipulation and improving the accuracy of distance determination, thus preventing unauthorized access.

Implementation Method 1

The first UWB antenna and the second UWB antenna are arranged at a distance from each other on the vehicle... upon reception of the same signal, it results in a propagation time difference between the signal from its transmission source to the first UWB antenna and the signal from its transmission source to the second UWB antenna

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

the distance between the first UWB antenna and the second UWB antenna is large enough that, upon reception of the same signal, it results in a propagation time difference between the signal from its transmission source to the first UWB antenna and the signal from its transmission source to the second UWB antenna that can be detected and/or evaluated by the communication system

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3695389B1Communications system of a vehicle
Publication Date: 2025.01.01 HUF HÜLSBECK & FÜRST GMBH & CO KG
  • EP3695389B1 patent drawingFigure 1
  • EP3695389B1 patent drawingFigure 2

AI summary

The invention relates to a communications system (1) of a vehicle (2). This enables the vehicle (2) to communicate with a portable ID transmitter (3) of an operator (4), which is configured for UWB communication, e.g. by means of a UWB transceiver. The communications system (1) has at least one first UWB receiver (6) with a first UWB antenna (7) and a second UWB receiver (6', 6'', 6''') with a second UWB antenna (7', 7'', 7'''). The first UWB antenna (7) and the second UWB antenna (7', 7'', 7''') are arranged spaced apart from one another on the vehicle (2). The communications system (1) is designed to evaluate UWB signals (12) of the ID transmitter (3) by means of a central UWB control unit (10) or a central control device (11).