Electronic Key System Ultra-Wideband Distance Verification
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Solution Overview
Problem
Conventional electronic key systems are vulnerable to unauthorized communication via relay devices, as the separation of request and response signal relay units can still allow for unauthorized communication, especially with UHF band signals covering long distances.
Innovation Solution
The electronic key system incorporates a key location determination unit and distance measurement request/response units using ultra-wideband signals to accurately determine the electronic key's location within a communication area, setting a threshold range for authorized communication based on measured distances, thereby preventing unauthorized communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the request signal relay unit and the response signal relay unit are separated to avoid jamming, then unauthorized communication can be established, but if they are placed close together, jamming occurs that prevents unauthorized communication
Solution Approach 1:
The patent introduces a distance measurement mechanism using ultra-wideband signals as an intermediary verification layer. The onboard device measures the actual distance to the electronic key and compares it with the distance calculated from signal transmission locations. This intermediary distance verification prevents relay attacks by detecting when the measured distance exceeds the threshold, thereby blocking unauthorized communication without requiring the relay units to be physically close together.
2Area of stationary object
If UHF band signals are used for long-distance communication, then the communication area is enlarged, but this allows relay devices to be arranged at greater distances enabling unauthorized communication
Solution Approach 1:
The patent implements a feedback mechanism where the onboard device continuously monitors the distance between itself and the electronic key using ultra-wideband signals. The system compares the measured distance with the expected distance based on signal transmission geometry. When the measured distance exceeds the threshold value, the system provides feedback to reject the authentication request, thereby maintaining security even when using long-range UHF band communication signals.
3Device complexity
If distance measurement is performed using existing communication signals, then the system complexity is reduced, but the measurement accuracy is insufficient for reliable authentication
Solution Approach 1:
The patent replaces the attempt to derive distance information from existing communication signals with a dedicated ultra-wideband distance measurement system. Instead of trying to extract precise distance data from LF or UHF communication signals which lack the necessary precision, the system substitutes this with a separate measurement mechanism using ultra-wideband time-of-flight measurement, achieving the required measurement accuracy for security authentication.
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
This configuration effectively limits unauthorized communication by ensuring the measurement distance is within a defined threshold, enhancing the accuracy and security of authorized communication verification.
Implementation Method 1
a distance measurement request unit included in one of the onboard device (20) and the electronic key (10), wherein the distance measurement request unit transmits a distance measurement request signal and receives a distance measurement response signal in response to the distance measurement request signal; and a distance measurement response unit included in the other one of the onboard device (20) and the electronic key (10), wherein the distance measurement response unit receives the distance measurement request signal and transmits the distance measurement response signal in response to the distance measurement request signal
Data Source
AI summary
An electronic key system determines that legitimate communication has been performed on the basis of conditions including that a measured distance from a ranging request unit to a ranging response unit measured on the basis of a ranging request signal and a ranging response signal is within a threshold range that is set on the basis of the distance from a communication area of a transmission antenna where an electronic key is determined to be located by a key location determination unit to one of either the ranging request unit or the ranging response unit that is provided in an on-board device.