Vehicle Access Authorization with BLE-Triggered UWB Ranging

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Solution Overview

Problem

Existing vehicle access systems using UWB and BLE communication face challenges with high power consumption, short range, and inaccurate distance determination due to variable environmental conditions, making precise authorization difficult.

Innovation Solution

Monitor the decrease in BLE signal strength as the identification transmitter moves away from the vehicle, store this as a reference value, and reactivate the UWB connection when the BLE signal strength exceeds this reference, allowing precise distance determination for vehicle access authorization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If UWB communication connection is used for distance determination, then measurement precision is improved, but use of energy increases and range decreases

Engineering Contradiction:
Improvedistance determination accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses periodic switching between BLE and UWB connections based on distance thresholds. BLE is used for initial detection and UWB is activated periodically only when needed for precise distance measurement, reducing overall power consumption while maintaining measurement precision when required

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

BLE serves as an intermediary communication layer that enables low-power initial contact and handoff to UWB. The BLE connection acts as a mediator that triggers UWB activation only when signal strength indicates proximity, thus reducing unnecessary UWB power consumption while preserving accurate distance determination capability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If UWB communication connection is used for distance determination, then measurement precision is improved, but range decreases

Engineering Contradiction:
Improvedistance determination accuracyVSAvoidcommunication range
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The communication range is segmented into two zones: an outer zone covered by BLE for initial detection and authentication, and an inner zone where UWB provides precise distance measurement. This segmentation allows the system to extend effective range using BLE while maintaining precision measurement capability in the critical near-field zone

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

BLE acts as an intermediary that extends the effective communication range by handling initial connection and authentication. The BLE signal strength evaluation serves as a trigger mechanism that activates UWB only when the device enters the proximity threshold, thus compensating for UWB's limited range while maintaining measurement precision

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If BLE signal strength threshold is used to activate UWB connection, then range is extended and power consumption is reduced, but measurement precision deteriorates due to environmental variability

Engineering Contradiction:
Improvepower consumptionVSAvoiddistance determination accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The system continuously monitors BLE signal strength and uses this feedback to dynamically activate or deactivate the UWB connection. When BLE signal strength exceeds the threshold, UWB is activated for precise measurement; when it falls below, UWB is deactivated to save power. This feedback loop ensures measurement precision is maintained when needed while optimizing power consumption

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the operational state parameter of the UWB connection (active/inactive) based on BLE signal strength parameters. By monitoring BLE signal strength as a proxy for distance and changing UWB activation state accordingly, the system maintains measurement precision in the critical proximity zone while reducing power consumption at larger distances

Inventive Principle:
Principle #35Parameter changes

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

Enables efficient power management and accurate distance measurement for vehicle access, enhancing convenience by automatically unlocking doors as the user approaches, without requiring hardware upgrades to existing smartphones.

Implementation Method 1

determining the required signal transmission time for signals transmitted between the identification transmitter and the vehicle and using this transmission time to calculate the desired distance between the vehicle and the identification transmitter

Methodology Applied
Scientific EffectTime of Flight: Time of Flight

Implementation Method 2

Low-frequency radio systems are typically used to communicate between the identification transmitter and the vehicle

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP4370386B1Method for authorizing access to a motor vehicle by means of a mobile electronic identification device
Publication Date: 2025.08.06 MERCEDES BENZ GROUP AG
  • EP4370386B1 patent drawingFigure 1

AI summary

The invention relates to a method for authorizing access to a motor vehicle (1) by means of a mobile electronic identification device (2), which motor vehicle can be unlocked by means of the identification device (2). The identification device (2) can communicate with the motor vehicle (1) so as to transmit data via a first wireless communication connection (3a), which operates according to the UWB standard, as well as a second wireless communication connection (3b), which operates according to the BLE standard, and the maximum range (RM1) of the first communication connection is shorter than the maximum range (RM2) of the second communication connection (3b). The method has the following steps: a) monitoring a drop in the signal strength (S) of the second communication connection (3b) while the identification device (2) is moved away from the motor vehicle (1) so that the distance (A) between the motor vehicle (1) and the identification device (2) increases, b) storing the current signal strength (S) of the second communication connection (3b) as a reference value as soon as the first communication connection (3a) between the motor vehicle (1) and the identification device (2) is deactivated/interrupted, and c) reactivating the first communication connection (3a) as soon as the signal strength (S) of the second communication connection (3b) exceeds the stored reference value due to the decreasing distance (A) between the motor vehicle (1) and the identification device (2) when the identification device (2) is moved back towards the motor vehicle (1).