BLE Key Fob Transceiver Activation for Battery Life
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Solution Overview
Problem
The battery life of key fobs in vehicles with passive entry/passive start systems is limited due to high power consumption during communication with the vehicle, particularly when establishing and maintaining a communication link.
Innovation Solution
A vehicle access system that includes a first transceiver and a short-range transceiver, where the first transceiver is activated only when within a predefined range, using a processor to control both, and utilizing a Bluetooth Low Energy (BLE) transceiver for initial proximity detection and a low-frequency or ultra-wide band transceiver for precise distance measurement, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first transceiver is continuously activated for communication, then communication reliability is improved, but battery life deteriorates
Solution Approach 1:
The first transceiver is activated periodically only when the key fob enters a predefined range of the vehicle, rather than continuously. The processor controls the first transceiver to activate based on proximity detection, creating a periodic activation pattern that reduces power consumption while maintaining communication reliability when needed.
Solution Approach 2:
The system performs preliminary distance measurement using the short-range transceiver before activating the first transceiver. This preliminary action allows the system to determine whether activation is necessary, preventing unnecessary power consumption while ensuring the first transceiver is activated in time when actually needed for communication.
2Duration of action of moving object
If the first transceiver is activated only when in range, then battery life is improved, but communication responsiveness deteriorates
Solution Approach 1:
The system continuously monitors distance using the short-range transceiver as a preliminary check before activating the first transceiver. This preliminary monitoring ensures that when the key fob enters the predefined range, the first transceiver can be activated immediately without delay, maintaining communication responsiveness while extending battery life.
Solution Approach 2:
The system uses feedback from the short-range transceiver's distance measurements to control the activation state of the first transceiver. When the measured distance indicates the key fob is within the predefined range, the processor activates the first transceiver; otherwise, it remains inactive. This feedback mechanism ensures responsive communication activation based on real-time proximity conditions.
3Measurement precision
If distance measurement is performed continuously with high precision, then measurement accuracy is improved, but power consumption increases
Solution Approach 1:
The distance measurement function is segmented into two parts: continuous low-precision measurement using the short-range transceiver, and periodic high-precision measurement using the first transceiver only when needed. This segmentation allows the system to maintain accurate distance measurement capability while minimizing power consumption by using the high-precision first transceiver only when the key fob is near the vehicle.
Solution Approach 2:
The system applies different measurement qualities to different spatial zones: the short-range transceiver provides continuous measurement for distant detection, while the first transceiver provides high-precision measurement only in the local predefined range where accurate measurement is critical for communication activation decisions.
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 approach significantly extends the battery life of the key fob by minimizing continuous power usage, allowing the key fob to maintain accurate communication and access control while reducing power draw, potentially doubling the battery life.
Implementation Method 1
The distance measurement is based on one of at least one of time of flight, phase angle, phase delay, angle of arrival, and angle of departure.
Implementation Method 2
The distance measurement is based on one of at least one of time of flight, phase angle, phase delay, angle of arrival, and angle of departure.
Implementation Method 3
the first transceiver comprises at least one of a low frequency receiver and an ultra-wide band transceiver.
Data Source
AI summary
A vehicle access system includes an identification device with a first transceiver, a short-range transceiver and a processor configured to control the first transceiver and the short-range transceiver to activate the first transceiver only when a distance measurement between the identification device and a vehicle is within a predefined range as determined utilizing the short-range transceiver.