BLE Tire Pressure Sensor Auto-Location With Delay Compensation
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Solution Overview
Problem
Existing tire pressure monitoring systems face challenges in accurately identifying and locating tire pressure monitoring sensors on a vehicle due to transmission delays and the transition from ultra-high frequency (UHF) to Bluetooth Low Energy (BLE) systems, which complicates the correlation of wheel unit angular information with vehicle ABS data.
Innovation Solution
The system employs a method to compensate for transmission delays in BLE-based tire pressure monitoring systems by calculating and adding randomized delays to the Look Back Time (LBT) using a processor, and incorporating methods to determine and report inter-event and inter-frame delays, allowing accurate auto-location of tire pressure sensors using BLE technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If randomized inter-event delay is implemented in BLE transmission, then compliance with Bluetooth standards and reduced battery consumption are achieved, but transmission delay compensation becomes more complex
Solution Approach 1:
The system pre-calculates and stores multiple randomized delay values in a lookup table during system initialization. When transmission is needed, the pre-computed delay value is selected and applied directly, avoiding real-time random generation and complex calculations during actual transmission operations.
Solution Approach 2:
The patent compensates for randomized transmission delays by pre-calculating the Look Back Time (LBT) value and adding the randomized delay to it before transmission. This advance compensation ensures that the receiving system can accurately determine wheel position despite the randomized delay, cushioning against the uncertainty introduced by BLE's random delay mechanism.
2Measurement precision
If Look Back Time is compensated for randomized delay, then accurate wheel position determination is achieved, but calculation complexity increases
Solution Approach 1:
The base Look Back Time value is pre-calculated and stored during system initialization based on expected transmission conditions. During actual operation, the system only needs to retrieve this pre-computed value and add the randomized delay component, significantly reducing the calculation complexity compared to computing LBT from scratch each time.
Solution Approach 2:
The system proactively compensates for the randomized delay by adding it to the Look Back Time before transmission occurs. This advance compensation ensures that the receiving end can accurately correlate the transmitted position data with the actual wheel position, maintaining high measurement precision despite the added calculation step.
3Use of energy by moving object
If BLE technology is used instead of UHF, then battery consumption is reduced, but transmission delay compensation mechanisms are required
Solution Approach 1:
The system pre-computes the Look Back Time value and stores randomized delay values in lookup tables during initialization. This preliminary preparation allows the system to quickly apply delay compensation during transmission without complex real-time calculations, making the BLE implementation practical despite the added mechanism.
Solution Approach 2:
The patent introduces the Look Back Time (LBT) parameter as an intermediary that bridges the gap between the randomized BLE transmission delay and the wheel position determination. By encoding the compensated LBT value in the transmission data, the system mediates between the random delay introduced by BLE and the precise position measurement requirement.
Data Source
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AI summary
Embodiments included herein are directed towards systems and methods for tire pressure monitoring. Embodiments may include transmitting a first Bluetooth Low Energy ("BLE") event at a Phase Auto-Location ("PAL") block associated with a vehicle electronic control unit ("ECU"). Embodiments may further include generating a random number to be used for an inter-event delay associated with a BLE system, wherein the inter-event delay includes a fixed time and a randomized delay. Embodiments may also include calculating a time for the randomized delay and adding the time to an encoded Look Back Time ("LBT") from the first BLE event to generate frame contents. Embodiments may further include providing the frame contents and the random number to a stack for transmission.