VHF-UHF Bidirectional Polling for PEPS Battery Drain Reduction
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Solution Overview
Problem
Current passive entry passive start (PEPS) systems using low frequency pulsed signals for polling vehicle key fobs drain vehicle battery quickly due to high current requirements, limiting the duration of polling operations and necessitating frequent sleep modes.
Innovation Solution
Implementing a system that uses pulsed polling signals in the VHF-UHF band, which reduces power consumption to 5 mA per pulse, allowing for extended battery life and enabling detection of authorized users with infrared detectors or multiple transceivers for directional awareness, and allowing the key fob to transmit command signals based on received authorization messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low frequency pulsed signals are used for polling key fobs, then directional detection capability is achieved, but vehicle battery life is significantly reduced due to high current consumption
Solution Approach 1:
The patent changes the frequency parameter of the polling signal from low frequency (30-300 kHz) to VHF-UHF band (30-3000 MHz). This parameter change reduces current consumption from approximately 700 mA to 5 mA per pulse, extending battery life from 12-24 hours to potentially much longer durations while maintaining polling functionality.
Solution Approach 2:
The patent introduces an intermediary approach where the vehicle transmits a polling signal in VHF-UHF band, the key fob receives and processes it, then transmits a response signal back to the vehicle. This two-way communication allows the vehicle to determine key fob location and direction without continuously transmitting high-power signals, thus conserving battery energy.
2Area of stationary object
If low frequency pulsed polling signals are transmitted continuously, then authorized user detection range is improved, but power consumption increases causing frequent sleep modes
Solution Approach 1:
The patent implements periodic polling where the vehicle transmits VHF-UHF polling signals at predetermined intervals rather than continuously. The key fob responds periodically when detecting the polling signal, allowing the vehicle to monitor for authorized users over extended periods with minimal power consumption, eliminating the need for frequent sleep modes.
Data Source
AI summary
A system and method for providing a polling signal transmitted from a vehicle that is received by a key fob held by an authorized user of the vehicle as the user approaches the vehicle, where the polling signal is a pulsed polling signal in the VHF-UHF band. The polling signal tells the key fob to transmit a command signal that causes the vehicle to perform a predetermined vehicle operation. Alternately, the polling signal is transmitted by the key fob where the vehicle sends an authorization message back to the key fob if it receives the polling signal that tells the key fob to transmit the command signal.