Hands-Free Vehicle Access Using Carrier RSSI and Noise Checks
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Solution Overview
Problem
Existing hands-free vehicle access systems incorrectly authorize unlocking due to interference from nearby vehicles transmitting similar location frames, leading to erroneous RSSI measurements.
Innovation Solution
A system that transmits location frames with modulated signals and pure carrier signals during specific time intervals, includes noise detection by measuring signal strength and presence of noise, and adjusts access authorization based on these measurements to prevent incorrect unlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the hands-free identifier performs RSSI measurement on location frames from nearby vehicles, then it can detect signals from multiple vehicles, but it returns erroneous RSSI measurements leading to incorrect access authorization decisions
Solution Approach 1:
The patent segments the location frame transmission into distinct time windows with pure carrier signals separated from modulated signals. This segmentation allows the hands-free identifier to perform RSSI measurements only during pure carrier time windows when no other vehicle is transmitting, thereby eliminating interference from nearby vehicles while maintaining the ability to detect signals from multiple vehicles.
2Speed
If the system transmits location frames continuously, then access control responsiveness is improved, but interference from simultaneous transmissions by nearby vehicles increases
Solution Approach 1:
The patent implements periodic action by transmitting location frames in structured time windows that alternate between pure carrier signal transmission and modulated signal transmission. This periodic structure with specific time intervals allows multiple vehicles to transmit location frames without continuous interference, as each vehicle transmits in synchronized time slots, thereby maintaining responsiveness while reducing signal interference.
Data Source
AI summary
A system for hands-free access to a vehicle includes a hands-free access device that transmits a location frame of a modulated signal and a pure carrier signal, receives a measurement of a received signal strength of a primary received signal performed on the pure carrier signal by a hands-free identifier, and receives information on an absence or presence of noise in the location frame. Additionally, the hands-free access device authorizes or prevents access to the vehicle. The system further includes a hands-free identifier that receives the location frame, performs a measurement of the received signal strength of the primary received signal on the pure carrier signal, sends the hands-free access device the measurement of the received signal strength of the primary received signal, checks the presence of noise in the location frame, and sends the hands-free access device information on the absence or presence of noise in the location frame.