Passive remote keyless entry system with level-based anti-theft feature
First Claim
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1. A method for preventing security breaches of passive remote keyless entry systems for a vehicle comprising:
- transmitting an inquiry signal from a remote keyless entry controller associated with the vehicle to a fob when a door handle contact is detected;
receiving the inquiry signal at the fob;
transmitting an inquiry signal response from the fob to the remote keyless entry controller that contains a fob identifier;
receiving the inquiry signal response at the remote keyless entry controller;
determining, at the remote keyless entry controller, if the received inquiry signal response containing the fob identifier is valid;
when the remote keyless entry controller determines that the received inquiry signal response containing the fob identifier is valid, transmitting broadcast instructions from the remote keyless entry controller at the vehicle to the fob, the broadcast instructions including a particular sequence of power level changes for a response signal from the fob to follow;
receiving the broadcast instructions at the fob;
transmitting the response signal from the fob to the remote keyless entry controller at the vehicle at the power level which changes in the particular sequence received in the broadcast instructions; and
receiving the response signal at the remote keyless entry controller at the vehicle;
detecting, with the remote keyless entry controller, anomalies in the particular sequence of the response signal by;
1) comparing detected absolute signal amplitudes in the particular sequence of the response signal to corresponding predetermined absolute signal amplitude ranges stored in the vehicle to determine incorrect absolute amplitudes in the particular sequence; and
2) detecting incorrect relative signal amplitudes in the particular sequence.
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Abstract
Method for preventing security breaches via the two-thief method of attack of passive remote keyless entry systems for vehicles. The method involves the transmission of a signal between a fob and the vehicle, where the level of the signal changes in a particular pattern. At the receiving side, anomalies in the pattern of the received signal (e.g., levels, timing) are detected and used to detect attempts to mimic the signal.
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Citations
18 Claims
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1. A method for preventing security breaches of passive remote keyless entry systems for a vehicle comprising:
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transmitting an inquiry signal from a remote keyless entry controller associated with the vehicle to a fob when a door handle contact is detected; receiving the inquiry signal at the fob; transmitting an inquiry signal response from the fob to the remote keyless entry controller that contains a fob identifier; receiving the inquiry signal response at the remote keyless entry controller; determining, at the remote keyless entry controller, if the received inquiry signal response containing the fob identifier is valid; when the remote keyless entry controller determines that the received inquiry signal response containing the fob identifier is valid, transmitting broadcast instructions from the remote keyless entry controller at the vehicle to the fob, the broadcast instructions including a particular sequence of power level changes for a response signal from the fob to follow; receiving the broadcast instructions at the fob; transmitting the response signal from the fob to the remote keyless entry controller at the vehicle at the power level which changes in the particular sequence received in the broadcast instructions; and receiving the response signal at the remote keyless entry controller at the vehicle; detecting, with the remote keyless entry controller, anomalies in the particular sequence of the response signal by; 1) comparing detected absolute signal amplitudes in the particular sequence of the response signal to corresponding predetermined absolute signal amplitude ranges stored in the vehicle to determine incorrect absolute amplitudes in the particular sequence; and 2) detecting incorrect relative signal amplitudes in the particular sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for preventing security breaches of a passive remote keyless entry system for a vehicle comprising:
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transmitting an inquiry signal from a remote keyless entry controller associated with the vehicle to a fob when door handle contact is detected; receiving the inquiry signal at the fob; transmitting an inquiry signal response from the fob to the remote keyless entry controller that contains a fob identifier; receiving the inquiry signal response at the remote keyless entry controller; determining, at the remote keyless entry controller, if the received inquiry signal response containing the fob identifier is valid; when the remote keyless entry controller determines that the received inquiry signal response containing the fob identifier is valid, transmitting broadcast instructions from the remote keyless entry controller at the vehicle to the fob, the broadcast instructions including a particular sequence of power level changes for a response signal from the fob to follow; receiving the broadcast instructions at the fob; transmitting the response signal from the fob to the remote keyless entry controller at the vehicle at the power level which changes in the particular sequence received in the broadcast instructions; receiving the response signal at the remote keyless entry controller at the vehicle; detecting, with the remote keyless entry controller, deviations of the received response signal from the particular sequence by; 1) comparing detected absolute signal amplitudes in the sequence to corresponding predetermined absolute signal amplitude ranges stored in the vehicle to determine incorrect absolute amplitudes in the sequence, and 2) detecting incorrect relative signal amplitudes in the sequence; and performing a vehicle function only if the deviations are within acceptable limits. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification