An LF transmitter of a vehicle-mounted device sends a request signal, and first and second measurement signals to a portable device. The LF transmitter sends to the portable device the second measurement signal with a transmission intensity different from that of the first measurement signal. An UHF receiver of the vehicle-mounted device receives, from the portable device, a response signal containing information on reception intensities of the first and second measurement signals. The vehicle-mounted device authenticates the portable device based on a relation between the information on the reception intensity of the first measurement signal and the information on the reception intensity of the second measurement signal contained in the response signal received by the UHF receiver and a relation between the transmission intensity of the first measurement signal and the transmission intensity of the second measurement signal sent from the LF transmitter.
VEHICLE-MOUNTED DEVICE, PORTABLE DEVICE, AND VEHICLE WIRELESS COMMUNICATION SYSTEM
2018-09-27
Patent
Electronic Resource
English
IPC: | G07C TIME OR ATTENDANCE REGISTERS , Zeit- oder Anwesenheitskontrollgeräte / B60R Fahrzeuge, Fahrzeugausstattung oder Fahrzeugteile, soweit nicht anderweitig vorgesehen , VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR / G08C Übertragungssysteme für Messwerte, Regel-, Steuer- oder ähnliche Signale , TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS |
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