| 摘要 |
PROBLEM TO BE SOLVED: To make implementation of relay attack difficult.SOLUTION: Upon receiving an authentication request signal transmitted from an on-vehicle communication device, a portable device transmits a response signal to the on-vehicle communication device. The transmission control unit of the portable device changes the maximum frequency shift in the way, when transmitting the response signal while performing FSK modulation. In response thereto, the reception unit of the on-vehicle communication device changes the maximum frequency shift in the way, when receiving and demodulating the response signal. The invention is applicable to a communication system for vehicle, for example. |
