| 摘要 |
PROBLEM TO BE SOLVED: To provide a keyless entry system which enables transmission of a wakeup signal with more sureness.SOLUTION: A keyless entry system 1 includes an onboard device 10 and a mobile unit 20, to control an onboard equipment by utilizing a wakeup signal and a command signal. The onboard device 10 transmits by radio, to the mobile unit 20, a first transmission signal containing the wakeup signal and a second transmission signal about detection of an interference wave which interferes with the first transmission signal, by using a radio signal of a frequency different from each other. The mobile unit 20, if the first transmission signal is correctly received, transmits by radio a third transmission signal containing a command signal to the onboard device 10, and receives the second transmission signal, and in addition, if the first transmission signal is not correctly received, performs detection of the interference wave that interferes with the first transmission signal, and transmits by radio, to the onboard device 10, a fourth transmission signal which requests re-transmission of the first transmission signal. |
