| 摘要 |
PROBLEM TO BE SOLVED: To prevent interference with adjacent roadside devices for narrow-band communication. SOLUTION: The roadside devices around the present location of a vehicle are retrieved from roadside device installation place information, when a plurality of roadside devices are installed around the present location, a threshold value of field intensity is made higher than in the case that a single roadside device is installed around the present location and when the field intensity of a control signal of the roadside device is equal to or more than the threshold value, communication is requested to the roadside device. In addition, an application is discriminated based on the control signal of the roadside device and the field intensity threshold value corresponding to the application of a discrimination result is read from a field intensity threshold value storage means. Then, whether or not the field intensity of the control signal of the roadside device is equal to or more than the threshold value and when the field intensity of the control signal of the roadside device is judged to be equal to or more than the threshold value, the communication is requested to the roadside device. COPYRIGHT: (C)2005,JPO&NCIPI
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