| 摘要 |
PROBLEM TO BE SOLVED: To provide a road side radio device for improving reliability on transmitting/receiving information by suppressing communication errors, an on-vehicle device and a radio communication method. SOLUTION: The road side radio device 1 receives response signals sent by on-vehicle device 5 several times, samples their intensities and stores them in array in reception order. In accordance with intensity data stored in array, a dispersion basic equation for a primary regression line is used for calculating a smoothness r<2> of an intensity graph. In accordance with the intensity data, an inclination b of the intensity graph is calculated. Whether the on-vehicle device 5 is located or not in a stable region of a radio sphere formed by the road side radio device 1 is discriminated from these values for the r<2> and the b. After that the on-vehicle device 5 is moved into the region of the stable radio sphere with the movement of a vehicle 4 is discriminated, relatively important information such as fee payment information can be transmitted/received between the road side radio device 1 and the on-vehicle device 5. |
