| 摘要 |
The invention has the object of avoiding congestion while reducing differences between parameters for communication among vehicles. The vehicle-mounted device performing communication by radio signals with predetermined vehicle-mounted devices respectively equipped in a plurality of vehicles includes: a radio unit detecting radio signals to measure congestion level; a processor receiving, from each of the predetermined vehicle-mounted devices, a value of, among parameters relating to communication of the predetermined vehicle-mounted devices, a predetermined parameter for which the degree of contribution to congestion increases with increase in the value of the predetermined parameter; and a controller decreasing, when the congestion level measured by the radio unit exceeds a predetermined threshold value, the value of the predetermined parameter of its own device if the value of the predetermined parameter of its own device is greater than the average of the values of the predetermined parameter received at the processor. |
