| 摘要 |
PROBLEM TO BE SOLVED: To prevent another on-board communication device, which does not know a time zone for a way side communication device, from impeding roadside-vehicle communications in a communication area of the way side communication device. SOLUTION: The on-board communication device 3 performs wireless communications according to a carrier sensing method. The on-board communication device 3 includes a transmitter 31, a carrier sensing controller 35, a detector 38, and a coordinator 39. The transmitter 31 transmits radio signals. The carrier sensing controller 35 detects radio signals in a propagation path, in order to obtain opportunity for transmission by the transmitter 31. The detector 38 detects that the on-board communication device 3 approaches a communication area A of a way side communication device 2, which performs transmission of radio signals in a time zone T1 for way side communication devices. If it is detected that the on-board communication device 3 approaches the communication area A, the coordinator 39 coordinates communication condition so as to decrease opportunity when radio signals transmitted by the transmitter 31 are received by other on-board communication devices 3, compared with the situation before the approach to the communication area A. COPYRIGHT: (C)2010,JPO&INPIT |
