| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a communication system and a communication method that allow a road side communication device to simply estimate the own downlink area.SOLUTION: A downlink signal for being received by an on-vehicle communication device 3 is transmitted to a target downlink area from a road side communication device 2, and when receiving predetermined information (for example, time information) included in the downlink signal from the road side communication device 2, each on-vehicle communication device 3 includes the number of relays set to 0 (zero) in an uplink signal together with position information, and transmits the uplink signal, and further, when receiving the predetermined information from the other on-vehicle communication devices 3, the on-vehicle communication device 3 includes the incremented number of relays in the uplink signal together with the position information, and transmits the uplink signal. The road side communication device 2 estimates the downlink area on the basis of a position and distribution of the number of relays acquired from a plurality of received uplink signals.</p> |
