Patent ID: 7443314

Claim:
A communication device mountable on one of a plurality of movable bodies for exchanging information with other communication devices mounted on other movable bodies comprising: a surrounding detecting means for detecting a surrounding of the movable body; an appropriateness of relay determining means for determining an appropriateness of relay by determining whether or not an obstacle interrupts a wireless communication on the basis of the result detected by the surrounding detecting means; a first transmitting process means for transmitting a first signal including information indicating a condition of the movable body and the result determined by the appropriateness of relay determining means; a first receiving process means for receiving the first signal sent by the first transmitting process means and memorizing the first signal in a memorizing means; a second transmitting process means for determining whether or not the relay is required on the basis of the first signal memorized in the memorizing means, and transmitting a second signal including information of a movable body assigned to be requested to relay the signal; and a second receiving process means for receiving the second signal sent by the second transmitting process means in order to determine whether or not the relay request exists, and relaying the signal to the movable body assigned to be requested to relay the signal, wherein the first transmitting process means of the communication device of one of the movable bodies sends the first signal to each of the other communication devices of the other movable bodies by way of the first transmitting process means, each of the other movable bodies receives the first signal by way of the first receiving process means and memorizes the first signal in the memorizing means, the second transmitting process means of each of the other communication devices of the other movable bodies determines the appropriateness for relaying on the basis of the first signal memorized in the memorizing means, the second transmitting process means of each of the other communication devices of the other movable bodies sends the second signal to the second receiving process means of the communication device of the one of the movable bodies, and the second receiving process means determines whether or not the relay requests exists and relays the signal to the movable body assigned to be requested to relay the signal.