COMMUNICATION SYSTEM AND COMMUNICATION UNIT

摘要

PROBLEM TO BE SOLVED: To avoid collision of addresses in a communication system for recognition where a communication terminal returns a replay packet with respect to a recognition packet from a recognition terminal, the recognition terminal transmits an ACK packet with respect to the reply packet and a terminal receiving the ACK packet does not transmit any reply packet. SOLUTION: A communication terminal receiving a recognition packet from a recognition terminal transmits a reply packet through a random slot. In the case the recognition terminal can normally receive the reply packet, the recognition terminal transmits an ACK packet including information of an address and a slot number of the communication terminal. The communication terminal that transmits the reply packet with the same address but with a different slot number with respect to the preceding recognition packet decides the address again. Thus, even when the addresses of communication terminals having been decided at random collide with each other, the recognition terminal can recognize all communication available communication terminals.