One objective of the present invention is to determine a location for a relay terminal in a radio network, without preparatory surveying a radio status, and to arrange the relay terminal at the location. Another objective is to provide a method for retrieving the arranged relay terminal. When a relay terminal is to be arranged, the relay terminal transmits a survey packet to examine the quality of communication with a communication terminal or other relay terminal. Where a location is appropriate, the relay terminal gives a notice. The arranged terminal relays communication. Further, when the relay terminal is to be retrieved, the relay terminal carried by a user transmits a retrieval packet to the arranged relay terminal, which notifies the user of its presence by light, sounds, or returning a packet. In this manner, a single relay terminal provides functions of arrangement, relay and retrieval.