Abstract: A wireless communication system includes a first communication apparatus, a second communication apparatus, and a third communication apparatus which are mutually communicable by wireless. The second communication apparatus includes a receiving section for receiving a signal and a transmission section. The transmission section transmits a first transmission signal whose destination is the third communication apparatus with power enough to reach both the first communication apparatus and the third communication apparatus, and transmits a second transmission signal whose destination is the third communication apparatus in accordance with a response signal from the third communication apparatus including an information related to received power or receipt quality of the first transmission signal in the third communication apparatus with power enough to reach the third communication apparatus.

Abstract: A communication apparatus includes a frame generating device configured to generate a physical frame containing, of a plurality of MAC frames to be transmitted, a MAC frame which requires acknowledgement indicating that the frame is received by a receiving side, a MAC frame which does not require the acknowledgement, and identification information which indicates necessity/unnecessity of acknowledgement for each MAC frame depending on whether each MAC frame requires acknowledgement, and a transmitting device configured to transmit the physical frame generated by the frame generating device.

Abstract: A radio communication apparatus which can communicate with a base station in radio communication, comprising: an antenna; a reception processing unit which receives a signal transmitted from the base station via the antenna; an indication signal processing unit which processes an indication signal including information on the base station, the indication signal being transmitted from the base station periodically; and an authentication processing unit which performs authentication processing with the base station to establish communication connection between the base station and the radio communication apparatus, wherein, when the reception processing unit and the indication signal processing unit are in ON state, unitthe authentication processing unit is in OFF state.unitunit.