In this manner, the radio communication device 300 or the radio terminal 400 determines the most-desirable transmission sector for the communication between the radio communication device 300 and the radio terminal 400 through the TSXX, and determines the determined most-desirable transmission sector as the transmission sector used in transmitting a radio signal to the radio communication device 300 or the radio terminal 400.

FIG. 5 illustrates how the RXSS is performed as an example. In FIG. 5, the upper lateral portion indicates a process of the radio communication device 300 or the radio terminal 400 as the initiator, and the lower lateral portion indicates a process of the radio communication device 300 or the radio terminal 400 as the responder. In FIG. 5, the lateral axis serves as a time axis.

As illustrated in FIG. 5, in a first period 531₁, the initiator sequentially transmits first to fifth SSW packets at predetermined intervals using the most-desirable transmission sector of the initiator, which has been determined in the TXSS. The first to fifth SSW packets may be identical or different.

In synchronization with the transmission timings of the first to fifth SSW packets, the responder receives each SSW packet while switching the reception sector of the responder among the sectors 1 to 5 (see FIG. 2) with high directivity.