A wireless communication system including a plurality of wireless communication stations including a wireless base station (AP) and a plurality of wireless communication terminals (STA), wherein the wireless base station (AP) communicates with the plurality of wireless communication terminals (STA) including a primary wireless communication terminal on a primary channel and a secondary wireless communication terminal on a secondary channel according to a wireless communication standard supporting an orthogonal frequency division multiple access, OFDMA, wherein the first wireless communication terminal supports the primary channel and the second wireless communication terminal supports both the primary channel and the secondary channel, wherein the wireless base station (AP) further comprises a transmission opportunity acquisition part configured to acquire a transmission opportunity, TXOP, with at least one wireless communication terminal selected from among the plurality of wireless communication terminals (STA) in a predetermined period, TXOP period, upon generating transmitting data, a controller configured to determine a first condition indicating unavailability of the primary channel (S102, YES) and a second condition indicating availability of the second channel for the orthogonal frequency division multiple access, OFDMA, (S103, YES); and a wireless communication part configured to, upon satisfying the first condition and the second condition, send a first frame (RTS) to the secondary wireless communication terminal (STA14) supporting both the primary channel and the secondary channel such that the secondary wireless communication terminal (STA14) subsequently resends a second frame (CTS) to the wireless base station (AP) while the primary wireless communication terminal (STA11) supporting the primary channel sets a network allocation vector, NAV, to temporarily suspend its data transmission (S104), and transmit first data to the primary wireless communication terminal on the primary channel and to transmit second data to the secondary wireless communication terminal on the secondary channel (S106). wherein the wireless base station (AP) further comprises a transmission opportunity acquisition part configured to acquire a transmission opportunity, TXOP, with at least one wireless communication terminal selected from among the plurality of wireless communication terminals (STA) in a predetermined period, TXOP period, upon generating transmitting data, a controller configured to determine a first condition indicating unavailability of the primary channel (S102, YES) and a second condition indicating availability of the second channel for the orthogonal frequency division multiple access, OFDMA, (S103, YES); and a wireless communication part configured to, upon satisfying the first condition and the second condition, send a first frame (RTS) to the secondary wireless communication terminal (STA14) supporting both the primary channel and the secondary channel such that the secondary wireless communication terminal (STA14) subsequently resends a second frame (CTS) to the wireless base station (AP) while the primary wireless communication terminal (STA11) supporting the primary channel sets a network allocation vector, NAV, to temporarily suspend its data transmission (S104), and transmit first data to the primary wireless communication terminal on the primary channel and to transmit second data to the secondary wireless communication terminal on the secondary channel (S106). <EOS>