A wireless communications system configured to perform wireless communication by using a first band dedicated to the system and a second band shared by the system and another wireless communications system, the system including: a base station configured to transmit in the first band to the terminal, a control signal permitting data transmission in the second band from a terminal to the base station; and the terminal configured to detect an available carrier wave of the second band after a predetermined time from the transmission of the control signal by the base station, the terminal performing the data transmission after waiting until detection of the available carrier wave.