A wireless communications system is 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 includes a base station configured to transmit in the first band to a terminal when detecting an available carrier wave of the second band, a control signal permitting data transmission in the second band from the terminal to the base station, the base station continuously sending out a radio wave of the second band during a period until the data transmission; and the terminal configured to perform the data transmission after a predetermined time from transmission of the control signal by the base station.