The method includes receiving, at a user equipment, a request-to-send (RTS) signal from a base station in an unlicensed channel, the RTS signal including individual IDs or group IDs of multiple user equipments, the multiple user equipments including the user equipment; and identifying whether the RTS signal includes an individual ID or group ID of the user equipment, wherein the identifying includes sending a clear-to-send (CTS) signal to the base station in a licensed channel or the unlicensed channel to allow the base station to perform data transmission to the user equipment in response to the RTS signal including the individual ID or group ID of the user equipment; and ignoring the RTS signal in response to the RTS signal not including the individual ID or group ID of the user equipment.