A method of control information transmission for a terminal in a mobile communication system, and an apparatus therefor are provided. In the method of control information transmission, the terminal acquires unlicensed frequency channel occupancy information based on the control information received from a base station and transmits the unlicensed frequency channel occupancy information to other terminals operating on the same unlicensed frequency. The method of control information transmission includes receiving a first control information from a base station using a first radio communication protocol, acquiring channel occupancy information based on the first control information, and transmitting a second control information including the channel occupancy information to another terminal using a second radio communication protocol.