A method of transmitting data in a wireless communication system, includes: transmitting first data via a first frame for a first wireless communication system; transmitting second data via a second frame for a second wireless communication system supporting backward compatibility with respect to the first wireless communication system; and transmitting control information with respect to the first and second frames, wherein the control information includes a frame control header (FCH) which indicates information about the second frame by using a reserved bit region of the first frame.