A method of transmitting a broadcast signal includes encoding mobile data for FEC (Forward Error Correction); encoding signaling information for signaling the mobile data; allocating the encoded mobile data and signaling data into a transmission frame; and transmitting the broadcast signal including the transmission frame, wherein the transmission frame includes a service signaling table having service_type information identifying a type of a service of the mobile data and hidden information indicating whether the service of the mobile data is hidden or not.