A method of transmitting a broadcast signal in a transmitter is provided. First data is encoded by adding parity data, and second data is encoded by adding parity data with different code rates, respectively. Signaling data is encoded. The encoded first data, the encoded second data, and the encoded signaling data are arranged in a frame among frames. The frames are modulated and transmitted. The frame among frames includes known data for channel estimation. The frames include a plurality of subframes that include a plurality of data units. The frame among frames includes the encoded first data unit and the encoded second data unit. The signaling data includes information for fast service acquisition which allows a receiver to locate upper layer signaling information. The signaling data further includes information on encoding type of data in a data unit, and information on a number of data units carried within a subframe.