In order to achieve the above-described technical object of the present invention, a method of transmitting broadcast data in a transmitter is disclosed. The method may comprise Forward Error Correction (FEC) encoding transmission unit data that carries broadcast service data, interleaving the FEC-encoded transmission unit data, demultiplexing the interleaved transmission unit data, symbol-mapping the demultiplexed transmission unit data onto constellations. MIMO-encoding the mapped transmission unit data, time-interleaving the MIMO-encoded transmission unit data. building a frame including the time-interleaved transmission unit data and physical signaling data, modulating the frame by an Orthogonal Frequency Division Multiplexing (OFDM) method. Herein the physical signaling data includes information on a MIMO encoding process is applied to an associated transmission unit data.