As an aspect of the present invention, an embodiment of the invention provides a method of transmitting broadcast data, the method comprising: encoding transmission units for forward error correction, wherein the transmission units carry the broadcast data which carry a service or service component; mapping the encoded transmission units on constellations; MIMO encoding the mapped transmission units; time-interleaving the MIMO encoded transmission units; building signal frames including the time-interleaved transmission units; modulating the signal frames by Orthogonal Frequency Division Multiplexing, OFDM scheme; and transmitting the modulated signal frames, wherein the transmitted signal frames include preambles, the preambles having physical signaling data for the transmission units.