According to one embodiment, a method of transmitting at least one broadcasting signal having PLP (Physical Layer Pipe) data and preamble data includes: encoding the PLP data; encoding the preamble data; mapping the encoded PLP data to PLP data symbols by QAM (Quadrature Amplitude Modulation) modulations; mapping the encoded preamble data to preamble data symbols by QAM modulations; building a signal frame including the PLP data symbols and the preamble data symbols, wherein the preamble data symbols include first signaling information and second signaling information, wherein the first signaling information is for the second signaling information and includes size information of the second signaling information, and wherein the second signaling information is for the PLP data symbols; modulating the signal frame by an Orthogonal Frequency Division Multiplexing (OFDM) method; and transmitting the modulated signal frame.