Dtv receiving system and method of processing dtv signal

A broadcast transmitter for processing broadcast data, the broadcast transmitter comprising:

• a first encoder configured to encode mobile service data to add parity data;
• a first interleaver configured to first interleave the encoded mobile service data;
• a second interleaver configured to second interleave the first interleaved mobile service data;
• a second encoder configured to encode signaling data for signaling the mobile service data;
• a modulator configured to modulate a frame including the second interleaved mobile service data and the encoded signaling data;
• and
• a transmitting unit configured to transmit a broadcast signal including the modulated frame,
• wherein the broadcast signal further includes main service data,
• wherein the signaling data comprise first signaling data and second signaling data,
• wherein the first signaling data are located at a forepart of the frame and the second signaling data are located after the first signaling data, and
• wherein the first signaling data include information for identifying the mobile service data and the main service data.