Digital broadcasting system and method of processing data

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

• a processor to:
• encode first data to add first parity data,
• permute the encoded first data,
• perform block interleaving on a block including the permuted first data by writing and reading the permuted first data of the block into and from an interleaving unit based on an interleaving pattern,
• wherein, when a size of the block is smaller than a size of the interleaving unit, the interleaving unit includes the permuted first data of the block and dummy data, and
• wherein the dummy data are not read out from the interleaving unit during a reading processing,
• convolutional interleave the block-interleaved first data,
• first encode signaling data for signaling the first data and second data to add second parity data,
• second encode signaling data for signaling the first data at a second coding rate, and
• block interleave the second-encoded signaling data;
• a modulator to modulate the convolutional-interleaved first data, the block-interleaved signaling data, and the second data multiplexed with the first data;
• and
• a transmitting unit to transmit a broadcast signal including the modulated data,
• wherein the signaling data in the broadcast signal includes multiplexing information of the first data and the second data,
• wherein the first data in the broadcast signal has a different robustness level from the second data in the broadcast signal, and
• wherein the first data is enhanced data and the second data is main data.