Transmitting/receiving system and method of processing broadcasting signal in transmitting/receiving system

A method of processing a broadcast signal of a transmitting system, comprising:

• performing error correction encoding on an RS frame payload including mobile service data so as to form an RS frame, and dividing the RS frame into a plurality of portions;
• performing one of ½-rate encoding and ¼-rate encoding on each bit of the mobile service data included in each portion;
• mapping a portion including symbols of the ¼-rate encoded mobile service data and symbols of the ½-rate encoded mobile service data to a corresponding region of a data group;
• and
• performing trellis encoding on the symbols of the ¼-rate encoded mobile service data and the symbols of the ½-rate encoded mobile service data of the data group.

A receiving system comprising:

• a tuner receiving for a broadcast signal including a data group, wherein the data group includes mobile service data that are encoded at a coding rate of ½ and then processed with trellis encoding, mobile service data that are encoded at a coding rate of ¼ and then processed with trellis encoding, and a plurality of known data sequences;
• a demodulator for demodulating the received broadcast signal;
• a first decoder for matching the mobile service data being outputted from the demodulator in block sizes for turbo-decoding with mobile service data that are symbol-decoded and fed-back, and performing trellis decoding on the matched mobile service data;
• a first symbol mapper for converting a corresponding soft-decision value of the trellis-decoded mobile service data to an input format of a second decoder, when the soft-decision value of the trellis-decoded mobile service data corresponds to a soft-decision value of a ¼-rate encoded symbol, thereby outputting the converted soft-decision value to the second decoder;
• a second decoder for performing symbol-decoding on the soft-decision value being outputted from the first symbol mapper;
• a second symbol mapper for converting a corresponding soft-decision value of the symbol-decoded mobile service data to an input format of the first decoder, when the soft-decision value of the symbol-decoded mobile service data corresponds to a soft-decision value of a ¼-rate encoded symbol, thereby outputting the converted soft-decision value to the first decoder;
• and
• an RS frame decoder for performing error correction decoding on an RS frame including the mobile service data that are symbol-decoded by the second decoder.

A method of processing a broadcast signal of a receiving system, comprising:

• receiving a broadcast signal including a data group, wherein the data group includes mobile service data that are encoded at a coding rate of ½ and then processed with trellis encoding, mobile service data that are encoded at a coding rate of ¼ and then processed with trellis encoding, and a plurality of known data sequences;
• demodulating the received broadcast signal;
• matching the mobile service data being demodulated and outputted in block sizes for turbo-decoding with mobile service data being symbol-decoded and fed-back, and performing trellis decoding on the matched mobile service data, thereby performing a first decoding process;
• converting a corresponding soft-decision value of the trellis-decoded mobile service data to an input format of a second decoding process, when the soft-decision value of the trellis-decoded mobile service data corresponds to a soft-decision value of a ¼-rate encoded symbol, thereby performing a first symbol-mapping process;
• performing symbol-decoding on the soft-decision value of the mobile service data being outputted after being processed with the first symbol-mapping process, thereby performing the second decoding process;
• converting a corresponding soft-decision value of the symbol-decoded mobile service data to an input format of the first decoding process, when the soft-decision value of the symbol-decoded mobile service data corresponds to a soft-decision value of a ¼-rate encoded symbol, thereby feeding-back the converted soft-decision value to the first decoding process, so as to perform the second symbol-mapping process;
• and
• performing error correction decoding on an RS frame including the symbol-decoded mobile service data.