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

A receiving system comprising:

• a tuner configured to receive a passband broadcast signal including a data group that comprises mobile service data, signaling data, and a plurality of known data sequences,
• wherein one of the plurality of known data sequences includes a first M symbol sequence and a second M symbol sequence each having a first data pattern and the remaining known data sequences include N symbol sequences each having a second data pattern that is different from the first data pattern;
• a known sequence detector configured to:
• estimate an initial frequency offsets;
• and
• detect a position of at least one known data sequence based on the known data sequence having the first data pattern;
• a carrier recovery unit configured to perform carrier recovery based on the estimated initial frequency offset and position information of the at least one known data sequence;
• a baseband converter configured to perform complex multiplication between the passband broadcast signal and an output of the carrier recovery unit in order to convert the passband broadcast signal to a baseband broadcast signal;
• a channel equalizer configured to estimate a channel impulse response (CIR) based on the position information of the at least one known data sequence and compensate for a channel distortion in the baseband broadcast signal;
• and
• a turbo decoder configured to perform Parallel Concatenated Convolutional Code (PCCC) decoding on the signaling data in the channel-distortion-compensated baseband broadcast signal,
• wherein the turbo decoder comprises:
• a first decoder configured to perform a first decoding process to generate first-decoded signaling data in response to receiving the signaling data in the channel-distortion-compensated baseband broadcast signal and receiving deinterleaved signaling data;
• an interleaver configured to interleave the first-decoded signaling data;
• a second decoder configured to perform a second decoding process to generate second-decoded signaling data in response to receiving the signaling data in the channel-distortion-compensated broadcast signal and receiving the interleaved signaling data;
• and
• a deinterleaver configured to deinterleave the second-decoded signaling data and provide the deinterleaved signaling data to the first decoder,
• wherein the first decoder repeatedly performs the first decoding process and the second decoder repeatedly performs the second decoding process for a predetermined number of times.