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

A receiving system comprising:

• a tuner for receiving a broadcast signal comprising data groups, wherein each of the data groups comprises mobile service data and a plurality of known data sequences;
• a demodulator for demodulating the received broadcast signal;
• an equalizer for channel-equalizing the demodulated broadcast signal using at least one of the plurality of known data sequences;
• a block decoder for performing turbo-decoding in block units on the mobile service data of the channel-equalized broadcast signal;
• and
• a Reed-Solomon (RS) frame decoder for building an RS frame including the turbo-decoded mobile service data, estimating a number of errors by performing Cyclic Redundancy Check (CRC)-decoding on each row of the RS frame, generating a reliability map including reliability information corresponding to each data byte of the RS frame, the reliability information set-up as a soft value having at least two bits to indicate a reliability level, and correcting errors in the RS frame based on the estimated number of errors and the reliability information of the reliability map,
• wherein the RS frame comprises a plurality of mobile and handheld (M/H) transport packets, each of the plurality of M/H transport packets including a 2-byte header, k bytes of stuffing data and an (N−2-k)-byte payload, wherein the 2-byte header of each of the plurality of M/H transport packets includes stuffing indication information indicating whether the stuffing data are included in the M/H transport packet,
• wherein the payload of at least one of the plurality of M/H transport packets includes the turbo-decoded mobile service data,
• wherein N is an integer, and
• wherein k is equal to or greater than 0.