DTV receiving system and method of processing DTV signal

Abstract

A digital television (DTV) receiving system includes a tuner, a demodulator, a known data detector, an equalizer, a transmission detector, and a block decoder. The tuner receives a DTV signal having a data frame in which main and mobile service data are multiplexed. The demodulator demodulates the DTV signal, and the known data detector detects known data included in the mobile service data. The equalizer equalizes the demodulated DTV signal using the detected known data, and the transmission parameter detector detects an error correction mode from the equalized DTV signal. Finally, the block decoder decodes the equalized DTV signal for error correction using the detected error correction mode.

What is claimed is: 
     
       1. A method of processing broadcast data in a broadcast transmitter, the method comprising:
 performing, by a Reed Solomon (RS) encoder, RS encoding and Cyclic Redundancy Check (CRC) encoding on mobile service data, thereby packaging the mobile service data into an RS frame;   mapping, by a group formatter, a portion of the RS frame into at least one region of a group that comprises a plurality of regions, and adding a first known data sequence, a plurality of second known data sequences, a transmission parameter, and MPEG header data holder bytes to the group;   replacing, by a packet formatter, the MPEG header data holder bytes in the group with MPEG header data, thereby outputting mobile service data packets;   multiplexing, by a multiplexer, the mobile service data packets with main service data packets including main service data;   trellis encoding, by a trellis encoder, data in the multiplexed data packets; and   modulating, by a modulator, a broadcast signal including the trellis-encoded data,   wherein the first known data sequence has a first pattern and the plurality of second known data sequences have a second pattern that is different from the first pattern, wherein the transmission parameter is positioned between the first known data sequence and one of the plurality of second known data sequences, and wherein the first known data sequence and the one of the plurality of second known data sequences differ from each other in length.   
     
     
       2. The method of  claim 1 , wherein the first pattern of the first known data sequence includes a first M-symbol sequence and a second M-symbol sequence that have the same pattern, wherein M is an integer greater than 1. 
     
     
       3. The method of  claim 1 , wherein at least two of the plurality of second known data sequences have different lengths, and wherein the second pattern is positioned at last N symbols in each of the plurality of second known data sequences. 
     
     
       4. The method of  claim 1 , wherein the RS frame comprises a payload of (N column*K row)-byte, RS parity data generated to each column direction based on the payload, and CRC checksum data generated to each row direction based on the payload and the RS parity data, the payload including the mobile service data. 
     
     
       5. A broadcast transmitter comprising:
 a Reed Solomon (RS) encoder for performing RS encoding and Cyclic Redundancy Check (CRC) encoding on mobile service data, thereby packaging the mobile service data into an RS frame;   a group formatter for mapping a portion of the RS frame into at least one region of a group that comprises a plurality of regions, and adding a first known data sequence, a plurality of second known data sequences, a transmission parameter, and MPEG header data holder bytes to the group;   a packet formatter for replacing the MPEG header data holder bytes in the group with MPEG header data, thereby outputting mobile service data packets;   a multiplexer for multiplexing the mobile service data packets with main service data packets including main service data;   a trellis encoder for trellis encoding data in the multiplexed data packets; and   a modulator for modulating a broadcast signal including the trellis-encoded data,   wherein the first known data sequence has a first pattern and the plurality of second known data sequences have a second pattern that is different from the first pattern, wherein the transmission parameter is positioned between the first known data sequence and one of the plurality of second known data sequences, and wherein the first known data sequence and the one of the plurality of second known data sequences differ from each other in length.   
     
     
       6. The broadcast transmitter of  claim 5 , wherein the first pattern of the first known data sequence includes a first M-symbol sequence and a second M-symbol sequence that have the same pattern, wherein M is an integer greater than 1. 
     
     
       7. The broadcast transmitter of  claim 5 , wherein at least two of the plurality of second known data sequences have different lengths, and wherein the second pattern is positioned at last N symbols in each of the plurality of second known data sequences. 
     
     
       8. The broadcast transmitter of  claim 5 , wherein the RS frame comprises a payload of (N column*K row)-byte, RS parity data generated to each column direction based on the payload, and CRC checksum data generated to each row direction based on the payload and the RS parity data, the payload including the mobile service data. 
     
     
       9. A method for processing broadcast data, the method comprising:
 preprocessing broadcast data to output packetized broadcast data;   encoding the packetized broadcast data for forward error correction by adding parity data;   wherein the broadcast data is encoded into first type data and second type data based on different code rates,   interleaving the encoded broadcast data, wherein dummy data is included in a memory for the interleaving and a number of interleaving data added by the dummy data are larger than a number of data to be interleaved;   modulating a frame including known data and the interleaved broadcast data; and   transmitting the modulated frame,   wherein the modulated frame includes signal information, first type data and second type data,   wherein the first type data and the second type data are transmitted through respective transmission units in the modulated frame,   wherein the signal information includes information on code rates used for the transmission units,   wherein the signal information includes information on the number of the transmission units,   wherein the known data include at least two pre-defined patterns that are inserted in predetermined positions in the frame, and wherein values of the known data are previously known to a receiver before transmitting the known data.   
     
     
       10. The method of claim 9, wherein the modulated frame further includes known data that are periodically located. 
     
     
       11. The method of claim 9, wherein the modulated frame further includes sync data that are used for synchronization of the frame.