DTV transmitter and method of coding data in DTV transmitter

Abstract

A DTV transmitter includes a pre-processor expanding original enhanced data, a data formatter generating enhanced data packets including the expanded enhanced data and inserting known data place holders into the data packets, a multiplexer multiplexing the enhanced data packets with main data packets including main data, and an RS encoder adding systematic RS parity data to each main data packet and adding non-systematic RS parity data holders to each enhanced data packet. It further includes a data interleaver interleaving the RS-coded data packets, a known data generator generating know data symbols, a converter converting the interleaved data packet into symbols, and a symbol processor processing the converted symbols. The symbol processor removes symbols representing the null data, encodes symbols representing the original enhanced data at a rate of N/M, and replaces symbols representing the know data place holders with known data symbols.

What is claimed is: 
     
       1. A digital television (DTV) receiver comprising:
 a tuner for receiving a digital broadcast signal comprising main data, enhanced data and known data sequences;   a known data detector for detecting information of the known data sequences from the digital broadcast signal;   a demodulator for demodulating the digital broadcast signal by performing carrier recovery on the digital broadcast signal;   an equalizer for compensating a channel distortion of the demodulated digital broadcast signal based on the detected information of the known data sequences; and   a decoder for decoding the channel-distortion-compensated digital broadcast signal,   wherein the received digital broadcast signal results from a process comprising:   generating a digital broadcast signal having main data and enhanced data, wherein generating the digital broadcast signal comprises pre-coding the enhanced data, packet-formatting the pre-coded enhanced data, multiplexing enhanced data packets including the packet-formatted data with main data packets including the main data, Reed-Solomon (RS)-encoding the multiplexed main and enhanced data packets by adding systematic RS parity data to the main data packets and adding non-systematic RS parity data to the enhanced data packets, and interleaving data in the RS-encoded main and enhanced data packets, and   modulating the digital broadcast signal,   wherein generating the digital broadcast signal further comprises:   first encoding, by a first encoder, the enhanced data with a coding rate of N/M, wherein M is greater than N, and   second encoding, by a second encoder, the first-encoded enhanced data and the known data sequences with a coding rate of M/L, wherein L is greater than M, and wherein at least one memory in the second encoder is initialized at each start of the known data sequences, wherein initialization data required to initialize the at least one memory in the second encoder are determined based on a value of the at least one memory,   wherein generating the digital broadcast signal further comprises recalculating new RS parity data of a corresponding data packet in the multiplexed data packets and replacing the added RS parity data with the re-calculated RS parity data.   
     
     
       2. The DTV receiver of  claim 1 , wherein the first encoder is a convolutional encoder for convolutional encoding the enhanced data with the coding rate of N/M. 
     
     
       3. The DTV receiver of  claim 1 , wherein the second encoder is a trellis encoder for trellis encoding the first-encoded enhanced data with the coding rate of M/L. 
     
     
       4. The DTV receiver of  claim 1 , wherein N is 1, M is 2, and L is 3. 
     
     
       5. A method for processing digital broadcast data in a digital television (DTV) receiver, the method comprising:
 receiving a digital broadcast signal comprising main data, enhanced data and known data sequences; 
 detecting information of the known data sequences from the digital broadcast signal; 
 demodulating the digital broadcast signal by performing carrier recovery on the digital broadcast signal; 
 compensating a channel distortion of the demodulated digital broadcast signal based on the detected information of the known data sequences; and 
 decoding the channel-distortion-compensated digital broadcast signal, 
 wherein the received digital broadcast signal results from a process comprising: comprising generating a digital broadcast signal having main data and enhanced data, 
 wherein generating the digital broadcast signal comprises
 pre-coding the enhanced data,;  
 packet-formatting the pre-coded enhanced data,;  
 multiplexing enhanced data packets including the packet-formatted data with main data packets including the main data,;  
 Reed-Solomon (RS)-encoding the multiplexed main and enhanced data packets by adding systematic RS parity data to the main data packets and adding non-systematic RS parity data to the enhanced data packets, and;  
 interleaving data in the RS-encoded main and enhanced data packets,; and 
 modulating the digital broadcast signal, 
 
 wherein generating the digital broadcast signal further comprises: 
 first encoding, by a first encoder, the enhanced data with a coding rate of N/M, wherein M is greater than N,; and 
 second encoding, by a second encoder, the first-encoded enhanced data and the known data sequences with a coding rate of M/L, wherein L is greater than M, and wherein at least one memory of the second encoder is initialized at each start of the known data sequences, wherein initialization data required to initialize the at least one memory in the second encoder are determined based on a value of the at least one memory,; and  
 wherein generating the digital broadcast signal further comprises recalculating new RS parity data of a corresponding data packet in the multiplexed data packets and replacing the added RS parity data with the re-calculated RS parity data. 
 
     
     
       6. The method of  claim 5 , wherein first encoding the enhanced data comprises performing convolutional encoding on the enhanced data with the coding rate of N/M. 
     
     
       7. The method of  claim 5 , wherein second encoding the first-encoded enhanced data comprises performing trellis encoding on the first-encoded enhanced data with the coding rate of M/L. 
     
     
       8. The method of  claim 5 , wherein N is 1, M is 2, and L is 3. 
     
     
       9. The method of claim 5, wherein the known data sequences are inserted in specified locations.