Method and apparatus for encoding and decoding channel in a communication system using low-density parity-check codes

A method for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the method comprising:

• (a) generating a plurality of column groups by categorizing columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups;
• (b) determining a range of the information word desired to be obtained by performing shortening;
• (c) based on the determined range of the information word, performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern;
• and
• (d) LDPC encoding the shortened information word;
• wherein performing column group-by-column group shortening comprises including 168 Bose-Chaudhuri-Hocquenghem (BCH) parity bits in an information word desired to be obtained by performing shortening, and shortening columns except for columns in positions corresponding to the 168 BCH parity bits.

An apparatus for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the apparatus comprising:

• a parity-check matrix extractor for generating a plurality of column groups by grouping columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups;
• a shortening pattern applier for determining a range of an information word desired to be obtained by performing shortening, and based on a determined range of the information word, for performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern;
• and
• an encoder for LDPC encoding the shortened information word.

An apparatus for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the apparatus comprising:

• a parity-check matrix extractor for generating a plurality of column groups by grouping columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups;
• a shortening pattern applier for determining a range of an information word desired to be obtained by performing shortening, and based on the determined range of the information word, for performing column group-by-column group shortening on the column groups in order according to a predetermined shortening pattern;
• and
• an encoder for LDPC encoding the shortened information word;
• wherein in performing column group-by-column group shortening, the shortening pattern applier includes 168 Bose-Chaudhuri-Hocquenghem (BCH) parity bits in an information word desired to be obtained by performing shortening, and shortens columns except for columns in positions corresponding to the 168 BCH parity bits.

A method for decoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the method comprising:

• (a) demodulating a signal transmitted from a transmitter;
• (b) determining a position of a shortened bit by estimating information on a shortening pattern of an LDPC code from the demodulated signal from (a);
• and
• (c) decoding data using the determined position of the shortened bit.

An apparatus for decoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code, the apparatus comprising:

• a demodulator for demodulating a signal transmitted from a transmitter;
• a shortening pattern determiner for determining a position of a shortened bit by estimating information on a shortening pattern of an LDPC code from the demodulated signal;
• and
• a decoder for decoding data using the determined position of the shortened bit.