Apparatus and method for transmitting/receiving a signal in a communication system using a low density parity check code

A method for transmitting a signal in a communication system using a low density parity check (LDPC) code, the method comprising:

• generating an LDPC codeword by encoding at a coding rate an information word;
• generating a puncturing pattern when a hybrid automatic repeat request (HARQ) scheme to be applied to the LDPC codeword is an incremental redundancy (IR) scheme and generating an additional pattern when the HARQ scheme to be applied to the LDPC codeword is a partial chase combining (CC) scheme;
• transmitting a signal by applying the puncturing pattern to the LDPC codeword at an associated coding rate when the HARQ scheme to be used is the IR scheme;
• and
• transmitting a signal by applying the additional pattern to the LDPC codeword at an associated coding rate when the HARQ scheme to be used is the partial CC scheme, wherein when the LDPC code is a block-LDPC (B-LDPC) code, a size of a base matrix is M×N, sizes of a permutation matrix and a zero matrix are L×L, a size of a parity check matrix is LM×LN, and a B-LDPC codeword comprises L(N−M) information bits and LM parity bits, generating the puncturing pattern comprises:
• generating a total of M groups by grouping parity bits included in the B-LDPC codeword in a unit of L bits;
• setting to 1 an element value of the puncturing pattern to be applied to a first group of the M groups;
• and
• generating the puncturing pattern such that parity bits before the B-LDPC codeword is punctured are arranged at regular distances when the M groups are permuted in relation to an element value of the puncturing pattern to be applied to (M−1) parity groups excluding the first parity group of the M groups.

An apparatus for transmitting a signal in a communication system using a low density parity check (LDPC) code, the apparatus comprising:

• an LDPC encoder for generating an LDPC codeword by encoding at a coding rate an information word;
• a controller for generating a puncturing pattern when a hybrid automatic repeat request (HARQ) scheme to be applied to the LDPC codeword is an incremental redundancy (IR) scheme, generating an additional pattern when the HARQ scheme to be applied to the LDPC codeword is a partial chase combining (CC) scheme, and controlling an operation for transmitting a signal by applying the puncturing pattern to the LDPC codeword at an associated coding rate when the HARQ scheme to be used is the IR scheme and an operation for transmitting a signal by applying the additional pattern to the LDPC codeword at an associated coding rate when the HARQ scheme to be used is the partial CC scheme;
• a transmission bit decision unit for deciding bits to be transmitted in the LDPC codeword under control of the controller;
• and
• a transmission processor for transmitting the bits decided by the transmission bit decision unit, wherein when the LDPC code is a block-LDPC (B-LDPC) code, a size of a base matrix is M×N, sizes of a permutation matrix and a zero matrix are L×L, a size of a parity check matrix is LM×LN, and a B-LDPC codeword comprises L(N−M) information bits and LM parity bits,
• the controller generates a total of M groups by grouping parity bits included in the B-LDPC codeword in a unit of L bits, sets to 1 an element value of the puncturing pattern to be applied to a first group of the M groups, and generates the puncturing pattern such that a message to be transferred from a check node of the B-LDPC codeword to an information node has a uniform value when the M groups are permuted in relation to an element value of the puncturing pattern to be applied to (M−1) parity groups excluding the first parity group of the M groups.

An apparatus for transmitting a signal in a communication system using a low density parity check (LDPC) code, the apparatus comprising:

• an LDPC encoder for generating an LDPC codeword by encoding at a coding rate an information word;
• a controller for generating a puncturing pattern when a hybrid automatic repeat request (HARQ) scheme to be applied to the LDPC codeword is an incremental redundancy (IR) scheme, generating an additional pattern when the HARQ scheme to be applied to the LDPC codeword is a partial chase combining (CC) scheme, and controlling an operation for transmitting a signal by applying the puncturing pattern to the LDPC codeword at an associated coding rate when the HARQ scheme to be used is the IR scheme and an operation for transmitting a signal by applying the additional pattern to the LDPC codeword at an associated coding rate when the HARQ scheme to be used is the partial CC scheme;
• a transmission bit decision unit for deciding bits to be transmitted in the LDPC codeword under control of the controller;
• and
• a transmission processor for transmitting the bits decided by the transmission bit decision unit, wherein when the LDPC code is a block-LDPC (B-LDPC) code, a size of a base matrix is M×N, sizes of a permutation matrix and a zero matrix are L×L, a size of a parity check matrix is LM×LN, and a B-LDPC codeword comprises L(N−M) information bits and LM parity bits,
• the controller generates a total of M groups by grouping parity bits comprised in the B-LDPC codeword in a unit of L bits, sets to 1 an element value of the puncturing pattern to be applied to a first group of the M groups, and generates the puncturing pattern such that parity bits before the B-LDPC codeword is punctured are arranged at regular distances when the M groups are permuted in relation to an element value of the puncturing pattern to be applied to (M−1) parity groups excluding the first parity group of the M groups.