Abstract: A system and method for processing a block Low Density Parity Check (LDPC) code are provided. The system includes, a decoding apparatus for decoding a block LDPC code using a parity check matrix, the parity check matrix including an information part and a parity part, the parity part including a first section (B) including a plurality of first permutation matrices, a second section (D) including a second permutation matrix, a third section (T) including a plurality of identity matrices (I) arranged diagonally within the third section and a plurality of third permutation matrices arranged below the plurality of identity matrices, and a fourth section (E) including a fourth permutation matrix.

Abstract: A matrix multiplier multiplies the signal output from a first adder by an inverse matrix T?1 of a partial matrix T of a parent parity check matrix, and outputs the multiplication result to a first switch. The output of the matrix multiplier becomes a second parity vector P2. A second switch is switched on at a transmission time of the information word vector ‘s’, a third switch is switched on at a transmission time of the first parity vector P1, and the first switch is switched on at a transmission time of the second parity vector P2. When a puncturing scheme is applied to the parent parity check matrix, a controller controls the first and second switches to puncture the parity according to the corresponding coding rate.

Abstract: An apparatus and method for compensating for phase noise in a receiver supporting Orthogonal Frequency Division Multiplexing (OFDM) by receiving a frequency-domain recovered signal and a time-domain received signal, estimating an average phase noise for each of the partial blocks of the signals, calculating an overall average phase noise using the average phase noises of the partial blocks, and removing the phase noise from the time-domain received signal using the calculated total average phase noise.

Abstract: An apparatus and method for generating a parity-check matrix of a Low-Density Parity-Check (LDPC) code are provided. Parameters for designing the LDPC code are determined, and a first parity-check matrix of a quasi-cyclic LDPC code is formed according to the determined parameters. A second parity-check matrix is created through the elimination of a predetermined portion of a parity part in the first parity-check matrix, and a third parity-check matrix is created by rearranging the second parity-check matrix.

Abstract: A method for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code is provided. The method includes determining a number of parity bits for puncturing; dividing the parity bits at predetermined intervals, and determining a number of puncturing parity bits, which are subjected to puncturing within the predetermined intervals; determining a modulation scheme; determining positions of puncturing parity bits corresponding to the determined number of the puncturing parity bits within the predetermined intervals according to the modulation scheme; repeatedly performing puncturing on puncturing parity bits corresponding to the determined positions at the predetermined intervals; and transmitting remaining bits except for the punctured bits according to the modulation scheme.

Abstract: An apparatus and method for transmitting/receiving a signal in a communication system are provided. The method includes inputting an information word during initial transmission and transmitting a first code word created by encoding the inputted information word based on a first coding ratio, and transmitting a portion of a second code word created by encoding the first code word based on a second coding ratio at a retransmission request. Accordingly, the apparatus and method provide for transmitting/receiving signals in a communication system in such a manner that the complexity of the communication system is reduced.

Abstract: A method for transmitting data in a communication system using a Low Density Parity Check (LDPC) matrix includes generating an LDPC codeword by encoding information data bits, interleaving the LDPC codeword, mapping the interleaved LDPC codeword to a modulation signal, and generating a mapped signal by mapping the LDPC codeword bits separately to a bit corresponding to a real part and a bit corresponding to an imaginary part of said modulation signal, among bits constituting the modulation signal, generating a modulation signal by high-order-modulating the mapped signal and Radio Frequency (RF)-processing the modulation signal, and transmitting the RF-processed signal via a transmission antenna.

Abstract: A method and apparatus for encoding and decoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code. The encoding method includes determining a modulation scheme for transmitting a symbol; determining a shortening pattern in consideration of the determined modulation scheme; grouping columns corresponding to an information word in a parity-check matrix of the LDPC code into a plurality of column groups; ordering the column groups; determining a range of a resulting information word desired to be obtained by shortening the information word; based on the range of the resulting information word, performing column group-by-column group shortening on the ordered column groups of the information word, according to the determined shortening pattern; and LDPC-encoding the shortened information word.

Abstract: A method for encoding a channel in a communication system using a Low-Density Parity-Check (LDPC) code. The method includes generating a plurality of column groups by grouping (categorizing) columns corresponding to an information word in a parity-check matrix of the LDPC code, and ordering the column groups; determining a range of an information word desired to be obtained by performing shortening; 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 LDPC encoding the shortened information word.

Abstract: An apparatus and method to encode a block Low Density Parity Check (LDPC) code in a signal transmission apparatus is disclosed. The method includes generating a first block LDPC codeword by encoding an information vector using a first parity check matrix when a code rate to be used in the signal transmission apparatus is a first code rate as a code rate of the first parity check matrix, and generating a second block LDPC codeword by encoding the information vector using a second parity check matrix when the code rate to be used in the signal transmission apparatus is a second code rate as a code rate of the second parity check matrix.

Abstract: An apparatus and method for compensating for phase noise in a receiver supporting Orthogonal Frequency Division Multiplexing (OFDM) by receiving a frequency-domain recovered signal and a time-domain received signal, estimating an average phase noise for each of the partial blocks of the signals, calculating an overall average phase noise using the average phase noises of the partial blocks, and removing the phase noise from the time-domain received signal using the calculated total average phase noise.

Abstract: A method for channel coding by a transmitter in a communication system is provided. The method includes determining a degree of coded bits of a Luby-Transform (LT) code based on a coding rate of a pre-code and the number of coded bits of the LT code, selecting at least one associated bit used for coding of the coded bits of the LT code from among information bits of the LT code, depending on the determined degree, and generating the coded bits of the LT code by applying a coding function to the selected associated bits.

Abstract: A signal reception apparatus for a communication system is disclosed in which the signal reception apparatus receives a signal and decodes the received signal using a second decoding scheme approximated from a first decoding scheme. The second decoding scheme is a scheme of applying a correction value to a third decoding scheme approximated from the first decoding scheme, and the correction value is a value for correcting a difference between a first signal obtained by decoding the received signal using the first decoding scheme and a second signal obtained by decoding the received signal using the third decoding scheme.

Abstract: An apparatus and method of encoding a block Low Density Parity Check (LDPC) code in a signal transmission apparatus is disclosed. The method includes generating a block LDPC codeword by encoding an information vector using a second parity check matrix when a code rate to be used in the signal transmission apparatus is a second code rate less than a code rate of a first parity check matrix as a first code rate.

Abstract: A system and method for processing a block Low Density Parity Check (LDPC) code are provided. The system includes, a decoding apparatus for decoding a block LDPC code using a parity check matrix, the parity check matrix including an information part and a parity part, the parity part including a first section (B) including a plurality of first permutation matrices, a second section (D) including a second permutation matrix, a third section (T) including a plurality of identity matrices (I) arranged diagonally within the third section and a plurality of third permutation matrices arranged below the plurality of identity matrices, and a fourth section (E) including a fourth permutation matrix.

Abstract: A method for generating a parity check matrix of a block LDPC code. The parity check matrix includes an information part corresponding to an information word and a first parity part and a second parity part each corresponding to a parity.

Abstract: An apparatus and method of receiving a signal in a communication system are provided, in which a signal is received and decoded by a PPS scheme being an LDPC decoding scheme in which an order of performing a node operation is scheduled.

Abstract: A signal transmission apparatus in a communication system is disclosed. A channel interleaver generates an interleaved vector by channel-interleaving a Low Density Parity Check (LDPC) codeword according to a channel interleaving rule, and a modulator generates a modulation symbol by modulating the interleaved vector according to a modulation scheme. The channel interleaving rule is one of a first channel interleaving rule and a second channel interleaving rule. The first channel interleaving rule is a rule for setting degree distribution for nodes in a factor graph of the LDPC codeword separately for individual levels supported by the modulation scheme. The second channel interleaving rule is a rule for allowing coded bits included in the LDPC codeword to be interleaved according to an unequal error characteristic of the modulation scheme.

Abstract: An apparatus and method for retransmitting a codeword packet in a system using Hybrid Automatic Repeat reQuest (HARQ) are provided. The HARQ retransmission method includes defining multiple mother codes, and selecting one of code rates of the mother codes as an initial transmission code rate according to channel condition, determining a retransmission unit for each of codeword packets coded with code rates corresponding to the mother codes and retransmitting corresponding codeword packets in units of the determined retransmission units every time there is a retransmission request.

Abstract: Provided are an apparatus and method for transmitting/receiving signal, supporting a variable coding rate, in a communication system. The method includes receiving an information vector, generating a child parity check matrix based on a parent parity check matrix according to a coding rate to be applied for generating a block Low Density Parity Check (LDPC) codeword using the information vector, and encoding the information vector into the block LDPC codeword according to the child parity check matrix.