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: An apparatus and method for transmitting/receiving a signal in a communication system are provided. A signal reception apparatus of a communication system receives a signal and generates a child Low Density Parity Check (LDPC) codeword vector by decoding the received signal according to a child parity check matrix supporting a first coding rate. The child LDPC codeword vector includes an information vector including A (A?1) information bits, and when the first coding rate is equal to a coding rate for a case where D (D?1) parity bits are punctured among B (B?1)+C (C?1) parity bits included in a parent LDPC codeword vector generated by encoding the information vector according to a parent parity check matrix supporting a second coding rate, a child bipartite graph corresponding to the child parity check matrix is generated such that a parent bipartite graph corresponding to the parent parity check matrix corresponds to an edge merge 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: Disclosed is an apparatus and method for transmitting/receiving a signal in a communication system, in which an MCS level or a modulation scheme to be used to an information vector to be transmitted is determined when the information vector is generated, and a codeword vector is generated by encoding the information vector in an encoding scheme corresponding to the determined MCS level or modulation scheme. Thus, a signal can be transmitted in such a manner as to have optimal performance for each MCS level or modulation 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 method for generating a parity check matrix of a block LDPC code is disclosed. 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: 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: 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 encoding/decoding a non-binary low density parity check (LDPC) code in a communication system. The apparatus and method includes receiving an information vector; generating a non-binary LDPC code by encoding the information vector into a non-binary LDPC code according to a non-binary LDPC encoding scheme.

Abstract: An apparatus and method for coding an irregular Repeat Accumulate (RA) code. A repeater repeats a received information word such that the information word corresponds to weights of a first information part and a second information part of a parity check matrix in which permutation matrixes are arranged in the first information part and the second information part corresponding to the information word such that a minimum length of a cycle on a factor graph of the irregular RA code becomes a predetermined length and weights are irregular, and a dual diagonal matrix is arranged in a parity part corresponding to a parity. An interleaver interleaves a signal output from the repeater using an interleaving scheme predefined for the parity check matrix. An accumulator generates the irregular RA code by accumulating a signal output from the interleaver according to a weight of the parity part.

Abstract: An apparatus for transmitting a signal in a Multiple Input Multiple Output (MIMO) communication system includes determining transmission antennas to be used by a signal transmission apparatus depending on channel quality information received from a reception apparatus, encoding an input information data stream into a codeword using a coding scheme, mapping the codeword using a MIMO mapping scheme thereby generating at least one mapped symbol, modulating the mapped symbols into modulation symbols according to a modulation scheme, and performing transmission processing on the modulation symbols thereby generating transmission streams, and transmitting the transmission streams via the determined transmission antennas.

Abstract: A method for transmitting a signal in a signal transmission apparatus of a communications system including receiving an information vector, and encoding the information vector according to a zigzag B-LDPC encoding scheme to generate a zigzag B-LDPC codeword, thereby advantageously reducing the encoding complexity together with enhanced error correction capability.

Abstract: Disclosed is an apparatus and a method for transmitting/receiving a signal in a communication system, which generates an Affine Permutation Matrix-Low Density Parity Check (APM-LDPC) codeword by encoding an information vector in an APM-LDPC encoding scheme which is a preset structured LDPC encoding scheme, and detects the information vector by decoding the signal in a decoding scheme corresponding to the APM-LDPC encoding scheme, thereby making it possible to generate a Low Density Parity Check (LDPC) code in the form of maximizing a girth while minimizing complexity.

Abstract: Provided are an apparatus and method for transmtting/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.

Abstract: A method and apparatus is provided for receiving data in a receiver of a communication system. In the receiver, a first calculator calculates a Log Likelihood Ratio (LLR) value of data transmitted from a transmitter, a decoder performs iterative decoding on the transmitted data using the LLR value calculated by the first calculator. A second calculator determines whether there is an error in the decoded data by calculating an error of the data decoded by the decoder. A storage stores an LLR value of the decoded data according to the determination result of the second calculator. An adder adds up the LLR value calculated by the first calculator and the LLR value stored in the storage.

Abstract: Disclosed is a device and method for coding a block low density parity check (LDPC) code having a variable length. The a device and method include receiving an information word; and coding the information word into a block LDPC code according to a first parity check matrix or a second parity check matrix depending on a length to be applied when generating the information word into the block LDPC code.

Abstract: An apparatus is provided for transmitting a signal in a communication system using a Low Density Parity Check (LDPC) code. A controller determines a number of ‘0’s to be inserted in information data according to a first coding rate to be applied when generating the information data into an LDPC code, and determines the number of ‘0’s to be removed from the LDPC code. A ‘0’ inserter inserts ‘0s’ in the information data according to control of the controller. An LDPC encoder generates the LDPC code by encoding the ‘0’-inserted signal according to a first parity check matrix. A ‘0’ remover removes the inserted ‘0’s from the LDPC code.

Abstract: Disclosed is a method for transmitting a signal in a signal transmission system, which includes demultiplexing a bit stream to be transmitted into a first bit stream and a second bit stream; generating a first coded bit stream by coding the first bit stream according to a first coding rate and generating a second coded bit stream by coding the second bit stream according to a second coding rate; and generating a coded symbol by concatenating the first coded bit stream and the second coded bit stream.

Abstract: In a communication system, information data bits are encoded in a preset coding scheme when the information data bits are input, and a Low Density Parity Check (LDPC) codeword is generated. The LDPC codeword is interleaved according to a preset channel-interleaving rule. A channel-interleaved LDPC codeword is modulated in a preset modulation scheme and a modulation symbol is generated.

Abstract: An apparatus and method for transmitting a signal in a communication system. An information vector is encoded using a structured low density parity check (LDPC) coding scheme supporting a first coding rate, to generate a first structured LDPC codeword vector including a first part mapped to the information vector and a second part mapped to a parity vector. The first structured LDPC codeword vector is transmitted to a signal reception apparatus. If there is an error in the first structured LDPC codeword vector, the information vector is encoded using a structured LDPC coding scheme supporting a second coding rate, to generate a second structured LDPC codeword vector including the first part, the second part, and a third part mapped to an additional parity vector of the information vector. The third part is transmitted to the signal reception apparatus.