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: Disclosed is a method for transmitting a channel signal in a base station of a mobile communication system which scrambles a common channel signal using a primary scrambling code for identifying the base station. The method comprises determining an identifier (ID) of a secondary scrambling code, upon receipt of a dedicated channel assignment request from a mobile station; transmitting the determined ID of the secondary scrambling code to the mobile station and awaiting a response; upon receipt of a response message from the mobile station, generating a primary scrambling code and a secondary scrambling code using an ID of the primary scrambling code and said ID of the secondary scrambling code; and scrambling a common channel signal using the primary scrambling code, scrambling a dedicated channel signal using the secondary scrambling code, and transmitting the scrambled channel signals.

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

Abstract: Disclosed is a method and apparatus for completely recovering received data with high reliability using LDPC codes without short-sized cycles in a digital communication system using an error-correcting code. The method includes performing exponent conversion of a predetermined number of exponent matrixes stored in advance in a memory so as to generate new exponent matrixes based on the exponent conversion, and generating new LDPC codes using the new exponent matrixes.

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: 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: 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. 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: 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: An apparatus and method for coding a semi-systematic block low density parity check (LDPC) code in which an information word is received and coded into a codeword including the information word, a first parity, a second parity, and a third parity, based on one of a first parity check matrix and a second parity check matrix, depending on a size to be applied when generating the information word into a semi-systematic block LDPC code. A part having a degree being at least equal to a predetermined degree is punctured from the information word, generating the semi-systematic block LDPC code. The semi-systematic block LDPC code includes the information word, the part of which was punctured, the first parity, the second parity, and the third parity.

Abstract: Disclosed is a device and procedure for coding a block low density parity check (LDPC) code having a variable length. The a device and procedure includes 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 and method for coding a block Low Density Parity Check (LDPC) code having a variable coding rate. The apparatus receives an information word and encodes the information word into a block LDPC code based on one of a first parity check matrix and a second parity check matrix, depending on a coding rate to be applied when generating the information word into the block LDPC code.

Abstract: An apparatus and method for coding a block Low Density Parity Check (LDPC) code having a variable coding rate. The apparatus receives an information word and encodes the information word into a block LDPC code based on one of a first parity check matrix and a second parity check matrix, depending on a coding rate to be applied when generating the information word into the block LDPC code.

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 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 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: 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: 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 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: 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.