633results about "Error correction/detection using LDPC codes" patented technology

A method for low-density parity-check (LDPC) encoding of data comprises defining a first M×N parity check matrix; generating, based on the first parity check matrix, a second parity check matrix having an M×M triangular sub-matrix; and, mapping the data into an LDPC code word based on the second parity check matrix. The method is particularly useful for data communications applications, but may also be employed in other applications such as, for example, data storage.

An approach is provided for a method of encoding structure Low Density Parity Check (LDPC) codes. Memory storing information representing a structured parity check matrix of Low Density Parity Check (LDPC) codes is accessed during the encoding process. The information is organized in tabular form, wherein each row represents occurrences of one values within a first column of a group of columns of the parity check matrix. The rows correspond to groups of columns of the parity check matrix, wherein subsequent columns within each of the groups are derived according to a predetermined operation. An LDPC coded signal is output based on the stored information representing the parity check matrix.

A data processing apparatus communicates data bits on a predetermined number of sub-carrier signals of an Orthogonal Frequency Division Multiplexed (OFDM) symbol. The data processing apparatus comprises a parity interleaver operable to perform parity interleaving on Low Density Parity Check (LDPC) encoded data bits obtained by performing LDPC encoding according to a parity check matrix of an LDPC code including a parity matrix corresponding to parity bits of the LDPC code, the parity matrix having a stepwise structure, so that a parity bit of the LDPC encoded data bits is interleaved to a different parity bit position. A mapping unit maps the parity interleaved bits onto data symbols corresponding to modulation symbols of a modulation scheme of the OFDM sub-carrier signals. A symbol interleaver is arranged in operation to read-into a symbol interleaver memory the predetermined number of data symbols for mapping onto the OFDM sub-carrier signals, and to read-out of the interleaver memory the data symbols for the OFDM sub-carriers to effect the mapping, the read-out being in a different order than the read-in, the order being determined from a set of addresses, with the effect that the data symbols are interleaved on the sub-carrier signals. The set of addresses are generated by an address generator which has been optimised to interleave the data symbols on to the sub-carrier signals of the OFDM carrier signals for a given operating mode of the OFDM system, such as a 32K operating mode for DVB-T2 or DVB-C2.

An interleaving method performed by a transmitter for a communication system with quasi-cyclic low-density parity-check codes, spatial multiplexing, and T transmit antennas is used for applying permutation to N cyclic blocks of a codeword in order to map bits of the permutated cyclic blocks onto T constellation words constituting multiple spatial-multiplexing blocks from the codeword. Each cyclic block consists of Q bits.

A method for low-density parity-check (LDPC) encoding of data comprises defining a first MxN parity check matrix; generating, based on the first parity check matrix, a second parity check matrix having an MxM triangular sub-matrix; and, mapping the data into an LDPC code word based on the second parity check matrix. The method is particularly useful for data communications applications, but may also be employed in other applications such as, for example, data storage.

A transmitter apparatus and a receiver apparatus are provided. The transmitter apparatus includes: an encoder configured to generate a low density parity check (LDPC) by performing LDPC encoding; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a modulation symbol. The modulator maps a bit included in a predetermined group from among a plurality of groups constituting the LDPC codeword onto a predetermined bit in the modulation symbol.

An apparatus for transmitting data in a communication system using a Low Density Parity Check (LDPC) matrix is provided. The apparatus includes an interleaver for interleaving a descending bit-ordered codeword having a predetermined size and in accordance with a predetermined modulation scheme; and a bit mapper for mapping codeword bits constituting the interleaved codeword in accordance with a predetermined mapping scheme that takes into account degrees of the codeword bits and reliability characteristics of modulation symbol-constituting bits based on the predetermined modulation scheme.

A transmitting apparatus is provided. The transmitting apparatus includes: an encoder configured to generate a low-density parity check (LDPC) codeword by LDPC encoding based on a parity check matrix; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a modulation symbol, wherein the modulator is further configured to map a bit included in a predetermined bit group from among a plurality of bit groups constituting the LDPC codeword onto a predetermined bit of the modulation symbol.

An approach is provided for bit labeling of a signal constellation. A transmitter generates encoded signals using, according to one embodiment, a structured parity check matrix of a Low Density Parity Check (LDPC) code. The transmitter includes an encoder for transforming an input message into a codeword represented by a plurality of set of bits. The transmitter includes logic for mapping non-sequentially (e.g., interleaving) one set of bits into a higher order constellation (Quadrature Phase Shift Keying (QPSK), 8-PSK, 16-APSK (Amplitude Phase Shift Keying), 32-APSK, etc.), wherein a symbol of the higher order constellation corresponding to the one set of bits is output based on the mapping.

In transmitter apparatus for a digital television (DTV) broadcasting system, internet-protocol (IP) packets of digital television information are subjected to multilevel concatenated Bose-Chaudhuri-Hocquenghem (BCH) coding and low-density parity-check convolutional coding (LDPCCC) before being bit-interleaved and mapped to quadrature-amplitude-modulation (QAM) constellations. The QAM constellations are used in coded orthogonal frequency-division modulation (COFDM) of plural carrier waves up-converted to a radio-frequency broadcast television channel. In receiver apparatus for the DTV broadcasting system the results of de-mapping QAM constellations recovered from demodulating the COFDM carrier waves are de-interleaved, and the constituent LDPCCC codewords are decoded to recover constituent BCH codewords of the multilevel BCH coding. The constituent BCH codewords are decoded to correct remnant bit errors in them. Then, IP packets of digital television information are reconstituted from the systematic data bits in those BCH codewords.

In one embodiment, a method for generating an adaptive air interface waveform includes generating a waveform that includes a variable carrier frequency and variable bandwidth signal. The variable bandwidth signal includes one or more subcarriers that are dynamically placeable over a range of frequencies, and each subcarrier is separately modulated according to a direct sequence (DS) spread spectrum (SS) technique. The waveform has an embedded pilot usable to optimize one or more spectrum efficiencies of the waveform. A modulation constellation, a code rate, and a code length of the generated waveform are adapted according to an available spectrum and one or more sub-carrier conditions.

A transmitting apparatus is provided. The transmitting apparatus includes: an encoder configured to generate a low-density parity check (LDPC) codeword by LDPC encoding of input bits based on a parity check matrix including information word bits and parity bits, the LDPC codeword including a plurality of bit groups each including a plurality of bits; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a modulation symbol, wherein the interleaver is further configured to interleave the LDPC codeword such that a bit included in a predetermined bit group from among the plurality of bit groups constituting the LDPC codeword onto a predetermined bit of the modulation symbol.

A transmitting apparatus is provided. The transmitting apparatus includes: an encoder configured to perform a low-density parity check (LDPC) encoding on input bits using a parity check matrix to generate an LDPC codeword comprising information word bits and parity bits; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a modulation symbol, wherein the modulator is further configured to map a bit included in a predetermined bit group from among a plurality of bit groups constituting the LDPC codeword onto a predetermined bit of the modulation symbol.

A method for mapping of coded bits using a low density parity check (LDPC) code, comprises encoding information bits by using the LDPC code to generate coded bits, sorting the coded bits in accordance with degrees of variable nodes represented by a parity check matrix of the LDPC code, dividing the sorted coded bits into a plurality of groups in accordance with a using modulation scheme, and mapping the coded bits to respective modulation signal points by considering an error resistance of each of the groups and an error resistance of a corresponding one of the modulation signal points.

Apparatus, and an associated method, for allocating communication data for communication in a multi-channel communication system, such as an OFDM system. An adaptive bit, power, and code rate scheme for a sending station that utilizes LDPC codes selects together bit, power, and code rates of data that are to be communicated upon different ones of the channels in manners that optimize a selected performance criteria.

LDPC (Low Density Parity Check) coding and interleaving implemented in multiple-input-multiple-output (MIMO) communication systems. Initially, a novel approach is presented by which a wide variety of irregular LDPC codes may be generated using GRS or RS codes. These irregular LDPC codes can provide better overall performance than regular LDPC codes in terms of providing for lower BER (Bit Error Rate) as a function of SNR (Signal to Noise Ratio). A variety of communication device types are also presented that may employ the error correcting coding using a GRS-based irregular LDPC code, along with appropriately selected interleaving, to provide for even better performance. These communication devices may be implemented to in wireless communication systems including those that comply with the recommendation practices and standards being developed by the IEEE 802.11n Task Group (i.e., the Task Group that is working to develop a standard for 802.11 TGn (High Throughput)).

A transmitting apparatus is provided. The transmitting apparatus includes: an encoder configured to generate a low density parity check (LDPC) codeword by LDPC encoding based on a parity check matrix; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a modulation symbol, wherein the modulator is further configured to map a bit included in a predetermined bit group from among a plurality of bit groups constituting the LDPC codeword onto a predetermined bit of the modulation symbol.

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.

A low density parity check (LDPC) code that is particularly well adapted for hardware implementation of a belief propagation decoder circuit (38) is disclosed. The LDPC code is arranged as a parity check matrix (H) whose rows and columns represent check sums and input nodes, respectively. The parity check matrix is grouped into subsets of check sum rows, in which the column weight is a maximum of one. The decoder circuitry includes a parity check value estimate memory (52). Adders (54) generate extrinsic estimates, from immediately updated input node probability estimates, and the extrinsic estimates are applied to parity check update circuitry (56) for generating new parity check sum value estimates. These parity check sum value estimates are stored back into the memory (52), and after addition with the extrinsic estimates, are stored in a column sum memory (66) of a corresponding bit update circuit (60) as updated probability values for the input nodes.

A transmitting apparatus and a receiving apparatus are provided. The transmitting apparatus includes an encoder configured to generate a low density parity check (LDPC) codeword by performing LDPC encoding, an interleaver configured to interleave the LDPC codeword, and a modulator configured to modulate the interleaved LDPC codeword according to a modulation method to generate a modulation symbol. The interleaver performs interleaving by dividing the LDPC codeword into a plurality of groups, rearranging an order of the plurality of groups in group units, and dividing the plurality of rearranged groups based on a modulation order according to the modulation method.

A transmitting apparatus and a receiving apparatus are provided. The transmitting apparatus includes: an encoder configured to generate a low density parity check (LDPC) codeword by performing LDPC encoding; an interleaver configured to interleave the LDPC codeword; and a modulator configured to modulate the interleaved LDPC codeword according to a modulation method to generate a modulation symbol. The interleaver includes a block interleaver formed of a plurality of columns each comprising a plurality of rows, and the block interleaver is configured to divide the plurality of columns into at least two parts and interleave the LDPC codeword.

A transmitter includes a plurality of encoders configured to receive source bit streams from m information sources, each of the plurality encoders including identical (n,k) low-density parity check (LDPC) codes of code rate r=k / n, where k is a number of information bits and n is codeword length. An interleaver is configured to collect m row-wise codewords from the plurality of encoders, and a mapper is configured to receive m bits at a time column-wise from the interleaver and to determine an M-ary signal constellation point. A modulator is configured to modulate a light source in accordance with the output of the mapper at a transmission rate Rs / r (Rs—the symbol rate, r—the code rate). A receiver and transmission and receiving methods are also disclosed.

Provided is a method for transmitting data in a communication or broadcasting system using a linear block code by generating a codeword by encoding input information data bits, interleaving the codeword; outputting modulation signal-constituting bits by bit-mapping the interleaved codeword using a bit-mapping table predetermined depending on a modulation scheme and a coding rate, outputting a modulation signal by modulating the modulation signal-constituting bits and transmitting the modulation signal via a transmit antenna.

A transmitting apparatus is provided. The transmitting apparatus includes: an encoder configured to generate a low-density parity check (LDPC) codeword by LDPC encoding of input bits based on a parity check matrix including information word bits and parity bits, the LDPC codeword including a plurality of bit groups each including a plurality of bits; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a modulation symbol, wherein the interleaver is further configured to interleave the LDPC codeword such that a bit included in a predetermined bit group from among the plurality of bit groups constituting the LDPC codeword onto a predetermined bit of the modulation symbol.

A transmitting apparatus and a receiving apparatus are provided. The transmitting apparatus includes an encoder configured to generate a low density parity check (LDPC) codeword by performing LDPC encoding, an interleaver configured to interleave the LDPC codeword, and a modulator configured to modulate the interleaved LDPC codeword according to a modulation method to generate a modulation symbol. The interleaver performs interleaving by dividing the LDPC codeword into a plurality of groups, rearranging an order of the plurality of groups in group units, and dividing the plurality of rearranged groups based on a modulation order according to the modulation method.

A digital communication decoding method for low-density parity-check coded messages. The decoding method decodes the low-density parity-check coded messages within a bipartite graph having check nodes and variable nodes. Messages from check nodes are partially hard limited, so that every message which would otherwise have a magnitude at or above a certain level is re-assigned to a maximum magnitude.

A bit interleaver, a bit-interleaved coded modulation (BICM) device and a bit interleaving method are disclosed herein. The bit interleaver includes a first memory, a processor, and a second memory. The first memory stores a low-density parity check (LDPC) codeword having a length of 64800 and a code rate of 4 / 15. The processor generates an interleaved codeword by interleaving the LDPC codeword on a bit group basis. The size of the bit group corresponds to a parallel factor of the LDPC codeword. The second memory provides the interleaved codeword to a modulator for 256-symbol mapping.

The present invention discloses a method for channel coding and modulation mapping in HARQ of the LDPC code, comprising: performing structural LDPC encoding of an information bit sequence with a length of K input by a channel encoder, and sending a generated codeword to a HARQ buffer; rearranging codeword bits of a LDPC HARQ mother code in the HARQ buffer, and sequentially selecting codeword bits to generate a binary sequence of a HARQ packet; mapping codeword bits of the HARQ packet to a constellation, and high-order bits in encoding blocks of the HARQ packet being mapped to high reliability bits in the constellation. The present invention provides the LDPC codeword with the maximal constellation gain, so that the LDPC HARQ channel encoding has the optimal performance.