Methods and apparatus are provided for controlling wireless signal transmissions, wherein problematic symbol patterns are relocated to an erasure region of a data packet prior to erasure encoding and transmission. Relocating the problematic symbol patterns is done so that, when the resulting erasure codeword is punctured and transmitted, the problematic patterns are not transmitted. Yet, those patterns can be restored by the decoder at the receiving device using an erasure decoder in accordance with erasure decoding techniques, e.g., punctured low-density parity-check (LDPC) decoding techniques. In this manner, problematic symbol patterns that may be corrupting during transmission due to noise are removed (punctured) prior to transmission, then restored by the decoder during decoding.

The present technology relates to a data processing device and a data processing method which can ensure high communication quality in data transmission using LDPC codes. In group-wise interleaving, an LDPC code having a code length N of 64800 bits and a coding rate r of 11/15 is interleaved in a unit of a bit group of 360 bits. In group-wise deinterleaving, a sequence of bit groups of the LDPC code which has been subjected to the group-wise interleaving is returned to an original sequence. The present technology can be applied to, for example, a case in which data transmission is performed using LDPC codes.

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 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.

A decoding method of low-density parity-check (LDPC) codes based on partial average residual belief propagation includes the following steps: S1: calculating a size of a cluster π in a protograph based on a code length m and a code rate of a target codeword; S2: pre-computing an edge residual r.sub.c.sub.i.sub..fwdarw.v.sub.j corresponding to each edge from a variable node to a check node in a check matrix H; S3: calculating, based on π, a partial average residual (PAR) value corresponding to each cluster in the check matrix H; S4: sorting m/π clusters in descending order of corresponding PAR values, and updating an edge with a largest edge residual in each cluster; S5: updating edge information m.sub.c.sub.i.sub..fwdarw.v.sub.i from a check node c.sub.i to a variable node v.sub.j, and then updating a log-likelihood ratio (LLR) value L(v.sub.j) of the variable node v.sub.j; and S6: after the updating, making a decoding decision.

The present invention provides an apparatus of transmitting broadcast signals, the apparatus including, an encoder for encoding service data, a frame builder for building at least one signal frame by mapping the encoded service data, a modulator for modulating data in the built at least one signal frame by an Orthogonal Frequency Division Multiplexing, OFDM, scheme and a transmitter for transmitting the broadcast signals having the modulated data.

A transmitter is provided. The transmitter includes: an outer encoder configured to encode input bits to generate outer-encoded bits including the input bits and parity bits; a zero padder configured to generate a plurality of bit groups each of which is formed of a same number of bits, maps the outer-encoded bits to some of the bits in the bit groups, and pads zero bits to remaining bits in the bit groups, based on a predetermined shortening pattern, thereby to constitute Low Density Parity Check (LDPC) information bits; and an LDPC encoder configured to encode the LDPC information bits, wherein the remaining bits in which zero bits are padded include some of the bit groups which are not sequentially disposed in the LDPC information bits.

A decoding method of low-density parity-check (LDPC) codes based on partial average residual belief propagation includes the following steps: S1: calculating a size of a cluster π in a protograph based on a code length m and a code rate of a target codeword; S2: pre-computing an edge residual r.sub.c.sub.i.sub..fwdarw.v.sub.j corresponding to each edge from a variable node to a check node in a check matrix H; S3: calculating, based on π, a partial average residual (PAR) value corresponding to each cluster in the check matrix H; S4: sorting m/π clusters in descending order of corresponding PAR values, and updating an edge with a largest edge residual in each cluster; S5: updating edge information m.sub.c.sub..fwdarw.v.sub.i from a check node c.sub.i to a variable node v.sub.j, and then updating a log-likelihood ratio (LLR) value L(v.sub.j) of the variable node v.sub.j; and S6: after the updating, making a decoding decision.

According to certain embodiments, a method is provided for fast layered decoding for Low-density Parity-Check (LDPC) codes with a Parity-Check Matrix (PCM) that includes at least a first layer and a second layer. The method includes reading, from a memory, Variable Node (VN) soft information, wherein the VN soft information is associated with a message from a VN to a Check Node (CN) of the second layer of the PCM. A new CN to VN message is calculated from the CN of the second layer of the PCM. New VN soft information is calculated for the VN. The new VN soft information is calculated based on the VN soft information and a new CN to VN message from a CN of the first layer to the VN and an old CN to VN message from the CN of the first layer to the VN such that the updating of new VN soft information is delayed by at least one layer. The fast layered decoding has lower decoding latency and utilizes the decoding hardware more efficiently than standard layered decoding techniques. This may be achieved by keeping the memory access and processing hardware units active simultaneously to avoid excess decoding latency. More specifically, certain embodiments may carry out memory access and computation process simultaneously, without any effort to make the row layers mutually orthogonal to each other. Another technical advantage may be that the proposed decoding algorithm adjusts the LLRs to partially account for deviations from the layered decoding due to non-orthogonal rows.

A method for generating a code, a method for encoding and decoding data, and an encoder and a decoder performing the encoding and decoding are disclosed. In an embodiment, a method for lifting a child code from a base code for encoding and decoding data includes determining a single combination of a circulant size, a lifting function, and a labelled base matrix PCM according to an information length and a code rate using data stored in a lifting table. The lifting table was defined at a code generation stage. The method also includes calculating a plurality of shifts for the child code. Each shift is calculated by applying the lifting function to the labelled base matrix PCM with a defined index using the circulant size and using the derived child PCM to encode or decode data.