Seho Myung - Academia.edu (original) (raw)

Papers by Seho Myung

IEEE Access, Dec 31, 2022

La presente invention concerne procede de generation de matrices de verification de parite d'... more La presente invention concerne procede de generation de matrices de verification de parite d'un bloc de code LDPC. Ce procede consiste a determiner une taille de matrice de verification de parite a partir d'un debit de codage et d'une longueur de mot de code, a diviser une matrice de verification de parite de la taille determinee en un certain nombre de blocs predetermines, a classer ces blocs en blocs correspondant a la partie information, a agencer des matrices de permutation en blocs predetermines provenant de blocs classes dans la premiere partie de parite, a agencer des matrices d'identite strictement triangulaire inferieure en blocs predetermines provenant des blocs classes dans la seconde de partie de parite et, a agencer les matrices de permutation dans les blocs classes dans la partie information de sorte qu'une longueur de cycle minimum soit maximisee et que des valeurs de ponderation soient irregulieres sur un graphe de facteurs du bloc de code LDPC.

A method of encoding a channel in a communication system using a check code deparidad low density... more A method of encoding a channel in a communication system using a check code deparidad low density (LDPC), comprising the steps of: reading a check matrix stored parity; and perform LDPC encoding a signal using the check matrix stored parity; wherein the check matrix parity has N1 columns, where N1 are 16,200 columns, the matrix decomprobacion parity has an information part and a data part, wherein the part of informaciontiene K1 columns, where K 1 is 9720, and the parity part has a dual diagonal shape and (N1-K1) columns, where (N1-K1) is 6480, wherein the information part comprises a plurality of column groups, teniendocada group of columns M1 columns, where M1 is 360 and the number of column groups is K 1 / M1 where K1 / M1es 27; wherein a code rate is 3/5, sequences position '1's in the column in the 0th group ** ** Formula

In this paper, we propose a method for avoiding high error floors of low-density parity-check (LD... more In this paper, we propose a method for avoiding high error floors of low-density parity-check (LDPC) codes for broadcasting systems. Harmful trapping sets which may introduce high error floors are investigated and removed by using the proposed method. Applying this method, the error floor of a DVB-S2 LDPC code is dramatically lowered by modifying only two numbers in its sequence representation.

arXiv (Cornell University), Jan 8, 2019

In this paper, we investigate the fundamentals of puncturing and shortening for polar codes, base... more In this paper, we investigate the fundamentals of puncturing and shortening for polar codes, based on binary domination which plays a key role in polar code construction. We first prove that the orders of encoder input bits to be made incapable (by puncturing) or to be shortened are governed by binary domination. In particular, we show that binary domination completely determines incapable or shortened bit patterns for polar codes, and that all the possible incapable or shortened bit patterns can be identified. We then present the patterns of the corresponding encoder output bits to be punctured or fixed, when the incapable or shortened bits are given. We also demonstrate that the order and the pattern of puncturing and shortening for polar codes can be aligned. In the previous work on the rate matching for polar codes, puncturing of encoder output bits begins from a low-indexed bit, while shortening starts from a high-indexed bit. Unlike such a conventional approach, we show that encoder output bits can be punctured from high-indexed bits, while keeping the incapable bit pattern exactly the same. This makes it possible to design a unified circular-buffer rate matching (CB-RM) scheme that includes puncturing, shortening, and repetition.

arXiv (Cornell University), Nov 22, 2022

In the conventional successive cancellation (SC) decoder for polar codes, all the future bits to ... more In the conventional successive cancellation (SC) decoder for polar codes, all the future bits to be estimated later are treated as random variables. However, polar codes inevitably involve frozen bits, and their concatenated coding schemes also include parity bits (or dynamic frozen bits) causally generated from the past bits estimated earlier. We refer to the frozen and parity bits located behind a target decoding bit as its future constraints (FCs). Although the values of FCs are deterministic given the past estimates, they have not been exploited in the conventional SC-based decoders, not leading to optimality. In this paper, with a primary focus on the binary erasure channel (BEC), we propose SC-check (SCC) and belief propagation SCC (BP-SCC) decoding algorithms in order to leverage FCs in decoding. We further devise an improved tree search technique based on stack-based backjumping (SBJ) to solve dynamic constraint satisfaction problems (CSPs) formulated by FCs. Over the BEC, numerical results show that a combination of the BP-SCC algorithm and the SBJ tree search technique achieves the erasure recovery performance close to the dependence testing (DT) bound, a bound of achievable finite-length performance.

2022 IEEE International Symposium on Information Theory (ISIT)

IEEE Transactions on Communications, 2022

This paper presents density evolution (DE) techniques based on reciprocal channel approximation (... more This paper presents density evolution (DE) techniques based on reciprocal channel approximation (RCA) for general bit-interleaved coded modulation (BICM) systems. The original RCA-based DE (RCA-DE) technique is implemented under the assumption of binary-input additive white Gaussian noise channels (BI-AWGNCs). In BICM systems, however, <inline-formula> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula>-ary modulation schemes are generally used, and they can be regarded as to be a parallel transmission of <inline-formula> <tex-math notation="LaTeX">$\log _{2} M$ </tex-math></inline-formula> bits. Thus, <inline-formula> <tex-math notation="LaTeX">$\log _{2} M$ </tex-math></inline-formula> separate bit-level channels, which are not Gaussian equivalent, need to be considered. In order to extend the conventional RCA-DE technique to BICM systems, we first establish a model of protograph BICM ensembles. Two methods are developed based on the bit error rate (BER) and the BICM capacity in order to find a corresponding BI-AWGNC that models each of the bit-level channels. Using these methods, we implement the protograph RCA-DE technique for BICM systems and show that it achieves an accurate estimation. As a practical application of the proposed RCA-DE method, we design bit interleavers in order to achieve better BICM performance in the 3GPP New Radio (NR) LDPC coding system. Numerical results show that performance gain of up to 0.3 dB is consistently achieved over a wide range of parameter values.

IEEE Transactions on Broadcasting, 2019

Recently, low-density parity-check (LDPC) codes have been adopted in Advanced Television Systems ... more Recently, low-density parity-check (LDPC) codes have been adopted in Advanced Television Systems Committee 3.0 and 3rd Generation Partnership Project 5G standards. In this paper, we present their structures in detail. They are delicately designed, based on the structures of quasi-cyclic LDPC codes and multi-edge type LDPC codes. The differences in their base matrices and parity-check matrices used in both standards are highlighted from the viewpoint of the distinction between broadcasting and cellular communication systems. Numerical results show that they are very competitive in their respective areas.

IEEE Transactions on Broadcasting, 2016

The physical layer [layer-1 (L1)] signaling (L1 signaling) of Advanced Television Systems Committ... more The physical layer [layer-1 (L1)] signaling (L1 signaling) of Advanced Television Systems Committee (ATSC) 3.0 is studied. In the new digital broadcasting system, ATSC 3.0, L1 signaling is designed to be more efficient but still robust compared with preceding standards such as DVB-T2. We introduce the error protection scheme of ATSC 3.0 in detail. Especially advanced methods newly employed in ATSC 3.0 are investigated with regard to its purpose and benefit in comparison to conventional DVB-T2.

IEEE Access, Dec 31, 2022

La presente invention concerne procede de generation de matrices de verification de parite d'... more La presente invention concerne procede de generation de matrices de verification de parite d'un bloc de code LDPC. Ce procede consiste a determiner une taille de matrice de verification de parite a partir d'un debit de codage et d'une longueur de mot de code, a diviser une matrice de verification de parite de la taille determinee en un certain nombre de blocs predetermines, a classer ces blocs en blocs correspondant a la partie information, a agencer des matrices de permutation en blocs predetermines provenant de blocs classes dans la premiere partie de parite, a agencer des matrices d'identite strictement triangulaire inferieure en blocs predetermines provenant des blocs classes dans la seconde de partie de parite et, a agencer les matrices de permutation dans les blocs classes dans la partie information de sorte qu'une longueur de cycle minimum soit maximisee et que des valeurs de ponderation soient irregulieres sur un graphe de facteurs du bloc de code LDPC.

A method of encoding a channel in a communication system using a check code deparidad low density... more A method of encoding a channel in a communication system using a check code deparidad low density (LDPC), comprising the steps of: reading a check matrix stored parity; and perform LDPC encoding a signal using the check matrix stored parity; wherein the check matrix parity has N1 columns, where N1 are 16,200 columns, the matrix decomprobacion parity has an information part and a data part, wherein the part of informaciontiene K1 columns, where K 1 is 9720, and the parity part has a dual diagonal shape and (N1-K1) columns, where (N1-K1) is 6480, wherein the information part comprises a plurality of column groups, teniendocada group of columns M1 columns, where M1 is 360 and the number of column groups is K 1 / M1 where K1 / M1es 27; wherein a code rate is 3/5, sequences position '1's in the column in the 0th group ** ** Formula

In this paper, we propose a method for avoiding high error floors of low-density parity-check (LD... more In this paper, we propose a method for avoiding high error floors of low-density parity-check (LDPC) codes for broadcasting systems. Harmful trapping sets which may introduce high error floors are investigated and removed by using the proposed method. Applying this method, the error floor of a DVB-S2 LDPC code is dramatically lowered by modifying only two numbers in its sequence representation.

arXiv (Cornell University), Jan 8, 2019

In this paper, we investigate the fundamentals of puncturing and shortening for polar codes, base... more In this paper, we investigate the fundamentals of puncturing and shortening for polar codes, based on binary domination which plays a key role in polar code construction. We first prove that the orders of encoder input bits to be made incapable (by puncturing) or to be shortened are governed by binary domination. In particular, we show that binary domination completely determines incapable or shortened bit patterns for polar codes, and that all the possible incapable or shortened bit patterns can be identified. We then present the patterns of the corresponding encoder output bits to be punctured or fixed, when the incapable or shortened bits are given. We also demonstrate that the order and the pattern of puncturing and shortening for polar codes can be aligned. In the previous work on the rate matching for polar codes, puncturing of encoder output bits begins from a low-indexed bit, while shortening starts from a high-indexed bit. Unlike such a conventional approach, we show that encoder output bits can be punctured from high-indexed bits, while keeping the incapable bit pattern exactly the same. This makes it possible to design a unified circular-buffer rate matching (CB-RM) scheme that includes puncturing, shortening, and repetition.

arXiv (Cornell University), Nov 22, 2022

In the conventional successive cancellation (SC) decoder for polar codes, all the future bits to ... more In the conventional successive cancellation (SC) decoder for polar codes, all the future bits to be estimated later are treated as random variables. However, polar codes inevitably involve frozen bits, and their concatenated coding schemes also include parity bits (or dynamic frozen bits) causally generated from the past bits estimated earlier. We refer to the frozen and parity bits located behind a target decoding bit as its future constraints (FCs). Although the values of FCs are deterministic given the past estimates, they have not been exploited in the conventional SC-based decoders, not leading to optimality. In this paper, with a primary focus on the binary erasure channel (BEC), we propose SC-check (SCC) and belief propagation SCC (BP-SCC) decoding algorithms in order to leverage FCs in decoding. We further devise an improved tree search technique based on stack-based backjumping (SBJ) to solve dynamic constraint satisfaction problems (CSPs) formulated by FCs. Over the BEC, numerical results show that a combination of the BP-SCC algorithm and the SBJ tree search technique achieves the erasure recovery performance close to the dependence testing (DT) bound, a bound of achievable finite-length performance.

2022 IEEE International Symposium on Information Theory (ISIT)

IEEE Transactions on Communications, 2022

This paper presents density evolution (DE) techniques based on reciprocal channel approximation (... more This paper presents density evolution (DE) techniques based on reciprocal channel approximation (RCA) for general bit-interleaved coded modulation (BICM) systems. The original RCA-based DE (RCA-DE) technique is implemented under the assumption of binary-input additive white Gaussian noise channels (BI-AWGNCs). In BICM systems, however, <inline-formula> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula>-ary modulation schemes are generally used, and they can be regarded as to be a parallel transmission of <inline-formula> <tex-math notation="LaTeX">$\log _{2} M$ </tex-math></inline-formula> bits. Thus, <inline-formula> <tex-math notation="LaTeX">$\log _{2} M$ </tex-math></inline-formula> separate bit-level channels, which are not Gaussian equivalent, need to be considered. In order to extend the conventional RCA-DE technique to BICM systems, we first establish a model of protograph BICM ensembles. Two methods are developed based on the bit error rate (BER) and the BICM capacity in order to find a corresponding BI-AWGNC that models each of the bit-level channels. Using these methods, we implement the protograph RCA-DE technique for BICM systems and show that it achieves an accurate estimation. As a practical application of the proposed RCA-DE method, we design bit interleavers in order to achieve better BICM performance in the 3GPP New Radio (NR) LDPC coding system. Numerical results show that performance gain of up to 0.3 dB is consistently achieved over a wide range of parameter values.

IEEE Transactions on Broadcasting, 2019

Recently, low-density parity-check (LDPC) codes have been adopted in Advanced Television Systems ... more Recently, low-density parity-check (LDPC) codes have been adopted in Advanced Television Systems Committee 3.0 and 3rd Generation Partnership Project 5G standards. In this paper, we present their structures in detail. They are delicately designed, based on the structures of quasi-cyclic LDPC codes and multi-edge type LDPC codes. The differences in their base matrices and parity-check matrices used in both standards are highlighted from the viewpoint of the distinction between broadcasting and cellular communication systems. Numerical results show that they are very competitive in their respective areas.

IEEE Transactions on Broadcasting, 2016

The physical layer [layer-1 (L1)] signaling (L1 signaling) of Advanced Television Systems Committ... more The physical layer [layer-1 (L1)] signaling (L1 signaling) of Advanced Television Systems Committee (ATSC) 3.0 is studied. In the new digital broadcasting system, ATSC 3.0, L1 signaling is designed to be more efficient but still robust compared with preceding standards such as DVB-T2. We introduce the error protection scheme of ATSC 3.0 in detail. Especially advanced methods newly employed in ATSC 3.0 are investigated with regard to its purpose and benefit in comparison to conventional DVB-T2.