記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electronics, Information and Communications Engineers (IEICE)  

DOI： 10.1587/transfun.2021tap0008

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.23919/icact51234.2021.9370400

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/globecom42002.2020.9322258

担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/globecom38437.2019.9013593

担当区分：筆頭著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/isit.2019.8849304

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1587/transfun.E101.A.2135

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1587/transfun.E101.A.2125

担当区分：筆頭著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/itw.2018.8613495

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.23919/isita.2018.8664339

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.23919/isita.2018.8664318

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.23919/isita.2018.8664309

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.23919/isita.2018.8664369

掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electronics, Information and Communication, Engineers, IEICE  

Index-less Indexed Flash Code (ILIFC) is a coding scheme for flash memories in which one bit of a data sequence is stored in a slice consisting of several cells but the index of the bit is stored implicitly. Although several modified ILIFC schemes have been proposed, inthis research we consider an ILIFC with inversion cells (I-ILIFC). The I-ILIFC reduces the total number of cell level changes at each write request. Computer simulation is used to show that the I-ILIFC improves the average performance of the ILIFC in many cases. This paper presents our derivation of the lower bound on the number of write operations by I-ILIFC and shows that the worst-case performance of the I-ILIFC is better than that of the ILIFC if the code length is sufficiently large. Additionally, we consider another lower bound thereon. The results show that the threshold of the code length that determines whether the I-ILIFC improves the worst-case performance of the ILIFC is lower than that in the first lower bound.

DOI： 10.1587/transfun.E100.A.2662

Scopus

担当区分：筆頭著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/itw.2017.8277982

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/itw.2017.8277956

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/isit.2017.8006604

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/isit.2017.8006976

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：INST ENGINEERING TECHNOLOGY-IET  

A family of rate-compatible capacity-approaching codes is obtained by spatially coupling multiple identical copies of rate-compatible base codes. The base code consists of a given regular low-density parity-check (LDPC) code and a parameter-adjustable repeat-accumulate (RA) extension. The RA-extension repeatedly accumulates all of the variable nodes of the given LDPC code by q + 1 times to generate q + 1 blocks of accumulated nodes, in which all of the accumulated variable nodes in the first q blocks and the -fractional accumulated variable nodes in the last block are transmitted. The spatially coupled versions of the base codes, called RA-extended spatially coupled LDPC (SC-LDPC) codes, achieve arbitrary rates by simply adjusting parameters q and , and thus they are rate-compatible. The potential thresholds of the base code ensembles are calculated to predict the iterative decoding performance of the proposed RA-extended SC-LDPC codes. Numerical results and simulations show that the authors' proposed rate-compatible codes are capacity-approaching over binary erasure channels.

DOI： 10.1049/iet-com.2015.1031

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

A form of spatially coupled codes is obtained by coupling multiple identical concatenated codes consisting of a block outer code (a repetition code followed by a single-parity code) concatenated with a convolutional inner code of infinite impulse response. The coupling operation involves only the outer code of the block-convolutional concatenated code. Because of the simple outer code and diverse inner code, the proposed codes have simple encoding implementation and flexible designation space. Extrinsic information functions are used to analyze the belief propagation (BP) thresholds of the proposed codes over an additive white Gaussian noise channel. The numerical results demonstrate that the proposed codes have better BP threshold and error correction performances than conventional spatially coupled repeat-accumulate codes and spatially coupled low-density parity-check codes. In particular, the proposed codes with a rate of about 0.5 and length of 15628 have a bit-error-rate (BER) of 10(-5) at Eb/N0 of 1.13 dB that is less than 1 dB away from the Shannon limit.

DOI： 10.1109/LCOMM.2015.2497242

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In this paper, we evaluate the input-parity weight distribution of terminated recursive systematic convolutional (RSC) codes. On the trellis of convolutional codes, the paths are ended at any state of the code after information sequence input. The number of paths ended at the zero-state can be described by the number of error events which can easily be obtained. For the paths at non-zero state of the code after information sequence input, we equivalent the input-parity weight distribution of these paths to input-parity weight distribution of some sets of error events. Using the number of weight distribution that have ended at each of the states, we provide the input-parity weight distribution of terminated RSC codes. Our algorithm provides input-parity weight distributions for all input weights and it is a precise result for terminated RSC codes that is necessary for the performance analysis of code.

Web of Science

掲載種別：研究論文（学術雑誌）  

2016. (Poster)

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

A coding scheme of (k + 1)-ary error-correcting signature codes for a noisy multiple-access adder channel is proposed. Given a signature matrix A and a difference matrix D = D+ - D- a priori, a larger signature matrix is obtained by replacing each element in the Hadamard matrix with A, or D+, or D- depending on the values of the elements and their locations in the Hadamard matrix. The set of rows in the proposed matrix gives an error-correcting signature code. Introducing a difference matrix makes it possible to construct an error-correcting signature code whose sum rate is increased with an increase in the order of the Hadamard matrix. Either binary or non-binary signature codes are constructed when the pairs of matrices A and D are given.

DOI： 10.1109/TIT.2015.2479219

Web of Science

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE Computer Society  

We propose the construction of rate-compatible spatially coupled low-density parity-check (SC-LDPC) codes. For a given high-rate SC-LDPC mother code, a family of low-rate member codes can be obtained by extending the protogragh of the mother code with repeat-accumulation (RA). Rate compatibility is obtained by adjusting the RA-extension parameters. Continuous code rate is achieved without extra cost. Density evolution analysis shows that the iterative decoding thresholds of all the member codes of the rate-compatible family are very close to the Shannon limits over the binary erasure channels.

DOI： 10.1109/ISTC.2014.6955091

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

A multi-user coding scheme is proposed for a noisy multiple-access adder channel. Given T-a-user delta(a)-decodable k-ary code A and T-d-subset delta(d)-decodable difference set D with its two component sets D+ and D a priori, larger error-correcting multi-user code C is obtained. Introducing difference set D makes the total rate of generated code C higher than that of conventional code.

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

A recursive construction of (k+1)-ary error-correcting signature code is proposed to identify users for MAAC, even in the presence of channel noise. The recursion is originally from a trivial signature code. In the (j-1)-th recursion, from a signature code with minimum distance of 2(j-2), a longer and larger signature code with minimum distance of 2(J-1) is obtained. The decoding procedure of signature code is given, which consists of error correction and user identification.

DOI： 10.1587/transfun.E96.A.2368

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Physical-layer network coding with binary turbo coding in a two-way relay channel is considered. A two-user turbo decoding scheme is proposed with a simplified sum trellis. For two-user iterative decoding at a relay, the component decoder with its simplified sum trellis decodes the superimposed signal to the arithmetic sum of two users' messages. The simplified sum trellis is obtained by removing one of the states in a pair of mutual symmetrical states from a sum trellis. This removal reduces the decoding complexity to half of that with the sum trellis, and does not degrade decoding performance over AWGN channel since two output sequences from the pair of mutual symmetrical states are the same.

DOI： 10.1587/transcom.E96.B.73

Web of Science

掲載種別：研究論文（学術雑誌）  

2013.

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

We propose a generalized construction scheme of error-correcting signature code. We form a signature matrix whose rows become the non-zero codewords of the signature code. In the coding scheme, a signature matrix is obtained from a Hadamard matrix by replacing every element by an initial signature matrix or its associated matrix depending on the element's binary value. The proposed code has longer length, higher decodability, and larger cardinality. In this coding scheme, the initial signature matrix is in a general form and can be a signature matrix of any initial signature code. Different initial matrices provide different error-correcting signature codes, including conventional codes. This general form makes it possible to obtain error-correcting signature codes with a higher sum rate than conventional codes. © 2013 IEEE.

DOI： 10.1109/ISIT.2013.6620508

Scopus

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Signature code is for user identification in a T-user multiple-access communication system with multiple-access adder channel. In the system, each user is assigned to two codewords and the common zero codeword is shared among all T users. A decoding rule for a non-binary signature code is proposed. For the non-binary signature code, a matrix is introduced whose product with Hadamard matrix is a block diagonal matrix. The block diagonal matrix guarantees the decoding of the non-binary signature code. The procedure of error correction and user identification is given for the system.

Web of Science

DOI： 10.1109/globecom42002.2020.9322258

記述言語：英語   出版者・発行元：電子情報通信学会  

CiNii Books

担当区分：筆頭著者   記述言語：英語   出版者・発行元：電子情報通信学会  

CiNii Books

記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

We survey error-correcting signature codes for multiple-access adder channel. First, we give the recursive construction of a (k+1)-ary signature code with minimum distance 2^<j-1>. Also we give the decoding rule for the signature code, consisting of error correction and user identification. Second, we give the construction of binary error-correcting signature code. By using a Hadamard matrix of order n, we construct a binary signature code with the minimum distance of n/2. These (k+1)-ary and binary codes are used to identify users through the multiple-access adder channel, even in the presence of channel noise.

CiNii Books

記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Signature code is for user identification in a T-user multiple-access communication system with multiple-access adder channel. In the system, each user is assigned to two codewords and the common zero codeword is shared among all T users. A decoding rule for a non-binary signature code is proposed. For the non-binary signature code, a matrix is introduced whose product with Hadamard matrix is a block diagonal matrix. The block diagonal matrix guarantees the decoding of the non-binary signature code. The procedure of error correction and user identification is given for the system.

CiNii Books

記述言語：英語  

会議種別：口頭発表（一般）  

会議種別：口頭発表（一般）  

会議種別：口頭発表（招待・特別）  

会議種別：口頭発表（一般）