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Construction method of UEP convolutional codes based on conditional weight distributions

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1998年第10期E81A卷 2019-2024页

作者： Yamaguchi, K Watanabe, T Kobayashi, K Univ Electrocommun Dept Comp Sci & Informat Math Chofu Tokyo 1828585 Japan

In this paper, we study unequal error protection (UEP) capabilities of punctured convolutional codes. For constructing the good UEP convolutional codes, the conditional weight distributions of UEP convolutional codes are defined and evaluated. The conditional weight distributions are computed by using the transfer functions of time-varying trellis structures of punctured convolutional codes. The best UEP convolutional codes from the viewpoint of the weight distributions are listed.

关键词： unequal error protection code convolutional code punctured code weight distribution

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On accelerating the computation of weight enumerators for convolutional codes

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2008年第6期7卷 2009-2014页

作者： Au, Edward K. S. Mow, Wai Ho Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Hong Kong Hong Kong Peoples R China

The input-output weight enumerator of a convolutional code characterizes the distance spectrum and allows error probability bounds to be conveniently evaluated. To efficiently compute the weight enumerator, Pimentel recently introduced the so-called state reduction algorithm which has a convenient implementation using existing symbolic mathematical software. In this paper, we propose a dynamic state elimination ordering heuristic to further accelerate the algorithm. As demonstrated by our empirical results, the accelerated state reduction algorithm can achieve impressive complexity savings relative to the original algorithm when applied to compute the weight enumerators and its various truncated versions of convolutional codes with moderate-to-large constraint lengths.

关键词： convolutional code elimination order graph reduction signal flow graph weight enumerator

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Performance of Unequally Punctured convolutional codes

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2009年第8期8卷 3903-3909页

作者： Moon, Hichan Cox, Donald C. Samsung Elect Co Ltd Suwon South Korea Stanford Univ Sch Elect Engn Stanford CA 94305 USA

In practical applications, some coded symbols are unequally punctured for rate matching of terminated convolutional codes. In this letter, performance upper bounds are proposed for a terminated convolutional code punctured with an arbitrary pattern. To obtain the upper bounds, a weight enumerator is defined to represent the relation between the Hamming weight of the coded outputs and that of the selected input information bits. A method is presented to compute the weight enumerator based on a modified trellis diagram. Simulation and numerical analysis show that the proposed bounds are tight to the performance of terminated convolutional codes.

关键词： convolutional code upper bound weight enumerator rate matching

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A Novel Cooperative Communication System Based on Multilevel convolutional codes

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WIRELESS PERSONAL COMMUNICATIONS 2017年第4期95卷 3539-3556页

作者： Aneja, Sakshi Sharma, Sanjay Thapar Univ Dept Elect & Commun Engn Patiala Punjab India

The authors propose a system where single antenna mobile users share antennas to transmit their information cooperatively to the common base station. Each mobile user overhears the coded information transmitted by other users, detects it and further encodes it along with its own information. The encoding is done using multilevel coding scheme with convolutional codes as component codes. The proposed system considers the self-information of user u at level u to reduce complexity while decoding. The coded symbols are mapped to M-ary quadrature amplitude modulation constellation using multi-resolution modulation partitioning. This enables the component codes to be designed for lower order constellation. Each cooperative user transmits multilevel coded symbols to the common base station, thus creating transmit diversity. The base station receives noisy superposition of independent Rayleigh faded signals transmitted by cooperative users and pass it through a multistage decoder. The multistage decoder employs maximum likelihood based Viterbi decoder at each stage to detect the information of each user. The Viterbi decoder applies max-log approximation to reduce the branch metric complexity. The proposed cooperative multilevel coding system outperforms non-cooperative multilevel coding system and is less complex than the existing cooperative multilevel coding system.

关键词： Cooperative diversity Multilevel coding convolutional code Diversity methods Channel coding Rayleigh fading channel

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On the Security of Chaotic convolutional coder

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS 2011年第3期58卷 595-606页

作者： Zhou, Jiantao Au, Oscar C. Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Kowloon Hong Kong Peoples R China Hong Kong Univ Sci & Technol Multimedia Technol Res Ctr Kowloon Hong Kong Peoples R China Hong Kong Univ Sci & Technol Comp Engn CPEG Program Kowloon Hong Kong Peoples R China

This paper evaluates the security of the generalized chaotic convolutional coder, which is a recently proposed joint error-correction and encryption scheme integrating the chaotic encryption into the convolutional coding. Our results show that the probability of fully recovering the pseudorandom sequence (PRS) controlling the chaotic switches is at least 0.289 under known-plaintext attack, if the number of available plaintext/ciphertext pairs p is equal to the constraint length k of the chaotic convolutional coder. In the case that p = k + e, where e is an element of Z(+), we prove that the probability to fully deduce the PRS is lower bounded by 1 - 2(-e). Furthermore, we propose four types of *** attack with different decoding complexities and efficiencies to fully derive the PRS.

关键词： Chaos convolutional code cryptography error correction

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Parallel concatenated convolutional codes from linear systems theory viewpoint

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SYSTEMS & CONTROL LETTERS 2016年第0期96卷 15-22页

作者： Climent, Joan-Josep Herranz, Victoria Perea, Carmen Univ Alacant Dept Matemat Campus St Vicent del RaspeigApartat Correus 99 E-03080 Alacant Spain Univ Miguel Hernandez Ctr Invest Operat Dept Estadist Matemat & Informat Av Univ S-N E-03202 Elche Spain

The aim of this work is to characterize two models of concatenated convolutional codes based on the theory of linear systems. The problem we consider can be viewed as the study of composite linear system from the classical control theory or as the interconnection from the behavioral system viewpoint. In this paper we provide an input-state-output representation of both models and introduce some conditions for such representations to be both controllable and observable. We also introduce a lower bound on their free distances and the column distances. (C) 2016 Elsevier B.V. All rights reserved.

关键词： convolutional code Concatenated convolutional code Free distance Column distances Observable pair Controllable pair Observable convolutional code Input-state-output representation Minimal representation

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Embedded test resource for SoC to reduce required tester channels based on advanced convolutional codes

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2006年第2期55卷 389-399页

作者： Han, YH Li, XW Li, HW Chandra, A Chinese Acad Sci Adv Test Technol Lab Inst Comp Technol Beijing Peoples R China Grad Univ Chinese Acad Sci Beijing Peoples R China Synopsys Inc Mountain View CA 94043 USA

Test resources can be embedded on the chip to reduce required external tester channels. In order to obtain the maximal reduction of tester channels, a single-output encoder based on the check matrix of the (n, n-1, m,3) convolutional code is presented. When the five proposed theorems are satisfied, the encoder can avoid two and any odd erroneous bit cancellations, handle one unknown bit (X-bit), and diagnose one erroneous bit. Two types of encoders are proposed to implement the check matrix of the convolutional code. A large number of X-bits can be tolerated by choosing a proper memory size and weight of the check matrix, which can also be obtained by an optimized input assignment algorithm. In order to get the full diagnostic capability, the proposed encoder can be reconfigured into a simple linear-code-based encoder by adding some additional gates. Experimental results show that the proposed encoder has an acceptable level of X-bits tolerance and a low aliasing probability.

关键词： automatic test equipment convolutional code diagnosis error cancellation masking unknown bits (X-bits)

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Superregular matrices and applications to convolutional codes

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LINEAR ALGEBRA AND ITS APPLICATIONS 2016年 499卷 1-25页

作者： Almeida, P. J. Napp, D. Pinto, R. Univ Aveiro Dept Math CIDMA Ctr Res & Dev Math & Applicat P-3800 Aveiro Portugal

The main results of this paper are twofold: the first one is a matrix theoretical result. We say that a matrix is superregular if all of its minors, that are not trivially zero are nonzero. Given a a x b, a >= b, superregular matrix over a field, we show that if all of its rows are nonzero then any linear combination of its columns, with nonzero coefficients, has at least a b 1 nonzero entries. Secondly, we make use of this result to construct convolutional codes that attain the maximum possible distance for some fixed parameters of the code, namely, the rate and the Forney indices. These results answer some open questions on distances and constructions of convolutional codes posted in the literature [6,9]. (C) 2016 Elsevier Inc. All rights reserved.

关键词： convolutional code Forney indices Optimal code Superregular matrix

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Construction of High Rate Punctured convolutional codes by Exhaustive Search and Partial Search

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2013年第12期E96A卷 2374-2381页

作者： Moriya, Sen Sasano, Hiroshi Kinki Univ Sch Sci & Engn Higashiosaka Osaka 5778502 Japan

We consider two methods for constructing high rate punctured convolutional codes. First, we present the best high rate R = (n-1)/n punctured convolutional codes, for n = 5, 6, ..., 16, which are obtained by exhaustive searches. To obtain the best code, we use a regular convolutional code whose weight spectrum is equivalent to that of each punctured convolutional code. We search these equivalent codes for the best one. Next, we present a method that searches for good punctured convolutional codes by partial searches. This method searches the codes that are derived from rate 1/2 original codes obtained in the first method. By this method, we obtain some good punctured convolutional codes relatively faster than the case in which we search for the best codes.

关键词： convolutional code weight spectrum exhaustive search partial search

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On Low-Complexity Maximum-Likelihood Decoding of convolutional codes

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第12期54卷 5756-5765页

作者： Luo, Jie Colorado State Univ Dept Elect & Comp Engn Ft Collins CO 80523 USA

This letter considers the average complexity of maximum-likelihood (ML) decoding of convolutional codes. ML decoding can be modeled as finding the most probable path taken through a Markov graph. Integrated with the Viterbi algorithm (VA), complexity reduction methods often use the sum log likelihood (SLL) of a Markov path as a bound to disprove the optimality of other Markov path sets and to consequently avoid exhaustive path search. In this letter, it is shown that SLL-based optimality tests are inefficient if one fixes the coding memory and takes the codeword length to infinity. Alternatively, optimality of a source symbol at a given time index can be testified using bounds derived from log likelihoods of the neighboring symbols. It is demonstrated that such neighboring log likelihood (NLL)-based optimality tests, whose efficiency does not depend on the codeword length, can bring significant complexity reduction. The results are generalized to NIL sequence detection in a class of discrete-time hidden Markov systems.

关键词： Coding complexity convolutional code hidden Markov model maximum-likelihood (ML) decoding Viterbi algorithm (VA)

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