检索结果-内蒙古大学图书馆

Metrics for syndrome decoding of convolutional codes

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 1996年第12期79卷 22-30页

作者： Tajima, M Department of Electronics and Computer Science Faulty of Engineering Toyama University Toyama Japan 930

This paper derives soft decision metrics for syndrome decoding of convolutional codes. It is shown that, given a received sequence Z, syndrome decoding of convolutional codes can be seen as the problem of finding error sequence E. This sequence may be a possible cause of the syndrome sequence computed from Z and for which the joint probability mu L(Z, E) is maximum. Then the soft decision metrics are derived by actually evaluating the probability mu(Z, E). In particular, a concrete representation of the symbol metrics for an AWGN channel is given. After expressing the derived metric in terms of the inner product, the basic properties of the metric for syndrome decoding are clarified and the similarity between the metrics for syndrome and Viterbi decoding are shown.

关键词： convolutional code syndrome decoding metric soft decision Viterbi decoding

来源：评论

学校读者我要写书评

暂无评论

The Performance of Channel code in OFDM Underwater Acoustic Communication 3

The Performance of Channel Code in OFDM Underwater Acoustic ...

引用

3rd Asia-Pacific Conference on Communications Technology and Computer Science (ACCTCS)

作者： Cheng, Jiting Shenzhen Univ Shenzhen Peoples R China

ISBN: (纸本)9798350310801

With the deepening of research on the ocean, the development of UAC(underwater acoustic communication)has become a hot issue of concern. OFDM and channel coding techniques greatly impact the improvement of UAC. In this paper, channel coding is combined with OFDM to improve the OFDM UACS(underwater acoustic communication system) performance by adding some channel codes. When the coding rate is 1/2, the error correction capability is poor and the error rate is higher than when the coding rate is 1/4. The performance is better when using 1/3 bit rate in Turbo coding compared to 1/2 bit. A performance gain of about 4 dB is obtained using LDPC channel coding. The channel coding and decoding methods of convolutional, Turbo and LDPC codes can significantly improve the performance of OFDM UACS.

关键词： convolutional code Turbo code LDPC code OFDM UAC

来源：评论

学校读者我要写书评

暂无评论

PAPR reduction in WLAN-OFDM system using code repetition technique

PAPR reduction in WLAN-OFDM system using code repetition tec...

引用

Student Conference on Research and Development

作者： Ngajikin, N Fisal, N Yusof, SK Univ Teknol Malaysia Fac Elect Engn Skudai 81310 Johor Malaysia

ISBN: (纸本)0780381734

Orthogonal Frequency Division Multiplexing (OFDM) is the best choice to achieve high data rate transmission in wireless environment. OFDM system shows many favorable property such as high spectral efficiency, robustness to channel fading and immunity to impulse interference. However, there are some obstacles in using OFDM in transmission system, which is in contrast to its advantages. One of the major drawbacks is a very high peak to average power ratio (PAPR) of the OFDM signals. Therefore this paper analyzes the capability of code Repetition (CR) to reduce PAPR in WLAN/OFDM system. The analysis is on a network model designed by WLAN 802.11a standard using Matlab, a mathematical simulation software tool. The network model has been simulated in AWGN channel environment to investigate the behavior of PAPR and BER performance. The proposed technique to reduce PAPR in the WLAN/OFDM channel coding consists of two part;convolutional code and CR. Simulation model with different number of repetition has been analyzed and the results were compared with the conventional coded OFDM (COFDM). The simulation results show that the proposed technique based on CR reduces PAPR down to 5 dB compared to COFDM model.

关键词： OFDM PAPR wireless LAN802.11a code repetition convolutional code

来源：评论

学校读者我要写书评

暂无评论

Improved Cedervall-Johannesson algorithm for computing the distance spectrum of convolutional codes

引用

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 1996年第1期79卷 67-80页

作者： Morii, M Tanigawa, K Sasano, H KINKI UNIV FAC SCI & ENGNHIGASHIOSAKAOSAKA 577JAPAN

In the convolutional code, the minimum free distance is the important parameter to evaluate the performance of the code. Recently, it has been considered necessary, however, for a more strict evaluation of the performance to examine the number of code words with weights around the minimum free distance, i.e., the more general distance spectrum. In general, it is difficult to derive the distance spectrum of a code, including the derivation of the minimum free distance when the code size is enlarged, and it will be significant if it is derived easily. This paper proposes an algorithm that can derive the distance spectrum with a high speed, compared to the method already proposed. The algorithm presented in this paper is an improvement of the fast algorithm for searching trees (FAST) proposed by M. Cedervall and R. Johannesson. The distance spectrum can be derived with approximately one-half the computational complexity compared to FAST.

关键词： convolutional code distance spectrum minimum free distance distance profile FAST

来源：评论

学校读者我要写书评

暂无评论

An Improved Blind Recognition Method for Synchronization Position and Coding Parameters of k/n Rate convolutional codes in a Noisy Environment

引用

IEEE ACCESS 2020年 8卷 171305-171315页

作者： Ding, Yong Huang, Zhiping Zhou, Jing Natl Univ Def Technol Coll Artificial Intelligence Changsha 410073 Peoples R China

In digital communication systems, error correction codes are used to recover data that has been disturbed in a noisy environment. convolutional code is a commonly used error correction code. In non-cooperative communication systems, it is very meaningful to blindly identify the synchronization position and coding parameters of convolutional codes. Existing reference had proposed a blind recognition algorithm for coding parameters of k/n rate convolutional codes in a noisy environment, but it didn't take into account the case where the received code words were not synchronized. In this paper, this problem is improved by using the quasi-correlation between the receive sequence and the check matrix to estimate the synchronization position, while obtaining the check matrix. It implements blind recognition of the synchronization position and coding parameters of k/n rate convolutional codes in a noisy environment. Simulation experimental results show that the improved algorithm in this paper is effective.

关键词： convolutional codes Synchronization Encoding Noise measurement Error correction codes Generators Parity check codes Blind recognition coding parameters convolutional code non-cooperative communication synchronization position

来源：评论

学校读者我要写书评

暂无评论

Linear Systems Defined Over a Finite Field, LQ Theory and convolutional codes

引用

IFAC Proceedings Volumes 1995年第8期28卷 413-418页

作者： J. Rosenthal E.V. York Department of Mathematics University of Notre Dame Notre Dame IN 46556 USA

In this note, we describe several different representations of a convolutional code as a linear system. We then show how this leads one to a natural interpretation of one of the the main problems in coding theory in systems theoretic terms. In particular, we show how the computation of the free distance of a code can be viewed as a modified LQ problem. Dans ce papier nous faisons une description des représentations vairiées d'un code de convolution. Ensuite nous expliquous un problème principal dans la théorie de codage en user un langage d'analyse du système. En particulier nous faisons la démonstration que l'évaluation de la distance d'un code de convolution est un problème modifié du type LQ.

关键词： convolutional code linear quadratic regulator free distance autoregressive systems

来源：评论

学校读者我要写书评

暂无评论

A butterfly structure for rate 2/n convolutional codes

引用

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2006年第2期E89A卷 630-632页

作者： Hsu, CY Kuo, TS Tatung Hosp Grad Inst Commun Engn Taipei 104 Taiwan

In this letter, we propose a butterfly structure for rate 2/n convolutional codes to reduce the computational complexity of Viterbi decoders. By using the butterfly structure, the branch metric computation complexity ... 详细信息

关键词： butterfly structure convolutional code Viterbi decoder

来源：评论

学校读者我要写书评

暂无评论

Decoding mechanism of a scarce state transition-type viterbi decoder for general nonsystematic convolutional codes and its asymptotic behavior on a very noisy channel

引用

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 1995年第7期78卷 11-20页

作者： Tajima, M Member Department of Electronics and Computer Science Faculty of Engineering Toyama University Toyama Japan 930

When a scarce state transition (SST) Viterbi decoder is used to decode general nonsystematic convolutional codes (not included among quick look-in (QLI) codes), metrics based on the maximum a posteriori probability (MAP) estimation method must be computed in order for the main decoder to operate under the criterion of minimizing the decoding error probability. in this case, however, it becomes necessary to extend the original code trellis structure by introducing augmented trellis states in order to incorporate the newly induced correlation among the apparent information sequence. This paper shows that the extended trellis degenerates into the original one as the channel error probability q approaches one-half. By performing an equivalent transformation of metrics, it is shown also that the branch metrics derived based on the MAP estimation method converge to those computed using the conventional one as q approaches one-half.

关键词： convolutional code nonsystematic code Viterbi decoding SST Viterbi decoder MAP estimation methods

来源：评论

学校读者我要写书评

暂无评论

Relative completeness and specifiedness properties of continuous linear dynamical systems

引用

SYSTEMS & CONTROL LETTERS 2010年第11期59卷 695-703页

作者： Lomadze, Vakhtang Govt Coll Univ Abdus Salam Sch Math Sci Lahore Pakistan A Razmadze Math Inst GE-0193 Tbilisi Georgia

The properties of relative completeness and specifiedness are introduced for (continuous) linear dynamical systems. It is shown then that having these two properties and the differentiation-invariance property is necessary and sufficient for a (continuous) linear dynamical system to be represented by means of a linear constant coefficient differential equation. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Dynamical system Flat functions Analytic functions Transfer module Zero initial condition Relatively complete Specified Formal language convolutional code

来源：评论

学校读者我要写书评

暂无评论

Trellis-coded modulation with bit interleaving and iterative decoding

引用

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1999年第4期17卷 715-724页

作者： Li, XD Ritcey, JA Univ Washington Dept Elect Engn Seattle WA 98195 USA

This paper considers bit-interleaved coded modulation (BICM) for bandwidth-efficient transmission using software radios. A simple iterative decoding (ID) method with hard-decision feedback is suggested to achieve better performance. The paper shows that convolutional codes with good Hamming distance property can provide both high diversity order and large free Euclidean distance for BICM-ID, The method offers a common framework for coded modulation over channels with a variety of fading statistics. In addition, BICM-ID allows an efficient combination of punctured convolutional codes and multiphase/level modulation, and therefore provides a simple mechanism for variable-rate transmission.

关键词： bit interleaving convolutional code flat fading iterative decoding Rayleigh fading signal labeling trellis-coded modulation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：