• Title/Summary/Keyword: Convolutional code.

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Sufficient Conditions for the Existence of an (n, 1) Mother Code and Its Puncturing Pattern to Generating a Given Convolutional Code (임의의 생성다항식 행렬을 갖는 길쌈부호도 (n, 1) 마더부호의 천공으로 생성 가능한가?)

  • Chung, Habong;Seong, Jinwoo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.4
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    • pp.379-386
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    • 2016
  • Puncturing is the most common way of increasing the rate of convolutional codes. The puncturing process is done to the original code called the mother code by a specific puncturing pattern. In this article, we investigate into the question whether any convolutional code is obtainable by puncturing some (n, 1) mother codes. We present two sufficient conditions for the mother code and the puncturing pattern to satisfy in order that the punctured code is equivalent to the given (N, K) convolutional code.

Analysis Performance of Convolutional Code and Turbo code Using The Semi-Random Interleaver (길쌈부호와 세미 랜덤 인터리버를 사용한 터보코드의 성능분석)

  • 홍성원
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.5 no.6
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    • pp.1184-1189
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    • 2001
  • In this paper was analyzed the performance of turbo code using semi-random interleaver which proposed a reference numbers 11. Which was analyzed comparison the performance of between the current mobile communication system had been used the viterbe decoding algorithm of convolutional code and turbo codes when fixed constraint length. The result was defined that the performance of turbo code rose a $E_{b/}$ $N_{o}$=4.7[㏈] than convolutional code, when convolutional code and turbo code was fixed by BER = 10$^{-4}$ and constraint length K 5.5.5.

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Linear Unequal Error Protection Codes based on Terminated Convolutional Codes

  • Bredtmann, Oliver;Czylwik, Andreas
    • Journal of Communications and Networks
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    • v.17 no.1
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    • pp.12-20
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    • 2015
  • Convolutional codes which are terminated by direct truncation (DT) and zero tail termination provide unequal error protection. When DT terminated convolutional codes are used to encode short messages, they have interesting error protection properties. Such codes match the significance of the output bits of common quantizers and therefore lead to a low mean square error (MSE) when they are used to encode quantizer outputs which are transmitted via a noisy digital communication system. A code construction method that allows adapting the code to the channel is introduced, which is based on time-varying convolutional codes. We can show by simulations that DT terminated convolutional codes lead to a lower MSE than standard block codes for all channel conditions. Furthermore, we develop an MSE approximation which is based on an upper bound on the error probability per information bit. By means of this MSE approximation, we compare the convolutional codes to linear unequal error protection code construction methods from the literature for code dimensions which are relevant in analog to digital conversion systems. In numerous situations, the DT terminated convolutional codes have the lowest MSE among all codes.

On the Existence of the (2,1) Mother Code of (n,n-1) Convolutional Code ((n,n-1) 길쌈부호에 대한 (2,1) 마더부호의 존재)

  • Jang, Hwan-Seok;Chung, Ha-Bong;Seong, Jin-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.4
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    • pp.165-171
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    • 2014
  • The rate of the channel code can be controlled by various methods. Puncturing is one of the methods of increasing the code rate, and the original code before puncturing is called the mother code. Any (n,k) convolutional code is obtainable by puncturing some mother codes, and the process of finding the mother code is necessary for designing the optimum channel decoder. In this paper, we proved that any (n,n-1) convolutional code has (2,1) mother codes regardless of the puncturing pattern and showed that they must be equivalent.

LDPC Generation and Decoding concatenated to Viterbi Decoder based on Sytematic Convolutional Encoder (길쌈부호기를 이용한 LDPC 패리티검사 행렬생성 및 비터비 복호 연계 LDPC 복호기)

  • Lee, Jongsu;Hwang, Eunhan;Song, Sangseob
    • Smart Media Journal
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    • v.2 no.2
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    • pp.39-43
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    • 2013
  • In this paper, we suggest a new technique for WPC parity-check matrix (H-matrix) generation and a corresponding decoding process. The key idea is to construct WPC H-matrix by using a convolutional encoder. It is easy to have many different coderates from a mother code with convolutional codes. However, it is difficult to have many different coderates with LDPC codes. Constructing LDPC Hmatrix based on a convolutional code can easily bring the advantage of convolutional codes to have different coderates. Moreover, both LDPC and convolutional decoding algorithms can be applied altogether in the decoding part. This process prevents the performance degradation of short-length WPC code.

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Performance Analysis of STBC Concatenated Convolutional Code for Improvement of Transmission Reliability (STBC의 전송 신뢰성 향상을 위한 컨볼루션 코드 연계 시스템)

  • Shin, Hyun-jun;Oh, Chang-Heon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.05a
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    • pp.586-589
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    • 2013
  • In this paper, the proposed scheme is STBC system combined with convolutional code to ensure the reliability of data transmission for a high rate wireless communication. In addition, this scheme uses a modified viterbi algorithm in order to get a high system gain when data is transmitted. Because we combine STBC and comvolutional code, the proposed scheme can get a diversity gain of STBC and coding gain of convolutional code at the same time. Unlike existing viterbi docoding algorithm using Hamming distance in order to calculate branch matrix, the modified viterbi algorithm uses Euclidean distance value between received symbol and reference symbol. To analyze the system proposed, it was simulated by changing the constraint length of the convolutional code and the number of transmit and receive antennas of STBC.

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Performance Analysis of Interleaved Super Orthogonal Convolutional Coded UWB-IR System for Wireless Fading Environment (무선 페이딩 환경에 적합한 인터리브된 초직교 길쌈 부호화 UWB-IR 시스템의 성능 분석)

  • Kim Chang-Joong;Lee Ho-Kyoung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.6 s.97
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    • pp.556-562
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    • 2005
  • In this paper, we propose interleaved super-orthogonal convolutional coded ultra wide-band impulse radio(ISOC-UWB-IR) system, and analyze its performance. The proposed system uses interleaver and deinterleaver to decorrelate the temporal correlation of the fading process and to obtain the diversity gain. We also suggest the three types of interleavers, which are pulse-wise interleaver(PI), pulse sub-group-wise interleaver(PSGI), and pulse group-wise interleaver(PGI). Performance analysis result shows that the interleaving scheme, rather than the code rate of super orthogonal convolutional code(SOC) encoder, affects the performance for the Rayleigh fading channel.

Blind Block Deinterleaving using Convolutional Code Reconstruction Method (길쌈 부호 복원 기법을 이용한 블라인드 블록 디인터리빙)

  • Jeong, Jin-Woo;Yoon, Dong-Weon;Park, Cheol-Sun;Yun, Sang-Bom;Lee, Sang-Hyeon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.9
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    • pp.10-16
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    • 2011
  • Interleaving is applied to prevent from exceeding the error-correction capability of channel code. At the receiver, burst errors are converted into random errors after deinterleaving, so the error-correction capability of channel code is not exceeded. However, when a receiver does not have any information on parameters used at an interleaver, interleaving can be seen as an encryption with some pattern. In this case, deinterleaving becomes complicated. In the field of blind deinterleaving, there have recently been a number of researches using linearity of linear block code. In spite of those researches, since the linearity is not applicable to a convolutional code, it is difficult to estimate parameters as in a linear block code. In this paper, we propose a method of blind block deinterleaving using convolutional code reconstruction method.

Performance analysis on the complexity of turbo code with short frame sizes (프레임 크기가 작은 터보 코드의 복잡도에 대한 성능 분석)

  • Kim, Yeun-Goo;Ko, Young-Hoon;Kim, Nam
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.7A
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    • pp.1046-1051
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    • 1999
  • It is well known that Parallel Concatenated Convolutional Codes(turbo codes) has a good performance for long block sizes. This thesis has analyzed the performance of turbo code which is based on voice or control frames with short frame sizes in the future mobile communication system. Also, at the similar decoding complexity, the performance of turbo code and convolutional codes in the speech/control frames, and the applicability of this system are considered. As a result, turbo code in short frame sizes present the performance of a BER of $10^{-3}$ or more over 3 iterations in the future mobile communication system. However, at a BER of $10^{-3}$ , if the same complexity is considered, the performance of rate 1/2 turbo code with K = 5 is better than that of convolutional code with K = 9 at low $E_b/N_0$, and the performance of turbo code with K = 3 is superior to that of convolutional code with K = 7. Rate 1/3 turbo code with K = 3 and 5 have similar to performance of rate 1/2 turbo code.

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Performance Improvement of Multi-Code CDMA Systems Using Bi-Orthogonal Modulation (Bi-Orthogonal 변조를 이용한 Multi-Code CDMA 시스템의 성능 개선)

  • 한재광;신요안
    • Proceedings of the IEEK Conference
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    • 2000.06a
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    • pp.29-32
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    • 2000
  • In this paper, we present an extension of the multi-code CDMA (code division multiple access) systems based on bi-orthogonal modulation by employing a convolutional encoder and an interleaver before serial-to-parallel conversion in the modulator. Bandwidth expansion by the convolutional encoder can be compensated for by the bi-orthogonal modulation, and the interleaver in the system scrambles the convolutionally encoded data bits so that, after serial-to-parallel conversion, each code channel conveys those bits far apart in time. The result is that the proposed system with several order of magnitude less implementational complexity, achieves quite close performance of the conventional systems comprised of Walsh modulation and multiple convolutional encoders and interleavers in all the code channels.

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