• Title, Summary, Keyword: decoding

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Combined Horizontal-Vertical Serial BP Decoding of GLDPC Codes with Binary Cyclic Codes (이진 순환 부호를 쓰는 GLDPC 부호의 수평-수직 결합 직렬 복호)

  • Chung, Kyuhyuk
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.10
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    • pp.585-592
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    • 2014
  • It is well known that serial belief propagation (BP) decoding for low-density parity-check (LDPC) codes achieves faster convergence without any increase of decoding complexity per iteration and bit error rate (BER) performance loss than standard parallel BP (PBP) decoding. Serial BP (SBP) decoding, such as horizontal SBP (H-SBP) decoding or vertical SBP (V-SBP) decoding, updates check nodes or variable nodes faster than standard PBP decoding within a single iteration. In this paper, we propose combined horizontal-vertical SBP (CHV-SBP) decoding. By the same reasoning, CHV-SBP decoding updates check nodes or variable nodes faster than SBP decoding within a serialized step in an iteration. CHV-SBP decoding achieves faster convergence than H-SBP or V-SBP decoding. We compare these decoding schemes in details. We also show in simulations that the convergence rate, in iterations, for CHV-SBP decoding is about $\frac{1}{6}$ of that for standard PBP decoding, while the convergence rate for SBP decoding is about $\frac{1}{2}$ of that for standard PBP decoding. In simulations, we use recently proposed generalized LDPC (GLDPC) codes with binary cyclic codes (BCC).

The Effects of Listening Comprehension and Decoding Skills on Spelling Achievement of EFL Freshman Students

  • Al-Jarf, Reima Sado
    • English Language & Literature Teaching
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    • v.11 no.2
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    • pp.35-50
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    • 2005
  • Thirty six EFL freshman students at the College of Languages and Translation, King Saud University, Riyadh, Saudi Arabia were given a dictation, a listening comprehension test and a decoding test. The purpose of the study was to find out whether EFL freshmen students' spelling ability correlates with their listening comprehension and decoding skills. Data analysis showed that the typical EFL freshman student misspelled 41.5% of the words on the dictation, gave 49.5% correct responses on the listening comprehension test, and 52% correct responses on the decoding test. The median and mean scores showed that the subjects' spelling, listening and decoding achievement is low, which implied that the subjects were having spelling, listening comprehension and decoding difficulties. The students' spelling errors and correct listening comprehension and decoding responses revealed strong correlations between spelling ability, listening comprehension and decoding skills. This means that good spelling ability in EFL is related to good listening comprehension and good decoding skills. The better the listening comprehension and decoding abilities, the fewer the spelling errors. When listening comprehension and decoding skills are poor, spelling ability is also poor. Recommendations for spelling, listening and decoding instruction are given.

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Fano Decoding with Timeout: Queuing Analysis

  • Pan, W. David;Yoo, Seong-Moo
    • ETRI Journal
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    • v.28 no.3
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    • pp.301-310
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    • 2006
  • In mobile communications, a class of variable-complexity algorithms for convolutional decoding known as sequential decoding algorithms is of interest since they have a computational time that could vary with changing channel conditions. The Fano algorithm is one well-known version of a sequential decoding algorithm. Since the decoding time of a Fano decoder follows the Pareto distribution, which is a heavy-tailed distribution parameterized by the channel signal-to-noise ratio (SNR), buffers are required to absorb the variable decoding delays of Fano decoders. Furthermore, since the decoding time drawn by a certain Pareto distribution can become unbounded, a maximum limit is often employed by a practical decoder to limit the worst-case decoding time. In this paper, we investigate the relations between buffer occupancy, decoding time, and channel conditions in a system where the Fano decoder is not allowed to run with unbounded decoding time. A timeout limit is thus imposed so that the decoding will be terminated if the decoding time reaches the limit. We use discrete-time semi-Markov models to describe such a Fano decoding system with timeout limits. Our queuing analysis provides expressions characterizing the average buffer occupancy as a function of channel conditions and timeout limits. Both numerical and simulation results are provided to validate the analytical results.

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The majority-logic decoding for cyclic codes (순환성 코드를 사용한 Majority logic 디코딩)

  • 강창언;정연호
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • pp.22-24
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    • 1984
  • In this paper, the (15,7) cylic codesused EG(2,2) were decoded by one step majority logic decoding. This decoding algorithm is based on the properties of finite geometries and can be simply implemented for moderate length n. especially one step majority logic decoding is attractive because the complexity and the cost of the majority logic decoder increase very rapidly with L, the number of decoding steps. The theorectical and experimental results show that the majority logic decoding presented in this paper is a relatively effective decoding scheme.

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Iterative Reliability-based Decoding of LDPC Codes with Low Complexity BEC Decoding (이진 소실 채널 복호를 이용한 신뢰기반 LDPC 반복 복호)

  • Kim, Sang-Hyo
    • Proceedings of the IEEK Conference
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    • pp.14-15
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    • 2008
  • In this paper, a new iterative decoding of LDPC codes is proposed. The decoding is based on the posteriori probability of each belief propagation (BP) decoding and an additional postprocessing, that is, erasure decoding of LDPC codes. It turned out that the new method consistently improves the decoding performance on various classes of LDPC codes. For example it removes the error floor of Margulis codes effectively.

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Principles and Current Trends of Neural Decoding (뉴럴 디코딩의 원리와 최신 연구 동향 소개)

  • Kim, Kwangsoo;Ahn, Jungryul;Cha, Seongkwang;Koo, Kyo-in;Goo, Yong Sook
    • Journal of Biomedical Engineering Research
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    • v.38 no.6
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    • pp.342-351
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    • 2017
  • The neural decoding is a procedure that uses spike trains fired by neurons to estimate features of original stimulus. This is a fundamental step for understanding how neurons talk each other and, ultimately, how brains manage information. In this paper, the strategies of neural decoding are classified into three methodologies: rate decoding, temporal decoding, and population decoding, which are explained. Rate decoding is the firstly used and simplest decoding method in which the stimulus is reconstructed from the numbers of the spike at given time (e. g. spike rates). Since spike number is a discrete number, the spike rate itself is often not continuous and quantized, therefore if the stimulus is not static and simple, rate decoding may not provide good estimation for stimulus. Temporal decoding is the decoding method in which stimulus is reconstructed from the timing information when the spike fires. It can be useful even for rapidly changing stimulus, and our sensory system is believed to have temporal rather than rate decoding strategy. Since the use of large numbers of neurons is one of the operating principles of most nervous systems, population decoding has advantages such as reduction of uncertainty due to neuronal variability and the ability to represent a stimulus attributes simultaneously. Here, in this paper, three different decoding methods are introduced, how the information theory can be used in the neural decoding area is also given, and at the last machinelearning based algorithms for neural decoding are introduced.

A Parallelization Technique with Integrated Multi-Threading for Video Decoding on Multi-core Systems

  • Hong, Jung-Hyun;Kim, Won-Jin;Chung, Ki-Seok
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.10
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    • pp.2479-2496
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    • 2013
  • Increasing demand for Full High-Definition (FHD) video and Ultra High-Definition (UHD) video services has led to active research on high speed video processing. Widespread deployment of multi-core systems has accelerated studies on high resolution video processing based on parallelization of multimedia software. Even if parallelization of a specific decoding step may improve decoding performance partially, such partial parallelization may not result in sufficient performance improvement. Particularly, entropy decoding has often been considered separately from other decoding steps since the entropy decoding step could not be parallelized easily. In this paper, we propose a parallelization technique called Integrated Multi-Threaded Parallelization (IMTP) which takes parallelization of the entropy decoding step, with other decoding steps, into consideration in an integrated fashion. We used the Simultaneous Multi-Threading (SMT) technique with appropriate thread scheduling techniques to achieve the best performance for the entire decoding step. The speedup of the proposed IMTP method is up to 3.35 times faster with respect to the entire decoding time over a conventional decoding technique for H.264/AVC videos.

Efficient Decoding Algorithm for Rate-2, $2{\times}2$ Space-Time Codes (Rate-2인 $2{\times}2$ 시공간 부호를 위한 효율적인 복호 알고리즘)

  • Kim, Jeong-Chang;Cheun, Kyung-Whoon
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.3
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    • pp.9-14
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    • 2009
  • Recently, a rate-2, $2{\times}2$ space-time code with simple ML decoding has been designed. Though the simple ML decoding algorithm does reduce the ML decoding complexity, there is still need for improvement. In this paper, we propose an efficient decoding algorithm for the rate-2, $2{\times}2$ space-time code using interference cancellation techniques with performance virtually identical to that of ML decoding. Also, the decoding complexity of the proposed algorithm is significantly reduced compared to the conventional simple ML decoding, especially for large modulation orders.

A New Iterative LT Decoding Algorithm for Binary and Nonbinary Galois Fields

  • Mao, Yuexin;Huang, Jie;Wang, Bing;Huang, Jianzhong;Zhou, Wei;Zhou, Shengli
    • Journal of Communications and Networks
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    • v.15 no.4
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    • pp.411-421
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    • 2013
  • Digital fountain codes are record-breaking codes for erasure channels. They have many potential applications in both wired and wireless communications. Most existing digital fountain codes operate over binary fields using an iterative belief-propagation (BP) decoding algorithm. In this paper, we propose a new iterative decoding algorithm for both binary and nonbinary fields. The basic form of our proposed algorithm considers both degree-1 and degree-2 check nodes (instead of only degree-1 check nodes as in the original BP decoding scheme), and has linear complexity. Extensive simulation demonstrates that it outperforms the original BP decoding scheme, especially for a small number of source packets. The enhanced form of the proposed algorithm combines the basic form of the algorithm and a guess-based algorithm to further improve the decoding performance. Simulation results demonstrate that it can provide better decoding performance than the guess-based algorithm with fewer guesses, and can achieve decoding performance close to that of the maximum likelihood decoder at a much lower decoding complexity. Last, we show that our nonbinary scheme has the potential to outperform the binary scheme when choosing suitable degree distributions, and furthermore it is insensitive to the size of the Galois field.

Trellis-Based Decoding of High-Dimensional Block Turbo Codes

  • Kim, Soo-Young;Yang, Woo-Seok;Lee, Ho-Jin
    • ETRI Journal
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    • v.25 no.1
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    • pp.1-8
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    • 2003
  • This paper introduces an efficient iterative decoding method for high-dimensional block turbo codes. To improve the decoding performance, we modified the soft decision Viterbi decoding algorithm, which is a trellis-based method. The iteration number can be significantly reduced in the soft output decoding process by applying multiple usage of extrinsic reliability information from all available axes and appropriately normalizing them. Our simulation results reveal that the proposed decoding process needs only about 30% of the iterations required to obtain the same performance with the conventional method at a bit error rate range of $10^{-5}\;to\;10^{-6}$.

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