• Title/Summary/Keyword: successive decoding

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Multiple Node Flip Fast-SSC Decoding Algorithm for Polar Codes Based on Node Reliability

  • Rui, Guo;Pei, Yang;Na, Ying;Lixin, Wang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.2
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    • pp.658-675
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    • 2022
  • This paper presents a fast-simplified successive cancellation (SC) flipping (Fast-SSC-Flip) decoding algorithm for polar code. Firstly, by researching the probability distribution of the number of error bits in a node caused by channel noise in simplified-SC (SSC) decoder, a measurement criterion of node reliability is proposed. Under the guidance of the criterion, the most unreliable nodes are firstly located, then the unreliable bits are selected for flipping, so as to realize Fast-SSC-Flip decoding algorithm based on node reliability (NR-Fast-SSC-Flip). Secondly, we extended the proposed NR-Fast-SSC-Flip to multiple node (NR-Fast-SSC-Flip-ω) by considering dynamic update to measure node reliability, where ω is the order of flip-nodes set. The extended algorithm can correct the error bits in multiple nodes, and get good performance at medium and high signal-to-noise (SNR) region. Simulation results show that the proposed NR-Fast-SSC-Flip decoder can obtain 0.27dB and 0.17dB gains, respectively, compared with the traditional Fast-SSC-Flip [14] and the newly proposed two-bit-flipping Fast-SSC (Fast-SSC-2Flip-E2) [18] under the same conditions. Compared with the newly proposed partitioned Fast-SSC-Flip (PA-Fast-SSC-Flip) (s=4) [18], the proposed NR-Fast-SSC-Flip-ω (ω=2) decoder can obtain about 0.21dB gain, and the FER performance exceeds the cyclic-redundancy-check (CRC) aided SC-list (CRC-SCL) decoder (L=4).

Performance of Successive-Cancellation List Decoding of Extended-Minimum Distance Polar Codes (최소거리가 확장된 극 부호의 연속 제거 리스트 복호 성능)

  • Ryu, Daehyeon;Kim, Jae Yoel;Kim, Jong-Hwan;Kim, Sang-Hyo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.1
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    • pp.109-117
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    • 2013
  • Polar codes are the first provable error correcting code achieving the symmetric channel capacity in a wide case of binary input discrete memoryless channel(BI-DMC). However, finite length polar codes have an error floor problem with successive-cancellation list(SCL) decoder. From previous works, we can solve this problem by concatenating CRC(Cyclic Redundancy Check) codes. In this paper we propose to make polar codes having extended-minimum distance from original polar codes without outer codes using correlation with generate matrix of polar codes and that of RM(Reed-Muller) codes. And we compare performance of proposed polar codes with that of polar codes concatenating CRC codes.

Interference Cancellation for Relay-Assisted D2D Communication

  • Zhao, Hongyi;Cao, Yang;Liu, Yingzhuang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.9
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    • pp.3276-3292
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    • 2015
  • Relay-assisted D2D communication extends the communication range of the D2D pairs and helps users to form D2D pairs effectively. However, due to the introduction of the multi-hop relaying, the D2D communication has to occupy extra transmission time, which may decrease the efficiency of the communication system. In this paper, we propose a scheme to make node receive D2D signal and BS signal at overlapping time to improve the spectrum efficiency according to ZigZag decoding and successive-interference-cancellation (SIC). In this way, more data can be delivered during the same duration, thus the network throughput can be further improved. Numerical results verify the performance improvement of the proposed scheme when compared with a baseline scheme. Moreover, we expand the proposed scheme from one-hop relay scenario to multi-hop relay scenario.

Almost-Sure Convergence of the DLMS Algorithm (DLMS 알고리즘의 수렴에 관한 연구)

  • Ahn, Sang Sik
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.9
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    • pp.62-70
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    • 1995
  • In some practical applications of the LMS Algorithm the coefficient adaptation can be performed only after some fixed delay. The resulting algorithm is known as the Delayed Least Mean Square (DLMS) algorithm in the literature. There exist analyses for this algorithm, but most of them are based on the unrealistic independence assumption between successive input vectors. Inthis paper we consider the DLMS algorithm with decreasing step size .mu.(n)=n/a, a>0 and prove the almost-sure convergence ofthe weight vector W(n) to the Wiener solution W$_{opt}$ as n .rarw. .inf. under the mixing unput condition and the satisfaction of the law of large numbers. Computer simulations for decision-directed adaptive equalizer with decoding delay are performed to demonstrate the functioning of the proposed algorithm.m.

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Block-Ordered Layered Detector for MIMO-STBC Using Joint Eigen-Beamformers and Ad-Hoc Power Discrimination Scheme

  • Lee Won-Cheol
    • Journal of Communications and Networks
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    • v.8 no.3
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    • pp.275-285
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    • 2006
  • Suitable for multi-input multi-output (MIMO) communications, the joint beamforming space-time block coding (JBSTBC) scheme is proposed for high-speed downlink transmission. The major functionality of the scheme entails space-time block encoder and joint transmit and receive eigen-beamformer (EBF) incorporating with block-ordered layered decoder (BOLD), and its operating principle is described in this paper. Within these functionalities, the joint EBFs will be utilized for decorrelating fading channels to cause an enhancement in the spatial diversity gain. Furthermore, to fortify the capability of layered successive interference cancellation (LSIC) in block-ordered layered decoding process, this paper will develop a simple ad-hoc transmit power discrimination scheme (TPDS) based on a particular power discrimination function (PDF). To confirm the superior behavior of the proposed JBSTBC scheme employing ad-hoc TPDS, computer simulations will be conducted under various channel conditions with the provision of detailed mathematical derivations for clarifying its functionality.

Joint OSIC and Soft ML Decoding Scheme for Coded Layered Space-Time OFDM Systems

  • Lee, Hye-Jeong;Chung, Jae-Ho;Park, Se-Jun;Lee, Seong-Choon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.5A
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    • pp.487-493
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    • 2008
  • In this paper, we consider coded layered space-time architecture in MIMO-OFDM channels. Vertical Bell Lab Layered Space-Time(V-BLAST) scheme employing ordered successive interference cancellation(OSIC) algorithm provides very high spectral efficiency with low computational complexity. However, the error propagation is a major drawback constraining the overall performance of the V-BLAST system significantly. Based on this problem, we derive an improved detector using soft bit log-likelihood ratio(LLR) value. Simulation results show that the proposed detector outperforms the conventional V-BLAST scheme under spatially uncorrelated as well as correlated fading channels.

Adaptive Irregular Binning and Its Application to Video Coding Scheme Using Iterative Decoding (적응 불규칙 양자화와 반복 복호를 이용한 비디오 코딩 방식에의 응용)

  • Choi Kang-Sun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.4C
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    • pp.391-399
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    • 2006
  • We propose a novel low complexity video encoder, at the expense of a complex decoder, where video frames are intra-coded periodically and frames in between successive intra-coded frames are coded efficiently using a proposed irregular binning technique. We investigate a method of forming an irregular binning which is capable of quantizing any value effectively with only small number of bins, by exploiting the correlation between successive frames. This correlation is additionally exploited at the decoder, where the quality of reconstructed frames is enhanced gradually by applying POCS(projection on the convex sets). After an image frame is reconstructed with the irregular binning information at the proposed decoder, we can further improve the resulting quality by modifying the reconstructed image with motion-compensated image components from the neighboring frames which are considered to contain image details. In the proposed decoder, several iterations of these modification and re-projection steps can be invoked. Experimental results show that the performance of the proposed coding scheme is comparable to that of H.264/AVC coding in m mode. Since the proposed video coding does not require motion estimation at the encoder, it can be considered as an alternative for some versions of H.264/AVC in applications requiring a simple encoder.

Fast Scene Change Detection Algorithm in MPEG Compressed Video by Minimal Decoding (MPEG으로 압축된 비디오에서 최소 복호화에 의한 빠른 장면전환검출 알고리듬)

  • Kim, Gang-Uk;Lee, Jae-Seung;Kim, Jong-Hun;Hwang, Chan-Sik
    • The KIPS Transactions:PartB
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    • v.9B no.3
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    • pp.343-350
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    • 2002
  • A scene change detection which involves finding a cut between two consecutive shots is an important step for video indexing and retrieval. This paper proposes an algorithm for fast and accurate detection of abrupt scene changes in an MPEG compressed domain with minimal decoding requirements arid computational effort. The proposed method compares two successive DC images of I-frames for finding the GOP (group of picture) which contain a scene change and uses macroblock-coded type information contained in B-frames to detect the exact frame where the scene change occurred. The experiment results demonstrate that the proposed algorithm has better detection performance, such as precision and recall rate, than the existing method using all DC images. The algorithm has the advantage of speed, simplicity and accuracy. In addition, it requires less amount of storage.

A Composition of Mosaic Images based on MPEG Compressed Information (MPEG 압축 정보를 이용한 모자이크 구성)

  • 설정규;이승희;이준환
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.1C
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    • pp.47-55
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    • 2003
  • This paper proposes a composition method of mosaic image from the compressed MPEG-2 video stream, in which the displacement between successive frames according to the camera operation is estimated directly from the information involved in the stream. In the proposed method. the approximated optical flow is constructed from motion vectors of macro blocks, and it is used to determine the parameters of the displacements according to the camera operation associated with pan and tilt. The extracted parameters are used to determine the geometric transform of successive video frames in order to construct a mosaic image. The construction of mosaic uses several blending techniques including the one proposed by Nichols in which an analytic weight is used to determine pixel values. Through the experiment, the blending technique based on analytic weights was superior to the others such as averaging and median-based techniques. It provided more smooth changes in background and made use of instantaneous frame information to construct a mosaic. The mosaic in the paper puts the emphasis on the reduction of computation because it is constructed from the motion vectors included in the compressed video without decoding and recalculating exact optical flows. The constructed mosaic can be used in the retrieval of the compressed video as the representative frame of a shot.

Fast Scene Change Detection Algorithm in Compressed Video by a phased-approach Method (압축 비디오에서 단계적 접근방법에 의한 빠른 장면전환검출 알고리듬)

  • 이재승;천이진;윤정오
    • Journal of Korea Society of Industrial Information Systems
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    • v.6 no.3
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    • pp.115-122
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    • 2001
  • A scene change detection is an important step for video indexing and retrieval. This paper proposes an algorithm by a phased algorithm for fast and accurate detection of abrupt scene changes in an MPEG compressed domain with minimal decoding requirements and computational effort. The proposed method compares two successive I-frames for locating a scene change occurring within the GOP and uses macroblock-coded type information contained in B-frames to detect the exact frame where the scene change occurred. The algorithm has the advantage of speed, simplicity and accuracy. In addition, it requires less amount of storage. The experiment results demonstrate that the proposed algorithm has better detection performance, such as precision and recall rate, than the existing method using all DC images.

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