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Efficient encoding and decoding algorithm for triangular discrete global grid based on Hybrid Transformation Strategy

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COMPUTERS ENVIRONMENT AND URBAN SYSTEMS 2018年 68卷 110-120页

作者： Zhou, Liangchen Lian, Wenjie Lv, Guonian Zhu, A-Xing Lin, Bingxian Nanjing Normal Univ Minist Educ Key Lab Virtual Geog Environm Nanjing 210023 Jiangsu Peoples R China State Key Lab Cultivat Base Geog Environm Evolut Nanjing 210023 Jiangsu Peoples R China Jiangsu Ctr Collaborat Innovat Geog Informat Reso Nanjing 210023 Jiangsu Peoples R China Univ Wisconsin Madison Deportment Geog Madison WI 53706 USA

Grid codes are an important part of a grid system and provide a unique identifier for the cells in the spherical triangular discrete global grid, where the transformation between geographic coordinates and grid codes is the basis of global spatial data integration and various analytical applications. Owing to the particularity of the topological properties, the spherical space cannot be continuously paved with the same grid cells as those in the plane space. Thus, the recursive approximation method is typically used to establish the transformation algorithm between the geographic coordinates and the grid codes. The efficiency of those algorithms that were based on recursive approximation obviously decreased with the increased grid subdivision level;thus, it is not conducive to the integration of massive high-resolution spatial data. Whereas the geometric properties of the grid cells in the spherical triangular discrete global grid differ during the initial subdivision levels, as the level increases, these geometric properties tend to be the same, along with the properties of the local regions similar to the plane. Considering this characteristic, this paper proposes a hybrid bidirectional transformation algorithm. In the proposed algorithm, the recursive approximation method is used at the lower level where there is a large difference in the geometrical properties of the grid cells, and the direct mapping method using a similar plane grid is used at the higher level where the geometrical properties of the grid cells are virtually the same. In experiments conducted using the proposed algorithm with geographic coordinates at different scales and grid codes at different levels, the running time remained stable with no significant change throughout increases in the hierarchical level. Further, it was proven to satisfy the requirements of the absolute accuracy evaluation method. Compared with the traditional recursive approximation algorithm, the proposed algorithm has o

关键词： decoding algorithm Encoding algorithm Discrete global grid Icosahedron Triangular discrete global grid

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Application of LDPC Code decoding algorithm in Digital Watermarking

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AUTOMATIC CONTROL AND COMPUTER SCIENCES 2022年第5期56卷 393-402页

作者： Wang, Zhongxun Bao, Zhankai Meng, Lingzeng Yantai Univ Inst Sci & Technol Optoelect Informat Yantai 264005 Peoples R China

At present, while there are many conveniences in people's lives, lots of problem have also appeared with the development of information technology. In order to solve the problem of increasingly serious intellectual property disputes, the research on digital watermarking is particularly important. Due to the digital watermarking for real-time requirement is not high. We improve the decoding algorithm in response to the oscillating iterative phenomenon that occurs during the LDPC code decoding algorithm;and the improved decoding algorithm has been introduced into the digital watermark technology. Finally, the simulation is realized through MATLAB, the results show that the improved LDPC code decoding algorithm significantly improves the robustness of digital watermarking obviously.

关键词： digital watermarking LDPC code decoding algorithm oscillation iteration

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SCMA Joint Coding and decoding algorithm Based on Code Reliability

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MOBILE NETWORKS & APPLICATIONS 2023年第1期28卷 285-295页

作者： Zhao, Hongwei Wang, Huanzhu Yan, Yue Northwestern Polytech Univ Sch Elect & Informat Xian 710129 Peoples R China

The wide application of the Internet of Things (IoT), large-scale satellite clusters and drone clusters requires multiple access capabilities for massive devices. In order to meet the high-capacity and low-latency access requirements in application scenarios such as the IoT, this paper proposes to apply sparse code multiple access (SCMA) technology to the massive terminal access of the IoT, focusing on the study of SCMA decoding algorithm. Aiming at the high complexity of its traditional decoding algorithm, a decoding algorithm based on codeword reliability is proposed. The algorithm reduces the number of codeword iterations with higher reliability by setting a threshold to reduce the algorithm complexity. The simulation results show that the algorithm reduces the complexity of the algorithm while the loss of bit error rate performance is very small. Then, aiming at the poor bit error rate performance of SCMA technology under the condition of low signal-to-noise ratio, a joint coding and decoding simulation link based on soft input and soft output Turbo code and SCMA technology is proposed. The simulation results prove that Turbo codes can speed up the convergence speed of the decoding algorithm. When the SNR is 4 dB, the bit error rate of the joint system has been reduced to below 10e-3, which has obvious advantages compared with the SCMA system without Turbo coding. Therefore, the two methods proposed in this paper can be used for the high-capacity demand of the IoT communication system.

关键词： Internet of things High capacity Sparse code multiple access decoding algorithm

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Low-density parity-check-Feher quadrature phase shift keying signalling with frequency-offset compensated iterative demodulation and decoding algorithm

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IET COMMUNICATIONS 2014年第13期8卷 2264-2271页

作者： Yang, Zhihua Li, Yunhe Li, Huiyuan Qin, Jiao Zhang, Qinyu Cao, Bin Harbin Inst Technol Shenzhen Grad Sch Dept Elect & Informat Engn Shenzhen 518055 Peoples R China

The Feher quadrature phase shift keying (FQPSK) modulation is significantly susceptible to frequency and phase offsets under low signal-to-noise ratios. In this study, the authors proposed a serially concatenated signalling scheme with FQPSK modulation and low-density parity-check coding, which could efficiently resist residual frequency offset by employing an intended compensation algorithm. The designed maximum-likelihood estimation-enabled compensation algorithm is incorporated into the iterative concatenated demodulation-decoding process by using soft-input-soft-output-based maximum-a-posteriori-probability criterion. On the other side, the codeword sequence to be transmitted at the sender is re-arranged in a pre-configured order different from original codeword, in order to help the compensation algorithm diminish the impacts of frequency offsets. Simulation results show that the bit error rate of the proposed scheme can be improved efficiently up to three orders of magnitude with the frequency offsets from 100 to 700 ppm.

关键词： quadrature phase shift keying parity check codes maximum likelihood estimation iterative decoding demodulation probability error statistics frequency-offset iterative demodulation decoding algorithm Feher quadrature phase shift keying FQPSK modulation phase offsets signal-to-noise ratios low-density parity-check coding residual frequency offset maximum-likelihood estimation compensation algorithm iterative concatenated demodulation-decoding process soft-input-soft-output maximum-a-posteriori-probability criterion codeword sequence bit error rate

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A novel memory-efficient Huffman decoding algorithm and its implementation

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SIGNAL PROCESSING 1997年第2期62卷 207-213页

作者： Chung, KL Lin, YK Natl Taiwan Univ Sci Dept Informat Management Grad Program Informat Engn Taipei 10672 Taiwan

This paper first presents a new array data structure to represent the Huffman tree. The memory required in the proposed data structure is less than the previous methods (Huffman, 1952;Roman, 1992), which also use array data structure to store the corresponding Huffman tree, and is the lower bound of the one in (Hashemian, 1995). We then present an efficient Huffman decoding algorithm based on the proposed data structure;given a Huffman code, the search time for finding the source symbol is O(d), where d denotes the depth of the Huffman tree. This time bound is equal to the ones in (Hashemian, 1995;Huffman, 1952;Roman, 1992). Some experimentations on real images are carried out to demonstrate the performance of space and search time among our method and the previous ones. (C) 1997 Elsevier Science B.V.

关键词： data structure decoding algorithm Huffman code image compression

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COMPLETE decoding algorithm OF (11, 6, 5) GOLAY CODE

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ELECTRONICS LETTERS 1989年第17期25卷 1191-1192页

作者： WEI, SW WEI, CH NATL CHIAO TUNG UNIV CTR TELECOMMUN RES HSINCHU TAIWAN

A simple complete decoding algorithm for the (11, 6, 5) perfect ternary Golay code is presented. This algorithm is based on a step-by-step method and requires only 17 shift operations for decoding one received word.

关键词： (11 6 5) Golay code decoding decoding algorithm error correction codes perfect ternary Golay code received word shift operations step-by-step method

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Joint Viterbi detection and decoding algorithm for bluetooth low energy systems

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ELECTRONICS LETTERS 2020年第6期56卷 310-312页

作者： Park, Chulhyun Jung, Yongchul Kim, Jihoon Jung, Yunho Korea Aerosp Univ Sch Elect & Informat Engn Goyang Si 10540 Gyeonggi Do South Korea Ewha Womans Univ Dept Elect & Elect Engn Seoul 03760 South Korea

An efficient joint Viterbi detection and decoding (JVDD) algorithm for a bluetooth low energy (BLE) system is proposed. Since the convolutional coded Gaussian minimum-shift keying (GMSK) signal is specified in the BLE 5.0 standard, two Viterbi processors are needed for detection and decoding. However, the proposed JVDD scheme uses only one Viterbi processor by modifying the branch metric with inter-symbol interference information from GMSK modulation;therefore, the hardware complexity can be significantly reduced without performance degradation.

关键词： convolutional codes decoding Bluetooth intersymbol interference Viterbi detection minimum shift keying Viterbi decoding decoding algorithm bluetooth low energy system efficient joint Viterbi detection convolutional coded Gaussian minimum-shift keying signal BLE 5 Viterbi processor JVDD scheme

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A parallel decoding algorithm for IFS codes without transient behavior

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IEEE TRANSACTIONS ON IMAGE PROCESSING 1996年第3期5卷 411-415页

作者： Pei, SC Tseng, CC Lin, CY Department of Electrical Engineering National Taiwan University Taipei Taiwan Department Of Electrical Engineering National Taiwan University Taipei Taiwan

Iterated function systems (IFS's) have received great attention in encoding and decoding fractal images, Barnsley has shown that IFS's for image compression can achieve a very high compression ratio for a single image, However, the major drawback of such a technique is the large computation load required to both encode and decode a fractal image, In this paper, we provide a novel algorithm to decode IFS codes, The main features of this algorithm are that it is very suitable for parallel implementation and has no transient behavior, Also, from the decoding process of this method we can understand the encoding procedure explicitly, One example is illustrated to demonstrate the quality of its performance.

关键词： compression ratio Image compression decoding algorithm Data compression algorithms decoding Iterated Function System coding Codes Parallel Lines Transient performance

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An efficient joint channel estimation and decoding algorithm for turbo-coded space-time orthogonal frequency division multiplexing receivers

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IET COMMUNICATIONS 2008年第7期2卷 886-894页

作者： Dogan, H. Cirpan, H. A. Panayirci, E. Istanbul Univ Dept Elect & Elect Engn TR-34850 Istanbul Turkey Kadir Has Univ Dept Elect Engn TR-34230 Istanbul Turkey

The challenging problem in the design of digital receivers of today's and future high-speed, high data-rate wireless communication systems is to implement the optimal decoding and channel estimation processes jointly in a computationally feasible way. Without realising such a critical function perfectly at receiver, the whole system will not work properly within the desired performance limits. Unfortunately, direct implementation of such optimal algorithms is not possible mainly due to their mathematically intractable and computationally prohibitive nature. A novel algorithm that reaches the performance of the optimal maximum a posteriori (MAP) algorithm with a feasible computational complexity is proposed. The algorithm makes use of a powerful statistical signal processing tool called the expectation-maximisation (EM) technique. It iteratively executes the MAP joint channel estimation and decoding for space-time block-coded orthogonal frequency division multiplexing systems with turbo channel coding in the presence of unknown wireless dispersive channels. The main novelty of the work comes from the facts that the proposed algorithm estimates the channel in a non-data-aided fashion and therefore except a small number of pilot symbols required for initialisation, no training sequence is necessary. Also the approach employs a convenient representation of the discrete multipath fading channel based on the Karhunen-Loeve (KL) orthogonal expansion and finds MAP estimates of the uncorrelated KL series expansion coefficients. Based on such an expansion, no matrix inversion is required in the proposed MAP estimator. Moreover, optimal rank reduction is achieved by exploiting the optimal truncation property of the KL expansion resulting in a smaller computational load on the iterative estimation approach.

关键词： fading channels wireless dispersive channels joint channel estimation radio receivers turbo-codes expectation maximisation technique iterative estimation approach Karhunen'Loeve orthogonal expansion maximum-a posteriori algorithm optimal decoding channel estimation turbo codes space-time orthogonal frequency division multiplexing receivers MAP algorithm EM discrete multipath fading channel channel coding optimal algorithm turbo channel coding space-time codes OFDM modulation data-rate wireless communication systems KL decoding algorithm

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On reducing complexity of a soft-decision decoding algorithm for cyclic codes based on energy minimization principle

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1998年第10期E81A卷 1998-2004页

作者： Shiozaki, A Aoki, K Univ Osaka Prefecture Coll Engn Sakai Osaka 5998531 Japan Osaka Electrocommun Univ Grad Sch Engn Neyagawa Osaka 5728530 Japan

We propose a novel soft-decision decoding algorithm for cyclic codes based on energy minimization principle. The well-known soft-decision decoding algorithms for block codes perform algebraic (hard-decision) decoding several times in order to generate candidate codewords using the reliability of received symbols. In contrast, the proposed method defines energy as the Euclidean distance between the received signal and a codeword and alters the values of information symbols so as to decrease the energy in order to seek the codeword of minimum energy, which is the most likely codeword. We let initial positions be the information parts of signals obtained by cyclically shifting a received signal and look for the point, which represents a codeword, of minimum energy by moving each point from several initial positions. This paper presents and investigates reducing complexity of the soft-decision decoding algorithm. We rank initial positions in order of reliability and reduce the number of initial positions in decoding. Computer simulation results show that this method reduces decoding complexity.

关键词： error-correcting-codes error-control decoding algorithm soft-decision decoding energy minimization principle

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