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Low-Density Parity-Check (LDPC) coded OFDM systems: Bit error rate and the number of decoding iterations

IEICE TRANSACTIONS ON COMMUNICATIONS 2003年第11期E86B卷 3310-3316页

作者： Futaki, H Ohtsuki, T Tokyo Univ Sci Grad Sch Sci & Technol Noda Chiba 2788510 Japan Tokyo Univ Sci Fac Sci & Technol Noda Chiba 2788510 Japan

In this letter, we propose the Low-Density Parity-Check (LDPC) coded Orthogonal Frequency Division Multiplexing (OFDM) systems to improve the error rate performance of OFDM. We also evaluate the iterative decoding performance on both an AWGN and a frequency-selective fading channels. We show that when the energy per information bit to the noise power spectral density ratio E-b/N-0 is not small, the LDPC coded OFDM (LDPC-COFDM) systems have the good error rate performance with a small number of iterations. We also show that when the E-b/N-0 is small, the BER of the LDPC-COFDM systems is worse than that of the Turbo coded OFDM (TCOFDM) systems, while when the E-b/N-0 is not small, the BER of the LDPC-COFDM systems is better with a small number of iterations.

关键词： OFDM turbo codes low-density parity-check codes belief propagation algorithm

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An effective error correction using a combination of algebraic geometric codes and parity codes for HDD

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IEEE TRANSACTIONS ON MAGNETICS 2005年第10期41卷 2992-2994页

作者： Mita, S Matsui, H Toyota Technol Inst Nagoya Aichi 4688511 Japan

This paper describes the performance of an efficient error-correcting system for hard disk drives. The performance of the codes on algebraic curves, such as Hermitian codes over GF(2(8)), elliptic codes over GF(2(9)), and Fermat codes over GF(2(10)) is compared with that of conventional Reed-Solomon (RS) codes. In particular, an adoption of Hermitian codes can reduce the redundant part by approximately 800 bits more than the RS codes when an error-correcting capability of 240 bytes is adopted for a long sector size. Moreover, we propose an error-correcting system based on a combination of algebraic geometric codes and parity codes. This combination system can cover a bit-error rate of approximately 10(-2) under a condition of EEPR4 channel and additive Gaussian noise.

关键词： algebraic geometric codes Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm belief propagation algorithm magnetic recording channels parity codes Reed-Solomon (RS) codes

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Cylindrical panoramic mosaicing from a pipeline video through MRF based optimization

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VISUAL COMPUTER 2013年第4期29卷 253-263页

作者： Niu, Chuan Zhong, Fan Xu, Songhua Yang, Chenglei Qin, Xueying Shandong Univ Sch Comp Sci & Technol Jinan 250100 Peoples R China Shandong Prov Key Lab Software Engn Jinan Peoples R China Oak Ridge Natl Lab Oak Ridge TN 37830 USA

Stratum structure detection is a fundamental problem in geological engineering. One of the most commonly employed detection technologies is to shoot videos of a borehole using a forward moving camera. Using this technology, the problem of stratum structure detection is transformed into the problem of constructing a panoramic image from a low quality video. In this paper, we propose a novel method for creating a panoramic image of a borehole from a video sequence without the need of camera calibration and tracking. To stitch together pixels of neighboring image frames, our camera model is designed with a focal length changing feature, along with a small rotational freedom in the two-dimensional image space. Our camera model assumes that target objects lie on a cylindrical wall and that the camera moves forward along the central axis of the cylindrical wall. Based on these two assumptions, our method robustly resolves these two degrees-of-freedoms in our camera model through KLT feature tracking. Since the quality of the result video is affected by possible illumination overflow, camera lens blurring, and low video resolution, we introduce a cost function for eliminating seams between stitching strips. Our cost function is designed based on Markov Random Field and optimized using a belief propagation algorithm. Using our method, we can automatically construct a panorama image with good resolution, smoothness, and continuousness both in the texture and illumination space. Experiment results show that our method could efficiently generate panoramas for long video sequences with satisfying visual quality.

关键词： Panorama MRF optimization Forward moving camera belief propagation algorithm

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A Generalized Labeled Multi-Bernoulli Filter Based on Track-before-Detect Measurement Model for Multiple-Weak-Target State Estimate Using belief propagation

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REMOTE SENSING 2022年第17期14卷 4209-4209页

作者： Cao, Chenghu Zhao, Yongbo Xian Univ Posts Telecommunicat Sch Elect Engn Xian 710121 Peoples R China Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Peoples R China

In this paper, we propose the specific recursion formula for the generalized labeled multi-Bernoulli filter based on the track-before-detect strategy (GLMB-TBD) using a belief propagation algorithm. The proposed method aims to track multiple weak targets with superior performance. Compared to the Murty algorithm-based and Gibbs sampling-based implementation of GLMB-TBD filter, the proposed algorithm improves the tracking accuracy of multiple weak targets without pruning operation to preserve the relevant association information. The superior performance in tracking accuracy of the algorithm is validated for simulated scenarios using OSPA((2)) metric. More importantly, the simulation results demonstrate that the proposed algorithm outputs both the Gibbs sampling-based version and Murty algorithm-based version in computational cost due to linear complex in the number of both Bernoulli components and measurements.

关键词： generalized labeled multi-Bernoulli filter based on track-before-detect strategy relevant association information belief propagation algorithm OSPA((2)) metric linear complexity

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Real-time State Estimation on Micro-grids

Real-time State Estimation on Micro-grids

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International Joint Conference on Neural Networks (IJCNN)

作者： Hu, Ying Kuh, Anthony Kavcic, Aleksandar Nakafuji, Dora Univ Hawaii Manoa Dept Elect Engn Honolulu HI 96822 USA Hawaiian Elect Co Inc Honolulu HI 96840 USA

ISBN: (纸本)9781424496365

This paper presents a new probabilistic approach of the real-time state estimation on the micro-grid. The grid is modeled as a factor graph which can characterize the linear correlations among the state variables. The factor functions are defined for both the circuit elements and the renewable energy generation. With the stochastic model, the linear state estimator conducts the belief propagation algorithm on the factor graph utilizing real-time measurements from the smart metering devices. The result of the statistical inference presents the optimal estimates of the system state. The new algorithm can work with sparse measurements by delivering the optimal statistical estimates rather than the solutions. In addition, the proposed graphical model can integrate new models for solar/wind correlation that will help with the integration study of renewable energy. Our state-of-art approach provides a robust foundation for the smart grid design and renewable integration applications.

关键词： Correlation Mathematical model Reactive power Real time systems Renewable energy resources Signal processing algorithms State estimation belief propagation algorithm circuit elements factor functions factor graph graph theory linear state estimator message passing micro-grids power system measurement power system state estimation probabilistic approach probability real-time state estimation renewable energy generation smart grid design smart metering devices smart power grids solar correlation statistical analysis statistical inference stochastic model wind correlation

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Sign Alterations of LLR Values Based Early Termination Method for LT BP Decoder 25

Sign Alterations of LLR Values Based Early Termination Metho...

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25th Signal Processing and Communications Applications Conference (SIU)

作者： Albayrak, Cenk Simsek, Cemaleddin Turk, Kadir Karadeniz Tech Univ Elekt Elekt Muhendisligi Trabzon Turkey Gumushane Univ Elekt Elekt Muhendisligi Gumushane Turkey

ISBN: (纸本)9781509064946

In this letter, a new early termination method is proposed for Luby transform (LT) belief propagation (BP) decoder. The proposed method is decided whether BP decoder output converges to original data bits by observing only sign alterations of log-likelihood ratio (LLR) messages in BP decoder structure. Simulation results and complexity analyzes show that proposed method has low computational complexity and small average iteration amounts compared to conventional early termination methods in literature. In addition to this, the proposed method doesn't cause any performance degradation in BP decoder. The method can be easily applied to code families which can be decoded by BP algorithm such as low density parity check (LDPC) codes, polar codes and Raptor codes.

关键词： belief propagation algorithm early termination method rateless codes LT codes

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Symbol-based BP Detection for MIMO Systems associated with Non-Binary LDPC Codes

Symbol-based BP Detection for MIMO Systems associated with N...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Haroun, Ali Nour, Charbel Abdel Arzel, Matthieu Jego, Christophe Telecom Bretagne Inst Mines Telecom STICC CNRS LabUMR 3192 Brest France Univ Europeenne Bretagne Rennes France Enseirb Matmeca IPB CNRS IMS UMR 5218 Bordeaux France Univ Bordeaux Bordeaux France

ISBN: (纸本)9781479930838

In this paper, an efficient iterative receiver for digital communication systems is investigated. It combines a Non-Binary Low Density Parity-Check (NB-LDPC) decoder with a high-order constellation demapper and a Multiple-Input Multiple-Output (MIMO) detector. A suboptimal MIMO detector based on the belief propagation (BP) algorithm is investigated as an alternative to a Maximum Likelihood (ML) detector. Extrinsic information is exchanged between the detector and the decoder thanks to an iterative process. EXtrinsic Information Transfer (EXIT) charts enable to analyze the convergence behaviour of the proposed MIMO-BP detector. A suitable schedule for the different types of iterations is finally proposed to reduce the receiver latency and improve its error correction performance.

关键词： MIMO communication belief maintenance iterative decoding maximum likelihood detection parity check codes radio receivers EXIT charts MIMO-BP detector NB-LDPC decoder belief propagation algorithm digital communication systems error correction performance extrinsic information transfer charts high-order constellation demapper iterative receiver maximum likelihood detector multiple-input multiple-output detector nonbinary low-density parity-check decoder receiver latency Decoding Detectors Iterative decoding MIMO Schedules Silicon

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An Interactive Image Inpainting algorithm Based on Markov Random Field

An Interactive Image Inpainting Algorithm Based on Markov Ra...

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IEEE International Conference on Mechatronics and Automation

作者： Sun, Junxi Hao, Defang Gu, Dongbing Liu, Guangwen Cai, Hua Changchun Univ Sci & Technol Sch Elect & Informat Engn 7089 Weixing Rd Changchun 130022 Peoples R China Univ Essex Sch Comp Sci & Elect Engn Colchester C04 3SQ Essex England

ISBN: (纸本)9781424426928

A novel approach to image inpainting is introduced in this paper. The novelty lies in the combination of pixel-diffusing technique and a user interaction mechanism. This combination takes both local geometrical information via the pixel-diffusing technique and global structure information via the user interaction to improve the image inpainting quality. The user interaction mechanism manually specifies important missing structure information by drawing some curves from the known to the unknown regions and synthesizes image structure along these user-specified curves in the unknown region using structure information selected around the curves in the known region. The pixel-diffusing technique builds on the Markov Random Field (MRF) model to exploit the image contextual knowledge. The interactive inpainting algorithm fills in the remaining unknown regions based on the MRF model. The experiment results show this interactive algorithm is reasonable and efficient.

关键词： image inpainting belief propagation algorithm MRF model

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Polar Code and Polarization using Bhattacharya Parameter 9

Polar Code and Polarization using Bhattacharya Parameter

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9th IEEE Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON)

作者： Mude, Shoban Bhukya, RajendraNaik Osmania Univ Univ Coll Engn Dept Elect & Commun Engn Hyderabad Telangana India

ISBN: (纸本)9781538672662

Performance test of a communication channel generally measured using bit error rate (BER) or signal to noise ratio (SNR) over various channels AWGN, BEC, BSC and BI-DMC. To improve channel capacity further by enhanced belief propagation algorithm for polar codes over BI-DMC it has better response, lower complexity at receiver by using Bhattacharya parameter Z (W)-factor it reaches near to Shannon's capacity.

关键词： BER SNR Polar Codes channel capacity belief propagation algorithm

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Performance Comparison of Hybrid Partial Response Detectors over Frequency-Selective Fading Channels

Performance Comparison of Hybrid Partial Response Detectors ...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Peng, Yanjie Huang, Xinming Worcester Polytech Inst Dept Elect & Comp Engn Worcester MA 01609 USA

ISBN: (纸本)9781479934324

Frequency-selective fading channels are encountered in many modern wireless communication systems. In order to combat the intersymbol interference (IS!) introduced by such fading, equalization is required for reliable symbol detection. The maximum-likelihood sequence detector is the optimal equalization scheme;however its implementation complexity increases exponentially with the channel length and thus can be prohibitively high. In this paper, we compare the performance of two practically implementable suboptimal symbol detectors, including the partial response maximum-likelihood (PRML) detector and the partial response belief propagation (PRBP) detector, under frequency-selective fading channels. Both detectors employ a hybrid two-stage scheme, and allow a tradeoff between performance and complexity. The first stage is a partial response equalizer implemented as a linear filter which transforms the original channel impulse response to a target impulse response with reduced ISI. The residual ISI is then cancelled in the second stage using a more sophisticated nonlinear detector. In simulations, we consider a slow fading environment and use the ITU-R 3G channel models. From the numerical results, it is shown that in frequency-selective fading wireless channels, the PRBP detector provides superior performance over both the traditional minimum mean squared error linear equalizer and the PRML detector. Due to the effect of colored noise, the PRML detector in fading wireless channels is not as effective as it is in magnetic recording applications.

关键词： belief propagation algorithm partial response equalization maximum-likelihood sequence estimation frequency-selective fading

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