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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Li, Wenchao Niu, Meihua Zhang, Yongchao Huang, Yulin Yang, Jianyu Univ Elect Sci & Technol China Sch Informat & Commun Engn Chengdu Sichuan Peoples R China

ISBN: (纸本)9781538691540

In this paper, an accelerated maximum a posteriori (AMAP) algorithm is proposed to realize fast and effective super resolution imaging of real beam scanning radar. The main idea of this algorithm is to construct a prediction vector based on the first and the second order of difference information before iteration. By using Taylor expansion series and second-order vector extrapolation technique, it aims to enhance the convergence speed of maximum a posteriori algorithm. Finally, the proposed algorithm is verified by simulations.

关键词： Real beam scanning radar super-resolution imaging deconvolution maximum a posteriori algorithm acceleration

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SPACE VARIANT-BASED maximum A posteriori ANGULAR SUPER-RESOLUTION algorithm FOR REAL-BEAM SCANNING RADAR 38

SPACE VARIANT-BASED MAXIMUM A POSTERIORI ANGULAR SUPER-RESOL...

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38th IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Tan, Ke Li, Wenchao Zhang, Yongchao Huang, Yulin Yang, Jianyu Yang, Xiaobo Univ Elect Sci & Technol China Sch Elect Engn Chengdu Sichuan Peoples R China

ISBN: (纸本)9781538671504

This paper proposes a space variant-based maximum a posteriori (MAP) angular super-resolution algorithm for highspeed moving real-beam scanning radar. Firstly, the aberration model of the antenna modulation function is established through analyzing the relationship between the scanning angle and the sight angle. Afterwards, an efficient piecewise constant model is formulated for the sake of reducing the computational complexity and restoring cost. Finally, the space variant-based MAP algorithm is derived based on the aberrant model. Simulation experiments demonstrate that the proposed method can improve the super-resolution performance of the high-speed platforms more efficiently than the traditional MAP method.

关键词： Real-beam scanning radar angular super-resolution maximum a posteriori algorithm space variant

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Bit error rate evaluation of concatenated turbo and parity-check product codes

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IEICE TRANSACTIONS ON COMMUNICATIONS 2002年第7期E85B卷 1231-1238页

作者： Nakajima, S Sato, E Niigata Inst Technol Dept Informat & Electron Engn Kashiwazaki 9451195 Japan

We examine a concatenated code which consists of a rate 1/2, 4-state turbo code (an inner code) and a single-parity-check product code (an outer code), and discuss the decoding structure called a double concatenated decoding scheme. From our Monte Carlo simulation trials, we show the advantage of the concatenated codes over turbo codes alone. Specifically, when we use an interleaver of 4096 bits, the E-b/N-o to obtain a BER of 10(-6) is about 1.45 dB for the concatenated code. On the other hand, it is more than 2.5 dB for the turbo code alone. So, the E-b/N-o improvement can be achieved by about 1 dB. This improvement in E-b/N-o was also obtained for the interleavers of 8192 and 2048 bits. Therefore, the concatenated codes using a double concatenated decoding scheme can solve the problem of the BER flattening in decoding of turbo codes.

关键词： turbo code parity-check product code iterative decoding maximum a posteriori algorithm

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Bayesian reconstruction in SPECT with entropy prior and iterative statistical regularization

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2004年第1期51卷 136-141页

作者： Denisova, NV Inst Theoret & Appl Mech Novosibirsk 630090 Russia

When reconstructing SPECT data using the maximum a posteriori algorithm with entropy-based prior (MAP-ENT), the effectiveness. of the algorithm depends strongly upon the choice of regularization parameter. The problem of choosing an optimal parameter remains still an open question in SPECT. Convergence properties of the MAP-ENT algorithm depending on a regularization parameter are investigated in this paper. The main goal was to study the effect of iteratively adjusting the regularization parameter on stability of the reconstruction process. Numerical tests have shown that there is a tradeoff between the resolution and noise level of the image that changes with iterations. It entails the choice of an appropriate regularization parameter at each iteration step. The iterative regularization was performed in the following way: the "best" regularization parameter was selected at each iteration. step by using the adaptive chi-square criterion. A comparison with the maximum-likelihood-based OS-EM algorithm has shown that both,(OS-EM and MAP-ENT) algorithms rather confidently lead the solution to a 'feasible' image in a few iterations. Then, as the iteration number increases, the OS-EM solution passes the feasibility area and produces images that begin to deteriorate. The MAP-ENT algorithm retains the solution within the interval due to the dynamic choice of an appropriate regularization parameter.

关键词： entropy concept iterative statistical regularization maximum a posteriori algorithm regulariztion parameter

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Bit-Level Extrinsic Information Exchange Method for Double-Binary Turbo Codes

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS 2009年第1期56卷 81-85页

作者： Kim, Ji-Hoon Park, In-Cheol Korea Adv Inst Sci & Technol Sch Elect Engn & Comp Sci Taejon 305701 South Korea

Nonbinary turbo codes have many advantages over single-binary turbo codes, but their decoder implementations require much more memory, particularly for storing symbolic extrinsic information to be exchanged between two soft-input-soft-output (SISO) decoders. To reduce the memory size required for double-binary turbo decoding, this paper presents a new method to convert symbolic extrinsic information to bit-level information and vice versa. By exchanging bit-level extrinsic information, the number of extrinsic information values to be exchanged in double-binary turbo decoding is reduced to the same amount as that in single-binary turbo decoding. A double-binary turbo decoder is designed for the WiMAX standard to verify the proposed method, which reduces the total memory size by 20%.

关键词： Double-binary turbo codes extrinsic information maximum a posteriori algorithm turbo decoding

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MAP-based probabilistic diffusion method for correspondence and line field estimation

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ELECTRONICS LETTERS 2000年第7期36卷 627-628页

作者： Lee, SH Park, JI Lee, CW Seoul Natl Univ Sch Elect Engn Inst New Media & Commun Kwanak Gu Seoul 151742 South Korea Hanyang Univ Dept Elect & Comp Engn Sungdong Gu Seoul 133791 South Korea

A new maximum aposteriori (MAP)-based probabilistic diffusion method is proposed for the estimation of dense correspondence and line fields. The proposed algorithm reflects the joint probabilistic distributions of the neighbourhood in the Markov random field, and implements them by using a plane configuration model. The probabilistic diffusion scheme showed fast convergence and improved object boundaries in the estimated fields.

关键词： image processing maximum likelihood estimation Markov random field convergence Markov processes MAP probabilistic diffusion method maximum a posteriori algorithm Optical, image and video signal processing Image recognition correspondence estimation line field estimation plane configuration model object boundary

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Bayesian algorithm for high-resolution DOA estimation

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ELECTRONICS LETTERS 2015年第21期51卷 1701-U106页

作者： Zhang, Yin Huang, Yulin Yang, Jianyu Univ Elect Sci & Technol China Sch Elect Engn Chengdu 611731 Sichuan Peoples R China

A maximum a posteriori (MAP) algorithm based on Bayesian criterion for high-resolution direction-of-arrival (DOA) estimation in array signal processing is proposed. The generalised Gaussian distribution was considered as the prior information of sources distribution for its wide applicability. The statistic parameter of the generalised Gaussian function can be transformed according to different sources distribution conditions. Only the sparse signal recovery problem is considered. It is found that with the generalised Gaussian sparse constraint, the proposed MAP algorithm provides high DOA estimation performance in the case of limited snapshots. Simulation results are given to verify the effectiveness and efficiency of the proposed algorithm.

关键词： Bayes methods Gaussian distribution direction-of-arrival estimation Bayesian algorithm Bayesian criterion array signal processing generalised Gaussian distribution generalised Gaussian sparse constraint high-resolution DOA estimation high-resolution direction-of-arrival estimation maximum a posteriori algorithm sources distribution sparse signal recovery problem statistic parameter

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Data width requirements in SISO decoding with modulo normalization

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IEEE TRANSACTIONS ON COMMUNICATIONS 2001年第11期49卷 1861-1868页

作者： Wu, YF Woerner, BD Blankenship, TK Virginia Polytech Inst & State Univ Mobile & Portable Radio Res Grp Blacksburg VA 24061 USA Virginia Polytech Inst & State Univ Dept Elect & Comp Engn Blacksburg VA 24061 USA

This letter studies the numerical properties of Log-MAP-based soft-input soft-output decoding. The ranges of the differences between the path metrics, the soft output, and the complete information are derived. Since the Log-MAP algorithm is functionally dependent only upon the differences between path metrics, not their magnitudes, a modulo normalization technique that is automatically implemented in two's complement arithmetic can be used to accommodate overflow of the path metrics. An expression for the minimum internal data width of a soft-input soft-output decoder that employs the modulo normalization technique is derived. As an application, the minimum internal data width of a decoder for the turbo code used in third-generation mobile communication systems is determined.

关键词： iterative decoding maximum a posteriori algorithm soft-input soft-output decoder turbo codes

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Performance Investigation of Joint Source-Channel Coding of Speech for Persian Dialectic, using MELP Vocoder and MAP Decoding 24

Performance Investigation of Joint Source-Channel Coding of ...

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24th Iranian Conference on Electrical Engineering (ICEE)

作者： Kasaeyan, Ahmad Moghaddan, Mohammad Hossein Assarzadeh, Ghasem KN Toosi Univ Technol Dept Elect Engn Tehran Iran Univ Tehran Coll Engn Sch Elect & Comp Engn Tehran Iran

ISBN: (纸本)9781467387897

Mixed-excitation linear prediction (MELP) is a United States department of defense speech coding standard used mainly in military applications and satellite communications, secure voice, and secure radio devices. MELP vocoder could provide an acceptable voice quality over prone erroneous channels in various environments by exploiting redundancy statistics of voice data. This paper explains performance investigation of the MELP vocoding algorithm in conjunction with convolutional codes, and maximum a posteriori techniques in both hard and soft decoding regimes which utilize speech redundancy statistics of Persian language. We have evaluated our results according to weighted spectral distortion (WSD) and ITU criterion, perceptual evaluation of speech quality (PESQ).

关键词： Mixed-excitation linear prediction redundancy statistics convolutional codes maximum a posteriori algorithm

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LOW COMPLEXITY DECODING OF VARIABLE LENGTH SOURCE-CHANNEL CODES

LOW COMPLEXITY DECODING OF VARIABLE LENGTH SOURCE-CHANNEL CO...

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IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Mercier, Hugues Wasae, Abdul Labeau, Fabrice Univ Neuchatel Inst Comp Sci CH-2000 Neuchatel Switzerland McGill Univ Elect & Comp Engn Montreal PQ H3A 0G4 Canada

ISBN: (纸本)9781479928934

Soft source decoders, in conjunction with error correcting channel codes, can be used to improve the error resilience of digital communication systems based on variable length codes. In this paper, we present a novel approach to reduce the complexity of maximum a posteriori variable length decoders implemented on a bit-symbol trellis. The decoding algorithm is implemented in a narrow corridor along the trellis diagonal to reduce the decoder complexity. Furthermore, by periodically adjusting the corridor boundaries, a significant reduction in complexity is achieved at the price of a small degradation in decoding performance.

关键词： Exponential Golomb Code variable length joint source-channel decoder maximum a posteriori algorithm bit-symbol trellis corridor decoding

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