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Improved upper bounds on the ml decoding error probability of parallel and serial concatenated turbo codes via their ensemble distance spectrum

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IEEE TRANSACTIONS ON INFORMATION THEORY 2000年第1期46卷 24-47页

作者： Sason, I Shamai, S Technion Israel Inst Technol Dept Elect Engn IL-32000 Haifa Israel

The ensemble performance of parallel and serial concatenated turbo codes is considered, where the ensemble is generated by a uniform choice of the interleaver and of the component codes taken from the set of time-varying recursive systematic convolutional codes, Following the derivation of the input-output weight enumeration functions of the ensembles of random parallel and serial concatenated turbo codes, the tangential sphere upper bound is employed to provide improved upper bounds on the block and bit error probabilities of these ensembles of codes for the binary-input additive white Gaussian noise (AWGN) channel, based on coherent detection of equi-energy antipodal signals and maximum-likelihood decoding, The influence of the interleaver length and the memory length of the component codes is investigated. The improved bounding technique proposed here is compared to the conventional union bound and to a recent alternative bounding technique by Duman and Salehi which incorporates modified Gallager bounds. The advantage of the derived bounds is demonstrated for a variety of parallel and serial concatenated coding schemes with either fix-ed or random recursive systematic convolutional component codes, and it is especially pronounced in the region exceeding the cutoff rate, where the performance of turbo codes is most appealing. These upper bounds are also compared to simulation results of the iterative decoding algorithm.

关键词： AWGN channel distance spectrum iterative decoding ml decoding turbo codes uniform interleaver

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ml decoding in Decode-and-Forward Based Cooperative Communication System

ML Decoding in Decode-and-Forward Based Cooperative Communic...

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

作者： Bhatnagar, Manav R. Hjorungnes, Are Indian Inst Technol Delhi Dept Elect Engn New Delhi 110016 India

ISBN: (纸本)9781457705397

In this paper, we derive a maximum-likelihood (ml) decoder of the decode-and-forward (DF) protocol utilizing an arbitrary complex-valued M-point constellation. Existing decoders of the DF based cooperative systems are applicable only to real-valued constellations like BPSK and M-PAM, hence, also to square M2-QAM. We have considered a DF based cooperative system with a single source-destination pair and one relay. The ml decoder is obtained by maximizing the probability density function (p.d.f.) of the received signal at the destination. The proposed ml decoder provides lower decoding complexity than an existing decoder. We also propose an approximate piecewise linear (PL) decoder for M-PSK constellation which performs similar to the proposed ml decoder. The proposed PL decoder provides significant lower decoding complexity than the proposed ml decoder. We analytically derive the approximate symbol error rate of the proposed PL decoder. The DF based cooperative system with the proposed ml and PL decoders outperforms the same rate amplify-and-forward based cooperative communication system from moderate to high signal-to-noise ratio values.

关键词： Cooperative communication decode-and-forward protocol low complexity decoder ml decoding SER analysis

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Tree Expectation Propagation for ml decoding of LDPC Codes over the BEC

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IEEE TRANSACTIONS ON COMMUNICATIONS 2013年第2期61卷 465-473页

作者： Salamanca, Luis Olmos, Pablo M. Jose Murillo-Fuentes, Juan Perez-Cruz, Fernando Univ Seville Escuela Super Ingenieros Dept Teoria Senal & Comunicac Seville 41092 Spain Univ Carlos III Madrid Dept Teoria Senal & Comunicac Madrid 28911 Spain

We propose a decoding algorithm for LDPC codes that achieves the maximum likelihood (ml) solution over the binary erasure channel (BEC). In this channel, the tree-structured expectation propagation (TEP) decoder improves the peeling decoder (PD) by processing check nodes of degree one and two. However, it does not achieve the ml solution, as the tree structure of the TEP allows only for approximate inference. In this paper, we provide the procedure to construct the structure needed for exact inference. This algorithm, denoted as generalized tree-structured expectation propagation (GTEP), modifies the code graph by recursively eliminating any check node and merging this information in the remaining graph. The GTEP decoder upon completion either provides the unique ml solution or a tree graph in which the number of parent nodes indicates the multiplicity of the ml solution. We also explain the algorithm as a Gaussian elimination method, relating the GTEP to other ml solutions. Compared to previous approaches, it presents an equivalent complexity, it exhibits a simpler graphical message-passing procedure and, most interesting, the algorithm can be generalized to other channels.

关键词： ml decoding LDPC codes tree-structured expectation propagation graphical models binary erasure channel

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Reduced Cluster Search ml decoding for QO-STBC Systems

Reduced Cluster Search ML Decoding for QO-STBC Systems

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1st International Conference on Advances in Satellite and Space Communications

作者： Suzuki, Isaque Abrao, Taufik Angelico, Bruno A. Ciriaco, Fernando Jeszensky, Paul Jean E. Casadevall, Fernando Univ Estadual Londrina Dept Elect Engn BR-86051990 Londrina PR Brazil Univ Sao Paulo Escola Politecn Dept Telecomm & Control Engn BR-05508900 Sao Paulo SP Brazil Univ Politecn Cataluna Dept Signal Theory & Commun ES-08034 Barcelona Spain

ISBN: (纸本)9781424444267

Since the maximum likelihood (ml) decoding results too complex when the modulation order and the number of receive antennas increase, an efficient reduced complexity ml-based decoding scheme applied to a multiple-input-multiple-output (MIMO) antenna systems with quasi-orthogonal space-time block code (QO-STBC) is proposed, and named reduced cluster search ml decoding (RCS-ml). Its performance and complexity aspects are compared to the conventional ml decoding approach. High-order modulation indexes and short low density parity check codes (LDPC) are considered. Numerical results have indicated no degradation in the performance and an increasing reduction in the complexity of RCS-ml decoding with respect to the conventional ml when the modulation order increases.

关键词： MIMO system QO-STBC ml decoding cluster search LDPC

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Generalized Distributive Law for ml decoding of STBCs

Generalized Distributive Law for ML Decoding of STBCs

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IEEE Information Theory Workshop (ITW)

作者： Natarajan, Lakshmi Prasad Srinath, K. Pavan Rajan, B. Sundar Indian Inst Sci Dept ECE Bangalore 560012 Karnataka India

ISBN: (纸本)9781457704376

The Generalized Distributive Law (GDL) is a message passing algorithm which can efficiently solve a certain class of computational problems, and includes as special cases the Viterbi's algorithm, the BCJR algorithm, the Fast-Fourier Transform, Turbo and LDPC decoding algorithms. In this paper GDL based maximum-likelihood (ml) decoding of Space-Time Block Codes (STBCs) is introduced and a sufficient condition for an STBC to admit low GDL decoding complexity is given. Fast-decoding and multigroup decoding are the two algorithms used in the literature to ml decode STBCs with low complexity. An algorithm which exploits the advantages of both these two is called Conditional ml (Cml) decoding. It is shown in this paper that the GDL decoding complexity of any STBC is upper bounded by its Cml decoding complexity, and that there exist codes for which the GDL complexity is strictly less than the Cml complexity. Explicit examples of two such families of STBCs is given in this paper. Thus the Cml is in general suboptimal in reducing the ml decoding complexity of a code, and one should design codes with low GDL complexity rather than low Cml complexity.

关键词： Block codes Complexity theory Ethics GDL based maximum-likelihood decoding Junctions MIMO communication ml decoding Maximum likelihood decoding STBC conditional maximum-likelihood decoding generalized distributive law maximum likelihood decoding message p

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Comparative Analysis of Convolutional Codes based on ml decoding 2

Comparative Analysis of Convolutional Codes based on ML Deco...

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2nd International Conference on Communication Control and Intelligent Systems (CCIS)

作者： Agrawal, Tarun Kumar, Anjan Saraswat, Shelesh Krishna GLA Univ Dept Elect & Commun Mathura India

ISBN: (纸本)9781509032105

Viterbi algorithm is based on Maximum Likelihood decoding Method. It finds a path from 2(k) total path through trellis that maximizes the path conditional probability. During decoding it compares the metric of all partial path entering each state. this paper involves brief information about Convolutional code in terms of strategies of encoding and decoding of convolutional codes and also, Recursive Systematic Convolutional Encoder is designed with BPSK Modulation and decoding is done by use of ml decoding Method, compares the BER vs SNR performance at different code rates and find that as SNR increases the BER improves and also as number of bits are increases the performance of communication system also improves. At 3 db SNR the BER is 10 boolean AND-2, when the number of bits are 2048 and 4096 at 4db SNR the BER is close to 10 boolean AND-3.

关键词： Convolutional Code LTE ml decoding MAP decoding Burst Error HSDPA Interleaver

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Distance Properties of Short LDPC Codes and Their Impact on the BP, ml and Near-ml decoding Performance 1

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5th International Castle Meeting on Coding Theory and Applications (ICMCTA)

作者： Bocharova, Irina E. Kudryashov, Boris D. Skachek, Vitaly Yakimenka, Yauhen St Petersburg Univ Informat Technol Mech & Opt St Petersburg 197101 Russia Univ Tartu EE-50409 Tartu Estonia

ISBN: (数字)9783319662787

ISBN: (纸本)9783319662787;9783319662770

Parameters of LDPC codes, such as minimum distance, stopping distance, stopping redundancy, girth of the Tanner graph, and their influence on the frame error rate performance of the BP, ml and near-ml decoding over a BEC and an AWGN channel are studied. Both random and structured LDPC codes are considered. In particular, the BP decoding is applied to the code parity-check matrices with an increasing number of redundant rows, and the convergence of the performance to that of the ml decoding is analyzed. A comparison of the simulated BP, ml, and near-ml performance with the improved theoretical bounds on the error probability based on the exact weight spectrum coefficients and the exact stopping size spectrum coefficients is presented. It is observed that decoding performance very close to the ml decoding performance can be achieved with a relatively small number of redundant rows for some codes, for both the BEC and the AWGN channels.

关键词： LDPC code Minimum distance Stopping distance Stopping redundancy BP decoding ml decoding

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Statistical approach to ml decoding of linear block codes on symmetric channels

Statistical approach to ML decoding of linear block codes on...

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IEEE International Symposium on Information Theory

作者： Vikalo, H Hassibi, B CALTECH Dept Elect Engn Pasadena CA 91125 USA

ISBN: (纸本)0780382803

Maximum-likelihood (ml) decoding of linear block codes on a symmetric channel is studied. Exact ml decoding is known to be computationally difficult. We propose an algorithm that finds the exact solution to the ml decoding problem by performing a depth-first search on a tree. The tree is designed from the code generator matrix and pruned based on the statistics of the channel noise. The complexity of the algorithm is a random variable. We characterize the complexity by means of its first moment, which for binary symmetric channels we find in closed-form. The obtained results indicate that the expected complexity of the algorithm is low over a wide range of system parameters.

关键词： maximum likelihood decoding channel coding linear codes block codes telecommunication channels matrix algebra statistical approach ml decoding maximum-likelihood decoding linear block codes binary symmetric channels code generator matrix channel noise tree design

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On the suitability of ml decoding in Analog Multiple Description Schemes 16

On the suitability of ML decoding in Analog Multiple Descrip...

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16th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)

作者： Saez, Aitziber Alustiza, Iker Crespo, Pedro M. Insausti, Xabier Univ Navarra CEIT Donostia San Sebastian 20018 Spain Univ Navarra TECNUN Donostia San Sebastian 20018 Spain

ISBN: (纸本)9781479919314

We consider analog multiple description joint source-channel schemes for the transmission of a Gaussian source over two independent AWGN parallel channels under a quadratic error distortion criteria. For such systems, Lines mapping was proved to be a simple and efficient mapping when MMSE decoding is used. However, MMSE decoding presents a high computational load. In order to reduce complexity of such schemes, this paper studies the suitability of replacing the MMSE decoders by the much simpler ml decoders. The scenario where the ml decoders have some additional side information (Wyner-Ziv scenario) is also analyzed. Their performances are compared with the corresponding theoretical bound and with the obtained simulation results of their MMSE counterparts.

关键词： Analog mappings ml decoding multiple description coding joint source-channel coding

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Efficient Approximate ml decoding Units for Polar List Decoders

Efficient Approximate ML Decoding Units for Polar List Decod...

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IEEE International Workshop on Signal Processing Systems (SiPS)

作者： Xiong, Chenrong Lin, Jun Yan, Zhiyuan Lehigh Univ Dept Elect & Comp Engn Bethlehem PA 18015 USA

ISBN: (纸本)9781467396042

Polar codes are of great interest since they are the first provably capacity-achieving forward error correction codes. To improve throughput of polar decoders, maximum likelihood (ml) decoding units are used by successive cancellation list (SCL) decoders as well as successive cancellation (SC) decoders. In this paper, an approximate ml (Aml) decoding unit with reduced complexity for SCL decoders is proposed. In particular, we investigate the distribution of frozen bits of polar codes designed for the binary erasure channel and additive white Gaussian noise channel, and take advantage of the distribution to reduce the complexity of the Aml decoding unit. Simulation and synthesis results show that the proposed Aml decoding unit has much lower complexity.

关键词： Error control codes polar codes successive cancellation list decoding ml decoding

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