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15th IEEE International Conference on Image Processing (ICIP 2008)

作者： Lee, Szu-Wei Kuo, C. -C. Jay Univ Southern Calif Ming Hsieh Dept Elect Engn Los Angeles CA 90089 USA Univ Southern Calif Signal & Image Proc Inst Los Angeles CA 90089 USA

ISBN: (纸本)9781424417650

complexity modeling of spatial-temporal compensations in H.264/AVC decoding is performed by examining a rich set of inter- and intra-prediction modes. Specifically, we study the relationship between motion vectors, frame sizes and properties of reference frames since they are related to cache management efficiency. The proposed models provide good estimation results for test video bit streams over a wide range of bit rates. As an application, an H.264/AVC encoder equipped with these models estimates the decoding complexity and chooses the best inter- or intra-prediction mode to meet the decoding complexity constraint of a target decoding platform. The decoding complexity of the resultant bit stream is reduced at the cost of small PSNR loss.

关键词： H.264/AVC motion compensation decoding complexity rate-distortion optimization (RDO)

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Flexible complexity Fast decoding of Multiplexed Alamouti Codes in Space-Time-Polarization Systems

Flexible Complexity Fast Decoding of Multiplexed Alamouti Co...

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2010 IEEE 71st Vehicular Technology Conference

作者： Davis, Linda M. Srinivasan, Sudharshan Sirianunpiboon, Songsri Univ South Australia Inst Telecommun Res Adelaide SA 5001 Australia Def Sci & Technol Org Chaklala Pakistan

ISBN: (纸本)9781424425198

Space-time codes built with multiplexed Alamouti components provide multiplexing as well as diversity gain. Their orthogonal structure also leads to simpler decoding algorithms. We consider a 4 x 2 system with multiplexed Alamouti codes. An exhaustive search maximum likelihood (ML) decoding for a 4 x 2 system is of order M-4, for a modulation scheme with constellation size M. For multiplexed orthogonal designs, an exact fast ML decoding algorithm has recently been reported whose complexity order is M-2 for a 4 x 2 system with QAM constellations. Nevertheless, the quadratic complexity of this fast ML algorithm may still be infeasible in practice for large constellations (e. g. M >= 64 QAM). In this paper, we present a method for designing low complexity sub-optimal decoders based on a combination of search based ML decoding and linear decoding. Our formulation facilitates a direct investigation of the trade-off between performance and complexity. The complexity of our hybrid decoder is flexible and it can be fixed based on the desired performance for a hardware implementation. Although extendable to more general multiplexed Alamouti systems, we focus here on a 4 x 2 space-time-polarization system comprising of two dual-polarized transmit antennas and one dual-polarized receive antenna.

关键词： space-time coding polarization maximum likelihood decoding complexity MIMO

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Reduced complexity decoding for Bit-Interleaved Coded Multiple Beamforming with Constellation Precoding

Reduced Complexity Decoding for Bit-Interleaved Coded Multip...

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7th IEEE International Wireless Communications and Mobile Computing Conference (IWCMC)

作者： Li, Boyu Park, Hong Ju Ayanoglu, Ender Univ Calif Irvine Ctr Pervas Commun & Comp Dept Elect Engn & Comp Sci Henry Samueli Sch Engn Irvine CA 92697 USA Samsung Elect Suwon South Korea

ISBN: (纸本)9781424495375

Multiple beamforming is realized by singular value decomposition of the channel matrix which is assumed to be known to both the transmitter and the receiver. Bit-Interleaved Coded Multiple Beamforming (BICMB) can achieve full diversity as long as the code rate R-c and the number of employed sub-channels S satisfy the condition RcS <= 1. Bit-Interleaved Coded Multiple Beamforming with Constellation Precoding (BICMB-CP), on the other hand, can achieve full diversity without the condition RcS <= 1. However, the decoding complexity of BICMB-CP is much higher than BICMB. In this paper, a reduced complexity decoding technique, which is based on Sphere decoding (SD), is proposed to reduce the complexity of Maximum Likelihood (ML) decoding for BICMB-CP. The decreased complexity decoding achieves several orders of magnitude reduction, in terms of the average number of real multiplications needed to acquire one precoded bit metric, not only with respect to conventional ML decoding, but also, with respect to conventional SD.

关键词： MIMO Beamforming Constellation Precoding Bit-Interleaved Coded Modulation SD decoding complexity

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A Low complexity Successive Cancellation List decoding Algorithm of Polar Codes

A Low Complexity Successive Cancellation List Decoding Algor...

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IEEE/CIC International Conference on Communications in China (ICCC)

作者： Miao, Jiansong Li, Weijie Hu, Xuejia Li, Hairui Beijing Univ Posts & Telecommun Beijing Lab Adv Informat Networks Beijing Peoples R China

ISBN: (纸本)9781728173276

Polar codes are the first provably capacity-achieving novel channel codes. Successive cancellation list (SCL) decoding algorithm has a performance close to maximum-likelihood decoding when code length is finite, though the complexity is high. To reduce the complexity of SCL, a partial path expansion with segmented check and pruning SCL (PPE-SCP-SCL) algorithm is proposed in this paper. Based on the successive decoding structure, if the decoding result of a bit is judged to be reliable enough, then a hard decision is made directly and no path expansion is necessary. Moreover, several parity-check points are introduced to perform segmented parity-check during the decoding process, and if the check fails, the current path is directly abandoned. The rationality of the operations is theoretically verified, and numerical simulations also verify that the proposed algorithm can significantly reduce the complexity of decoding with trivial loss of error performance.

关键词： polar codes SCL decoding complexity

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On the complexity of suboptimal decoding for list and decision feedback schemes

On the complexity of suboptimal decoding for list and decisi...

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International Workshop on Coding and Cryptography (WCC 2003)

作者： Freudenberger, J Zyablov, V Univ Ulm Dept Telecommun & Appl Informat Theory D-89081 Ulm Germany Russian Acad Sci Inst Informat Transmiss Problems Moscow 101447 Russia

We consider bounded distance list decoding, such that the decoder calculates the list of all codewords within a sphere around the received vector. We analyze the performance and the complexity of this suboptimum list decoding scheme for the binary symmetric channel. The reliability function of the list decoding scheme is equivalent to the sphere-packing bound, where the decoding complexity is asymptotically bounded by 2(nR)(1-R). Furthermore, we investigate a decision feedback strategy that is based on bounded distance list decoding. Here, any output with zero or many codewords will call for a repeated transmission. In this case the decoding complexity will be of the order 2(nR)(1-C), where C denotes the channel capacity. The reliability function is close to Forney's feedback exponent. (c) 2005 Elsevier B.V. All rights reserved.

关键词： list decoding decision feedback bounded distance decoding error exponent decoding complexity

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LEARNING-BASED POINT CLOUD decoding WITH INDEPENDENT AND SCALABLE REDUCED complexity 31

LEARNING-BASED POINT CLOUD DECODING WITH INDEPENDENT AND SCA...

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2024 International Conference on Image Processing

作者： Ghafari, Mohammadreza Guarda, Andre F. R. Rodrigues, Nuno M. M. Pereira, Fernando Inst Super Tecnico Univ Lisboa Lisbon Portugal ESTG Politecn Leiria Leiria Portugal Inst Telecomun Lisbon Portugal

ISBN: (纸本)9798350349405;9798350349399

Point Clouds (PCs) have gained significant attention due to their usage in diverse application domains, notably virtual and augmented reality. While PCs excel in providing detailed 3D visualization, this typically requires millions of points which must be efficiently coded for real-world deployment, notably storage and streaming. Recently, learning-based coding solutions have been adopted, notably in the JPEG Pleno Point Coding (PCC) standard, which uses a coding model with millions of model parameters. This requires the use of high-performance computing devices, which may not be available, notably at the decoder side. In this context, this paper proposes two reduced complexity decoding solutions, based on the adoption of scalability principles, to decode the same JPEG PCC compliant bitstreams. The design of these solutions is based on two innovative model pruning strategies which reduce the decoding complexity. The experimental results demonstrate the effective capability to significantly reduce the number of decoding model parameters with an acceptable penalty on Rate-Distortion (RD) performance compared to the full complexity model.

关键词： Learning-based Point Cloud Coding decoding complexity Scalability

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Research on encoding and decoding of non-binary polar codes over GF(2m)

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Digital Communications and Networks 2022年第3期8卷 359-372页

作者： Shufeng Li Mingyu Cai Robert Edwards Yao Sun Libiao Jin The State Key Laboratory of Media Convergence and Communication School of Information and EngineeringCommunication University of ChinaBeijing100024China The Wolfson School of Mechanical Electrical and Manufacturing Engineering Loughborough UniversityLeicestershireLE113TEUK James Watt School of Engineering University of GlasgowG128QQScotlandUK

Binary Polar Codes (BPCs) have advantages of high-efficiency and capacity-achieving but suffer from large latency due to the Successive-Cancellation List (SCL) decoding. Non-Binary Polar Codes (NBPCs) have been investigated to obtain the performance gains and reduce latency under the implementation of parallel architectures for multi-bit decoding. However, most of the existing works only focus on the Reed-Solomon matrix-based NBPCs and the probability domain-based non-binary polar decoding, which lack flexible structure and have a large computation amount in the decoding process, while little attention has been paid to general non-binary kernel-based NBPCs and Log-Likelihood Ratio (LLR) based decoding methods. In this paper, we consider a scheme of NBPCs with a general structure over GF(2m). Specifically, we pursue a detailed Monte-Carlo simulation implementation to determine the construction for proposed NBPCs. For non-binary polar decoding, an SCL decoding based on LLRs is proposed for NBPCs, which can be implemented with non-binary kernels of arbitrary size. Moreover, we propose a Perfect Polarization-Based SCL (PPB-SCL) algorithm based on LLRs to reduce decoding complexity by deriving a new update function of path metric for NBPCs and eliminating the path splitting process at perfect polarized (i.e., highly reliable) positions. Simulation results show that the bit error rate of the proposed NBPCs significantly outperforms that of BPCs. In addition, the proposed PPB-SCL decoding obtains about a 40% complexity reduction of SCL decoding for NBPCs.

关键词： Non-binary polar code Log-likelihood ratio Successive-cancellation list Perfect polarization based-SCL decoding complexity

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Extended EVENODD plus and STAR plus With Asymptotic Optimal Update and Efficient decoding

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IEEE TRANSACTIONS ON COMMUNICATIONS 2023年第5期71卷 2563-2575页

作者： Hou, Hanxu Dongguan Univ Technol Sch Elect Engn & Intelligentizat Dongguan 523808 Peoples R China

The increasing capacity of storage devices and the growing frequency of correlated failures demands better fault tolerance by using maximum distance separable (MDS) array codes with triple-parity. Although many constructions of triple-parity MDS array codes have been proposed, they either have large update complexity or have large encoding/decoding complexity or only support specified parameters. In this paper, we propose two classes of triple-parity MDS array codes, called extended EVENODD+ and STAR+ that both have asymptotically optimal update complexity and lower encoding/decoding complexity. We show that the existing extended EVENODD and STAR are a special case of our extended EVENODD+ and STAR+, respectively. Moreover, we show that our extended EVENODD+ and STAR+ have strictly less encoding/decoding/update complexity than that of extended EVENODD and STAR for most parameters.

关键词： Codes complexity theory Stars decoding Arrays Research and development Reliability Extended EVENODD STAR codes MDS array codes update complexity decoding complexity

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Analysis and design of a new fountain codec under belief propagation

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IET COMMUNICATIONS 2014年第1期8卷 27-40页

作者： Mirrezaei, Seyed Masoud Faez, Karim Yousefi, Shahram Amirkabir Univ Technol EE Tehran Iran Queens Univ ECE Kingston ON Canada

Error-prone patterns have been extensively studied for low-density parity-check codes yet they have never been fully explored for generator-based ‘Fountain codes’. It is shown here that these phenomena are related to certain combinatorial structures within the Tanner graph (TG) representation of the code, previously termed absorbing sets. The authors systematically define the ‘absorbing sets’ in the generator-based TG of a code. They then demonstrate how these substructures are damaging to the ‘realised rate, delay’ and ‘decoding cost’ of Fountain codes particularly at low error rates. They further analyse the existence probability of certain absorbing sets and propose a new encoder/decoder pair forming a new family of Fountain codes. The authors experimental results show that these new codecs lead to improvements in all system features. Typical gains for Luby-transform codes include 20 % reduction in the decoding complexity and simultaneous coding gains of 0.6 and 0.9 dB at bit error rates of 10 − 5 and 10 − 6 , respectively. As such, this work takes a step towards better rateless code design and construction.

关键词： belief maintenance graph theory parity check codes probability fountain codec belief propagation error-prone patterns low-density parity-check codes fountain codes combinatorial structures Tanner graph representation generator-based TG existence probability Luby-transform codes decoding complexity bit error rates

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High-Rate, Multisymbol-Decodable STBCs From Clifford Algebras

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IEEE TRANSACTIONS ON INFORMATION THEORY 2009年第6期55卷 2682-2695页

作者： Karmakar, Sanjay Rajan, B. Sundar Univ Colorado Elect & Comp Sci Engn Dept Boulder CO 80309 USA Indian Inst Sci Dept Elect Commun Engn Bangalore 560012 Karnataka India

It is well known that space-time block codes (STBCs) obtained from orthogonal designs (ODs) are single-symbol decodable (SSD) and from quasi-orthogonal designs (QODs) are double-symbol decodable (DSD). However, there are SSD codes that are not obtainable from ODs and DSD codes that are not obtainable from QODs. In this paper, a method of constructing g-symbol decodable (g-SD) STBCs using representations of Clifford algebras are presented which when specialized to g = 1, 2 gives SSD and DSD codes, respectively. For the number of transmit antennas 2(a) the rate (in complex symbols per channel use) of the g-SD codes presented in this paper is a+1-g/2(a-9). The maximum rate of the DSD STBCs from QODs reported in the literature is a/2(a-1) which is smaller than the rate a-1/2(a-2) of the DSD codes of this paper, for 2(a) transmit antennas. In particular, the reported DSD codes for 8 and 16 transmit antennas offer rates 1 and 3/4, respectively, whereas the known STBCs from QODs offer only 3/4 and 1/2, respectively. The construction of this paper is applicable for any number of transmit antennas. The diversity sum and diversity product of the new DSD codes are studied. It is shown that the diversity sum is larger than that of all known QODs and hence the new codes perform better than the comparable QODs at low signal-to-noise ratios (SNRs) for identical spectral efficiency. Simulation results for DSD codes at various spectral efficiencies are provided.

关键词： Clifford algebra decoding complexity diversity space-time block codes (STBCs)

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