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coding complexity Prediction for H.264/AVC Rate Control

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2009年第8期E92D卷 1592-1595页

作者： Zhou, Yimin Tian, Ling Univ Elect Sci & Technol China Sch Engn & Comp Sci Chengdu 610054 Sichuan Peoples R China

coding complexity is a crucial parameter in rate control scheme. Traditional measures for coding complexity are based on statistic and estimation. This way may cause the imprecise coding complexity and finally bring inaccurate output bit rate more or less. To resolve this problem, we propose a hypothetical virtual coding complexity to imitate the real coding complexity. Based on the proposed coding complexity measure, a novel rate control algorithm is proposed either. Experimental results and analysis show that the proposed mearsure for coding complexity is effective, and our scheme outperforms the JVT-W042 solution by providing more accurate QP prediction, reducing frame skipping, and improving visual quality.

关键词： rate control H.264/AVC coding complexity bit allocation

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A Low-complexity Multiuser coding Scheme With Near-Capacity Performance

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2017年第8期66卷 6775-6786页

作者： Song, Guanghui Wang, Xianbin Cheng, Jun Singapore Univ Technol & Design Cluster Sci Singapore 487372 Singapore Univ Western Ontario Dept Elect & Comp Engn London ON N6A 3K7 Canada Doshisha Univ Dept Intelligent Informat Engn & Sci Kyoto 6100321 Japan

Nonorthogonal multiuser coding is an essential technique for superimposed transmission and improving spectrum efficiency of future wireless communication networks. In this paper, a low-complexity nonorthogonal coding scheme, called multiuser repetition-aided irregular repeat-accumulate (IRA) code, is proposed for a multiple access channel (MAC), and the scheme can be applied to fifth-generation (5G) nonorthogonal multiple access systems. The main idea is that not only parity checks, which are generated by an IRA encoder, but repetitions as well, are used in each user's codeword to reduce the coding and decoding complexities. Repetition is a simple way to construct a low-rate code and is shown to be beneficial for multiuser decoding iteration. With a deliberate control of the fraction of repetitions in the codeword and a degree distribution optimization of the IRA encoder, near MAC capacity performance is achieved. It is shown that as the number of users increases, more repetitions can be used, and therefore, very low encoding and decoding complexities are required.

关键词： coding complexity low-rate code nonorthogonal multiple access (NOMA) repetition-aided irregular repeat-accumulate (IRA) code

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Low-complexity QTMT partition based on deep neural network for Versatile Video coding

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SIGNAL IMAGE AND VIDEO PROCESSING 2021年第6期15卷 1153-1160页

作者： Abdallah, Bouthaina Belghith, Fatma Ben Ayed, Mohamed Ali Masmoudi, Nouri Univ Sfax Elect & Informat Technol Lab Natl Engn Sch Sfax Sfax Tunisia

Versatile Video coding (VVC), the newest standard for future video coding, is currently under development. This proposal aimed to improve the encoder performance over the latest standard namely High Efficiency Video coding, carried with a high increase in coding complexity. The VVC partition structure is mainly based on the quadtree with nested multi-type tree (QTMT) block scheme. Such an improvement leads to a more flexible block partition and promotes a high encoding efficiency, but generates a huge coding complexity. In order to deal with this issue, a fast QTMT intra partition algorithm, based on a deep neural network named Early Terminated Hierarchical Convolution Neural Network, is applied to predict the 64x64 block QT partition structure. The proposed algorithm determines the QTMT partition structure based on the decision of whether to split or skip the corresponding CU, in order to get 128x128 coding Tree Unit partition architecture. In this paper, the proposed intra partition work achieves a significant speedup in encoding gain that reaches 32.96% in best cases for Ultra High Definition video sequences compared to the reference VVC software VTM-3.0. For all video sequences, 24.49% time saving is reached on average. This improvement comes with an increase of 4.18% and a decrease of 0.18 dB in terms of BDBR and BDPSNR, respectively.

关键词： Versatile Video coding (VVC) Nested multi-type tree (QTMT) coding complexity Intra partition Deep neural network

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Random coding error exponents for two-dimensional flat fading channels with complete channel state information

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IEEE TRANSACTIONS ON INFORMATION THEORY 1999年第4期45卷 1338-1346页

作者： Ahmed, WKM McLane, PJ AT&T Bell Labs Lucent Technol Holmdel NJ 07733 USA Queens Univ Dept Elect & Comp Engn Kingston ON K7L 3N6 Canada

In this correspondence, we consider the random coding error exponent for nondispersive two-dimensional (2-D) (quadrature) fading channels for which the channel state information (CSI) is perfectly known at the receiver and the input to the transmitter is constrained in its average power. Also, the effect of space diversity on improving the performance is demonstrated. The results obtained in this correspondence shed light on the effect of fading on communications reliability as well as the amount of coding complexity required to achieve a certain decoding error rate. A treatment for the random coding error exponent for time-correlated flat fading channels with Rayleigh fading and Bessel function correlation (the Jake's model) is also provided.

关键词： average and peak-power constraints coding complexity fading channels mobile fading model Nakagami fading model random coding exponent space diversity time-correlated fading

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On the redundancy of trellis lossy source coding

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IEEE TRANSACTIONS ON INFORMATION THEORY 2002年第1期48卷 205-218页

作者： Zhou, GC Zhang, Z Univ So Calif Dept Elect Engn Syst Inst Commun Sci Los Angeles CA 90089 USA

It is well known that trellis lossy source codes have better performance/complexity tradeoff than block codes, as shown by simulations. This makes the trellis coding technique attractive in practice. To get a better understanding of this fact, this paper studies the redundancy of trellis coding for memoryless sources and compares it with a similar result for block codes. It was known that for block codes of block length n, the nth-order distortion redundancy D-n(R) at fixed rate R greater than or equal to 0 equals - partial derivatived(p, R/partial derivativeR) ln n/2n + o(ln n/n), where partial derivatived(p, R/partial derivativeR) is the partial derivative of d(p, R), the distortion-rate function of a source p, evaluated at R and assumed to exist. Since e(nR), the number of codewords of the block code, can be used as an approximate measure of both the storage complexity C-s of the code and the computational complexity C-c per source symbol for full search encoding, the redundancy can be written as functions of the complexity measures in the form D(R, C-s) approximate to partial derivatived(p, R)/partial derivativeR R ln ln C-s/2 ln C-s and D(R, C-s) approximate to partial derivatived(p, R)/partial derivativeR R ln ln C-c/2 ln C-c In this paper, it is demonstrated that for a particular trellis lossy source code with storage complexity C-s = e(2nR) and computational complexity C-c = e(2nR) (assuming the Viterbi algorithm is used for encoding), the distortion redundancy satisfies D-n(R) less than or equal to c(p, R)/n where c(p, R) is a constant independent of n. For this code, the complexity/redundancy tradeoff can be written as D(R, C-s) approximate to 2Rc(p, R)/ln C-c + o(1/ln C-s) and D(R, C-c) approximate to 2Rc(p, R)/ln C-c + o(1/ln C-c) which shows that trellis coding improves the redundancy/complexity tradeoff over block coding by roughly a factor ln ln C-c.

关键词： coding complexity random coding argument rate distortion (distortion rate) function redundancy trellis source coding

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Fountain Communication using Concatenated Codes

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IEEE TRANSACTIONS ON COMMUNICATIONS 2013年第2期61卷 443-454页

作者： Wang, Zheng Luo, Jie Seagate Technol LLC Longmont CO 80503 USA Colorado State Univ Dept Elect & Comp Engn Ft Collins CO 80523 USA

This paper extends linear-complexity concatenated coding schemes to fountain communication over the discrete-time memoryless channel. Achievable fountain error exponents for one-level and multi-level concatenated fountain codes are derived. Several important properties of the concatenated coding schemes in multi-user fountain communication scenarios are demonstrated.

关键词： coding complexity concatenated codes error exponent fountain communication

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A Class of Binary Locally Repairable Codes

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IEEE TRANSACTIONS ON COMMUNICATIONS 2016年第8期64卷 3182-3193页

作者： Shahabinejad, Mostafa Khabbazian, Majid Ardakani, Masoud Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2R3 Canada

An (n, k) erasure code that can recover any coded symbol by at most r other coded symbols is called a locally repairable code (LRC) with locality r. LRCs have been recently implemented in distributed storage systems. coding complexity reduction can be significantly decreased by using binary LRCs (BLRCs) as they eliminate costly multiplication calculation. In this paper, motivated by the recently erasure codes with d = 4 used in practice, we propose BLRCs when (r + 1) vertical bar n and d = 4. We prove that our proposed binary codes are optimal for r is an element of {1, 3}, meaning that neither their locality nor their minimum distance can be improved by non-binary codes. For r >= 4, our proposed binary codes offer near-optimal code rate, with a rate gap of O(log r/n) compared with optimal non-binary codes. While keeping the bulk of code structure binary, we eliminate this rate gap by using fields with sizes as small as r + 2 for only two redundant symbols. These non-binary codes still eliminate the need for costly multiplications in many operations including a single failure repair (a dominant repair scenario). Using the construction of spanning BLRC with d = 4 as a backbone, we also construct LRCs with minimum distance d >= 6. Furthermore, we obtain a closed-form equation for the mean-time to data-loss of arbitrary erasure codes.

关键词： Erasure coding distributed storage systems coding complexity binary locally repairable codes

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Objective and subjective quality assessment between JPEG XR with overlap and JPEG 2000

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2012年第6期23卷 835-844页

作者： Fiorucci, Federico Baruffa, Giuseppe Frescura, Fabrizio DIEI Univ Perugia I-06125 Perugia Italy

JPEG XR (eXtended Range) is a recently standardized format for still images compression. It adopts a Lapped Biorthogonal Transform (LBT) that helps in reducing visual artifacts, in particular those due to blocking effects. In this paper, we compare JPEG XR with JPEG 2000, in terms of both objective and subjective visual quality. The adopted objective parameters are the computational complexity and the PSNR. In order to improve the analysis, and to evaluate if JPEG XR can be a feasible alternative to JPEG 2000, subjective tests in a projector-based environment have been set up, from which the benefits of the overlap operator of JPEG XR have been assessed, especially at high compression ratios. (c) 2012 Elsevier Inc. All rights reserved.

关键词： JPEG XR JPEG 2000 Overlap operator Subjective assessment Stimulus comparison Digital projection VIF coding complexity

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complexity scalable intra-prediction mode decision algorithm for mobile video applications

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IET COMMUNICATIONS 2014年第9期8卷 1654-1662页

作者： Song, Yun Long, Jizhen Yang, Kun Yang, Gaobo Hunan Univ Sch Informat Sci & Engn Changsha 410082 Hunan Peoples R China Changsha Univ Sci & Technol Sch Comp & Commun Engn Changsha 410004 Hunan Peoples R China Univ Essex Sch Comp Sci & Elect Engn Colchester CO4 3SQ Essex England

The full search scheme employed in H.264/AVC significantly improves the coding performance, but it also introduces a very high computational complexity which limits the applications in resource-constrained mobile devices. In this study, the authors firstly present a discretisation total variation and orientation gradient-based hierarchical intra-prediction mode decision method for mobile video applications. By shrinking the candidate mode set in the rate-distortion optimisation (RDO) process, the proposed algorithm reduces the computational complexity and power consumption of the encoder. Furthermore, they extend the hierarchical algorithm to a complexity scalable version in which the coding complexity is measured on five levels by reserving various numbers of modes for RDO. Experimental results demonstrate that the proposed mode decision algorithm reduces the coding complexity significantly with negligible performance degradation and the proposed complexity scalable algorithm is effective and efficient for mobile video application.

关键词： video coding rate distortion theory optimisation video streaming computational complexity gradient methods full search scheme H.264-AVC coding performance computational complexity resource-constrained mobile devices discretisation total variation candidate mode set rateâ€“distortion optimisation process RDO process power consumption encoder hierarchical algorithm coding complexity mode decision algorithm orientation gradient-based hierarchical intraprediction mode decision method mobile video applications

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Random coding error exponents for flat fading channels with realistic channel estimation

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2000年第3期18卷 369-379页

作者： Ahmed, WKM McLane, PJ Lucent Technol Bell Labs Holmdel NJ 07733 USA Queens Univ Dept Elect & Comp Engn Kingston ON K7L 3N6 Canada

Recently, there has been a considerable interest in determining the limits to communications over multipath fading channels. However, most studies have assumed that the channel is perfectly known at the receiver. In this paper, the random coding error exponent for flat fading channels with realisitic channel state information (CSI) is studied. It is assumed that the CSI is obtained via some practical technique which utilizes a linear estimation scheme. Two commonly used techniques for channel estimation are considered in this paper, namely pilot tone extraction and pilot symbol transmission. The degradation in the achievable performance due to partial CSI is assessed and comparison of the different channel estimation methods is made. The focus of this paper is on the Jake's mobile Rayleigh flat fading model. Although Jake's model does not have a Markov property, such as that found in the commonly used exponential correlation model, which is usually attractive from the mathematical tractability point of view, Jake's model has a physical basis. Also, this model is considered herein from the standpoint of the random coding exponent. The results in this paper shed light on the amount of degradation in the achievable performance that is expected when the receiver has partial CSI, Finally, the sensitivity of the loss in achievable performance for the various channel estimation techniques with respect to channel parameters, such as Doppler spread and signal-to-noise ratio (SNR), is studied.

关键词： average power constraints channel capacity channel state information (CSI) channels with side information coding complexity fading channels random coding error exponent reliability function Rician fading model

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