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Throughput performance of parallel and repetition coding in incremental decode-and-forward relaying

WIRELESS NETWORKS 2012年第8期18卷 881-892页

作者： Alves, Hirley Souza, Richard Demo Fraidenraich, Gustavo Pellenz, Marcelo Eduardo Fed Univ Technol UTFPR CPGEI BR-80230901 Curitiba Parana Brazil Univ Oulu CWC Oulu 90014 Finland Univ Campinas Unicamp Commun Dept BR-13083852 Campinas SP Brazil Pontifical Catholic Univ Parana PUC PR PPGIA BR-80215901 Curitiba Parana Brazil

The throughput performance of cooperative repetition and parallel coding in incremental decode-and-forward is investigated. Four transmission methods are considered: parallel coding with and without distributed space-time coding (PC-ST and PC, respectively);and repetition coding with and without Chase combining at the destination (RC and SC, respectively). The analysis is based on the mutual information seen at the receiver for each scheme. Exact expressions for the outage probability and throughput for all methods are derived. Both ad-hoc and infra-structured relaying scenarios are investigated. Results show that SC can perform very close to RC, PC and PC-ST in terms of throughput, specially in the case of infra-structured relaying or adequate power and rate allocation. The conclusion is that SC would be a better option in practice, since it requires a simpler receiver than PC-ST, PC, and RC.

关键词： Cooperative communications Incremental decode-and-forward Repetition coding parallel coding Power and rate allocation

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coding Regions of Intrinsic Disorder Accommodate parallel Functions

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TRENDS IN BIOCHEMICAL SCIENCES 2016年第11期41卷 898-906页

作者： Pancsa, Rita Tompa, Peter Vrije Univ Brussel Struct Biol Res Ctr Flanders Inst Biotechnol VIB Pl Laan 2 B-1050 Brussels Belgium Hungarian Acad Sci Res Ctr Nat Sci Inst Enzymol Magyar Tudosok Korutja 2 H-1117 Budapest Hungary

Numerous DNA- and RNA-level functions are embedded in protein-coding regions, which constrains their structure, function, and evolution. Accumulating evidence suggests that such additional, overlapping functions occur preferentially in the coding sequences of intrinsically disordered proteins/regions (IDPs/IDRs), especially in those that are newly incorporated and thus have reduced selective pressure. It is the lack of strict structural constraints that makes disordered proteins more tolerant to mutations and thus more permissive to the appearance of overlapping functions within their coding sequences than structured domains. Therefore, IDPs/IDRs are often mosaics of segments fulfilling protein functionalities and intervening regions primarily carrying nucleotide-level functions. The ensuing complexification of gene-regulatory circuits may have contributed to the evolutionary spread of structural disorder in complex eukaryotic organisms.

关键词： intrinsically disordered parallel coding overlapping codes structural constraint exonic regulatory code intrinsically disordered intervening region

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Real-Time Reconstruction of 3D Videos From Single-Photon LiDaR Data in the Presence of Obscurants

IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING

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IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING 2023年 9卷 106-119页

作者： Plosz, Sandor Maccarone, Aurora McLaughlin, Stephen Buller, Gerald S. Halimi, Abderrahim Heriot Watt Univ Sch Engn & Phys Sci Edinburgh EH14 4AS Scotland

Single-photon methods are emerging as a key approach to 3D imaging. This paper introduces a two step statistical based approach for real-time image reconstruction applicable to a transmission medium with extreme light scattering conditions. The first step is an optional target detection method to select informative pixels which have photons reflected from the target, hence allowing data compression. The second is a reconstruction algorithm that exploits data statistics and multiscale information to deliver clean depth and reflectivity images together with associated uncertainty maps. Both methods involve independent operations that are implemented in parallel on graphics processing units (GPUs), which enables real-time data processing of moving scenes at more than 50 depth frames per second for an image of 128 x 128 pixels. Comparisons with state-of-the-art algorithms on simulated and real underwater data demonstrate the benefit of the proposed framework for target detection, and for fast and robust depth estimation at multiple frames per second.

关键词： Photonics Reflectivity Imaging Real-time systems Object detection Laser radar Histograms 3D reconstruction Lidar obscurants real-time estimation GPUs parallel coding Poisson noise

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Optical parallel transmission with multi-wavelength for high speed communications on indoor channels

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IEICE TRANSACTIONS ON COMMUNICATIONS 1998年第4期E81B卷 729-736页

作者： Tanaka, Y Nakagawa, M Keio Univ Fac Sci & Technol Yokohama Kanagawa 2238522 Japan

In indoor optical channels. intersymbol interference (ISI) due to multipath propagation prevents high data rate transmission. In this paper, a new Optical Multi-Wavelength Modulation technique has been investigated for improving the quality of transmission. In this technique, parallel transmission is used, which lowers the data rate per channel and thus reduces the effects of ISI. Furthermore, parallel coding is used in predetermined parallel branches, so that coding can correct errors without changing the system data rate. Simulation results show that a combination of these methods can achieve high quality transmission without reduction of the total data rate.

关键词： optical wireless LAN intersymbol interference (ISI) multipath dispersive channel multi-wavelength transmission parallel coding

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Cooperative Transmission Based on Decode-and-Forward Relaying with Partial Repetition coding

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2009年第4期8卷 1716-1725页

作者： Khormuji, Majid Nasiri Larsson, Erik G. Royal Inst Technol KTH Sch Elect Engn S-10044 Stockholm Sweden Royal Inst Technol KTH ACCESS Linnaeus Ctr S-10044 Stockholm Sweden Linkoping Univ Dept Elect Engn ISY S-58183 Linkoping Sweden

We propose a novel half-duplex decode-and-forward relaying scheme based on partial repetition coding at the relay. In the proposed scheme, if the relay decodes the received message successfully, it re-encodes the message using the same channel code as the one used at the source, but retransmits only a fraction of the codeword. We analyze the proposed scheme and optimize the cooperation level (i.e., the fraction of the message that the relay should transmit). We compare our scheme with conventional repetition in which the relay retransmits the entire decoded message, with parallel coding, and additionally with dynamic decode-and-forward (DDF). We provide a finite-SNR analysis for all the collaborative schemes. The analysis reveals that the proposed partial repetition method can provide a gain of several dB over conventional repetition. It also shows that in general, power allocation is less important provided that one optimally allocates bandwidth. Surprisingly, the proposed scheme is able to achieve the same performance as that of parallel coding for some relay network configurations, but at a much lower complexity.

关键词： Relay channel cooperative diversity parallel coding repetition coding resource allocation power allocation bandwidth allocation

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parallel coded optical multicarrier frequency division multiplexing - A potential step towards high speed, high capacity and high reliability in optical transmission systems

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IEICE TRANSACTIONS ON COMMUNICATIONS 1996年第11期E79B卷 1677-1687页

作者： Raziq, P Nakagawa, M Department of Electrical Engineering Keio University Yokohama-shi 223 Japan

Optical Frequency Division Multiplexing (OFDM) is an attractive multiplexing approach for exploiting optical communication technology. Although considerable progress has been made in this approach, it still suffers from numerous potential impairments, stemming From several phenomena. (i.e., laser unstability, residual temperature variations, linear and nonlinear cross talk.). Conventional serial coding technique is not practical in lightwave systems, as it changes the system's bit rate that is not desirable. In this paper a new parallel Coded Optical Multicarrier Frequency Division Multiplexing (PCOM-FDM) technique has been investigated. The strategy of multicarriers, together with parallel Forward Error Control (PFEC) coding, is a potentially novel approach as in this approach we have, 1) Investigated optical multicarrier communication that is effective in combating dispersion and increasing throughput, 2) Proposed PFEC coding which is different from conventional serial coding in respect that it does not change the system bit rate per carrier and prevents the effects of channel wandering. It is highly desirable in lightwave systems and thus holds a vital importance in practical high speed optical communication systems. Theoretical treatment shows that the proposed approach is promising and practical.

关键词： parallel coding optical multicarrier FDM Hsiao codes error correction error erasure correction

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A real-time video watermarking system with buffer sharing for video-on-demand service

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COMPUTERS & ELECTRICAL ENGINEERING 2009年第2期35卷 395-414页

作者： Wang, Ju Liu, Jonathan C. L. Masilela, Mbonisi Virginia Commonwealth Univ Dept Comp Sci Richmond VA 23284 USA Univ Florida CISE Dept Gainesville FL USA

Real-time watermarking for streaming video (such as VOD service) requires significant amounts of computing resources. To address this issue, we present a scalable watermarking scheme integrated in a parallel MPEG-2 engine. A content-based block selection algorithm is proposed to efficiently embed the pseudo-random watermark signatures into DCT blocks. Our watermark scheme also provides a robust way to synchronize the watermarked video to the original source at detectors and is very resilient against cumulative and temporal attack. We optimize the parallel watermark engine to achieve real-time watermarking performance. We found that the system throughput could suffer significant degradation when processing high-level MPEG-2 video (such as HDTV) due to inefficient management of memory space. Therefore, we investigated an efficient buffer management scheme consisting of two methods: First we reduced the transmission buffer in slave nodes by frames sharing between frames in the Group-of-Picture (GOP) level. Then we further reduce the buffer space by a dynamic on-demand allocation on the slave side. By solving the memory-shortage bottleneck, the proposed system can support real-time watermarking for multiple high-resolution (up to 1404 x 960) video. Published by Elsevier Ltd.

关键词： Transcoding Video watermark Video-on-demand MPEG parallel coding Buffer management

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parallelization methodology for video coding - An implementation on the TMS320C80

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2000年第8期10卷 1413-1425页

作者： Leung, KK Yung, NHC Cheung, PYS Univ Hong Kong Dept Elect & Elect Engn Hong Kong Hong Kong Peoples R China

This paper presents a parallelization methodology for video coding based on the philosophy of hiding as much communications by computation as possible, It models the task/data size, processor cache capacity, and communication contention, through a systematic decomposition and scheduling approach. With the aid of Petri-nets and task graphs for representation and analysis, it employs a triple buffering scheme to enable the functions of frame capture, management, and coding to be performed in parallel. The theoretical speedup analysis indicates that this method offers excellent communication hiding, resulting in system efficiency well above 90%. To prove its practicality, a H.261 video encoder has been implemented on a TMS320C80 system using the method. Its performance was measured, from which the speedup and efficiency figures were calculated. The only difference detected between the theoretical and measured data is the program control overhead that has not been accounted for in the theoretical model. Even with this, the measured speedup of the H.261 is 3.67 and 3.76 on four parallel processors (PPs) for QCIF and 352 x 240 video, respectively, which correspond to frame rate of 30.7 and 9.25 frames per second, and system efficiency of 91.8 % and 94 %, respectively. This method is particularly efficient for platforms with small number of parallel processors.

关键词： efficiency H.261 H.263 parallel coding petri-net speedup

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parallel implementation of HEVC encoder on multicore ARM-based platform 16

Parallel implementation of HEVC encoder on multicore ARM-bas...

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16th International Multi-Conference on Systems, Signals and Devices (SSD)

作者： Bahri, Nejmeddine Maazouz, Mohamed Khemiri, Randa Masmoudi, Nouri Univ Sfax Natl Sch Engineers Lab Elect & Informat Technol Sfax Tunisia Univ Medea LSEA Lab Dept Elect Engn Saad Dahleb Blida Medea Algeria Univ Monastir Fac Sci Lab Elect & Microelect Monastir Tunisia

ISBN: (纸本)9781728118208

High Efficiency Video coding (HEVC) is the new emerging standard released as a successor to H.264/AVC. It aims to improve the encoding performance by saving 50% of the bitrate with the same visual quality. This encoding performance makes it more suitable for high definition video applications and could be the next embedded video codec on the majority of multimedia devices. However, this performance is coupled with tremendous computational complexity which makes it very hard to achieve a real-time video encoding with classic embedded processor architectures. Consequently, multicore technology of programmable processors offers a very promising solution to overcome this complexity. In this context, this paper presents a parallel implementation of the HEVC encoder All-Intra (AI) configuration on Quad-core ARM-based platform running at 1.7GHz. OpenMP is used as parallel programming paradigm exploiting the Frame Level parallelism technique. Experimental results show that parallel processing using four threads allows saving up to 73% of encoding time and speeds up the encoding process by a factor of 3.77 without any rate distortion in terms of video quality or bitrate.

关键词： HEVC parallel coding OpenMP multicore ARM architecture

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Research on a parallel Rate Control Algorithm of Macro-Block Layer 15th

Research on a Parallel Rate Control Algorithm of Macro-Block...

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15th International Forum on Digital TV and Multimedia Communication (IFTC)

作者： Ding, Min Huang, Lulu Li, Guoping Wang, Guozhong Shanghai Univ Sch Commun & Informat Engn Shanghai 200444 Peoples R China

ISBN: (纸本)9789811381386;9789811381379

In order to efficiently transmit video data while satisfying the channel bandwidth and transmission delay constraints, bit rate control of the video encoding process is required. According to ultra-high-definition video, traditional coding algorithms have a large amount of caculation and high computational complexity, thus, parallel coding methods such as inter-frame parallel coding and wavefront parallel coding (WPP) are proposed. However, the rate control of parallel coding is a difficult problem, especially the intra-frame rate control under the WPP coding mode, so this paper proposes a bit rate control algorithm within macro-block layer. By contrasting the PSNR, the encoding speed and the VBV (Video Buffer Verifier) buffer condition of the video sequences, the algorithm proposed in this paper has advantages of less computing cost and faster coding speed than the traditional algorithms.

关键词： parallel coding Rate control Intra-frame coding Quantization parameter Wavefront parallel processing

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