共查询到20条相似文献,搜索用时 31 毫秒
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Chih-Ming Fu Wen-Liang Hwang Chung-Lin Huang 《Journal of Visual Communication and Image Representation》2006,17(6):1164-1177
We propose an analytical rate-distortion optimized joint source and channel coding algorithm for error-resilient scalable encoded video for lossy transmission. A video is encoded into multiple independent substreams to avoid error propagation and is assigned forward error correction (FEC) codes and source bits using Lagrange optimization. Our method separates video coding and packetization into different tiers which can be easily incorporated into any coding structure that generates a set of independent compressed bit-streams. To demonstrate the performance, we use the 2-state Markov model to describe the burst loss channel and Reed-Solomon codes as forward error correction codes. Simulation results show that the proposed channel incorporated rate-distortion optimization approach have better performance. 相似文献
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In a downlink multiuser multiple-input multiple-output channel, joint transceiver designs based on geometric mean decomposition and uniform channel decomposition can provide a BER performance enhancement by making all substreams of each user have the same SINR. However, if a user power allocation (uPA) algorithm is not applied in their designs, they actually make the same SINR for all substreams in each user while causes different SINR with one another, and therefore the average BER is dominated by the user with the worst SINR. In this regards, it is possible to enhance BER performance further provided that the uPA algorithm is taken into account under a total power constraint. The objective of this paper is to maximize the worst user’s SINR by applying the uPA algorithm with the total power constraint. Because of proposed uPA algorithms, all substreams across all users can have the same SINR, which leads to minimization of average BER. Simulation results show that joint transceiver designs with proposed uPA algorithms have an SNR gain about 2 dB at the BER of \(10^{-3}\). 相似文献
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Reliable transmission of images and video over wireless networks must address both potentially limited bandwidths and the possibilities of loss. When bandwidth sufficient to transmit the bit stream is unavailable on a single channel, the data can be partitioned over multiple channels with possibly unequal bandwidths and error characteristics at the expense of more complex channel coding (i.e., error correction). This paper addresses the problem of efficiently channel coding and partitioning pre-encoded image and video bit streams into substreams for transmission over multiple channels with unequal and time-varying characteristics. Within channels, error protection is unequally applied based on both data decoding priority and channel packet loss rates, while cross-channel coding addresses channel failures. In comparison with conventional product codes, the resulting product code does not restrict the total encoded data to a rectangular structure; rather, the data in each channel is adaptively coded according to the channel's varying conditions. The coding and partitioning are optimized to achieve two performance criteria: maximum bandwidth efficiency and minimum delay. Simulation results demonstrate that this approach is effective under a variety of channel conditions and for a broad range of source material. 相似文献
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Joohee Kim Mersereau R.M. Altunbasak Y. 《IEEE transactions on image processing》2004,13(12):1547-1553
This paper presents a coordinated multiple-substream unequal error-protection and error-concealment algorithm for SPIHT-coded bitstreams transmitted over lossy channels. In the proposed scheme, we divide the video sequence corresponding to a group of pictures into two subsequences and independently encode each subsequence using a three-dimensional SPIHT algorithm. We use two different partitioning schemes to generate the substreams, each of which offers some advantages under the appropriate channel condition. Each substream is protected by an FEC-based unequal error-protection algorithm, which assigns unequal forward error correction codes to each bit plane. Any information that is lost during the transmission for any substream is estimated at the receiver by using the correlation between the substreams and the smoothness of the video signal. Simulation results show that the proposed multiple-substream UEP algorithm is simple, fast, and robust in hostile network conditions, and that the proposed error-concealment algorithm can achieve 2-3-dB PSNR gain over the case when error concealment is not used at high packet-loss rates. 相似文献
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无线信道中的联合信源信道编码 总被引:2,自引:0,他引:2
该文提出了一种噪声信道下传输渐进图像的联合信源信道编码方法。该方法根据信道条件的好坏动态的调整信源编码速率和信道编码速率,因此极大地提高了系统的性能和编码效率。同时该方法还具有结构简单,易于实现等优点。试验证明本方法与以前文献中提出的EEP方法以及UEP方法相比,在信噪比低时即信道条件恶劣的情况下,能够明显提高恢复图像的质量。 相似文献
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Transmit antenna selection in V-BLAST system 总被引:1,自引:0,他引:1
Feng Xingle Zhu Shihua Ren Pinyi 《电子科学学刊(英文版)》2006,23(4):510-514
In order to reduce the cost of Radio Frequency (RF) chains in the spatial multiplexing systems with Vertical-Bell Labs Layered Space-Time (V-BLAST) nonlinear receiver, a novel transmit antenna selection criterion is proposed with the motivation of minimizing the Vector Symbol Error Rate (VSER). In the proposed scheme, both the number of substreams and the mapping of substreams to antennas are dynamically adjusted based on the knowledge of channel. Simulation results illustrate that the proposed two-step selection criterion outperforms the existing eigenmode based selection criterion by 0.3dB at a VSER of 10^-3. 相似文献
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Shu-Ming Tseng Hsin-Lung Lee 《Communications, IEEE Transactions on》2005,53(4):587-591
The full parallel multistage detection for multiple-input multiple-output systems has less processing delay and better performance than the vertical Bell Laboratories layered space-time detection scheme. However, due to the disadvantage of full parallel interference cancellation, its performance degrades when the received power of the substreams at one receiving antenna is unbalanced and/or when the system is heavily loaded. Therefore, we introduce adaptive partial weighting coefficients into the parallel multistage detection. The weighting coefficients are evaluated using the average decision correct probabilities in the previous stage. The simulation results show that the uncoded error probability of the proposed method is lower than that of the recently proposed full parallel multistage detection scheme with perfect or imperfect channel estimation. 相似文献
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Layered maximum likelihood detection for MIMO systems in frequency selective fading channels 总被引:3,自引:0,他引:3
By transmitting different substreams in different antennas simultaneously, a multiple element antenna array system provides increased capacity that grows linearly with the number of transmit antennas. Layered space-time processing that performs ing, detection and cancellation for each substream can be used for reception, with a linear growth in receiver complexity. This paper considers this multi-input multi-output system over a slow time-varying frequency selective Rayleigh fading channel environment. With the equivalent channel tap delay line model, each delayed tap in every transmit-receive antenna pair can be considered as an imaginary antenna transmitting a delayed version of the substreams. Based on this idea, we propose a layered maximum likelihood detection (L-MLD) scheme which performs layered processing and maximum likelihood detection for each substream and its delayed elements. To further improve the performance, a group maximum likelihood detection (G-MLD) scheme is also proposed by grouping the substreams and performing layered processing in groups and maximum likelihood detection within the group. However, both schemes increase the required number of receiving antennas, which increases hardware cost and size. To reduce this requirement, we propose the use of oversampling technique to increase the dimension of the received signal. Simulation results show that the L-MLD scheme achieves frequency diversity and outperforms existing schemes such as the V-BLAST system with OFDM and multi-input multi-output decision feedback equalizers (MIMO-DFE). Moreover, the G-MLD scheme performs better than L-MLD with an increased detection complexity. In addition, it was showed that further increasing the oversampling rate beyond the minimum requirement does not improve the performance. 相似文献
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Qingxin Chen Sousa E.S. Pasupathy S. 《Selected Areas in Communications, IEEE Journal on》1996,14(9):1852-1858
A modified multicarrier (MC) direct-sequence code-division multiple-access (DS-CDMA) system has been proposed for use over slow multipath fading channels with frequency selectivity in the reverse link transmission of a cellular network. Instead of transmitting data substreams uniformly through subchannels, data substreams hop over subchannels with the hopping patterns adaptively adjusted to the channel fading characteristics. The problem of determining the optimal hopping pattern is formulated as a multiobjective optimization problem, for which an efficient algorithm, based on the water-filling (WF) principle, is designed to solve the problem practically. Simulation results show that the performance in terms of the average bit-error probability (BEP) (over all users) is better than that of single carrier RAKE receiver systems, conventional MC CDMA systems applying moderate error protection, or diversity systems with different combining techniques 相似文献
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《Vehicular Technology, IEEE Transactions on》2009,58(2):733-743
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Eigenbeamforming exploits the spatial diversity of the MIMO channel by multiplexing data substreams along orthogonal modes. Estimation errors result in self-interference, which must be taken into account in the selection of modes for transmission and the allocation of transmitter power. Using perturbation analysis to evaluate the self-interference, a technique is proposed for determining the power allocation which achieves a specified performance, based only on the information available at the receiver. 相似文献
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《Communications, IEEE Transactions on》2005,53(5):905-905
Joint Source/Channel Coding and MAP Decoding of Arithmetic Codes In this paper, a novel MAP estimation approach is employed for error correction of arithmetic codes with a forbidden symbol. The system is founded on the principle of joint source channel coding, which allows one to unify the arithmetic decoding and error correction takes into a single process, with superior performance compared to traditional separated techniques. The proposed system improves the performance in terms of error correction with respect to a separated source and channel coding approach based on convolutional codes, with the additional great advantage of allowing complete flexibility in adjusting the coding rate. The proposed MAP decoder is tested in the case of image transmission across the AWGN channel and compared against standard FEC techniques in terms of performance an complexity. Both hard and soft decodng are taken into account, and excellent result in terms of packet error rate and decoded image quality are obtained. 相似文献
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Julien Abot Christian Olivier Clency Perrine Yannis Pousset 《Signal Processing: Image Communication》2012,27(10):1066-1078
This paper proposes a Joint Source Channel Coding solution optimized for a wireless JPEG 2000 (JPWL ISO/IEC 15444-11) image transmission scheme over a MIMO channel. To ensure robustness of the transmission, channel diversity is exploited with a Closed-Loop MIMO-OFDM scheme. This relies on the Channel State Information (CSI) knowledge on the transmitter side, which allows the MIMO channel to be decomposed into several hierarchical SISO subchannels. In the proposed scheme, the JPWL codestream is divided into hierarchical quality layer passing through the SISO subchannels. With the CSI, a global and optimal method for adjusting all the system parameters of each SISO subchannel is provided. Accordingly, adaptive modulation, Unequal Error Protection (UEP), Unequal Power Allocation (UPA) and source coding rate is provided for each quality layers. The major strength of this work is to provide an optimal method that parameterizes several variables. These have an effect on the rate-distortion trade-off under bitrate, Quality of Service (QoS) and power constraints. Finally, the proposed work allows flexible and reactive coding of a JPWL codestream adapted to the instantaneous channel status. The performance of this technique is evaluated over a realistic time-varying MIMO channel provided by a 3D-ray tracing propagation model. A significant improvement in the quality of the image is demonstrated. 相似文献
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对噪声信道上的图像传输方法进行了研究,提出了一种新的基于不等纠错保护的图像传输方法,该方法在编码端利用纠错算术码对SPIHT码流进行不等纠错保护,根据SPIHT码流各个不同重要程度的部分采用不同禁用区间的纠错算术码进行不同程度的差错保护,相比传统的基于不等纠错保护图像传输方法而言,可获得近似连续可变的编码码率;在解码端,采用堆栈序列估计算法进行信道估计后再进行SPIHT解码,重建图像.实验结果表明,与经典的Guionnet不等纠错保护传输方法以及分离编码传输方法相比,所提出的传输方法具有较为明显的性能增益. 相似文献
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Self-recovery is a tamper-detection and image recovery methods based on data hiding. It generates two types of data and embeds them into the original image: authentication data for tamper detection and reference data for image recovery. In this paper, a region-based scalable self-recovery (RSS) method is proposed for salient-object images. As the images consist of two main regions, the region of interest (ROI) and the region of non-interest (RONI), the proposed method is aimed at achieving higher reconstruction quality for the ROI. Moreover, tamper tolerability is improved by using scalable recovery. In the RSS method, separate reference data are generated for the ROI and RONI. Initially, two compressed bitstreams at different rates are generated using the embedded zero-block coding source encoder. Subsequently, each bitstream is divided into several parts, which are protected through various redundancy rates, using the Reed-Solomon channel encoder. The proposed method is tested on 10 000 salient-object images from the MSRA database. The results show that the RSS method, compared to related methods, improves reconstruction quality and tamper tolerability by approximately 30% and 15%, respectively. 相似文献