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Low complexity joint source-channel decoding for transmission of wavelet compressed images 认领 引用
1
作者 殷玮玮 梅中辉 吴乐南 《Journal of Southeast University(English Edition)》 EI CAS 2006年第2期148-152,共5页
To utilize residual redundancy to reduce the error induced by fading channels and decrease the complexity of the field model to describe the probability structure for residual redundancy, a simplified statistical mode... To utilize residual redundancy to reduce the error induced by fading channels and decrease the complexity of the field model to describe the probability structure for residual redundancy, a simplified statistical model for residual redundancy and a low complexity joint source-channel decoding（JSCD） algorithm are proposed. The complicated residual redundancy in wavelet compressed images is decomposed into several independent 1-D probability check equations composed of Markov chains and it is regarded as a natural channel code with a structure similar to the low density parity check （LDPC） code. A parallel sum-product （SP） and iterative JSCD algorithm is proposed. Simulation results show that the proposed JSCD algorithm can make full use of residual redundancy in different directions to correct errors and improve the peak signal noise ratio （PSNR） of the reconstructed image and reduce the complexity and delay of JSCD. The performance of JSCD is more robust than the traditional separated encoding system with arithmetic coding in the same data rate. 展开更多
关键词 joint source-channel decoding sum-product algorithm generalized distribution law wavelet compressed image
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Joint Source-Channel Decoding Scheme for Image Transmission over Wireless Channel 认领 引用
2
作者 Xiao Dong-liang Sun Hong 《Wuhan University Journal of Natural Sciences》 EI CAS 2002年第3期307-312,共6页
We improve the iterative decoding algorithm by utilizing the “leaked” residual redundancy at the output of the source encoder without changing the encoder structure for the noisy channel. The experimental results sh... We improve the iterative decoding algorithm by utilizing the “leaked” residual redundancy at the output of the source encoder without changing the encoder structure for the noisy channel. The experimental results show that using the residual redundancy of the compressed source in channel decoding is an effective method to improve the error correction performance. 展开更多
关键词 turbo code joint source-channel decoding residual redundancy arithmetic coding
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Integrated Joint Source-Channel Decoding for H.264 Video Transmission 认领 引用 被引量：1
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作者 WU Jing CHEN Shuzhen 《Wuhan University Journal of Natural Sciences》 CAS 2007年第6期1057-1062,共6页
This paper proposes an integrated joint source-channel decoder （I-JSCD） using Max-Log-MAP method for sources encoded with exp-Golomb codes and convolutional codes, and proposes a system applying this method to decod... This paper proposes an integrated joint source-channel decoder （I-JSCD） using Max-Log-MAP method for sources encoded with exp-Golomb codes and convolutional codes, and proposes a system applying this method to decoding the VLC data, e.g. motion vector differences （MVDs）, of H.264 across an AWGN channel. This method combines the source code state-space and the channel code state-space together to construct a joint state-space, develops a 3-D trellis and a maximum a-posterior （MAP） algorithm to estimate the source sequence symbol by symbol, and then uses max-log approximation to simplify the algorithm. Experiments indicate that the proposed system gives significant improvements on peak signal-to-noise ratio （PSNR） （maximum about 15 dB） than a separate scheme. This also leads to a higher visual quality of video stream over a highly noisy channel. 展开更多
关键词 H.264 motion vector difference （MVD） integrated joint source-channel decoding （I-JSCD） variable-length code （VLC） exp-Golomb code max-log-MAP
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JOINT SOURCE-CHANNEL DECODING OF HUFFMAN CODES WITH LDPC CODES 认领 引用 被引量：1
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作者 Mei Zhonghui Wu Lenan 《Journal of Electronics(China)》 2006年第6期806-809,共4页
In this paper, we present a Joint Source-Channel Decoding algorithm (JSCD) for Low-Density Parity Check (LDPC) codes by modifying the Sum-Product Algorithm (SPA) to account for the source redun-dancy, which results fr... In this paper, we present a Joint Source-Channel Decoding algorithm (JSCD) for Low-Density Parity Check (LDPC) codes by modifying the Sum-Product Algorithm (SPA) to account for the source redun-dancy, which results from the neighbouring Huffman coded bits. Simulations demonstrate that in the presence of source redundancy, the proposed algorithm gives better performance than the Separate Source and Channel Decoding algorithm (SSCD). 展开更多
关键词 Low-Density Parity Check codes （LDPC） Variable Length Codes （VLC） Huffman code Sum-Product Algorithm（SPA） Joint Source-Channel Decoding （JSCD）
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Realtime robust speech communication based on iterative joint source-channel decoding and demodulation algorithm for MELP vocoder 认领 引用
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作者 彭坦 Cui Huijuan Tang Kun 《High Technology Letters》 EI CAS 2010年第2期111-116,共6页
Realtime speech communications require high efficient compression algorithms to encode speech signals. As the compressed speech parameters are highly sensitive to transmission errors, robust source and channel decodin... Realtime speech communications require high efficient compression algorithms to encode speech signals. As the compressed speech parameters are highly sensitive to transmission errors, robust source and channel decoding and demodulation schemes are both important and of practical use. In this paper, an it- erative joint souree-channel decoding and demodulation algorithm is proposed for mixed excited linear pre- diction （MELP） vocoder by both exploiting the residual redundancy and passing soft information through- out the receiver while introducing systematic global iteration process to further enhance the performance. Being fully compatible with existing transmitter structure, the proposed algorithm does not introduce addi- tional bandwidth expansion and transmission delay. Simulations show substantial error correcting perfor- mance and synthesized speech quality improvement over conventional separate designed systems in delay and bandwidth constraint channels by using the joint source-channel decoding and demodulation （JSCCM） algorithm. 展开更多
关键词 speech coding joint souree-channel coding and modulation （JSCCM） iterative decoding
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Integrated Joint Source-Channel Symbol-by-Symbol Decoding of Variable-Length Codes Using 3-D MAP Sequence Estimation 认领 引用 被引量：1
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作者 WU Jing CHEN Shuzhen 《Wuhan University Journal of Natural Sciences》 CAS 2007年第3期471-475,共5页
Most of multimedia schemes employ variable-length codes （VLCs） like Huffman code as core components in obtaining high compression rates. However VLC methods are very sensitive to channel noise. The goal of this pape... Most of multimedia schemes employ variable-length codes （VLCs） like Huffman code as core components in obtaining high compression rates. However VLC methods are very sensitive to channel noise. The goal of this paper is to salvage as many data from the damaged packets as possible for higher audiovisual quality. This paper proposes an integrated joint source-channel decoder （I-JSCD） at a symbol-level using three-dimensional （3-D） trellis representation for first-order Markov sources encoded with VLC source code and convolutional channel code. This method combines source code and channel code state-spaces and bit-lengths to construct a two-dimensional （2-D） state-space, and then develops a 3-D trellis and a maximum a-posterior （MAP） algorithm to estimate the source sequence symbol by symbol. Experiment results demonstrate that our method results in significant improvement in decoding performance, it can salvage at least half of （50%） data in any channel error rate, and can provide additional error resilience to VLC stream like image, audio, video stream over high error rate links. 展开更多
关键词 integrated joint source-channel decoding （I-JSCD） variable-length code （VLC） exp-Golomb code convolutional code： maximum a-oosteriori （MAP）
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Semantic Secure Communication Based on the Joint Source-Channel Coding 认领 引用
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作者 Yifeng Lin Yuer Yang +2 位作者 Jianxiang Xie Tong Ji Peiya Li 《Computers, Materials & Continua》 SCIE EI 2025年第8期2865-2882,共18页
Semantic secure communication is an emerging field that combines the principles of source-channel coding with the need for secure data transmission.It is of great significance in modern communications to protect the c... Semantic secure communication is an emerging field that combines the principles of source-channel coding with the need for secure data transmission.It is of great significance in modern communications to protect the confidentiality and privacy of sensitive information and prevent information leaks and malicious attacks.This paper presents a novel approach to semantic secure communication through the utilization of joint source-channel coding,which is based on the design of an automated joint source-channel coding algorithm and an encryption and decryption algorithm based on semantic security.The traditional and state-of-the-art joint source-channel coding algorithms are selected as two baselines for different comparison purposes.Experimental results demonstrate that our proposed algorithm outperforms the first baseline algorithm,the traditional source-channel coding,by 61.21%in efficiency under identical channel conditions(SNR=15 dB).In security,our proposed method can resist 2 more types of attacks compared to the two baselines,exhibiting nearly no increases in time consumption and error rate compared to the state-of-the-art joint source-channel coding algorithm while the secure semantic communication is supported. 展开更多
关键词 Secure semantic communication joint source-channel coding(JSCC) automaticed joint source-channel coding algorithm
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JOINT ITERATIVE DECODING FOR SIMPLE-ENCODING SYSTEMATIC IRREGULAR-LDPC-BASED CODED COOPERATION IN NON-IDEAL RELAY CHANNEL 认领 引用 被引量：3
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作者 Chen Jingwen Yang Fengfan +1 位作者 Luo Lin Tho Le-Ngoc 《Journal of Electronics(China)》 2010年第3期305-315,共11页
In this paper, a new kind of simple-encoding irregular systematic LDPC codes suitable for one-relay coded cooperation is designed, where the proposed joint iterative decoding is effectively performed in the destinatio... In this paper, a new kind of simple-encoding irregular systematic LDPC codes suitable for one-relay coded cooperation is designed, where the proposed joint iterative decoding is effectively performed in the destination which is in accordance with the corresponding joint Tanner graph characterizing two different component LDPC codes used by the source and relay in ideal and non-ideal relay cooperations. The theoretical analysis and simulations show that the coded cooperation scheme obviously outperforms the coded non-cooperation one under the same code rate and decoding complex. The significant performance improvement can be virtually credited to the additional mutual exchange of the extrinsic information resulted by the LDPC code employed by the source and its counterpart used by the relay in both ideal and non-ideal cooperations. 展开更多
关键词 Cooperative communication Low-density parity-check code Relay channel Joint Tanner graph Joint iterative decoding
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Joint Iterative Decoding for Network-Coding-Based Multisource LDPC-Coded Cooperative MIMO 认领 引用 被引量：1
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作者 张顺外 仰枫帆 唐蕾 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2014年第4期420-430,共11页
A network-coding-based multisource LDPC-coded cooperative MIMO scheme is proposed,where multiple sources transmit their messages to the destination with the assistance from a single relay.The relay cooperates with mul... A network-coding-based multisource LDPC-coded cooperative MIMO scheme is proposed,where multiple sources transmit their messages to the destination with the assistance from a single relay.The relay cooperates with multiple sources simultaneously via network-coding.It avoids the issues of imperfect frequencyiming synchronization and large transmission delay which may be introduced by frequency-division multiple access(FDMA)/code-division multiple access(CDMA)and time-division multiple access(TDMA)manners.The proposed joint″Min-Sum″iterative decoding is effectively carried out in the destination.Such a decoding algorithm agrees with the introduced equivalent joint Tanner graph which can be used to fully characterize LDPC codes employed by the sources and relay.Theoretical analysis and numerical simulation show that the proposed scheme with joint iterative decoding can achieve significant cooperation diversity gain.Furthermore,for the relay,compared with the cascade scheme,the proposed scheme has much lower complexity of LDPC-encoding and is easier to be implemented in the hardware with similar bit error rate(BER)performance. 展开更多
关键词 cooperative MIMO network coding LDPC codes equivalent joint Tanner graph joint iterative decoding
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Deep Learning Based Progressive Joint Source-Channel Coding for Wireless Image Transmission 认领 引用 被引量：1
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作者 Yuan Hongjie Xu Weizhang +2 位作者 Wei Lingzhou Yu Xingle Yin Hang 《China Communications》 SCIE EI CSCD 2025年第5期189-203,共15页
Deep learning-based Joint Source-Channel Coding(JSCC)is a crucial component in semantic communication,and recent research has made significant progress in adapting to different channels.In this paper,we propose a mult... Deep learning-based Joint Source-Channel Coding(JSCC)is a crucial component in semantic communication,and recent research has made significant progress in adapting to different channels.In this paper,we propose a multi-stage progressive technique called Deep learning based Progressive Joint Source-Channel Coding(DP-JSCC).This approach partitions the source into multiple stages and transmits the signals continuously.The receiver gradually enhances the quality of image reconstruction by progressively receiving the signals,offering greater flexibility compared to existing dynamic rate transmission methods.The model adopts a lightweight architectural design,where we introduce an efficient module called the Inverted Shuffle Attention Bottleneck(ISAB)and incorporate self-attention mechanisms in the encoding and decoding process to capture signal correlations and establish long-range dependencies.Additionally,we introduce the Progressive Focus Weight Allocation(PFWA)method to improve the image reconstruction capability in progressive transmission tasks.These design enhance the expressive capacity of the model.Simulation results demonstrate that DP-JSCC can flexibly adjust the transmission rate according to requirements without the need for retraining or deployment,enabling continuous optimization of signals at different rates.Furthermore,compared to stateof-the-art JSCC methods,DP-JSCC exhibits advantages in terms of computational complexity,parameter count,and reconstruction performance. 展开更多
关键词 broadcasting joint source-channel coding progressive refinement wireless image transmission
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MNTSCC:A VMamba-Based Nonlinear Joint Source-Channel Coding for Semantic Communications 认领 引用
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作者 Chao Li Chen Wang +2 位作者 Caichang Ding Yonghao Liao Zhiwei Ye 《Computers, Materials & Continua》 SCIE EI 2025年第11期3129-3149,共21页
Deep learning-based semantic communication has achieved remarkable progress with CNNs and Transformers.However,CNNs exhibit constrained performance in high-resolution image transmission,while Transformers incur high c... Deep learning-based semantic communication has achieved remarkable progress with CNNs and Transformers.However,CNNs exhibit constrained performance in high-resolution image transmission,while Transformers incur high computational cost due to quadratic complexity.Recently,VMamba,a novel state space model with linear complexity and exceptional long-range dependency modeling capabilities,has shown great potential in computer vision tasks.Inspired by this,we propose MNTSCC,an efficient VMamba-based nonlinear joint source-channel coding(JSCC)model for wireless image transmission.Specifically,MNTSCC comprises a VMamba-based nonlinear transform module,an MCAM entropy model,and a JSCC module.In the encoding stage,the input image is first encoded into a latent representation via the nonlinear transformation module,which is then processed by the MCAM for source distribution modeling.The JSCC module then optimizes transmission efficiency by adaptively assigning transmission rate to the latent representation according to the estimated entropy values.The proposedMCAMenhances the channel-wise autoregressive entropy model with attention mechanisms,which enables the entropy model to effectively capture both global and local information within latent features,thereby enabling more accurate entropy estimation and improved rate-distortion performance.Additionally,to further enhance the robustness of the system under varying signal-to-noise ratio(SNR)conditions,we incorporate SNR adaptive net(SAnet)into the JSCCmodule,which dynamically adjusts the encoding strategy by integrating SNRinformationwith latent features,thereby improving SNR adaptability.Experimental results across diverse resolution datasets demonstrate that the proposed method achieves superior image transmission performance compared to existing CNN-and Transformer-based semantic communication models,while maintaining competitive computational efficiency.In particular,under an Additive White Gaussian Noise(AWGN)channel with SNR=10 dB and a channel bandwidth ratio(CBR)of 1/16,MNTSCC consistently outperforms NTSCC,achieving a 1.72 dB Peak Signal-to-Noise Ratio(PSNR)gain on the Kodak24 dataset,0.79 dB on CLIC2022,and 2.54 dB on CIFAR-10,while reducing computational cost by 32.23%.The code is available at http://gffzz188fe103f8f1460askupbqcncvw5v6x0u.ffgz.tsg.suse.edu.cn/WanChen10/MNTSCC(accessed on 09 July 2025). 展开更多
关键词 Semantic communication VMamba wireless image transmission joint source-channel coding channel adaptation nonlinear transformation
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Joint Source-Channel Bit Allocation Based on Expected End-to-End Distortion Model 认领 引用 被引量：1
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作者 马汉杰 陈耀武 《Journal of Donghua University(English Edition)》 EI CAS 2010年第4期458-462,共5页
An adaptive joint source channel bit allocation method for video communications over error-prone channel is proposed.To protect the bit-streams from the channel bit errors,the rate compatible punctured convolution(RCP... An adaptive joint source channel bit allocation method for video communications over error-prone channel is proposed.To protect the bit-streams from the channel bit errors,the rate compatible punctured convolution(RCPC)code is used to produce coding rates varying from 4/5 to 1/2 using the same encoder and the Viterbi decoder.An expected end-to-end distortion model was presented to estimate the distortion introduced in compressed source coding due to quantization and channel bit errors jointly.Based on the proposed end-to-end distortion model,an adaptive joint source-channel bit allocation method was proposed under time-varying error-prone channel conditions.Simulated results show that the proposed methods could utilize the available channel capacity more efficiently and achieve better video quality than the other fixed coding-based bit allocation methods when transmitting over error-prone channels. 展开更多
关键词 joint source-channel coding end-to-end distortion bit allocation rate compatible punctured convolution code
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A New Arithmetic Coding System Combining Source Channel Coding and MAP Decoding 认领 引用
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作者 逄玉叶 孙军 王嘉 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第4期442-447,共6页
A new arithmetic coding system combining source channel coding and maximum a posteriori decoding were proposed. It combines source coding and error correction tasks into one unified process by introducing an adaptive ... A new arithmetic coding system combining source channel coding and maximum a posteriori decoding were proposed. It combines source coding and error correction tasks into one unified process by introducing an adaptive forbidden symbol. The proposed system achieves fixed length code words by adaptively adjusting the probability of the forbidden symbol and adding tail digits of variable length. The corresponding improved MAP decoding metric was derived. The proposed system can improve the performance. Simulations were performed on AWGN channels with various noise levels by using both hard and soft decision with BPSK modulation.The results show its performance is slightly better than that of our adaptive arithmetic error correcting coding system using a forbidden symbol. 展开更多
关键词 arithmetic code (AC) forbidden symbol joint source channel coding (JSCC) maximum a posteriori (MAP) decoding
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NEW ITERATIVE SUPER-TRELLIS DECODING WITH SOURCE A PRIORI INFORMATION FOR VLCS WITH TURBO CODES 认领 引用 被引量：3
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作者 Liu Jianjun Tu Guofang Wu Weiren 《Journal of Electronics(China)》 2007年第1期122-127,共6页
A novel Joint Source and Channel Decoding (JSCD) scheme for Variable Length Codes (VLCs) concatenated with turbo codes utilizing a new super-trellis decoding algorithm is presented in this letter. The basic idea of ou... A novel Joint Source and Channel Decoding (JSCD) scheme for Variable Length Codes (VLCs) concatenated with turbo codes utilizing a new super-trellis decoding algorithm is presented in this letter. The basic idea of our decoding algorithm is that source a priori information with the form of bit transition probabilities corresponding to the VLC tree can be derived directly from sub-state transitions in new composite-state represented super-trellis. A Maximum Likelihood (ML) decoding algorithm for VLC sequence estimations based on the proposed super-trellis is also described. Simu-lation results show that the new iterative decoding scheme can obtain obvious encoding gain especially for Reversible Variable Length Codes (RVLCs),when compared with the classical separated turbo decoding and the previous joint decoding not considering source statistical characteristics. 展开更多
关键词 Joint Source and Channel Decoding （JSCD） Variable Length Codes （VLCs） Turbo codes Super-trellis
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Physical twinning for joint encoding-decoding optimization in computational optics:a review 认领 引用 被引量：7
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作者 Liheng Bian Xinrui Zhan +3 位作者 Rong Yan Xuyang Chang Hua Huang Jun Zhang 《Light: Science & Applications》 SCIE EI CAS CSCD 2025年第6期1484-1503,共20页
Computational optics introduces computation into optics and consequently helps overcome traditional optical limitations such as low sensing dimension,low light throughput,low resolution,and so on.The combination of op... Computational optics introduces computation into optics and consequently helps overcome traditional optical limitations such as low sensing dimension,low light throughput,low resolution,and so on.The combination of optical encoding and computational decoding offers enhanced imaging and sensing capabilities with diverse applications in biomedicine,astronomy,agriculture,etc.With the great advance of artificial intelligence in the last decade,deep learning has further boosted computational optics with higher precision and efficiency.Recently,there developed an end-to-end joint optimization technique that digitally twins optical encoding to neural network layers,and then facilitates simultaneous optimization with the decoding process.This framework offers effective performance enhancement over conventional techniques.However,the reverse physical twinning from optimized encoding parameters to practical modulation elements faces a serious challenge,due to the discrepant gap in such as bit depth,numerical range,and stability.In this regard,this review explores various optical modulation elements across spatial,phase,and spectral dimensions in the digital twin model for joint encoding-decoding optimization.Our analysis offers constructive guidance for finding the most appropriate modulation element in diverse imaging and sensing tasks concerning various requirements of precision,speed,and robustness.The review may help tackle the above twinning challenge and pave the way for next-generation computational optics. 展开更多
关键词 computational optics optical encoding physical twinning joint encoding decoding optimization artificial intelligence deep learning computational decoding
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面向英语口语情感评价的多模态连续情感识别 认领 引用
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作者 王丽燕 张倩 +2 位作者 郭圆圆 陈海丰 李健 《计算机科学》 CSCD 北大核心 2026年第5期99-108,共10页
英语口语在英语学习中占据重要地位。针对现有的英语口语情感表达评价数据集稀缺及模态信息利用不足的问题,构建了一个名为英语口语多模态情感数据集(English Spoken Multimodal Emotion Dataset, ESMED)的新型数据集,并对其进行连续情... 英语口语在英语学习中占据重要地位。针对现有的英语口语情感表达评价数据集稀缺及模态信息利用不足的问题,构建了一个名为英语口语多模态情感数据集(English Spoken Multimodal Emotion Dataset, ESMED)的新型数据集,并对其进行连续情感(唤醒度、愉悦度)标注和情感质量评分。此外,提出了一个面向英语口语情感评价的创新网络模型,该模型首先通过感知重采样和多模态融合模块对连续情感信息进行压缩与融合,用于预测唤醒度和愉悦度。随后通过可学习的瓶颈层与联合解码层对特征进行特定变换,并通过情感质量评价模块将唤醒度、愉悦度与变换后的特征联合解码,得到最终量化后的情感质量分值。实验结果表明,在ESMED数据集上的一致性相关系数(CCC)达到0.500 3,平均绝对误差(MAE)为0.635 4,证明了该方法的有效性和准确性。 展开更多
关键词 情感识别 感知重采样 多模态融合 联合解码 情感质量评价
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Joint resource allocation for MIMO-OFDM video transmission systems with unequal error protection 认领 引用 被引量：4
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作者 张成文 刘鑫 谭学治 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第2期119-124,共6页
To improve the performance of MIMO-OFDM video transmission systems on the limitation of wireless bandwidth and transmitting power,we propose an adaptive joint resource allocation algorithm with unequal error protectio... To improve the performance of MIMO-OFDM video transmission systems on the limitation of wireless bandwidth and transmitting power,we propose an adaptive joint resource allocation algorithm with unequal error protection(UEP) based on joint source-channel coding(JSCC) according to H.264 video compression standard and RCPT channel coding.According to different thresholds of the average SNR of subchannels,the algorithm dynamically allocates the source coding parameters of original video data and the channel coding parameters of RCPT,which realizes UEP for the compressed video data of different importance.Through the bit and power allocation based on MQAM modulation and the subspace allocation based on beamforming technology for different subcarriers,an adaptive joint resource allocation making full use of space-frequency domain resources have been realized.The simulation results indicate that the algorithm improves the adaptability of video transmission systems in different wireless environments and the quality of video retrieval. 展开更多
关键词 video transmission MIMO-OFDM unequal error protection joint source-channel coding
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Using Walsh-m Composite Sequence and LDPC-QPSK Joint Iteration to Reduce ISI in Long-range Underwater Acoustic Systems 认领 引用 被引量：1
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作者 Fang Fu Dan-Feng Zhao 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2013年第1期87-92,共6页
To reduce inter-symbol-interference (ISI) in underwater acoustic (UWA) communication systems, a method based on LDPC-QPSK joint iteration and Walsh-m composite sequence is proposed in this paper. The method is intende... To reduce inter-symbol-interference (ISI) in underwater acoustic (UWA) communication systems, a method based on LDPC-QPSK joint iteration and Walsh-m composite sequence is proposed in this paper. The method is intended for use in long-range and low signal-to-noise ratio (SNR) UWA communications. At the transmitter, Walsh-m composite sequence is introduced to resist multipath effect. At the receiver, a soft-input soft-output (SISO) module is implemented in a joint iterative process between QPSK demodulator and LDPC decoder. This method is demonstrated in three types of UWA channel models: positive, negative and invariable sound velocity gradients channels. It is shown that through contrastive simulation experiments, this method is more efficient than conventional methods based on independent decoding and demodulation. After two rounds of joint iteration, the proposed method can obtain 2.5 dB over conventional method at BER of 10-5. Numerical results verify that the proposed method is a good candidate for long-range underwater acoustic communication systems. 展开更多
关键词 underwater acoustic communication joint iterative LDPC decoding QPSK demodulation Walsh-m composite sequence
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Improved List Sphere Decoder for Multiple Antenna Systems 认领 引用 被引量：1
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作者 宫丰奎 葛建华 李兵兵 《Journal of Southwest Jiaotong University(English Edition)》 2008年第1期1-9,共9页
An improved list sphere decoder （ILSD） is proposed based on the conventional list sphere decoder （LSD） and the reduced- complexity maximum likelihood sphere-decoding algorithm. Unlike the conventional LSD with fix... An improved list sphere decoder （ILSD） is proposed based on the conventional list sphere decoder （LSD） and the reduced- complexity maximum likelihood sphere-decoding algorithm. Unlike the conventional LSD with fixed initial radius, the ILSD adopts an adaptive radius to accelerate the list cdnstruction. Characterized by low-complexity and radius-insensitivity, the proposed algorithm makes iterative joint detection and decoding more realizable in multiple-antenna systems. Simulation results show that computational savings of ILSD over LSD are more apparent with more transmit antennas or larger constellations, and with no performance degradation. Because the complexity of the ILSD algorithm almost keeps invariant with the increasing of initial radius, the BER performance can be improved by selecting a sufficiently large radius. 展开更多
关键词 Iterative joint detection and decoding List sphere decoding （LSD） Maximum likelihood （ML） Soft in soft out （SISO） Multiple input multiple output （MIMO）
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低信噪比环境下无人机图传的双链路语义协同方法 认领 引用
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作者 王洲 赵长名 +1 位作者 黎钰辉 袁宁 《计算机技术与发展》 2026年第7期1-8,共8页
在城市环境下的无人机低空巡逻任务中,图像传输链路常因建筑物遮挡、电磁干扰等因素面临严峻挑战,具体表现为低信噪比与链路不稳定等问题。为此,该文提出一种适用于低信噪比环境下城市巡逻无人机图像的双链路语义联合解码传输方法。该... 在城市环境下的无人机低空巡逻任务中,图像传输链路常因建筑物遮挡、电磁干扰等因素面临严峻挑战,具体表现为低信噪比与链路不稳定等问题。为此,该文提出一种适用于低信噪比环境下城市巡逻无人机图像的双链路语义联合解码传输方法。该方法同时利用直连链路原始比特信息与语义链路的语义信息,通过LDPC编码提高传输的抗干扰能力,同时引入性能增益自适应因子,通过每轮迭代增益自适应调整权重,保证迭代过程的快速响应和迭代稳定性,并结合轻量级扩散模型对巡逻图像的语义特征进行增强与重建。实验结果表明,在低信噪比(-5 dB~0 dB)环境下,与传统JPEG+LDPC及DeepJSCC方法相比,该方法传输图像的PSNR值最高提升了5.31 dB,ED值最高降低了约74%,有效增强了无人机图像传输的视觉质量和目标特征保持能力,显著提升了无人机图像传输的质量,为城市巡逻与区域监控提供了一种高效的通信解决方案。 展开更多
关键词 语义通信 联合解码 扩散模型 低密度奇偶校验码 城市巡逻无人机
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