一种抗误码能力强的无线信道图像传输方案

本文提出一种新的综合源编码和信道编码的无线信道图像传输方案，对子波变换后各个子带采用基于统计特性的变系数定长（VCFL）编码，数据经过Reed-Solomon编码后选择不同码率的码率兼容删除卷积码（RCPC）编码以提供不同程度的差错保护（UEP），最后数据经交织后传输。在给定传输的总比特数的情况下，通过优化算法使总体失真最小。模拟结果表明新方案在无线衰落信道上表现出良好的性能。     

无线信道中的联合信源信道编码

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。     

Joint source/channel coding for image transmission with JPEG2000 over memoryless channels.

The high compression efficiency and various features provided by JPEG2000 make it attractive for image transmission purposes. A novel joint source/channel coding scheme tailored for JPEG2000 is proposed in this paper to minimize the end-to-end image distortion within a given total transmission rate through memoryless channels. It provides unequal error protection by combining the forward error correction capability from channel codes and the error detection/localization functionality from JPEG2000 in an effective way. The proposed scheme generates quality scalable and error-resilient codestreams. It gives competitive performance with other existing schemes for JPEG2000 in the matched channel condition case and provides more graceful quality degradation for mismatched cases. Furthermore, both fixed-length source packets and fixed-length channel packets can be efficiently formed with the same algorithm.     

基于H.264率失真模型的无线信源信道联合编码方案

针对H.264编码器的率失真特性,建立了一种新的H.264编码率失真(R-D,rate-distortion)模型:然后基于该R-D模型和Turbo码的抗差错特性,对无线环境下的端到端视频传输失真进行了深入的分析,提出了一种无线信道下的自适应视频信源信道联合编码(JSCC,joint source channel coding)方案,该方案可以自适应地根据当前无线信道的具体状况,将网络可用带宽在信道编码和信源编码之间进行最优的分配,使得端到端的传输失真达到最小.实验结果表明,与固定选择信道编码速率方案相比,该方案可以显著提高传输的可靠性,在接收端可以获得更好的视频重建质量.     

一种基于JPEG2000的自适应联合信源信道编码方法

针对JPEG2000图像在噪声条件未知的信道上有效和可靠传输问题,本文提出了一种基于反馈的自适应联合信源信道编码方案.首先采用基于子空间的信噪比估计方法实时估计信道的信噪比SNR,进而求得信道的误码率,解决了对信道的自适应问题.其次,充分利用了JPEG2000的码流质量分级特点,建立了实用的目标函数,从而根据数据包对重建图像贡献的不同,实施不同的保护,以低复杂度的运算实现了码率优化分配的自适应过程.仿真结果表明,和现有的联合信源信道编码算法相比,这种自适应联合优化编码方法可以取得较好的效果.     

A FINE GRANULAR JOINT SOURCE CHANNEL CODING METHOD

An improved FGS (Fine Granular Scalability) coding method is proposed in this letter,which is based on human visual characteristics.This method adjusts FGS coding frame rate according to the evaluation of video sequences so as to improve the coding efficiency and subject perceived quality of reconstructed images.Finally,a fine granular joint source channel coding is proposed based on the source coding method,which not only utilizes the network resources efficiently,but guarantees the reliable transmission of video information.     

一种码率自适应信源信道联合编码系统

双LDPC码系统是新近出现的一种信源信道联合编码系统,该系统的性能虽然好但不稳定,在信源熵增加时会产生很高的误码平台。为了解决这一问题,提出了一种码率自适应双LDPC码系统,此系统采用码率自适应LDPC码作为信源码,当信源熵变化时可以灵活地调整信源码率,从而保证系统在高低不同的信源熵情况下都具有优秀、稳定的性能。仿真结果显示,在高低不同的信源熵情况下,所提出的码率自适应双LDPC码系统性能均好于传统双LDPC码系统,而且在误比特率为10-6时都没有出现误码平台。     

A novel product coding and recurrent alternate decoding scheme for image transmission over noisy channels

In this letter, we present a novel product channel coding and decoding scheme for image transmission over noisy channels. Two convolutional codes with at least one recursive systematic convolutional code are employed to construct the product code. Received data are decoded alternately in two directions. A constrained Viterbi algorithm is proposed to exploit the detection results of cyclic redundancy check codes so that both reduction in error patterns and fast decoding speed are achieved. Experiments with image data coded by the algorithm of set partitioning in hierarchical trees exhibit results better than those currently reported in the literature.     

Robust image transmission over energy-constrained time-varyingchannels using multiresolution joint source-channel coding

We explore joint source-channel coding (JSCC) for time-varying channels using a multiresolution framework for both source coding and transmission via novel multiresolution modulation constellations. We consider the problem of still image transmission over time-varying channels with the channel state information (CSI) available at (1) receiver only and (2) both transmitter and receiver being informed about the state of the channel, and we quantify the effect of CSI availability on the performance. Our source model is based on the wavelet image decomposition, which generates a collection of subbands modeled by the family of generalized Gaussian distributions. We describe an algorithm that jointly optimizes the design of the multiresolution source codebook, the multiresolution constellation, and the decoding strategy of optimally matching the source resolution and signal constellation resolution “trees” in accordance with the time-varying channel and show how this leads to improved performance over existing methods. The real-time operation needs only table lookups. Our results based on a wavelet image representation show that our multiresolution-based optimized system attains gains on the order of 2 dB in the reconstructed image quality over single-resolution systems using channel optimized source coding     

SNR-adaptive deep joint source-channel coding scheme for image semantic transmission with convolutional block attention module

With the development of deep learning(DL), joint source-channel coding(JSCC) solutions for end-to-end transmission have gained a lot of attention. Adaptive deep JSCC schemes support dynamically adjusting the rate according to different channel conditions during transmission, enhancing robustness in dynamic wireless environment. However, most of the existing adaptive JSCC schemes only consider different channel conditions, ignoring the different feature importance in the image processing and tran...     

A robust coding scheme for packet video

Some of the important characteristics and requirements of packet video are discussed. A layered packet video coding algorithm based on a progressive transmission scheme is presented. The algorithm provides good compression and can handle significant packet loss with graceful degradation in the reconstruction sequence. A network simulator used in testing the scheme is introduced, and simulation results for various conditions are presented     

CDMA信道上一种实时图像传输方案

给出了一种在CDMA无线信道上进行图像实时传输的方案，实现结果表明，在保证图像质量下降不大的条件下该方案可实现在CDMA信道上每秒传送9－12幅QCIF灰度图像。     

A joint source and channel coding algorithm for error-resilient SPIHT-coded video bitstreams

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.     

JPEG image transmission over mobile network with an efficient channel coding and interleaving

This article studies improving of coloured JPEG image transmission over mobile wireless personal area network through the Bluetooth networks. This article uses many types of enhanced data rate and asynchronous connectionless packets. It presents a proposed chaotic interleaving technique for improving a transmission of coloured images over burst error environment through merging it with error control scheme. The computational complexity of the used different error control schemes is considered. A comparison study between different scenarios of the image transmission is held in to choose an effective technique. The simulation experiments are carried over the correlated fading channel using the widely accepted Jakes’ model. Our experiments reveal that the proposed chaotic interleaving technique enhances quality of the received coloured image. Our simulation results show that the convolutional codes with longer constraint length are effective if its complexity is ignored. It reveals also that the standard error control scheme of old Bluetooth versions is ineffective in the case of coloured image transmission over mobile Bluetooth network. Finally, the proposed scenarios of the standard error control scheme with the chaotic interleaver perform better than the convolutional codes with reducing the complexity.     

A general coding scheme for the two-way channel

A general coding scheme for the nonrestricted memoryless discrete two-way channel is presented based on the introduction of auxiliary random variables forming a stationary Markov process. The coding scheme yields an achievable rate region which exceeds the inner bound of Shannon in the general case. A finite cardinality bound for the auxiliary random variables is given, showing that the region is computable. Finally, the capacity region for the memoryless Gaussian two-way channel is established.     

On joint source-channel coding for the Wyner-Ziv source and the Gel'fand-Pinsker channel

We consider the problem of lossy joint source-channel coding in a communication system where the encoder has access to channel state information (CSI) and the decoder has access to side information that is correlated to the source. This configuration combines the Wyner-Ziv (1976) model of pure lossy source coding with side information at the decoder and the Shannon/Gel'fand-Pinsker (1958, 1980) model of pure channel coding with CSI at the encoder. We prove a separation theorem for this communication system, which asserts that there is no loss in asymptotic optimality in applying, first, an optimal Wyner-Ziv source code and, then, an optimal Gel'fand-Pinsker channel code. We then derive conditions for the optimality of a symbol-by-symbol (scalar) source-channel code, and demonstrate situations where these conditions are met. Finally, we discuss a few practical applications, including overlaid communication where the model under discussion is useful.     

Extending the BACIC algorithm for robust transmission over a noisy channel

This study introduces error control to the block arithmetic coding for image compression (BACIC): a new method for lossless bilevel image compression. BACIC can successfully transmit bilevel images when channel bit error rates are as high as 10/sup -3/ while providing compression ratios twice that of G3, the only facsimile standard which incorporates error control into its algorithm.     

A joint resource allocation‐channel coding design based on distributed source coding

Wireless sensor networks (WSNs) have found a wide variety of applications recently. However, the challenges in WSNs still remain in improving the sensor energy efficiency and information quality (distortion reduction) of the sensing data transmissions. In this paper, we propose a novel cross‐layer design of resource allocation and channel coding to protect distributed source coding (DSC)‐based data transmission. Resource allocation strategies include rate adaptation and automatic repeat‐request retransmissions. Our proposed joint design of resource allocation, channel coding, and DSC can improve the network energy efficiency and information quality while meeting the data transmission latency requirements. Further, we investigate how the resource allocation enables the network to achieve unequal error protection among correlated DSC streams. Our simulation studies demonstrate that the proposed joint design significantly improves the DSC‐based data transmission quality and the network energy efficiency. Copyright © 2013 John Wiley & Sons, Ltd.     

一种基于联合网络编码和信道解码的高效率中继技术

针对一个两用户单中继系统,研究了一种基于联合网络编码与信道解码的高效率传输技术.利用无线信道的广播特性以及常见信道编码的线性特性,所提出的方法只需要两个时隙即可完成两个用户的数据传输,具有和点对点直接传输一样的传输效率.在第一个时隙,两个用户将各自的数据同时广播给中继和接收端.在第二个时隙,中继进行联合网络编码与信道解...     

Joint source-channel coding using real BCH codes for robust image transmission.

In this paper, a new still image coding scheme is presented. In contrast with standard tandem coding schemes, where the redundancy is introduced after source coding, it is introduced before source coding using real BCH codes. A joint channel model is first presented. The model corresponds to a memoryless mixture of Gaussian and Bernoulli-Gaussian noise. It may represent the source coder, the channel coder, the physical channel, and their corresponding decoder. Decoding algorithms are derived from this channel model and compared to a state-of-art real BCH decoding scheme. A further comparison with two reference tandem coding schemes and the proposed joint coding scheme for the robust transmission of still images has been presented. When the tandem scheme is not accurately tuned, the joint coding scheme outperforms the tandem scheme in all situations. Compared to a tandem scheme well tuned for a given channel situation, the joint coding scheme shows an increased robustness as the channel conditions worsen. The soft performance degradation observed when the channel worsens gives an additional advantage to the joint source-channel coding scheme for fading channels, since a reconstruction with moderate quality may be still possible, even if the channel is in a deep fade.