检索结果-内蒙古大学图书馆

Precoder and Postcoder Design for Wireless Video Streaming with Overloaded Multiuser MIMO-OFDM Systems

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2019年第12期E102A卷 1825-1833页

作者： Tashiro, Koji Kurosaki, Masayuki Ochi, Hiroshi Kyushu Inst Technol Grad Sch Comp Sci & Syst Engn Iizuka Fukuoka 8208502 Japan

Mobile video traffic is expected to increase explosively because of the proliferating number of Wi-Fi terminals. An overloaded multiple-input multiple-output (MIMO) technique allows the receiver to implement smaller number of antennas than the transmitter in exchange for degradation in video quality and a large amount of computational complexity for postcoding at the receiver side. This paper proposes a novel linear precoder for high-quality video streaming in overloaded multiuser MIMO systems, which protects visually significant portions of a video stream. A low complexity postcoder is also proposed, which detects some of data symbols by linear detection and the others by a prevoting vector cancellation (PVC) approach. It is shown from simulation results that the combination use of the proposed precoder and postcoder achieves higher-quality video streaming to multiple users in a wider range of signal-to-noise ratio (SNR) than a conventional unequal error protection scheme. The proposed precoder attains 40 dB in peak signal-to-noise ratio even in poor channel conditions such as the SNR of 12 dB. In addition, due to the stepwise acquisition of data symbols by means of linear detection and PVC, the proposed postcoder reduces the number of complex additions by 76% and that of multiplications by 64% compared to the conventional PVC.

关键词： overloaded MU-MIMO video streaming scalable video coding joint source-channel coding

来源：评论

学校读者我要写书评

暂无评论

On Successive Refinement for the Kaspi/Heegard-Berger Problem

引用

IEEE TRANSACTIONS ON INFORMATION THEORY 2010年第8期57卷 3930-3945页

作者： Maor (Varshavsky), Alina Merhav, Neri Technion Israel Inst Technol Dept Elect Engn IL-32000 Haifa Israel

Consider a source that produces independent copies of a triplet of jointly distributed random variables {X-i, Y-i, Z(i)}(i=1)(infinity). The process {X-i} is observed at the encoder, and is supposed to be reproduced at two decoders, decoder Y and decoder Z, where {Y-i} and {Z(i)} are observed, respectively, in either a causal or noncausal manner. The communication between the encoder and the decoders is carried in two successive stages. In the first stage, the transmission is available to both decoders and they reconstruct the source according to the received bit-stream and the individual side information ({Z(i)} or {Y-i}). In the second stage, additional information is sent to both decoders and they refine the reconstructions of the source according to the available side information and the transmissions at both stages. It is desired to find the necessary and sufficient conditions on the communication rates between the encoder and decoders, so that the distortions incurred (at each stage) will not exceed given thresholds. For the case of causal availability of side information at the decoders, an exact single-letter characterization of the achievable region is derived for the case of pure source-coding. Then, for the case of communication between the encoder and decoders carried over independent memoryless discrete channels with random states known causally/noncausally at the encoder and with causal side information about the source at the decoders, a single-letter characterization of all achievable distortion in both stages is provided and it is shown that the separation theorem holds. The results are derived without assuming any structural restrictions on side information, such as a Markov structure, etc. Finally, for noncausal degraded side information, inner and outer bounds to the achievable rate-distortion region are derived. These bounds are shown to be tight for certain cases of reconstruction requirements at the decoders. Due to the system setup, these res

关键词： Causal/noncausal side information channel capacity degraded side-information joint source-channel coding separation theorem source coding successive refinement

来源：评论

学校读者我要写书评

暂无评论

A Construction of channel Code, joint source-channel Code, and Universal Code for Arbitrary Stationary Memoryless channels Using Sparse Matrices

引用

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2009年第9期E92A卷 2333-2344页

作者： Miyake, Shigeki Muramatsu, Jun NTT Corp NTT Network Innovat Labs Yokosuka Kanagawa 2390847 Japan NTT Corp NTT Commun Sci Labs Kyoto 6190237 Japan

A channel code is constructed using sparse matrices for stationary memoryless channels that do not necessarily have a symmetric property like a binary symmetric channel. It is also shown that the constructed code has the following remarkable properties. 1. joint source-channel coding: Combining channel code with lossy source code, which is also constructed by sparse matrices, a simpler joint source-channel code can be constructed than that constructed by the ordinary block code. 2. Universal coding: The constructed channel code has a universal property under a specified condition.

关键词： sparse matrices stationary memoryless channel joint source-channel coding universal channel coding

来源：评论

学校读者我要写书评

暂无评论

Wideband User Grouping for Uplink Multiuser mmWave MIMO Systems With Hybrid Combining

引用

IEEE ACCESS 2021年 9卷 41360-41372页

作者： Perez-Adan, Darian Fresnedo, Oscar Gonzalez-Coma, Jose P. Castedo, Luis Univ A Coruna Dept Comp Engn La Coruna 15071 Spain Univ A Coruna Ctr Res Informat & Commun Technol CITIC La Coruna 15071 Spain Spanish Naval Acad Def Univ Ctr Marin 36920 Spain

Analog-digital hybrid precoding and combining schemes constitute an interesting approach to millimeter-wave (mmWave) multiple-input multiple-output (MIMO) systems due to the low hardware complexity and/or low power required for its deployment. However, the design of the hybrid precoders and combiners of a wideband multiuser (MU) mmWave MIMO system is challenging because the signal processing in the analog domain is constrained to be frequency flat. Furthermore, the number of radio frequency (RF) chains limits the number of individual streams that a common base station (BS) can simultaneously serve. This work jointly addresses the user scheduling, the user precoder design, and the BS hybrid combining design for the uplink of wideband MU mmWave MIMO systems. On the one hand, user precoding and BS hybrid combining are jointly designed to minimize the impact of having frequency-flat RF components. On the other hand, a number of users larger than the number of RF chains are served at the BS by employing a distributed quantizer linear coding (DQLC)-based non-orthogonal multiple access (NOMA) scheme. The use of this encoding strategy also allows exploiting the spatial correlation between the source information. Simulation results show remarkable performance gains of the proposed approaches for wideband mmWave MIMO hardware-constrained systems.

关键词： User scheduling wideband mmWave multiuser communications non-orthogonal multiple access joint source-channel coding

来源：评论

学校读者我要写书评

暂无评论

Strong Coordination Over Noisy channels

引用

IEEE TRANSACTIONS ON INFORMATION THEORY 2021年第5期67卷 2716-2738页

作者： Obead, Sarah A. Vellambi, Badri N. Kliewer, Joerg New Jersey Inst Technol Dept Elect & Comp Engn Newark NJ 07102 USA Univ Cincinnati Dept Elect Engn & Comp Sci Cincinnati OH 45221 USA

We study the problem of strong coordination of the actions of two nodes X and Y that communicate over a discrete memoryless channel (DMC) such that the actions follow a prescribed joint probability distribution. We propose two novel random coding schemes and a polar coding scheme for this noisy strong coordination problem, and derive inner and outer bounds for the respective strong coordination capacity region. The first scheme is a joint coordination-channel encoding scheme that utilizes the randomness provided by the communication channel to reduce the amount of local randomness required to generate the sequence of actions at Node Y. Based on this random coding scheme, we provide a characterization of the capacity region for a special case of the noisy strong coordination setup, namely, when the DMC is a deterministic channel. The second scheme exploits separate coordination and channel encoding where local randomness is extracted from the channel after decoding. Moreover, by leveraging the random coding results for this problem, we present an example in which the proposed joint encoding scheme is able to strictly outperform the separate encoding scheme in terms of achievable communication rate for the same amount of injected randomness into both systems. Thus, we establish the sub-optimality of the separation of strong coordination and channel encoding with respect to the communication rate over the DMC in this problem. Finally, the third scheme is a joint coordination-channel polar coding scheme for strong coordination. We show that polar codes are able to achieve the established inner bound to the strong noisy coordination capacity region and thus provide a constructive alternative to a random coding proof. Our polar coding scheme also offers a constructive solution to a channel simulation problem where a DMC and shared randomness are employed together to simulate another DMC.

关键词： Strong coordination joint source-channel coding channel resolvability superposition coding polar codes

来源：评论

学校读者我要写书评

暂无评论

joint source-channel Distortion Modeling for MPEG-4 Video

引用

IEEE TRANSACTIONS ON IMAGE PROCESSING 2009年第1期18卷 90-105页

作者： Sabir, Muhammad Farooq Heath, Robert W., Jr. Bovik, Alan Conrad K WILL Corp San Jose CA 95134 USA Univ Texas Austin Dept Elect & Comp Engn Wireless Networking & Commun Grp Austin TX 78712 USA

Multimedia communication has become one of the main applications in commercial wireless systems. Multimedia sources, mainly consisting of digital images and videos, have high bandwidth requirements. Since bandwidth is a valuable resource, it is important that its use should be optimized for image and video communication. Therefore, interest in developing new joint source-channel coding (JSCC) methods for image and video communication is increasing. Design of any JSCC scheme requires an estimate of the distortion at different source coding rates and under different channel conditions. The common approach to obtain this estimate is via simulations or operational rate-distortion curves. These approaches, however, are computationally intensive and, hence, not feasible for real-time coding and transmission applications. A more feasible approach to estimate distortion is to develop models that predict distortion at different source coding rates and under different channel conditions. Based on this idea, we present a distortion model for estimating the distortion due to quantization and channel errors in MPEG-4 compressed video streams at different source coding rates and channel bit error rates. This model takes into account important aspects of video compression such as transform coding, motion compensation, and variable length coding. Results show that our model estimates distortion within 1.5 dB of actual simulation values in terms of peak-signal-to-noise ratio.

关键词： Distortion modeling joint source-channel coding MPEG-4 quality assessment video communication

来源：评论

学校读者我要写书评

暂无评论

Digital-Analog Transmission Framework for Task-Oriented Semantic Communications

引用

IEEE NETWORK 2024年第6期38卷 81-88页

作者： Fu, Yuzhou Cheng, Wenchi Zhang, Wei Wang, Jingqing Xidian Univ Sch Telecommun Engn Xian 710071 Peoples R China Univ New South Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

Task-Oriented Semantic Communication (TOSC) has been considered as a new communication paradigm to serve various smart devices that depend on Artificial Intelligence (AI) tasks in future wireless networks. The existing TOSC frameworks rely on the Neural Network (NN) model to extract the semantic feature from the source data. The semantic feature, constituted by analog vectors of a lower dimensionality relative to the original source data, reserves the meaning of the source data. By conveying the semantic feature, TOSCs can significantly reduce the amount of data transmission while ensuring the correct execution of the AI-driven downstream task. However, standardized wireless networks depend on digital signal processing for data transmission, yet they necessitate the conveyance of semantic features that are inherently analog. Although existing TOSC frameworks developed the Deep Learning (DL) based analog approach or conventional digital approach to transmit the semantic feature, but there are still many challenging problems to urgently be solved in actual deployment. In this article, we first propose several challenging issues associated with the development of the TOSC framework in the standardized wireless network. Then, we develop a Digital-Analog transmission framework based TOSC (DA-TOSC) to resolve these challenging issues. Future research directions are discussed to further improve the DA-TOSC.

关键词： Semantics Task analysis Feature extraction Wireless networks Artificial neural networks Digital-analog conversion Decoding Task-oriented semantic communication digital-analog transmission joint source-channel coding resource allocation

来源：评论

学校读者我要写书评

暂无评论

Robust vector quantizer design using self-organizing neural networks

引用

SIGNAL PROCESSING 2000年第7期80卷 1289-1298页

作者： Azami, SBZ Feng, G Ecole Natl Super Telecommun F-75634 Paris 13 France

In this paper we propose a new method to design vector quantizers for noisy channels. Self-organizing neural networks are known for their efficiency in voice and image data compression;we use self-organizing algorithm to create a topological similarity between the input space and the index space. This similarity reduces the effect of channel noise because any single bit error in a transmitted index will be translated to a close codevector in the input space which yields relatively small distortion. For an 8-bit vector quantizer, the proposed system resulted in 4.59 dB spectral distortion in a highly noisy channel while a simple LEG, LEG with splitting and 2-D self-organizing map (SOM) resulted in 5.96, 5.46 and 5.02 dB of distortion, respectively. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

关键词： robust vector quantization self-organizing neural networks competitive learning index assignment hamming distance vocoder joint source-channel coding

来源：评论

学校读者我要写书评

暂无评论

Distortion bounds for broadcasting with bandwidth expansion

引用

IEEE TRANSACTIONS ON INFORMATION THEORY 2006年第8期52卷 3778-3788页

作者： Reznic, Zvi Feder, Meir Zamir, Ram Tel Aviv Univ Dept Elect Engn Syst IL-69978 Ramat Aviv Israel

We consider the problem of broadcasting a single Gaussian source to two listeners over a Gaussian, broadcast channel, with rho channel uses per source sample, where rho > 1. A distortion pair (D-1, D-2) is said to be achievable if one can simultaneously achieve a mean-squared error (MSE) D-1 at receiver 1 and D-2 at receiver 2. The main result of this correspondence is an outer bound for the set of all achievable distortion pairs. That is, we find necessary conditions under which (D, 1 D2) is achievable. We then apply this result to the problem of point-to-point transmission over a Gaussian channel with unknown signal-to-noise ratio (SNR) and rho > 1. We show that if a system must be optimal at a certain SNRmin, then, asymptotically, the system distortion cannot decay faster than O(1/SNR). As for achievability, we show that a previously reported scheme, due to Mittal and Phamdo (2002), is optimal at high SNR. We introduce two new schemes for broadcasting with bandwidth expansion, combining digital and analog transmissions. We finally show how a system with a partial feedback, returning from the bad receiver to the transmitter and to the good receiver, achieves a distortion pair that lies on the outer bound derived here.

关键词： distortion region joint source-channel coding lossy broadcasting

来源：评论

学校读者我要写书评

暂无评论

Memory efficient adaptation of vector quantizers to time-varying channels

引用

SIGNAL PROCESSING 2003年第7期83卷 1519-1528页

作者： Görtz, N Kliewer, J Tech Univ Munich Inst Commun Engn LNT D-80290 Munich Germany Univ Kiel Inst Circuits & Syst Theory D-24143 Kiel Germany

channel-optimized vector quantization (COVQ) is approximated by the novel channel-adaptive scaled vector quantization (CASVQ). This new method uses a reference codebook that is optimal for one specific channel condition. However, for a bit-error rate being different from the design assumption for the reference codebook, all codevectors are scaled by a common factor, which depends on the channel condition. It is shown by simulations that a performance close to that of COVQ can be achieved in many practically important situations. Without a significant increase in complexity, the new CASVQ-scheme can be adapted to time-varying channels by adjusting the scaling factor to the current bit-error probability. Another advantage is that only one codebook needs to be stored for all error probabilities, while for COVQ either the performance degrades significantly due to channel mismatch, or a large set of codebooks, must be available at the encoder and the decoder. (C) 2003 Elsevier Science B.V. All rights reserved.

关键词： joint source-channel coding channel-optimized vector quantization time-varying channels complexity and memory requirements

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：