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Iterative Encoder-Controller Design for Feedback Control Over Noisy channels

IEEE TRANSACTIONS ON AUTOMATIC CONTROL 2011年第2期56卷 265-278页

作者： Bao, Lei Skoglund, Mikael Johansson, Karl Henrik Royal Inst Technol KTH Sch Elect Engn ACCESS Linnaeus Ctr SE-10044 Stockholm Sweden

We study a closed-loop control system with state feedback transmitted over a noisy discrete memoryless channel. With the objective to minimize the expected linear quadratic cost over a finite horizon, we propose a joint design of the sensor measurement quantization, channel error protection, and controller actuation. It is argued that despite that this encoder-controller optimization problem is known to be hard in general, an iterative design procedure can be derived in which the controller is optimized for a fixed encoder, then the encoder is optimized for a fixed controller, etc. Several properties of such a scheme are discussed. For a fixed encoder, we study how to optimize the controller given that full or partial side-information is available at the encoder about the symbols received at the controller. It is shown that the certainty equivalence controller is optimal when the encoder is optimal and has full side-information. For a fixed controller, expressions for the optimal encoder are given and implications are discussed for the special cases when process, sensor, or channel noise is not present. Numerical experiments are carried out to demonstrate the performance obtained by employing the proposed iterative design procedure and to compare it with other relevant schemes.

关键词： Discrete memoryless channel joint encoder-controller design joint source-channel coding limited information control quantized feedback control

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Error-resilient video encoding and transmission in multirate wireless LANs

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IEEE TRANSACTIONS ON MULTIMEDIA 2008年第5期10卷 691-700页

作者： Argyriou, Antonios Philips Res Labs NL-5656 AE Eindhoven Netherlands

In this paper, we present a cross-layer approach for video transmission in wireless LANs that employs joint source and application-layer channel coding, together with rate adaptation at the wireless physical layer (PHY). While the purpose of adopting PHY rate adaptation in modern wireless LANs like the IEEE 802.11a/b is to maximize the throughput, in this paper we exploit this feature to increase the robustness of wireless video. More specifically, we investigate the impact of adapting the PHY transmission rate, thus changing the throughput and packet loss channel characteristics, on the rate-distortion performance of a transmitted video sequence. To evaluate the video quality at the decoder, we develop a cross-layer modeling framework that considers jointly the effect of application-layer joint source-channel coding (JSCC), error concealment, and the PHY transmission rate. The resulting models are used by an optimization algorithm that calculates the optimal JSCC allocation for each video frame, and PHY transmission rate for each outgoing transport packet. The comprehensive simulation results obtained with the H.264/AVC codec demonstrate considerable increase in the PSNR of the decoded video when compared with a system that employs separately JSCC and PHY rate adaptation. Furthermore, our performance analysis indicates that the optimal PHY transmission rate calculated by the proposed algorithm, can be significantly different when compared with rate adaptation algorithms that target throughput improvement.

关键词： cross-layer design joint source-channel coding rate-adaptive PHY real-time video encoding video streaming wireless LAN

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A Unified Framework for One-Shot Achievability via the Poisson Matching Lemma

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IEEE TRANSACTIONS ON INFORMATION THEORY 2021年第5期67卷 2624-2651页

作者： Li, Cheuk Ting Anantharam, Venkat Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA Chinese Univ Hong Kong Dept Informat Engn Hong Kong Peoples R China

We introduce a fundamental lemma called the Poisson matching lemma, and apply it to prove one-shot achievability results for various settings, namely channels with state information at the encoder, lossy source coding with side information at the decoder, joint source-channel coding, broadcast channels, distributed lossy source coding, multiple access channels and channel resolvability. Our one-shot bounds improve upon the best known one-shot bounds in most of the aforementioned settings (except multiple access channels and channel resolvability, where we recover bounds comparable to the best known bounds), with shorter proofs in some settings even when compared to the conventional asymptotic approach using typicality. The Poisson matching lemma replaces both the packing and covering lemmas, greatly simplifying the error analysis. This paper extends the work of Li and El Gamal on Poisson functional representation, which mainly considered variable-length source coding settings, whereas this paper studies fixed-length settings, and is not limited to source coding, showing that the Poisson functional representation is a viable alternative to typicality for most problems in network information theory.

关键词： source coding Random variables Decoding Measurement uncertainty Distortion measurement Q measurement Extraterrestrial measurements One-shot achievability finite-blocklength analysis channels with state joint source-channel coding broadcast channels

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Image processing for multimedia terminals and related architectures

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SIGNAL PROCESSING 2000年第7期80卷 1167-1183页

作者： Macq, B Labeau, F Desset, C Vandendorpe, L Catholic Univ Louvain Commun & Remote Sensing Lab B-1348 Louvain Belgium

The multimedia terminals of tomorrow are seen today as toolboxes containing flexible solutions not only able to compress audio-visual flows, but also to interact with the contents, provide tools for copyright protection, adapt the signal representations to the communication channels, etc. The aim of this paper is to overview a flexible architecture suited for dynamically downloadable environments, discuss briefly new functionalities demanded for image communications and present more deeply a system globally optimized for noisy channels. The description of these three items illustrates the needs for image processing research to integrate in a global approach the communication software design, the new functionalities, among which security and copyright protection are of major importance, and to globally optimize the different codings, e.g. source and channel codings. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： image processing joint source-channel coding watermarking dynamic downloadable platform

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Optimal Design of Sequential Real-Time Communication Systems

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IEEE TRANSACTIONS ON INFORMATION THEORY 2009年第11期55卷 5317-5338页

作者： Mahajan, Aditya Teneketzis, Demosthenis Univ Michigan Dept Elect Engn & Comp Sci Ann Arbor MI 48109 USA

Optimal design of sequential real-time communication of a Markov source over a noisy channel is investigated. In such a system, the delay between the source output and its reconstruction at the receiver should equal a fixed prespecified amount. An optimal communication strategy must minimize the total expected symbol-by-symbol distortion between the source output and its reconstruction. Design techniques or performance bounds for such real-time communication systems are unknown. In this paper a systematic methodology, based on the concepts of information structures and information states, to search for an optimal real-time communication strategy is presented. This methodology trades off complexity in communication length (linear in contrast to doubly exponential) with complexity in alphabet sizes (doubly exponential in contrast to exponential). As the communication length is usually order of magnitudes bigger than the alphabet sizes, the proposed methodology simplifies the search for an optimal communication strategy. In spite of this simplification, the resultant optimality equations cannot be solved efficiently using existing algorithmic techniques. The main idea is to formulate a zero-delay communication problem as a dynamic team with nonclassical information structure. Then, an appropriate choice of information states converts the dynamic team problem into a centralized stochastic control problem in function space. Thereafter, Markov decision theory is used to derive nested optimality equations for choosing an optimal design. For infinite horizon problems, these optimality equations give rise to a fixed point functional equation. Communication systems with fixed finite delay constraint, a higher-order Markov source, and channels with memory are treated in the same manner after an appropriate expansion of the state space. Thus, this paper presents a comprehensive methodology to study different variations of real-time communication.

关键词： Dynamic teams information states joint source-channel coding nonclassical information structures real-time communication zero-delay communication

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Network Compression: Worst Case Analysis

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IEEE TRANSACTIONS ON INFORMATION THEORY 2015年第7期61卷 3980-3995页

作者： Asnani, Himanshu Shomorony, Ilan Avestimehr, A. Salman Weissman, Tsachy Ericsson Res & Dev Sillicon Valley San Jose CA 95134 USA Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA Univ So Calif Dept Elect Engn Los Angeles CA 90089 USA Stanford Univ Dept Elect Engn Stanford CA 94305 USA

We study the problem of communicating a distributed correlated memoryless source over a memoryless network, from source nodes to destination nodes, under quadratic distortion constraints. We establish the following two complementary results: 1) for an arbitrary memoryless network, among all distributed memoryless sources of a given correlation, Gaussian sources are least compressible, that is, they admit the smallest set of achievable distortion tuples and 2) for any memoryless source to be communicated over a memoryless additive-noise network, among all noise processes of a given correlation, Gaussian noise admits the smallest achievable set of distortion tuples. We establish these results constructively by showing how schemes for the corresponding Gaussian problems can be applied to achieve similar performance for (source or noise) distributions that are not necessarily Gaussian but have the same covariance.

关键词： Worst-case source worst-case noise network compression joint source-channel coding

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source-channel diversity for parallel channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2005年第10期51卷 3518-3539页

作者： Laneman, JN Martinian, E Wornell, GW Apostolopoulos, JG Univ Notre Dame Dept Elect Engn Notre Dame IN 46556 USA Mitsubishi Elect Res Labs Cambridge MA 02139 USA MIT Dept Elect Engn & Comp Sci Cambridge MA 02139 USA Hewlett Packard Labs Palo Alto CA 94304 USA

We consider transmitting a source across a pair of independent, nonergodic channels with random states (e.g., slow-fading channels) so as to minimize the average distortion. The general problem is unsolved. Hence, we focus on comparing two commonly used source and channel encoding systems which correspond to exploiting diversity either at the physical layer through parallel channel coding or at the application layer through multiple description (MD) source coding. For on-off channel models, source coding diversity offers better performance. For channels with a continuous range of reception quality, we show the reverse is true. Specifically,. we introduce a new figure of merit called the distortion exponent which measures how fast the average distortion decays with signal-to-noise ratio. For continuous-state models such as additive white Gaussian noise (AWGN) channels with multiplicative Rayleigh fading, optimal channel coding diversity at the physical layer is more efficient than source coding diversity at the application layer in that the former achieves a better distortion exponent. Finally, we consider a third decoding architecture: MD encoding with joint source-channel decoding. We show that this architecture achieves the same distortion exponent as systems with optimal channel coding diversity for continuous-state channels, and maintains the advantages of MD systems for on-off channels. Thus, the MD system with joint decoding achieves the best performance from among the three architectures considered, on both continuous-state and on-off channels.

关键词： application layer diversity diversity joint source-channel coding multiple description coding parallel channels

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Multi-path content delivery: Efficiency analysis and optimization algorithms

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2012年第8期23卷 1189-1198页

作者： Chakareski, Jacob Ecole Polytech Fed Lausanne Signal Proc Lab LTS4 CH-1015 Lausanne Switzerland

The paper studies the benefits of multi-path content delivery from a rate-distortion efficiency perspective. We develop an optimization framework for computing transmission schedules for streaming media packets over multiple network paths that maximize the end-to-end video quality, for the given bandwidth resources. We comprehensively address the two prospective scenarios of content delivery with packet path diversity. In the context of sender-driven systems, our framework enables the sender to compute at every transmission instance the mapping of packets to network paths that meets a rate constraint while minimizing the end-to-end distortion. In receiver-driven multi-path streaming, our framework enables the client to dynamically decide which packets, if any, to request for transmission and from which media servers, such that the end-to-end distortion is minimized for a given transmission rate constraint. Via simulation experiments, we carefully examine the performance of the scheduling framework in both multi-path delivery scenarios. We demonstrate that the optimization framework closely approaches the performance of an ideal streaming system working at channel capacity with an infinite play-out delay. We also show that the optimization leads to substantial gains in rate-distortion performance over a conventional content-agnostic scheduler. Through the concept of error-cost performance for streaming a single packet, we provide another useful insight into the operation of the optimization framework and the conventional scheduling system. (c) 2012 Elsevier Inc. All rights reserved.

关键词： Video streaming Multi-path delivery Rate-distortion optimization Packet scheduling Rate allocation Server diversity joint source-channel coding Markov decision processes

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A source-channel Separation Theorem With Application to the source Broadcast Problem

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IEEE TRANSACTIONS ON INFORMATION THEORY 2016年第4期62卷 1764-1781页

作者： Khezeli, Kia Chen, Jun McMaster Univ Dept Elect & Comp Engn Hamilton ON L8S 4K1 Canada Cornell Univ Sch Elect & Comp Engn Ithaca NY 14853 USA

A converse method is developed for the source broadcast problem. Specifically, it is shown that the separation architecture is optimal for a variant of the source broadcast problem, and the associated source-channel separation theorem can be leveraged, via a reduction argument, to establish a necessary condition for the original problem, which unifies several existing results in the literature. Somewhat surprisingly, this method, albeit based on the source-channel separation theorem, can be used to prove the optimality of non-separation-based schemes and determine the performance limits in certain scenarios where the separation architecture is suboptimal.

关键词： Bandwidth mismatch broadcast channel capacity region joint source-channel coding separation theorem side information

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Robust Predictive Quantization: Analysis and Design Via Convex Optimization

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IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING 2007年第4期1卷 618-632页

作者： Fletcher, Alyson K. Rangan, Sundeep Goyal, Vivek K. Ramchandran, Kannan Univ Calif Berkeley Berkeley CA 94720 USA Qualcomm Flar Technol Bedminster NJ 07921 USA MIT Cambridge MA 02139 USA

Predictive quantization is a simple and effective method for encoding slowly-varying signals that is widely used in speech and audio coding. It has been known qualitatively that leaving correlation in the encoded samples can lead to improved estimation at the decoder when encoded samples are subject to erasure. However, performance estimation in this case has required Monte Carlo simulation. Provided here is a novel method for efficiently computing the mean-squared error performance of a predictive quantization system with erasures via a convex optimization with linear matrix inequality constraints. The method is based on jump linear system modeling and applies to any autoregressive moving average (ARMA) signal source and any erasure channel described by an aperiodic and irreducible Markov chain. In addition to this quantification for a given encoder filter, a method is presented to design the encoder filter to minimize the reconstruction error. Optimization of the encoder filter is a nonconvex problem, but we are able to parameterize with a single scalar a set of encoder filters that yield low MSE. The design method reduces the prediction gain in the filter, leaving the redundancy in the signal for robustness. This illuminates the basic tradeoff between compression and robustness.

关键词： Differential pulse code modulation erasure channels joint source-channel coding linear matrix inequalities

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