We propose a coding scheme based on the use of systematic linear codes with low-density generator matrix (LDGM codes) for channelcoding and joint source-channel coding of multiterminal correlated binary sources. In b...
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We propose a coding scheme based on the use of systematic linear codes with low-density generator matrix (LDGM codes) for channelcoding and joint source-channel coding of multiterminal correlated binary sources. In both cases, the structures of the LDGM encoder and decoder are shown, and a concatenated scheme aimed at reducing the error floor is proposed. Several decoding possibilities are investigated, compared, and evaluated. For different types of noisy channels and correlation models, the resulting performance is very close to the theoretical limits.
Here, we design the efficient technique of transmitting the source transition probability matrix (STPM) by accompanied with the lowest frequency subband (LFS). The entries of this stochastic matrix are adaptively comp...
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ISBN:
(纸本)9781424451234
Here, we design the efficient technique of transmitting the source transition probability matrix (STPM) by accompanied with the lowest frequency subband (LFS). The entries of this stochastic matrix are adaptively computed by applying the first order Markov model with MPEG-4 zerotree sequences. Because of channel disturbances, we obtain the mismatched STPM at the ML-Viterbi receiver and then employ it for newly computed branch metrics at the MAP source-controlled channel decoder. For analysis, we also evaluate the residual redundancies for both the "Lena" and the "Barbara" images. The system performance is summarized in term of both PSNR (dB) and WER for three types of slow flat Rician fading channels. In the mismatched STPM simulation results, we still obtain the most PSNR improvement of about 0.14 dB.
This paper proposes a cooperative multiple-input multiple-output (MIMO) architecture to transmit the video reliably. By exploring the configurable resources of the scalable video and the coded MIMO system, we further ...
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ISBN:
(纸本)9781424456536
This paper proposes a cooperative multiple-input multiple-output (MIMO) architecture to transmit the video reliably. By exploring the configurable resources of the scalable video and the coded MIMO system, we further propose a novel joint source-channel coding (JSCC) framework with optimal tradeoff among diversity, multiplexing and coding gains. In this framework, the concatenated low-density parity-check codes (LDPC) and diversity-embedded space-time block codes (DE-STBC) provide double unequal error protection for the video layers, and the STBCs switching enables the adaptability to the varying channel. Experiments demonstrate the superiority of cooperative architecture and the effectiveness of our JSCC algorithm.
In this paper we address the problem of distributed transmission of functions of correlated sources over a fast fading multiple access channel (MAC). This is a basic building block in a hierarchical sensor network use...
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ISBN:
(纸本)9781424458707
In this paper we address the problem of distributed transmission of functions of correlated sources over a fast fading multiple access channel (MAC). This is a basic building block in a hierarchical sensor network used in estimating a random field where the cluster head is interested only in estimating a function of the observations. The observations are transmitted to the cluster head through a fast fading MAC. We provide sufficient conditions for lossy transmission when the encoders and decoders are provided with partial information about the channel state. Furthermore signal side information maybe available at the encoders and the decoder. Various previous studies are shown as special cases. Efficient joint-sourcechannelcoding schemes are discussed for transmission of discrete and continuous alphabet sources to recover function values.
Networked embedded control systems are present almost everywhere. A recent trend is to introduce radio communication in these systems to increase mobility and flex- ibility. Network nodes, such as the sensors, are oft...
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Networked embedded control systems are present almost everywhere. A recent trend is to introduce radio communication in these systems to increase mobility and flex- ibility. Network nodes, such as the sensors, are often simple devices with limited computing and transmission power and low storage capacity, so an important prob- lem concerns how to optimize the use of resources to provide sustained overall sys- tem performance. The approach to this problem taken in the thesis is to analyze and design the communication and control application layers in an integrated man- ner. We focus in particular on cross-layer design techniques for closed-loop control over non-ideal communication channels, motivated by future control systems with very low-rate and highly quantized sensor communication over noisy links. Several fundamental problems in the design of source–channelcoding and optimal control for these systems are discussed. The thesis consists of three parts. The first and main part is devoted to the joint design of the coding and control for linear plants, whose state feedback is trans- mitted over a finite-rate noisy channel. The system performance is measured by a finite-horizon linear quadratic cost. We discuss equivalence and separation proper- ties of the system, and conclude that although certainty equivalence does not hold in general it can still be utilized, under certain conditions, to simplify the overall design by separating the estimation and the control problems. An iterative opti- mization algorithm for training the encoder–controller pairs, taking channel errors into account in the quantizer design, is proposed. Monte Carlo simulations demon- strate promising improvements in performance compared to traditional approaches. In the second part of the thesis, we study the rate allocation problem for state feedback control of a linear plant over a noisy channel. Optimizing a time-varying communication rate, subject to a maximum average-rate constraint, can b
In this paper,we proposed a double-level error resilient joint source-channel coding scheme for image ***,we inserted one coordinative component named error resilient entropy coding (EREC) between sourcecoding and ch...
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In this paper,we proposed a double-level error resilient joint source-channel coding scheme for image ***,we inserted one coordinative component named error resilient entropy coding (EREC) between sourcecoding and channelcoding to achieve additional error resilient *** on the novel architecture,we proved that,in the aspects of computational complexity,coding redundancy and furthermore the decoding performance of image transmission,our scheme outperformed either separate source and channelcoding scheme or joint source-channel coding scheme with synchronization words.
In order to prove a key result for their development (Lemma 2), Taubman and Thic need the assumption that the upper boundary of the convex hull of the channelcoding probability-redundancy characteristic is sufficient...
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In order to prove a key result for their development (Lemma 2), Taubman and Thic need the assumption that the upper boundary of the convex hull of the channelcoding probability-redundancy characteristic is sufficiently dense. Since a floor value for the density level for which the claim to hold is not specified, it is not clear whether their lemma applies to practical situations. In this correspondence, we show that the constraint of sufficient density can be removed, and, thus, we validate the conclusion of the lemma for any scenario encountered in practice.
We consider joint source-channel coding with variable length codes (VLCs) and LDPC codes. We propose an iterative source-channel decoding system, which involves message passing between a soft-input-soft-output VLC dec...
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ISBN:
(纸本)142440049X
We consider joint source-channel coding with variable length codes (VLCs) and LDPC codes. We propose an iterative source-channel decoding system, which involves message passing between a soft-input-soft-output VLC decoder and an LDPC decoder. The proposed system utilizes the residual redundancy of the variable length code during the iterative decoding process, and is expected to exhibit decoding convergence at a lower SNR relative to the system in which source and channel decoding are performed separately. We present computer simulation results that confirm the expected gain of the proposed system.
We consider a single-hop data-gathering sensor network, consisting of a set of sensor nodes that transmit data periodically to a base-station. We are interested in maximizing the lifetime of this network. With our def...
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ISBN:
(纸本)9783540778707
We consider a single-hop data-gathering sensor network, consisting of a set of sensor nodes that transmit data periodically to a base-station. We are interested in maximizing the lifetime of this network. With our definition of network lifetime and the assumption that the radio transmission energy consumption forms the most significant portion of the total energy consumption at a sensor node, we attempt to enhance the network lifetime by reducing the transmission energy budget of sensor nodes by exploiting three system-level opportunities. We pose the problem of maximizing lifetime as a max-min optimization problem subject to the constraint of successful data collection and limited energy supply at each node. This turns out to be an extremely difficult optimization to solve. To reduce the complexity of this problem, we allow the sensor nodes and the base-station to interactively communicate with each other and employ instantaneous decoding at the base-station. The chief contribution of the paper is to show that the computational complexity of our problem is determined by the complex interplay of various system-level opportunities and challenges.
In this paper, we present a novel algorithm for dynamic quantization in distributed Wyner-Ziv video coding. In contrast with previous work where the quantization parameter is fixed and a feedback channel is used, our ...
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ISBN:
(纸本)9781424416875
In this paper, we present a novel algorithm for dynamic quantization in distributed Wyner-Ziv video coding. In contrast with previous work where the quantization parameter is fixed and a feedback channel is used, our proposed technique relies on theoretical calculations to jointly determine the number of quantization levels along with a suitable compression rate for each video frame. It employs a cross-layer approach that dynamically allocates unequal transmission rates for different users by taking into account the amount of motion in the captured video scenes on one hand and the transmission conditions for each sensor on the other. The application of this algorithm in a wireless video sensor network shows a significant improvement in the system performance when compared to a traditional system that allocates equal channel resources with a fixed quantization parameter.
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