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Joint JPEG2000/LDPC Code System Design for Image TelemetryJagiello, Kristin, Aydin, Mahmut Zafer, Ng, Wei-Ren 10 1900 (has links)
ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / This paper considers the joint selection of the source code rate and channel code rate in an image telemetry system. Specifically considered is the JPEG2000 image coder and an LDPC code family. The goal is to determine the optimum apportioning of bits between the source and channel codes for a given channel signal-to-noise ratio and total bit rate, R(total). Optimality is in the sense of maximum peak image SNR and the tradeoff is between the JPEG2000 bit rate R(source) and the LDPC code rate R(channel). For comparison, results are included for the industry standard rate-1/2, memory-6 convolutional code.
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Codage/décodage source-canal conjoint des contenus multimédia / Joint source-channel coding/decoding of multimedia contentsAbid, Manel 05 October 2012 (has links)
Dans cette thèse, nous nous intéressons aux schémas de codage et de décodage source-canal conjoint des contenus multimédia. Nous montrons comment la redondance laissée par le codeur vidéo peut être exploitée pour réaliser un décodage robuste des séquences transmises sur un lien radio-mobile bruité. grâce au schéma de décodage conjoint proposé, le nombre de paquets corrompus est significativement réduit au prix d'une très légère augmentation du débit. Nous appliquons ensuite ce schéma de décodage robuste à latransmission par descriptions multiples sur une architecture mixte Internet et radio-mobile. Le décodage source-canl conjoint des paquets reçus permet de corriger les erreurs de transmission et d'augmenter ainsi le nombre de paquets utilisés par le décodeur pour compenser les paquets perdus. L'efficacité de ce schéma est étudiée par rapport à un schéma classique basé sur les décisions dures du canal et sur un code correcteur d'erreurs introduisant le même niveau de redondance. Une deuxième partie de la thèse est consacrée à l'étude de schémas de codage source-canal conjoint basés sur une transformation redondante. Deux schémas d'estimation ont été proposés. Dans le premier, nous exploitons la redondance structurée introduite et le caractère borné du bruit de quantification pour construire un estimateur cohérent corrigeant les erreurs de transmission. Dans le deuxième schéma, nous appliquons l'algorithme de propagation de croyances pour évaluer les distributions a posteriori des composantes du signal d'entrée, à partir de sorties bruitées du canal. Nous appliquons alors ces deux schémas pour estimer l'entrée d'un banc de filtres suréchantillonnés. / This thesis aims at proposing and implementing efficient joint source-channel coding and decoding schemes in order to enhance the robustness of multimedia contents transmitted over unreliable networks. In a first time, we propose to identify and exploit the residual redundancy left by wavelet video coders in the compressed bit streams. an efficient joint-source channel decoding scheme is proposed to detect and correct some of the transmission errors occurring during a noisy transmission. This technique is further applied to multiple description video streams transmitted over a mixed architecture consisting of a wired lossy part and a wireless noisy part. In a second time, we propose to use the structured redundancy deliberately introduced by multirate coding systems, such as oversampled filter banks, in order to perform a robust estimation of the input signals transmitted over noisy channels. Two efficient estimation approaches are proposed and compared. The first one exploits the linear dependencies between the output variables, jointly to the bounded quantization noise, in order to perform a consistent estmiation of the source outcome. The second approach uses the belief propagation algorithm to estimate the input signal via a message passing procedure along the graph representing the linear dependencies between the variables. These schemes ares then applied to estimate the input of an oversampled filter bank and their performance are compared.
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JOINT SOURCE/CHANNEL CODING FOR TRANSMISSION OF MULTIPLE SOURCESWu, Zhenyu, Bilgin, Ali, Marcellin, Michael W. 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / A practical joint source/channel coding algorithm is proposed for the transmission of multiple images and videos to reduce the overall reconstructed source distortion at the receiver within a given total bit rate. It is demonstrated that by joint coding of multiple sources with such an objective, both improved distortion performance as well as reduced quality variation can be achieved at the same time. Experimental results based on multiple images and video sequences justify our conclusion.
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LDPC-BASED ITERATIVE JOINT SOURCE/CHANNEL DECODING SCHEME FOR JPEG2000Pu, Lingling, Wu, Zhenyu, Bilgin, Ali, Marcellin, Michael W., Vasic, Bane 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / This paper presents a joint source-channel decoding scheme based on a JPEG2000 source coder and an LDPC channel coder. At the encoder, JPEG2000 is used to perform source coding with certain error resilience (ER) modes, and LDPC codes are used to perform channel coding. At the decoder, after one iteration of LDPC decoding, the output codestream is then decoded by JPEG2000. With the error resilience mode switches on, the source decoder detects the position of the first error within each codeblock of the JPEG2000 codestream. This information is fed back to the channel decoder, and incorporated into the calculation of likelihood values of variable nodes for the next iteration of LDPC decoding. Our results indicate that the proposed method has significant gains over conventional separate channel and source decoding.
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Cross Layer Coding Schemes for Broadcasting and RelayingJohn Wilson, Makesh Pravin 2010 May 1900 (has links)
This dissertation is divided into two main topics. In the first topic, we study the
joint source-channel coding problem of transmitting an analog source over a Gaussian
channel in two cases - (i) the presence of interference known only to the transmitter and (ii) in the presence of side information about the source known only to the
receiver. We introduce hybrid digital analog forms of the Costa and Wyner-Ziv coding schemes. We present random coding based schemes in contrast to lattice based
schemes proposed by Kochman and Zamir. We also discuss superimposed digital and
analog schemes for the above problems which show that there are infinitely many
schemes for achieving the optimal distortion for these problems. This provides an
extension of the schemes proposed by Bross and others to the interference/source
side information case. The result of this study shows that the proposed hybrid digital analog schemes are more robust to a mismatch in channel signal-to-noise ratio
(SNR), than pure separate source coding followed by channel coding solutions. We
then discuss applications of the hybrid digital analog schemes for transmitting under
a channel SNR mismatch and for broadcasting a Gaussian source with bandwidth
compression. We also study applications of joint source-channel coding schemes for
a cognitive setup and also for the setup of transmitting an analog Gaussian source
over a Gaussian channel, in the presence of an eavesdropper.
In the next topic, we consider joint physical layer coding and network coding
solutions for bi-directional relaying. We consider a communication system where two transmitters wish to exchange information through a central relay. The transmitter
and relay nodes exchange data over synchronized, average power constrained additive
white Gaussian noise channels. We propose structured coding schemes using lattices
for this problem. We study two decoding approaches, namely lattice decoding and
minimum angle decoding. Both the decoding schemes can be shown to achieve the
upper bound at high SNRs. The proposed scheme can be thought of as a joint physical
layer, network layer code which outperforms other recently proposed analog network
coding schemes. We also study extensions of the bi-directional relay for the case with
asymmetric channel links and also for the multi-hop case. The result of this study
shows that structured coding schemes using lattices perform close to the upper bound
for the above communication system models.
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Combined source-channel coding for a power and bandwidth constrained noisy channelRaja, Nouman Saeed 17 February 2005 (has links)
This thesis proposes a framework for combined source-channel coding under power and bandwidth constrained noisy channel. The framework is then applied to progressive image coding transmission using constant envelope M-ary Phase Shift Key (MPSK) signaling over an Additive White Gaussian Channel (AWGN) channel. First the framework for uncoded MPSK signaling is developed. Then, its extended to include coded modulation using Trellis Coded Modulation (TCM) for MPSK signaling. Simulation results show that coded MPSK signaling performs 3.1 to 5.2 dB better than uncoded MPSK signaling depending on the constellation size. Finally, an adaptive TCM system is presented for practical implementation of the proposed scheme, which outperforms uncoded MPSK system over all signal to noise ratio (Es/No) ranges for various MPSK modulation formats.
In the second part of this thesis, the performance of the scheme is investigated from the channel capacity point of view. Using powerful channel codes like Turbo and Low Density Parity Check (LDPC) codes, the combined source-channel coding scheme is shown to be within 1 dB of the performance limit with MPSK channel signaling.
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Joint source channel coding for non-ergodic channels: the distortion signal-to-noise ratio (SNR) exponent perspectiveBhattad, Kapil 10 October 2008 (has links)
We study the problem of communicating a discrete time analog source over
a channel such that the resulting distortion is minimized. For ergodic channels,
Shannon showed that separate source and channel coding is optimal. In this work we
study this problem for non-ergodic channels.
Although not much can be said about the general problem of transmitting any
analog sources over any non-ergodic channels with any distortion metric, for many
practical problems like video broadcast and voice transmission, we can gain insights
by studying the transmission of a Gaussian source over a wireless channel with mean
square error as the distortion measure. Motivated by different applications, we consider three different non-ergodic channel models - (1) Additive white Gaussian noise
(AWGN) channel whose signal-to-noise ratio (SNR) is unknown at the transmitter; (2)
Rayleigh fading multiple-input multiple-output MIMO channel whose SNR is known
at the transmitter; and (3) Rayleigh fading MIMO channel whose SNR is unknown
at the transmitter.
The traditional approach to study these problems has been to fix certain SNRs
of interest and study the corresponding achievable distortion regions. However, the
problems formulated this way have not been solved even for simple setups like 2
SNRs for the AWGN channel. We are interested in performance over a wide range
of SNR and hence we use the distortion SNR exponent metric to study this problem.
Distortion SNR exponent is defined as the rate of decay of distortion with SNR in the high SNR limit.
We study several layered transmissions schemes where the source is first compressed in layers and then the layers are transmitted using channel codes that provide
variable error protection. Results show that in several cases such layered transmission
schemes are optimal in terms of the distortion SNR exponent. Specifically, if the band-
width expansion (number of channel uses per source sample) is b, we show that the
optimal distortion SNR exponent for the AWGN channel is b and it is achievable using
a superposition based layered scheme. For the L-block Rayleigh fading M x N MIMO
channel the optimal exponent is characterized for b < (|N - M|+1)= min(M;N) and
b > MNL2. This corresponds to the entire range of b when min(M;N) = 1 and
L = 1. The results also show that the exponents obtained using layered schemes
which are a small subclass of joint source channel coding (JSCC) schemes are, surprisingly, as good as and better in some cases than achievable exponent of all other
JSCC schemes reported so far.
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Multiple symbol decoding of differential space-time codesSinghal, Rohit 30 September 2004 (has links)
Multiple-symbol detection of space-time differential codes (MS-STDC) decodes N consecutive space-time symbols using maximum likelihood (ML) sequence detection to gain in performance over the conventional differential detection scheme. However its computational complexity is exponential in N . A fast algorithm for implementing the MD-STDC in block-fading channels with complexity O(N 4) is developed. Its performance in both block-fading and symbol-by-symbol fading channels is demonstrated through simulations. Set partitioning in hierarchical trees (SPIHT) coupled with rate compatible punctured convolution code (RCPC) and cyclic redundancy check (CRC) is employed as a generalized multiple description source coder with robustness to channel errors. We propose a serial concatenation of the above with a differential space-time code (STDC) and invoke an iterative joint source channel decoding procedure for decoding differentially space-time coded multiple descriptions. Experiments show a gain of up to 5 dB in PSNR with four iterations for image transmission in the absence of channel state information (CSI) at the receiver. A serial concatenation of SPIHT
+ RCPC/CRC is also considered with space-time codes (STC) instead of STDC. Experiments show a gain of up to 7 dB with four iterations in the absence of CSI
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Hybrid Digital-Analog Source-Channel Coding and Information Hiding: Information-Theoretic PerspectivesWang, Yadong 02 October 2007 (has links)
Joint source-channel coding (JSCC) has been acknowledged to have
superior performance over separate source-channel coding in terms of
coding efficiency, delay and complexity. In the first part of this
thesis, we study a hybrid digital-analog (HDA) JSCC system to
transmit a memoryless Gaussian source over a memoryless Gaussian
channel under bandwidth compression. Information-theoretic upper
bounds on the asymptotically optimal mean squared error distortion
of the system are obtained. An allocation scheme for distributing
the channel input power between the analog and the digital signals
is derived for the HDA system with mismatched channel conditions. A
low-complexity and low-delay version of the system is next designed
and implemented. We then propose an image communication application
demonstrating the effectiveness of HDA coding.
In the second part of this thesis, we consider problems in
information hiding. We begin by considering a single-user joint
compression and private watermarking (JCPW) problem. For memoryless
Gaussian sources and memoryless Gaussian attacks, an exponential
upper bound on the probability of error in decoding the watermark is
derived. Numerical examples show that the error exponent is positive
over a (large) subset of the entire achievable region derived by
Karakos and Papamarcou (2003).
We then extend the JCPW problem to a multi-user setting. Two
encoders independently embed two secret information messages into
two correlated host sources subject to a pair of tolerable
distortion levels. The (compressed) outputs are subject to multiple
access attacks. The tradeoff between the achievable watermarking
rates and the compression rates is studied for discrete memoryless
host sources and discrete memoryless multiple access channels. We
derive an inner bound and an outer bound with single-letter
characterization for the achievable compression and watermarking
rate region. We next consider a problem where two correlated sources
are separately embedded into a common host source. A single-letter
sufficient condition is established under which the sources can be
successfully embedded into the host source under multiple access
attacks. Finally, we investigate a public two-user information
hiding problem under multiple access attacks. Inner and outer bounds
for the embedding capacity region are obtained with single-letter
characterization. / Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2007-09-28 23:11:21.398
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Channel Optimized Vector Quantization: Iterative Design AlgorithmsEbrahimzadeh Saffar, Hamidreza 04 September 2008 (has links)
Joint source-channel coding (JSCC) has emerged to be a major field
of research recently. Channel optimized vector quantization (COVQ)
is a simple feasible JSCC scheme introduced for communication over
practical channels.
In this work, we propose an iterative design
algorithm, referred to as the iterative maximum a posteriori (MAP)
decoded (IMD) algorithm, to improve COVQ systems. Based on this
algorithm, we design a COVQ based on symbol MAP hard-decision
demodulation that exploits the non-uniformity of the quantization
indices probability distribution. The IMD design algorithm consists
of a loop which starts by designing a COVQ, obtaining the index
source distribution, updating the discrete memoryless channel (DMC)
according to the achieved index distribution, and redesigning the
COVQ. This loop stops when the point-to-point distortion is
minimized. We consider memoryless Gaussian and Gauss-Markov sources
transmitted over binary phase-shift keying modulated additive white
Gaussian noise (AWGN) and Rayleigh fading channels. Our scheme,
which is shown to have less encoding complexity than conventional
COVQ and less encoding complexity and storage requirements than
soft-decision demodulated (SDD) COVQ systems, is also shown to
provide a notable signal-to-distortion ratio (SDR) gain
over the conventional COVQ designed for hard-decision demodulated
channels while sometimes matching or exceeding the SDD COVQ
performance, especially for higher quantization dimensions and/or
rates.
In addition to our main result, we also propose another
iterative algorithm to design SDD COVQ based on the notion of the
JSCC error exponent. This system is shown to have some gain over
classical SDD COVQ both in terms of the SDR and the
exponent itself. / Thesis (Master, Mathematics & Statistics) -- Queen's University, 2008-08-29 17:58:52.329
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