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Universal source Controlled channel Decoding with Nonsystematic Quick-Look-In Turbo Codes

IEEE TRANSACTIONS ON COMMUNICATIONS 2009年第4期57卷 960-971页

作者： Shamir, Gil I. Xie, Kai ADC Telecomm Inc San Jose CA 95134 USA

Utilization of redundancy left in a channel coded sequence can improve channel decoding performance. Stronger improvement can usually be achieved with nonsystematic encoding. However, nonsystematic codes recently proposed for this problem are not robust to the statistical parameters governing a sequence and thus should not be used without prior knowledge of these parameters. In this work, decoders of nonsystematic quick-look-in turbo codes are adapted to extract and exploit redundancy left in coded data to improve channel decoding performance. Methods, based on universal compression and denoising, for extracting the governing statistical parameters for various source models are integrated into the channel decoder by also taking advantage of the code structure. Simulation results demonstrate significant performance gains over standard systematic codes that can be achieved with the new methods for a wide range of statistical models and governing parameters. In many cases, performance almost as good as that with perfect knowledge of the governing parameters is achievable.

关键词： joint source-channel coding quick-look-in turbo codes universal source controlled channel decoding

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Quantization of memoryless and Gauss-Markov sources over binary Markov channels

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IEEE TRANSACTIONS ON COMMUNICATIONS 1997年第6期45卷 668-675页

作者： Phamdo, N Alajaji, F Farvardin, N QUEENS UNIV DEPT MATH & STAT KINGSTON ON K7L 3N6 CANADA UNIV MARYLAND DEPT ELECT ENGN COLLEGE PK MD 20742 USA

joint source-channel coding for stationary memoryless and Gauss-Markov sources and binary Markov channels is considered, The channel is an additive-noise channel where the noise process is an Mth-order Markov chain, Two joint source-channel coding schemes are considered. The first is a channel-optimized vector quantizer - optimized for both source and channel, The second scheme consists of a scalar quantizer and a maximum a posteriori detector, In this scheme, it is assumed that the scalar quantizer output has residual redundancy that can be exploited by the maximum a posteriori detector to combat the correlated channel noise, These two schemes are then compared against two schemes which use channel interleaving, Numerical results show that the proposed schemes outperform the interleaving schemes, For very noisy channels with high noise correlation, gains of 4-5 dB in signal-to-noise ratio are possible.

关键词： channels with memory joint source-channel coding MAP detection Markov noise vector quantization

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Robust transmission of MELP-compressed speech: An illustrative example of joint source-channel decoding

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IEEE TRANSACTIONS ON COMMUNICATIONS 2003年第6期51卷 973-982页

作者： Fazel, T Fuja, T Hughes Network Syst Germantown MD 20876 USA Univ Notre Dame Dept Elect Engn Notre Dame IN 46556 USA

A mixed-excitation linear predictive (MELP) speech coder was selected as the U.S. federal standard for 2400 b/s speech compression. This paper examines the quality of MELP-compressed speech when transmitted over noisy communication channels in conjunction with a variety of error-control schemes. The focus is on channel decoders that exploit the "residual redundancy" inherent in the MELP bitstream. This residual redundancy, which is manifested by the correlation in time and the nonuniform distribution of various MELP parameters, can be quantified by modeling the parameters as one-step Markov chains and computing the entropy rate of the Markov chains based on the relative frequencies of transitions. Moreover, this residual redundancy can be exploited by an appropriately "tuned" channel decoder to provide substantial coding gain when compared with decoders that do not exploit it. channel coding schemes include conventional binary convolutional codes and iteratively-decoded parallel concatenated convolutional (turbo) codes.

关键词： error-correction coding joint source-channel coding speech coding turbo codes

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Secret-Key Generation Using Correlated sources and channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2012年第2期58卷 652-670页

作者： Khisti, Ashish Diggavi, Suhas N. Wornell, Gregory W. Univ Toronto Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada Univ Calif Los Angeles Dept Elect Engn Los Angeles CA 90095 USA MIT Dept Elect Engn & Comp Sci Cambridge MA 02139 USA

We study the secret-key capacity in a joint source-channel coding setup-the terminals are connected over a discrete memoryless channel and have access to side information, modelled as a pair of discrete memoryless source sequences. As our main result, we establish the upper and lower bounds on the secret-key capacity. In the lower bound expression, the equivocation terms of the source and channel components are functionally additive even though the coding scheme generates a single secret-key by jointly taking into account the source and channel equivocations. Our bounds coincide, thus establishing the capacity, when the underlying wiretap channel can be decomposed into a set of independent, parallel, and reversely degraded channels. For the case of parallel Gaussian channels and jointly Gaussian sources we show that Gaussian codebooks achieve the secret-key capacity. In addition, when the eavesdropper also observes a correlated side information sequence, we establish the secret-key capacity when both the source and channel of the eavesdropper are a degraded version of the legitimate receiver. We finally also treat the case when a public discussion channel is available, propose a separation based coding scheme, and establish its optimality when the channel output symbols of the legitimate receiver and eavesdropper are conditionally independent given the input.

关键词： Information theoretic security joint source-channel coding public discussion secret-key agreement wiretap channel

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The Capacity Region of the L-User Gaussian Inverse Compute-and-Forward Problem

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IEEE TRANSACTIONS ON INFORMATION THEORY 2016年第12期62卷 6953-6968页

作者： Chen, Yanying Song, Yiwei Devroye, Natasha Univ Illinois Chicago IL 60607 USA Univ Illinois Dept Elect & Comp Engn Chicago IL 60607 USA

We consider an L-user multiple access channel where transmitter m has access to the linear equation u(m) = circle plus(L)(l=1) f(ml) w(l), of independent messages w(l) is an element of F-p(kl) with f(ml) is an element of F-p, and the destination wishes to recover all L messages. This problem may be motivated as the last hop in a network where relay nodes employ the compute-and-forward strategy and decode linear equations of messages;we seek to do the reverse and extract messages from sums over a multiple access channel. In particular, we exploit the particular form of dependencies between the equations at the different relays to improve the reliable communication rates beyond those achievable by simply forwarding all equations to the destination independently. The presented achievable rate region for the discrete memoryless channel model is shown to be capacity for the additive white Gaussian noise channel.

关键词： Terms channel capacity multiple access channel compute-and-forward correlated sources joint source-channel coding multiuser channels

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An end-to-end embedded approach for multicast/broadcast of scalable video over multiuser CDMA wireless networks

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IEEE TRANSACTIONS ON MULTIMEDIA 2007年第3期9卷 655-667页

作者： Chan, Yee Sin Modestino, James W. Qu, Qi Fan, Xingzhe Univ Miami Dept Elect & Comp Engn Coral Gables FL 33124 USA Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

We investigate an embedded multicast/broadcast approach for transport of digital video over spread-spectrum code-division multiple access (CDMA) cellular networks. Previous work has shown that the incorporation of a scalable source coding scheme with multiresolution modulation provides a promising design paradigm for the practical realization of the information-theoretic performance predictions originally developed by Cover [1], which demonstrated that optimal multicast/broadcast performance could be achieved by an embedded transmission scheme. Hence, the major technical challenge associated with the design of an end-to-end embedded multicast/broadcast system is how to match an embedded modulation constellation with a scalable source coding scheme. In this work, taking into consideration both the interference-limited and bandwidth-limited characteristics of a CDMA system, we provide a cross-layer approach incorporating adaptive power allocation and channel coding strategies and effectively match a discrete cosine transform based scalable motion-compensated video encoder to an embedded multiresolution modulation scheme to simultaneously deliver a basic quality-of-service (QoS) to less capable receivers while maximizing both the QoS for more capable receivers and the system capacity. We demonstrate the efficacy of this approach using the ITU-T H.263+ video scalable hybrid coder, although the approach is generally extensible to other scalable coding schemes as well.

关键词： adaptive modulation and coding code-division multiple access (CDMA) cross-layer drift control embedded transmission H.263+ joint source-channel coding joint source coding-power control multicast/broadcast turbo codes wireless video

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AirNet: Neural Network Transmission Over the Air

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2024年第9期23卷 12126-12139页

作者： Jankowski, Mikolaj Gunduz, Deniz Mikolajczyk, Krystian Imperial Coll London Dept Elect & Elect Engn London SW7 2AZ England

State-of-the-art performance for many edge applications is achieved by deep neural networks (DNNs). Often, these DNNs are location- and time-sensitive, and must be delivered over a wireless channel rapidly and efficiently. In this paper, we introduce AirNet, a family of novel methods that allow DNNs to be efficiently delivered over wireless channels under stringent transmit power and latency constraints. It is a part of a new class of joint source-channel coding methods that maximize the accuracy of the DNNs transmitted to the receiver, rather than recover the DNNs with high fidelity. In AirNet, we propose to directly map the DNN parameters to the transmitted channel symbols, while training the network under the channel constraints with robustness to channel noise. AirNet achieves higher accuracy compared to the separation-based alternatives. We further improve its performance by pruning the network below the available bandwidth, and using bandwidth expansion for significant network parameters. We also exploit unequal error protection (UEP) by selectively expanding the important layers. Finally, we propose an ensemble training approach where networks for different channel conditions can be obtained simultaneously, resolving the impractical memory requirements of training distinct networks for different channel conditions.

关键词： Wireless communication Training Artificial neural networks Bandwidth Wireless sensor networks Atmospheric modeling Task analysis Neural network compression joint source-channel coding network pruning distributed inference

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Soft decoding and synchronization of arithmetic codes: Application of image transmission over noisy channels

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2003年第12期12卷 1599-1609页

作者： Guionnet, T Guillemot, C INRIA IRISA F-35042 Rennes France

This paper addresses the issue of robust and joint source-channel decoding of arithmetic codes. We first analyze dependencies between the variables involved in arithmetic coding by means of the Bayesian formalism. This provides a suitable framework for designing a soft decoding algorithm that provides high error-resilience. It also provides a natural setting for "soft synchronization," i.e., to introduce anchors favoring the likelihood of "synchronized" paths. In order to maintain the complexity of the estimation within a realistic range, a simple, yet efficient, pruning method is described. The algorithm can be placed in an iterative source-channel decoding structure, in the spirit of serial turbo codes. Models and algorithms are then applied to context-based arithmetic coding widely used in practical systems (e.g., JPEG-2000). Experimentation results with both theoretical sources and with real images code with JPEG-2000 reveal very good error resilience performances.

关键词： arithmetic codes entropy codes error correction image coding joint source-channel coding maximum likelihood decoding sequential decoding soft synchronization

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Performance analysis and design criteria for finite-alphabet source-channel codes

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IEEE TRANSACTIONS ON COMMUNICATIONS 2004年第11期52卷 1872-1879页

作者： Hedayat, A Nosratinia, A Univ Texas Multimedia Commun Lab Richardson TX 75083 USA

Efficient compression of finite-alphabet sources requires variable-length codes. (VLCs). However, in the presence of noisy channels, error propagation in the decoding of VLCs severely degrades performance. To address this problem, redundant entropy codes and iterative source-channel decoding have been suggested, but to date, neither performance bounds nor design criteria for the composite system have been available. We calculate performance bounds for the source-channel system by generalizing techniques originally developed for serial concatenated convolutional codes. Using this analysis, we demonstrate the role of a recursive structure for the inner code and the distance properties of the outer code. We use density evolution to study the convergence of our decoders. Finally, we pose the question: Under a fixed rate and complexity constraint, when should we use source-channel decoding (as opposed to separable decoding)? We offer answers in several specific cases. For our analysis and design rules, we use union bounds that are technically valid only above the cutoff rate, but interestingly, the codes designed with union-bound criteria perform well even in low signal-to-noise ratio regions, as shown by our simulations as well as previous works on concatenated codes.

关键词： concatenated coding iterative decoding joint source-channel coding variable-length codes (VLCs)

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joint source-channel codes for MIMO block-fading channels

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第1期54卷 116-134页

作者： Gunduz, Deniz Erkip, Elza Polytech Univ Dept Elect & Comp Engn Brooklyn NY 11201 USA Stanford Univ Dept Elect Engn Stanford CA 94305 USA

We consider transmission of a continuous amplitude source over an L-block Rayleigh-fading M-t x M-r, multiple-input multiple-output (MIMO) channel when the channel state information is only available at the receiver. Since the channel is not ergodic, Shannon's source-channel separation theorem becomes obsolete and the optimal performance requires a joint source-channel approach. Our goal is to minimize the expected end-to-end distortion, particularly in the high signal-to-noise ratio (SNR) regime. The figure of merit is the distortion exponent, defined as the exponential decay rate of the expected distortion with increasing SNR. We provide an upper bound and lower bounds for the distortion exponent with respect to the bandwidth ratio among the channel and source bandwidths. For the lower bounds, we analyze three different strategies based on layered source coding concatenated with progressive superposition or hybrid digital/analog transmission. In each case, by adjusting the system parameters we optimize the distortion exponent as a function of the bandwidth ratio. We prove that the distortion exponent upper bound can be achieved when the channel has only one degree of freedom, that is L = 1, and min {M-t, M-r} = 1. When we have more degrees of freedom, our achievable distortion exponents meet the upper bound for only certain ranges of the bandwidth ratio. We demonstrate that our results, which were derived for a complex Gaussian source, can be extended to more general source distributions as well.

关键词： broadcast codes distortion exponent diversity-multiplexing gain tradeoff hybrid digital/analog coding joint source-channel coding multiple-input multiple-output (MIMO) successive refinement

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