Results 11 - 20 of 496

Capacity and Lattice-Strategies for Cancelling Known Interference

by Uri Erez, Shlomo Shamai, Ram Zamir , 2000
"... We derive capacity formulas and strategies for transmission over the the channel Y = X + S + N , 1 n EkXk 2 PX , where the interference S is a (strong) stochastic process or an arbitrarily varying sequence, known causally or with nite anticipation at the transmitter but not at the receiver. In ..."
Abstract - Cited by 53 (9 self) - Add to MetaCart
We derive capacity formulas and strategies for transmission over the the channel Y = X + S + N , 1 n EkXk 2 PX , where the interference S is a (strong) stochastic process or an arbitrarily varying sequence, known causally or with nite anticipation at the transmitter but not at the receiver. In the causal side information case, we show that strategies associated with entropy constrained quantizers provide lower and upper bounds on the capacity. At high SNR conditions, i.e., if N is weak relative to the power constraint PX , these bounds coincide, the optimum strategies take the form of scalar lattice translations, and the capacity loss due to not having S at the receiver is shown to be exactly the \shaping gain" 0.254 bit. We also extend these ideas to any SNR and to non-causal side information, by incorporating \MMSE weighting", and by using k- dimensional lattices. For Gaussian N , the capacity loss of this scheme is upper bounded by 0:5 log(2eG k ), where G k is the normalize...

Great expectations: The value of spatial diversity in wireless networks

by Suhas N. Diggavi, Naofal Al-Dhahir, A. Stamoulis, A. R. Calderbank - PROCEEDINGS OF THE IEEE , 2004
"... In this paper, the effect of spatial diversity on the throughput and reliability of wireless networks is examined. Spatial diversity is realized through multiple independently fading transmit/receive antenna paths in single-user communication and through independently fading links in multiuser commu ..."
Abstract - Cited by 45 (8 self) - Add to MetaCart
In this paper, the effect of spatial diversity on the throughput and reliability of wireless networks is examined. Spatial diversity is realized through multiple independently fading transmit/receive antenna paths in single-user communication and through independently fading links in multiuser communication. Adopting spatial diversity as a central theme, we start by studying its information-theoretic foundations, then we illustrate its benefits across the physical (signal transmission/coding and receiver signal processing) and networking (resource allocation, routing, and applications) layers. Throughout the paper, we discuss engineering intuition and tradeoffs, emphasizing the strong interactions between the various network functionalities.
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Multiaccess Channels with State Known to One Encoder: A Case of Degraded Message Sets

by Shivaprasad Kotagiri, J. Nicholas Laneman , 2007
"... We consider a state-dependent multiple access channel p(y|x1, x2, s) whose output Y is controlled by the channel inputs X1 and X2 from two encoders and the channel state S. It is assumed that the channel state is known non-causally at one encoder, called the informed encoder. We derive the capacity ..."
Abstract - Cited by 44 (5 self) - Add to MetaCart
We consider a state-dependent multiple access channel p(y|x1, x2, s) whose output Y is controlled by the channel inputs X1 and X2 from two encoders and the channel state S. It is assumed that the channel state is known non-causally at one encoder, called the informed encoder. We derive the capacity region for the case of degraded messages in which the informed encoder knows the message of the uninformed encoder.

Quantization index modulation methods for digital watermarking and information embedding of multimedia. The

by Brian Chen, Gregory, W. Wornell - Journal of VLSI Signal Processing , 2001
"... Abstract. Copyright notification and enforcement, authentication, covert communication, and hybrid transmission applications such as digital audio broadcasting are examples of emerging multimedia applications for digital watermarking and information embedding methods, methods for embedding one signa ..."
Abstract - Cited by 44 (3 self) - Add to MetaCart
Abstract. Copyright notification and enforcement, authentication, covert communication, and hybrid transmission applications such as digital audio broadcasting are examples of emerging multimedia applications for digital watermarking and information embedding methods, methods for embedding one signal (e.g., the digital watermark) within another “host ” signal to form a third, “composite ” signal. The embedding is designed to achieve efficient trade-offs among the three conflicting goals of maximizing information-embedding rate, minimizing distortion between the host signal and composite signal, and maximizing the robustness of the embedding. We present a class of embedding methods called quantization index modulation (QIM) that achieve provably good rate-distortion-robustness performance. These methods, and low-complexity realizations of them called dither modulation, are provably better than both previously proposed linear methods of spread spectrum and nonlinear methods of low-bit(s) modulation against square-error distortion-constrained intentional attacks. We also derive information-embedding capacities for the case of a colored Gaussian host signal and additive colored Gaussian noise attacks. These results imply an information embedding capacity of about 1/3 b/s of embedded digital rate for every Hertz of host signal bandwidth and every dB drop in received host signal quality. We show that QIM methods achieve performance within 1.6 dB of capacity, and we introduce a form of postprocessing we refer to as distortion compensation that, when combined with QIM, allows capacity to be achieved.
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Writing on Wet Paper

by Jessica Fridrich, Miroslav Goljan, Petr Lisoněk, David Soukal
"... In this paper, we show that the communication channel known as writing in memory with defective cells [1][2] is a relevant information-theoretical model for a specific case of passive warden steganography when the sender embeds a secret message into a subset C of the cover object X without sharing ..."
Abstract - Cited by 42 (10 self) - Add to MetaCart
In this paper, we show that the communication channel known as writing in memory with defective cells [1][2] is a relevant information-theoretical model for a specific case of passive warden steganography when the sender embeds a secret message into a subset C of the cover object X without sharing C with the recipient. The set C, also called the selection channel, could be arbitrary, determined by the sender from the cover object using a deterministic, pseudo-random, or a truly random process. We call this steganography “writing on wet paper ” and realize it using a simple variable-rate random linear code that gives the sender a convenient flexibility and control over the embedding process and is thus suitable for practical implementation. The importance of the wet paper scenario for covert communication is discussed within the context of adaptive steganography and perturbed quantization steganography [3]. Heuristic arguments supported by tests using blind steganalysis [4] indicate that the wet paper steganography provides improved steganographic security and is less vulnerable to steganalytic attacks compared to existing methods with shared selection channels.

Quality-Aware Images

by Zhou Wang, Guixing Wu, Hamid R. Sheikh, Eero P. Simoncelli, En-hui Yang, Alan C. Bovik - IEEE TRANSACTIONS ON IMAGE PROCESSING, TO APPEAR 1 , 2004
"... We propose the concept of quality-aware image, in which certain extracted features of the original (highquality) image are embedded into the image data as invisible hidden messages. When a distorted version of such an image is received, users can decode the hidden messages and use them to provide ..."
Abstract - Cited by 40 (12 self) - Add to MetaCart
We propose the concept of quality-aware image, in which certain extracted features of the original (highquality) image are embedded into the image data as invisible hidden messages. When a distorted version of such an image is received, users can decode the hidden messages and use them to provide an objective measure of the quality of the distorted image. To demonstrate the idea, we build a practical quality-aware image encoding, decoding and quality analysis system1, which employs 1) a novel reducedreference image quality assessment algorithm based on a statistical model of natural images, and 2) a previously developed quantization watermarking-based data hiding technique in the wavelet transform domain.
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Advances in Digital Video Content Protection

by Eugene T. Lin, Ahmet M. Eskicioglu, Reginald L. Lagendijk, Edward J. Delp , 2005
"... The use of digital video offers immense opportunities for creators; however, the ability for anyone to make perfect copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution (“piracy”), plagiarism, and misappropriation. Popular Internet sof ..."
Abstract - Cited by 38 (8 self) - Add to MetaCart
The use of digital video offers immense opportunities for creators; however, the ability for anyone to make perfect copies and the ease by which those copies can be distributed also facilitate misuse, illegal copying and distribution (“piracy”), plagiarism, and misappropriation. Popular Internet software based on a peer-to-peer architecture has been used to share copyrighted movies, music, software, and other materials. Concerned about the consequences of illegal copying and distribution on a massive scale, content owners are interested in digital rights management (DRM) systems which can protect their rights and preserve the economic value of digital video. A DRM system protects and enforces the rights associated with the use of digital content. Unfortunately, the technical challenges for securing digital content are formidable and previous approaches have not succeeded. We overview the concepts and approaches for video DRM and describe methods for providing security, including the roles of encryption and video watermarking. Current efforts and issues are described in encryption, watermarking, and key management. Lastly, we identify challenges and directions for further investigation in video DRM.
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Preprocessed and Postprocessed Quantization Index Modulation Methods for Digital Watermarking

by Brian Chen, Gregory W. Wornell , 2000
"... Quantization index modulation (QIM) methods, a class of digital watermarking and information embedding methods, achievevery efficient trade-offs among the amount of embedded information (rate), the amount of embedding-induced distortion to the host signal, and the robustness to intentional and unint ..."
Abstract - Cited by 38 (1 self) - Add to MetaCart
Quantization index modulation (QIM) methods, a class of digital watermarking and information embedding methods, achievevery efficient trade-offs among the amount of embedded information (rate), the amount of embedding-induced distortion to the host signal, and the robustness to intentional and unintentional attacks. For example, we show that against independent additive Gaussian attacks, which are good models for at least some types of uninformed and unintentional attacks, QIM methods exist that achieve the best possible rate-distortion-robustness trade-offs (i.e., capacity) asymptotically at high rates and achieve performance within a few dB of capacity at all finite rates. Furthermore, low-complexity realizations of QIM methods, such as so-called dither modulation, have also been shown to achieve favorable rate-distortion-robustness trade-offs. We further develop preprocessing and postprocessing techniques that enable QIM to fully achieve capacity, not only against Gaussian attacks but also ag...

The Parallel-Gaussian Watermarking Game

by Pierre Moulin, M. Kıvanç Mıhçak - IEEE TRANS. ON INFORMATION THEORY , 2000
"... Rates of reliable transmission of hidden information are derived for watermarking problems involving parallel Gaussian sources, which are often used to model host images and audio signals. Constraints are imposed on the average squared-error distortion that can be introduced by the information hider ..."
Abstract - Cited by 35 (5 self) - Add to MetaCart
Rates of reliable transmission of hidden information are derived for watermarking problems involving parallel Gaussian sources, which are often used to model host images and audio signals. Constraints are imposed on the average squared-error distortion that can be introduced by the information hider and by the attacker. When distortions are measured with respect to the original host data, the optimal covert and attack channels are two banks of Gaussian test channels. The solution to the watermarking game involves an optimal allocation of distortions by the information hider and by the attacker to the different channels. A fast algorithm is given for computing the optimal solution based on duality theory. For each channel we derive analytical expressions for two asymptotic regimes: weak and strong host signals. Finally we extend these results to the class of stationary Gaussian host signals with bounded, continuous spectral density. The analysis also provides an upper bound on watermarking capacity for non-Gaussian host signals.

Video fingerprinting and encryption principles for digital rights management

by Deepa Kundur, Senior Member, Kannan Karthik, Student Member - Proceedings of the IEEE , 2004
"... This paper provides a tutorial and survey of digital fingerprinting and video scrambling algorithms based on partial encryption. Necessary design tradeoffs for algorithm development are highlighted for multicast communication environments. We also propose a novel architecture for joint fingerprintin ..."
Abstract - Cited by 35 (0 self) - Add to MetaCart
This paper provides a tutorial and survey of digital fingerprinting and video scrambling algorithms based on partial encryption. Necessary design tradeoffs for algorithm development are highlighted for multicast communication environments. We also propose a novel architecture for joint fingerprinting and decryption that holds promise for a better compromise between practicality and security for emerging digital rights management applications. Keywords—Digital fingerprinting tutorial, digital video encryption survey, joint fingerprinting and decryption (JFD), video scrambling. I.
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