Journal ArticleIEEE transactions on neural networks and learning systems · September 2020
The problem of completing high-dimensional matrices from a limited set of observations arises in many big data applications, especially recommender systems. The existing matrix completion models generally follow either a memory- or a model-based approach, ...
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Journal ArticleIEEE Transactions on Information Theory · May 1, 2019
Given a collection of strings, each with an associated probability of occurrence, the guesswork of each of them is their position in a list ordered from most likely to least likely, breaking ties arbitrarily. The guesswork is central to several application ...
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Journal ArticleIEEE Transactions on Communications · April 1, 2019
Multi-scale spectrum sensing is proposed to overcome the cost of full network state information on the spectrum occupancy of primary users (PUs) in dense multi-cell cognitive networks. Secondary users (SUs) estimate the local spectrum occupancies and aggre ...
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Journal ArticleIEEE Transactions on Information Theory · February 1, 2019
In multi-user wireless packet networks, interference, typically modeled as packet collision, is the throughput bottleneck. Users become aware of the interference pattern via feedback and use this information for contention resolution and packet retransmiss ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · December 14, 2018
Deep neural networks have proved very successful on archetypal tasks for which large training sets are available, but when the training data are scarce, their performance suffers from overfitting. Many existing methods of reducing overfitting are data-inde ...
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ConferenceEuropean Signal Processing Conference · November 29, 2018
Autoencoders are popular among neural-network-based matrix completion models due to their ability to retrieve potential latent factors from the partially observed matrices. Nevertheless, when training data is scarce their performance is significantly degra ...
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Journal ArticleIEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems · November 1, 2018
We extend the lifetime of Flash memory in embedded processors by exploiting the fact that data from sensors is inherently analog. Prior work in the computer architecture community has assumed that all data is digital and has overlooked the opportunities av ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018
Diagnosis of melanoma is fraught with uncertainty, and discordance rates among physicians remain high because of the lack of a definitive criterion. Motivated by this challenge, this paper first introduces the Patch Weyl transform (PWT), a 2-dimensional va ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · August 15, 2018
Quantum error-correcting codes can be used to protect qubits involved in quantum computation. This requires that logical operators acting on protected qubits be translated to physical operators (circuits) acting on physical quantum states. We propose a mat ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · August 15, 2018
We study the network-wide neighbour discovery problem in wireless networks in which each node in a network must discovery the network interface addresses (NIAs) of its neighbour. We work within the rapid on-off division duplex framework proposed by Guo and ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · August 15, 2018
In multi-user wireless packet networks interference is the throughput bottleneck. Users become aware of the interference pattern via feedback and use this information for contention resolution and for packet retransmission. We consider networks with spatia ...
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Conference2017 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2017 - Proceedings · March 7, 2018
We construct extremely sparse, near-equiangular tight frames which share the same row space as certain incomplete Delsarte-Goethals frames. Frames combining these properties have application in full duplex communication in ad-hoc wireless networks. We high ...
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Journal Article35th International Conference on Machine Learning, ICML 2018 · January 1, 2018
Filters in a Convolutional Neural Network (CNN) contain model parameters learned from enormous amounts of data. In this paper, we suggest to decompose convolutional filters in CNN as a truncated expansion with pre-fixed bases, namely the Decomposed Convolu ...
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ConferenceProceedings - 35th IEEE International Conference on Computer Design, ICCD 2017 · November 22, 2017
In this paper, we introduce Jenga, a new scheme for protecting 3D DRAM, specifically high bandwidth memory (HBM), from failures in bits, rows, banks, channels, dies, and TSVs. By providing redundancy at the granularity of a cache block rather than across b ...
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ConferenceIEEE MTT-S International Microwave Symposium Digest · October 4, 2017
Due to the increased demand for data rate, flexibility, and reliability of 5G cellular systems, new modulation formats need to be considered. A recently proposed scheme, Orthogonal Time Frequency Space (OTFS), offers various advantages in particular in env ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · August 9, 2017
A locally repairable code with availability has the property that every code symbol can be recovered from multiple, disjoint subsets of other symbols of small size. In particular, a code symbol is said to have (r, t)-availability if it can be recovered fro ...
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ConferenceIEEE International Conference on Communications · July 28, 2017
In this paper, a multi-scale approach to spectrum sensing in cognitive cellular networks is proposed. In order to overcome the huge cost incurred in the acquisition of full network state information, a hierarchical scheme is proposed, based on which local ...
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ConferenceConference Record of 51st Asilomar Conference on Signals, Systems and Computers, ACSSC 2017 · July 2, 2017
In this paper, a multi-scale approach to spectrum sensing and information exchange in millimeter wave cognitive cellular networks is proposed. In order to overcome the huge energy cost of acquiring full network state information on the occupancy of each ce ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · June 16, 2017
In backscatter communications, ultra-low power devices signal by modulating the reflection of radio frequency signals emitted from an external source. Unlike conventional one-way communication, the backscatter channel experiences unique self-interference a ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · June 2017
An information-theoretic projection design framework is proposed, of interest for feature design and compressive measurements. Both Gaussian and Poisson measurement models are considered. The gradient of a proposed information-theoretic metric (ITM) is der ...
Full textCite
Journal ArticleIEEE transactions on neural networks and learning systems · September 2020
The problem of completing high-dimensional matrices from a limited set of observations arises in many big data applications, especially recommender systems. The existing matrix completion models generally follow either a memory- or a model-based approach, ...
Full textCite
Journal ArticleIEEE Transactions on Information Theory · May 1, 2019
Given a collection of strings, each with an associated probability of occurrence, the guesswork of each of them is their position in a list ordered from most likely to least likely, breaking ties arbitrarily. The guesswork is central to several application ...
Full textCite
Journal ArticleIEEE Transactions on Communications · April 1, 2019
Multi-scale spectrum sensing is proposed to overcome the cost of full network state information on the spectrum occupancy of primary users (PUs) in dense multi-cell cognitive networks. Secondary users (SUs) estimate the local spectrum occupancies and aggre ...
Full textCite
Journal ArticleIEEE Transactions on Information Theory · February 1, 2019
In multi-user wireless packet networks, interference, typically modeled as packet collision, is the throughput bottleneck. Users become aware of the interference pattern via feedback and use this information for contention resolution and packet retransmiss ...
Full textCite
Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · December 14, 2018
Deep neural networks have proved very successful on archetypal tasks for which large training sets are available, but when the training data are scarce, their performance suffers from overfitting. Many existing methods of reducing overfitting are data-inde ...
Full textCite
ConferenceEuropean Signal Processing Conference · November 29, 2018
Autoencoders are popular among neural-network-based matrix completion models due to their ability to retrieve potential latent factors from the partially observed matrices. Nevertheless, when training data is scarce their performance is significantly degra ...
Full textCite
Journal ArticleIEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems · November 1, 2018
We extend the lifetime of Flash memory in embedded processors by exploiting the fact that data from sensors is inherently analog. Prior work in the computer architecture community has assumed that all data is digital and has overlooked the opportunities av ...
Full textCite
ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018
Diagnosis of melanoma is fraught with uncertainty, and discordance rates among physicians remain high because of the lack of a definitive criterion. Motivated by this challenge, this paper first introduces the Patch Weyl transform (PWT), a 2-dimensional va ...
Full textCite
Journal ArticleIEEE International Symposium on Information Theory - Proceedings · August 15, 2018
Quantum error-correcting codes can be used to protect qubits involved in quantum computation. This requires that logical operators acting on protected qubits be translated to physical operators (circuits) acting on physical quantum states. We propose a mat ...
Full textCite
ConferenceIEEE International Symposium on Information Theory - Proceedings · August 15, 2018
We study the network-wide neighbour discovery problem in wireless networks in which each node in a network must discovery the network interface addresses (NIAs) of its neighbour. We work within the rapid on-off division duplex framework proposed by Guo and ...
Full textCite
ConferenceIEEE International Symposium on Information Theory - Proceedings · August 15, 2018
In multi-user wireless packet networks interference is the throughput bottleneck. Users become aware of the interference pattern via feedback and use this information for contention resolution and for packet retransmission. We consider networks with spatia ...
Full textCite
Conference2017 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2017 - Proceedings · March 7, 2018
We construct extremely sparse, near-equiangular tight frames which share the same row space as certain incomplete Delsarte-Goethals frames. Frames combining these properties have application in full duplex communication in ad-hoc wireless networks. We high ...
Full textCite
Journal Article35th International Conference on Machine Learning, ICML 2018 · January 1, 2018
Filters in a Convolutional Neural Network (CNN) contain model parameters learned from enormous amounts of data. In this paper, we suggest to decompose convolutional filters in CNN as a truncated expansion with pre-fixed bases, namely the Decomposed Convolu ...
Open AccessCite
ConferenceProceedings - 35th IEEE International Conference on Computer Design, ICCD 2017 · November 22, 2017
In this paper, we introduce Jenga, a new scheme for protecting 3D DRAM, specifically high bandwidth memory (HBM), from failures in bits, rows, banks, channels, dies, and TSVs. By providing redundancy at the granularity of a cache block rather than across b ...
Full textCite
ConferenceIEEE MTT-S International Microwave Symposium Digest · October 4, 2017
Due to the increased demand for data rate, flexibility, and reliability of 5G cellular systems, new modulation formats need to be considered. A recently proposed scheme, Orthogonal Time Frequency Space (OTFS), offers various advantages in particular in env ...
Full textCite
ConferenceIEEE International Symposium on Information Theory - Proceedings · August 9, 2017
A locally repairable code with availability has the property that every code symbol can be recovered from multiple, disjoint subsets of other symbols of small size. In particular, a code symbol is said to have (r, t)-availability if it can be recovered fro ...
Full textCite
ConferenceIEEE International Conference on Communications · July 28, 2017
In this paper, a multi-scale approach to spectrum sensing in cognitive cellular networks is proposed. In order to overcome the huge cost incurred in the acquisition of full network state information, a hierarchical scheme is proposed, based on which local ...
Full textCite
ConferenceConference Record of 51st Asilomar Conference on Signals, Systems and Computers, ACSSC 2017 · July 2, 2017
In this paper, a multi-scale approach to spectrum sensing and information exchange in millimeter wave cognitive cellular networks is proposed. In order to overcome the huge energy cost of acquiring full network state information on the occupancy of each ce ...
Full textCite
ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · June 16, 2017
In backscatter communications, ultra-low power devices signal by modulating the reflection of radio frequency signals emitted from an external source. Unlike conventional one-way communication, the backscatter channel experiences unique self-interference a ...
Full textCite
Journal ArticleIEEE transactions on pattern analysis and machine intelligence · June 2017
An information-theoretic projection design framework is proposed, of interest for feature design and compressive measurements. Both Gaussian and Poisson measurement models are considered. The gradient of a proposed information-theoretic metric (ITM) is der ...
Full textCite
ConferenceIEEE Wireless Communications and Networking Conference, WCNC · May 10, 2017
A new two-dimensional modulation technique called Orthogonal Time Frequency Space (OTFS) modulation designed in the delay-Doppler domain is introduced. Through this design, which exploits full diversity over time and frequency, OTFS coupled with equalizati ...
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Journal ArticleJ Pediatr · April 2017
OBJECTIVES: To assess changes in quality of care for children at risk for autism spectrum disorders (ASD) due to process improvement and implementation of a digital screening form. STUDY DESIGN: The process of screening for ASD was studied in an academic p ...
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ConferenceIEEE Transactions on Signal Processing · November 15, 2016
This paper studies the classification of high-dimensional Gaussian signals from low-dimensional noisy, linear measurements. In particular, it provides upper bounds (sufficient conditions) on the number of measurements required to drive the probability of m ...
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ConferenceIEEE Transactions on Information Theory · November 1, 2016
This paper offers a characterization of fundamental limits on the classification and reconstruction of high-dimensional signals from low-dimensional features, in the presence of side information. We consider a scenario where a decoder has access both to li ...
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Journal ArticleScientific reports · November 2016
Pump-probe microscopy is an emerging technique that provides detailed chemical information of absorbers with sub-micrometer spatial resolution. Recent work has shown that the pump-probe signals from melanin in human skin cancers correlate well with clinica ...
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Conference2016 IEEE Information Theory Workshop, ITW 2016 · October 21, 2016
Recently, sequences of error-correcting codes with doubly-transitive permutation groups were shown to achieve capacity on erasure channels under symbol-wise maximum a posteriori (MAP) decoding. From this, it follows that Reed-Muller and primitive narrow-se ...
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ConferenceProceedings - 46th Annual IEEE/IFIP International Conference on Dependable Systems and Networks, DSN 2016 · September 29, 2016
Motivated by embedded systems and datacenters that require long-life components, we extend the lifetime of Flash memory using rewriting codes that allow for multiple writes to a page before it needs to be erased. Although researchers have previously explor ...
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Journal ArticleIEEE Transactions on Information Theory · September 1, 2016
We study the capacity region of two-user erasure interference channels with local delayed channel state information at the transmitters. In our model, transmitters have local mismatched outdated knowledge of the channel gains. We propose a transmission str ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · August 10, 2016
The quantum erasure channel is the simplest example of a quantum communication channel and its information capacity is known precisely. The subclass of quantum error-correcting codes called stabilizer codes is known to contain capacity-achieving sequences ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · August 10, 2016
An information-theoretic framework is presented for estimating the number of labeled samples needed to train a classifier in a parametric Bayesian setting. Ideas from rate-distortion theory are used to derive bounds for the average L1 or L∞ distance betwee ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · August 10, 2016
Fast fading wireless networks with delayed knowledge of the channel state information have received significant attention in recent years. An exception is networks where channels are spatially correlated. This paper characterizes the capacity region of two ...
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Journal ArticleIEEE Transactions on Signal Processing · June 15, 2016
This paper considers the classification of linear subspaces with mismatched classifiers. In particular, we assume a model where one observes signals in the presence of isotropic Gaussian noise and the distribution of the signals conditioned on a given clas ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 18, 2016
We develop a general framework for compressive linear-projection measurements with side information. Side information is an additional signal correlated with the signal of interest. We investigate the impact of side information on classification and signal ...
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Journal ArticleIEEE Transactions on Signal Processing · April 15, 2016
Subspace models play an important role in a wide range of signal processing tasks, and this paper explores how the pairwise geometry of subspaces influences the probability of misclassification. When the mismatch between the signal and the model is vanishi ...
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Conference2015 53rd Annual Allerton Conference on Communication, Control, and Computing, Allerton 2015 · April 4, 2016
Guesswork is the position at which a random string drawn from a given probability distribution appears in the list of strings ordered from the most likely to the least likely. We define the tilt operation on probability distributions and show that it param ...
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Conference2015 53rd Annual Allerton Conference on Communication, Control, and Computing, Allerton 2015 · April 4, 2016
We study the impact of delayed channel state information at the transmitters (CSIT) in two-unicast wireless networks with a layered topology and arbitrary connectivity. We introduce a technique to obtain outer bounds to the degrees-of-freedom (DoF) region ...
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Journal ArticleIEEE Transactions on Signal Processing · April 1, 2016
The Weyl transform is introduced as a rich framework for data representation. Transform coefficients are connected to the Walsh-Hadamard transform of multiscale autocorrelations, and different forms of dyadic periodicity in a signal are shown to appear as ...
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ConferenceConference Record - Asilomar Conference on Signals, Systems and Computers · February 26, 2016
We study the problem of making a distributed storage system information-theoretically secure against a passive eavesdropper, and aim to characterize coding schemes that are universally secure for up to a given number of eavesdropped nodes. Specifically, we ...
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Journal ArticlePLoS One · 2016
Early childhood anxiety disorders are common, impairing, and predictive of anxiety and mood disorders later in childhood. Epidemiological studies over the last decade find that the prevalence of impairing anxiety disorders in preschool children ranges from ...
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ConferenceProceedings of SPIE - The International Society for Optical Engineering · January 1, 2016
We propose deterministic sampling strategies for compressive imaging based on Delsarte-Goethals frames. We show that these sampling strategies result in multi-scale measurements which can be related to the 2D Haar wavelet transform. We demonstrate the effe ...
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ConferenceIEEE International Workshop on Machine Learning for Signal Processing, MLSP · November 10, 2015
An information-theoretic framework is presented for bounding the number of samples needed for supervised learning in a parametric Bayesian setting. This framework is inspired by an analogy with rate-distortion theory, which characterizes tradeoffs in the l ...
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ConferenceACM International Conference Proceeding Series · October 5, 2015
We integrate coding techniques and layout design to elimi- nate write-disturb in phase change memories (PCMs), while enhancing lifetime and host-visible capacity. We first pro- pose a checkerboard confguration for cell layout to elimi- nate write-disturb w ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · September 28, 2015
This paper offers a characterization of performance limits for classification and reconstruction of high-dimensional signals from noisy compressive measurements, in the presence of side information. We assume the signal of interest and the side information ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · September 28, 2015
The coherence time of a wireless channel is often smaller than the delay with which channel state information is available at transmitters. In this paper, we aim to find the most important subset of the channel state information that transmitters need to l ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · September 28, 2015
This paper studies the performance associated with the classification of linear subspaces corrupted by noise with a mismatched classifier. In particular, we consider a problem where the classifier observes a noisy signal, the signal distribution conditione ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · September 28, 2015
Guesswork forms the mathematical framework for quantifying computational security subject to brute-force determination by query. In this paper, we consider guesswork subject to a per-symbol Shannon entropy budget. We introduce inscrutability rate as the as ...
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ConferenceIEEE International Symposium on Information Theory - Proceedings · September 28, 2015
We consider linear cyclic codes with the locality property, or locally recoverable codes (LRC codes). A family of LRC codes that generalizes the classical construction of Reed-Solomon codes was constructed in a recent paper by I. Tamo and A. Barg (IEEE Tra ...
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Journal ArticleSIAM Journal on Imaging Sciences · September 17, 2015
The measurement matrix employed in compressive sensing typically cannot be known precisely a priori and must be estimated via calibration. One may take multiple compressive measurements, from which the measurement matrix and underlying signals may be estim ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 4, 2015
High dimensional data is modeled using low-rank subspaces, and the probability of misclassification is expressed in terms of the principal angles between subspaces. The form taken by this expression motivates the design of a new feature extraction method t ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 4, 2015
A novel multi-scale dictionary based Bayesian reconstruction algorithm is proposed for compressive X-ray imaging, which encodes the material's spectrum by Poisson measurements. Inspired by recently developed compressive X-ray imaging systems [1], this work ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 4, 2015
This paper introduces a new ESPRIT-based algorithm to estimate the direction-of-arrival of an arbitrary degree polynomial-phase signal with a single acoustic vector-sensor. The proposed time-invariant ESPRIT algorithm is based on a matrix-pencil pair deriv ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 4, 2015
The Poisson Factor Analysis (PFA) is applied to recover signals from a Poisson compressive sensing system. Motivated by the recently developed compressive X-ray imaging system, Coded Aperture Coherent Scatter Spectral Imaging (CACSSI) [1], we propose a new ...
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Journal ArticleIEEE Transactions on Information Theory · July 1, 2015
The linear model, in which a set of observations is assumed to be given by a linear combination of columns of a matrix (often termed a dictionary), has long been the mainstay of the statistics and signal processing literature. One particular challenge for ...
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ConferenceConference Record - Asilomar Conference on Signals, Systems and Computers · April 24, 2015
Linear, time-varying (LTV) systems are operators composed of time shifts, frequency shifts, and complex amplitude scalings that act on continuous finite-energy waveforms. This paper builds upon a novel, resource-efficient method previously proposed by the ...
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Journal ArticleIEEE Transactions on Signal Processing · April 15, 2015
Linear, time-varying (LTV) systems composed of time shifts, frequency shifts, and complex amplitude scalings are operators that act on continuous finite-energy waveforms. This paper presents a novel, resource-efficient method for identifying the parametric ...
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Journal ArticleIEEE Transactions on Information Theory · April 1, 2015
We derive fundamental limits on the reliable classification of linear and affine subspaces from noisy, linear features. Drawing an analogy between discrimination among subspaces and communication over vector wireless channels, we define two Shannon-inspire ...
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ConferenceProceedings of the IEEE International Conference on Computer Vision · February 17, 2015
Many recent efforts have been devoted to designing sophisticated deep learning structures, obtaining revolutionary results on benchmark datasets. The success of these deep learning methods mostly relies on an enormous volume of labeled training samples to ...
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ConferenceAdvances in Neural Information Processing Systems · January 1, 2015
This paper proposes a framework for learning features that are robust to data variation, which is particularly important when only a limited number of training samples are available. The framework makes it possible to tradeoff the discriminative value of l ...
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ConferenceProceedings - IEEE Global Communications Conference, GLOBECOM · January 1, 2015
In this paper, a multiscale approach to spectrum sensing in cognitive cellular networks is analyzed. Observing that wireless interference decays with distance, and that estimating the entire spectrum occupancy across the network entails substantial energy ...
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Conference · January 1, 2015
Compressed sensing was introduced some ten years ago as an effective way of acquiring signals, which possess a sparse or nearly sparse representation in a suitable basis or dictionary. Due to its solid mathematical backgrounds, it quickly attracted the att ...
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Conference · January 1, 2015
This chapter introduces Shannon-inspired performance limits associated with the classification of low-dimensional subspaces embedded in a high-dimensional ambient space from compressive and noisy measurements. In particular, it introduces the diversity-dis ...
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Journal ArticleIEEE Transactions on Signal Processing · May 1, 2014
This paper determines to within a single measurement the minimum number of measurements required to successfully reconstruct a signal drawn from a Gaussian mixture model in the low-noise regime. The method is to develop upper and lower bounds that are a fu ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 2014
We provide a rigorous mathematical analysis of two communication strategies: soft decode-and-forward (soft-DF) for relay channels and soft partial interference-cancelation (soft-IC) for interference channels. Both strategies involve soft estimation, which ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2014
Early detection and treatment of psychiatric disorders on children has shown significant impact in their subsequent development and quality of life. The assessment of psychopathology in childhood is commonly carried out by performing long comprehensive int ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2014
Using Shannon theory, we derive fundamental, asymptotic limits on the classification of low-dimensional subspaces from compressive measurements. We identify a syntactic equivalence between the classification of subspaces and the communication of codewords ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · January 1, 2014
Codes for storage systems aim to minimize the repair locality, which is the number of disks (or nodes) that participate in the repair of a single failed disk. Simultaneously, the code must sustain a high rate, operate on a small finite field to be practica ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · January 1, 2014
Repurposing tools and intuitions from Shannon theory, we derive fundamental limits on the reliable classification of high-dimensional signals from low-dimensional features. We focus on the classification of linear and affine subspaces and suppose the featu ...
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Conference31st International Conference on Machine Learning, ICML 2014 · January 1, 2014
We investigate design of general nonlinear functions for mapping high-dimensional data into a lower-dimensional (compressive) space. The nonlinear measurements are assumed contaminated by additive Gaussian noise. Depending on the application, we are either ...
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ConferenceJournal of Machine Learning Research · January 1, 2014
This paper studies conditions for high-dimensional inference when the set of observations is given by a linear combination of a small number of groups of columns of a design matrix, termed the "block-sparse" case. In this regard, it first specifies conditi ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 2014
Distributed storage systems employ codes to provide resilience to failure of multiple storage disks. In particular, an (n, κ) maximum distance separable (MDS) code stores k symbols in n disks such that the overall system is tolerant to a failure of up to n ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 19, 2013
Codes for distributed storage systems are often designed to sustain failure of multiple storage disks. Specifically, an (n, k) MDS code stores k symbols in n disks such that the overall system is tolerant to a failure of up to n - k disks. However, access ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 19, 2013
This paper presents fundamental limits associated with compressive classification of Gaussian mixture source models. In particular, we offer an asymptotic characterization of the behavior of the (upper bound to the) misclassification probability associated ...
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Journal Article2013 IEEE Information Theory Workshop, ITW 2013 · December 1, 2013
Motivated by applications in high-dimensional signal processing, we derive fundamental limits on the performance of compressive linear classifiers. By analogy with Shannon theory, we define the classification capacity, which quantifies the maximum number o ...
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Journal Article2013 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2013 - Proceedings · December 1, 2013
This paper puts forth projections designs for compressive classification of Gaussian mixture models. In particular, we capitalize on the asymptotic characterization of the behavior of an (upper bound to the) misclassification probability associated with th ...
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Journal Article2013 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2013 - Proceedings · December 1, 2013
We characterize the minimum number of measurements needed to drive to zero the minimum mean squared error (MMSE) of Gaussian mixture model (GMM) input signals in the low-noise regime. The result also hints at almost phase-transition optimal recovery proced ...
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Journal Article2013 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2013 - Proceedings · December 1, 2013
Estimating an image M* +m1×m2 from its linear measurements under Poisson noise is an important problem arises from applications such as optical imaging, nuclear medicine and x-ray imaging [1]. When the image M* has a low-rank structure, we can use a small ...
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Journal ArticleIEEE Transactions on Signal Processing · November 27, 2013
Many real world datasets exhibit an embedding of low-dimensional structure in a high-dimensional manifold. Examples include images, videos and internet traffic data. It is of great significance to estimate and track the low-dimensional structure with small ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 18, 2013
Compressive Sensing is possible when the sensing matrix acts as a near isometry on signals of interest that can be sparsely or compressively represented. The attraction of greedy algorithms such as Orthogonal Matching Pursuit is their simplicity. However t ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 18, 2013
Compressed sensing (CS) theory promises one can recover real-valued sparse signal from a small number of linear measurements. Motivated by network monitoring with link failures, we for the first time consider the problem of recovering signals that contain ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 18, 2013
We consider the problem of linear projection design for incoherent optical imaging systems. We propose a computationally efficient method to obtain effective measurement kernels that satisfy the physical constraints imposed by an optical system, starting f ...
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Journal Article2013 International Symposium on Network Coding, NetCod 2013 · September 9, 2013
The problem of securing data against eavesdropping in distributed storage systems is studied. The focus is on systems that use linear codes and implement exact repair to recover from node failures. The maximum file size that can be stored securely is deter ...
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Journal Article · July 29, 2013
Block coherence of matrices plays an important role in analyzing the
performance of block compressed sensing recovery algorithms (Bajwa and Mixon,
2012). In this paper, we characterize two block coherence metrics: worst-case
and average block coherence. Fi ...
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Journal ArticleProceedings - International Symposium on High-Performance Computer Architecture · July 23, 2013
Some recent memory technologies, including phase change memory (PCM), have lifetime reliabilities that are affected by write operations. We propose the use of coset coding to extend the lifetimes of these memories. The key idea of coset coding is that it p ...
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Journal ArticleIEEE Transactions on Signal Processing · April 5, 2013
The Delsarte-Goethals frame (DGF) has been proposed for deterministic compressive sensing of sparse and compressible signals. Results in compressive sensing theory show that the DGF enables successful recovery of an overwhelming majority of sufficiently sp ...
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Journal ArticleIEEE Transactions on Signal Processing · February 1, 2013
This paper presents a significant modification to the Random Demodulator (RD) of Tropp et al. for sub-Nyquist sampling of frequency-sparse signals. The modification, termed constrained random demodulator, involves replacing the random waveform, essential t ...
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Journal Article2013 IEEE International Conference on Image Processing, ICIP 2013 - Proceedings · January 1, 2013
In this paper, computer-based techniques for stylistic analysis of paintings are applied to the five panels of the 14th century Peruzzi Altarpiece by Giotto di Bondone. Features are extracted by combining a dual-tree complex wavelet transform with a hidden ...
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Journal ArticleIEEE Journal on Selected Topics in Signal Processing · January 1, 2013
We carry out a comprehensive study of the resource cost of averaging consensus in wireless networks. Most previous approaches suppose a graphical network, which abstracts away crucial features of the wireless medium, and measure resource consumption only i ...
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Conference2013 IEEE 5TH INTERNATIONAL WORKSHOP ON COMPUTATIONAL ADVANCES IN MULTI-SENSOR ADAPTIVE PROCESSING (CAMSAP 2013) · January 1, 2013Link to itemCite
Conference2013 IEEE 5TH INTERNATIONAL WORKSHOP ON COMPUTATIONAL ADVANCES IN MULTI-SENSOR ADAPTIVE PROCESSING (CAMSAP 2013) · January 1, 2013Link to itemCite
Journal Article2012 50th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2012 · December 1, 2012
In this paper, we present coherence-based performance guarantees of Orthogonal Matching Pursuit (OMP) for both support recovery and signal reconstruction of sparse signals when the measurements are corrupted by noise. In particular, two variants of OMP eit ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2012
We carry out a comprehensive study of the resource costs of distributed averaging consensus in wireless sensor networks. In particular, we consider two metrics appropriate to the wireless medium: total transmit energy and time-bandwidth product. Most previ ...
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Journal Article2012 50th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2012 · December 1, 2012
The goal of this paper is to extend the lifetime of Flash memory by reducing the frequency with which a given page of memory is erased. This is accomplished by increasing the number of writes that are possible before erasure is necessary. Redundancy is int ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2012
Efficient spectrum sensing is an important problem given the large and increasing demand for wireless spectrum and the need to protect incumbent users. We can more efficiently use large swaths of underutilized spectrum by designing spectrum sensors that ca ...
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Journal ArticleIEEE Transactions on Wireless Communications · November 29, 2012
Code diversity integrates space-time coding with beamforming by using a small number of feedback bits to select from a family of space-time codes. Different codes lead to different induced channels at the receiver, where Channel State Information (CSI) is ...
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Journal Article2012 IEEE Statistical Signal Processing Workshop, SSP 2012 · November 6, 2012
The challenge of Multiuser Detection (MUD) is that of demodulating mutually interfering signals given that at any time instant the number of active users is typically small. The promise of compressed sensing is the demodulation of sparse superpositions of ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
Melanoma detection relies on visual inspection of skin samples under the microscope via a qualitative set of indicators, causing large discordance among pathologists. New developments in pump-probe imaging enable the extraction of melanin intensity levels ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
In this paper, we investigate the problem of compressed learning, i.e. learning directly in the compressed domain. In particular, we provide tight bounds demonstrating that the linear kernel SVMs classifier in the measurement domain, with high probability, ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
We introduce an approach to gossip algorithms that exploits three aspects of the wireless medium: superposition, broadcast, and power control. Instead of sending pairwise messages between neighbors on a fixed network topology, we construct gossip algorithm ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
This paper is motivated by the challenge of high fidelity processing of images using a relatively small set of projection measurements. This is a problem of great interest in many sensing applications, for example where high photodetector counts are preclu ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
In this paper, we present a method of detecting the range and Doppler phase of a point target using multiple antennas. As a key illustrative example, we consider a 4 x 4 system employing a unitary matrix waveform set, e.g., formed from Golay complementary ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
We consider the problem of reconstructing a data stream from a small subset of its entries, where the data stream is assumed to lie in a low-dimensional linear subspace, possibly corrupted by noise. It is also important to track the change of underlying su ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · October 22, 2012
The role of random measurement in compressive sensing is analogous to the role of random codes in coding theory. In coding theory, decoders that can correct beyond the minimum distance of a code allow random codes to achieve the Shannon limit. In compresse ...
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Journal ArticleProceedings of the 29th International Conference on Machine Learning, ICML 2012 · October 10, 2012
We study the problem of supervised linear dimensionality reduction, taking an information-theoretic viewpoint. The linear projection matrix is designed by maximizing the mutual information between the projected signal and the class label. By harnessing a r ...
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Journal ArticleApplied and Computational Harmonic Analysis · July 1, 2012
This paper investigates two parameters that measure the coherence of a frame: worst-case and average coherence. We first use worst-case and average coherence to derive near-optimal probabilistic guarantees on both sparse signal detection and reconstruction ...
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Journal ArticlePhysical Communication · June 1, 2012
Many applications in cellular systems and sensor networks involve a random subset of a large number of users asynchronously reporting activity to a base station. This paper examines the problem of multiuser detection (MUD) in random access channels for suc ...
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Journal ArticleIEEE Transactions on Communications · April 1, 2012
In this paper, we study a practical coding scheme for the dying binary erasure channel (DBEC), which is a binary erasure channel (BEC) subject to a random fatal failure. We consider the rateless codes and optimize the degree distribution to maximize the av ...
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Journal ArticleSIAM Journal on Imaging Sciences · January 1, 2012
We consider the recovery of an underlying signal x ∈ ℂm based on projection measurements of the form y = Mx+w, where y ∈ ℂℓ and w is measurement noise; we are interested in the case ℓ ≪ m. It is assumed that the signal model p(x) is known and that w ~ CN(w ...
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Journal ArticleIEEE Vehicular Technology Conference · December 23, 2011
This paper addresses spectrally-efficient multiantenna multi-carrier uplink transmission scenarios where the users overlap in time and frequency and are separated using spatial processing at the base station. The robustness of the proposed training sequenc ...
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Journal Article2011 IEEE Information Theory Workshop, ITW 2011 · December 21, 2011
The Restricted Isometry Property or RIP introduced by Candes and Tao requires an n × p dictionary to act as a near isometry on all k-sparse signals. This paper provides a very simple condition under which a dictionary Φ (C) obtained by exponentiating codew ...
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Journal ArticleEuropean Signal Processing Conference · December 1, 2011
This paper proposes a new family of optimal training sequences in terms of minimizing the mean-square channel estimation error for spectrally-efficient Multi-User MIMO-OFDM systems with an arbitrary number of transmit antennas and an arbitrary number of tr ...
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Journal ArticleGLOBECOM - IEEE Global Telecommunications Conference · December 1, 2011
As it becomes common for wireless service providers (WSP) to employ multiple heterogeneous radio access technologies (RAT), the management of the combined resources across multiple RATs arises as an important issue. The WSP's objective is to assign differe ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2011
We present a general method for constructing radar transmit pulse trains and receive filters for which the radar point-spread function in delay and Doppler, given by the cross-ambiguity function of the transmit pulse train and the pulse train used in the r ...
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Journal Article2011 49th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2011 · December 1, 2011
We present an approach to gossip algorithms tailored to the practical considerations of wireless communications. Traditional gossip algorithms operate via the pairwise exchange of estimates, which fails to capture the broadcast and superposition nature of ...
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Journal Article2011 49th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2011 · December 1, 2011
Communication networks conventionally operate with half-duplex methods and interference avoiding schemes to manage multiple transceivers. Here we consider a method in which nodes transmit and receive in concert to achieve full duplex communication without ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · October 26, 2011
The sparse signal processing literature often uses random sensing matrices to obtain performance guarantees. Unfortunately, in the real world, sensing matrices do not always come from random processes. It is therefore desirable to evaluate whether an arbit ...
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Journal Article17th DSP 2011 International Conference on Digital Signal Processing, Proceedings · September 29, 2011
This paper examines the problem of multipath channel estimation in single-antenna orthogonal frequency division multiplexing (OFDM) systems. In particular, we study the problem of pilot assisted channel estimation in wideband OFDM systems, where the time-d ...
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Journal ArticleIEEE Workshop on Statistical Signal Processing Proceedings · September 5, 2011
Estimation of the level set of a function (i.e., regions where the function exceeds some value) is an important problem with applications in digital elevation maps, medical imaging, and astronomy. In many applications, however, the function of interest is ...
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Journal ArticleIEEE Transactions on Signal Processing · September 1, 2011
This paper provides performance bounds for compressed sensing in the presence of Poisson noise using expander graphs. The Poisson noise model is appropriate for a variety of applications, including low-light imaging and digital streaming, where the signal- ...
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Journal ArticleIEEE Transactions on Information Forensics and Security · September 1, 2011
This paper investigates the effect of eavesdroppers on network connectivity, using a wiretap model and percolation theory. The wiretap model captures the effect of eavesdroppers on link security. A link exists between two nodes only if the secrecy capacity ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
Technological constraints severely limit the rate at which analog-to-digital converters can reliably sample signals. Recently, Tropp et al. proposed an architecture, termed the random demodulator (RD), that attempts to overcome this obstacle for sparse ban ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
The aim of compressed sensing is to recover attributes of sparse signals using very few measurements. Given an overall bit budget for quantization, this paper demonstrates that there is value to redundant measurement. The measurement matrices considered he ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
Precoding has been extensively studied for point-to-point communications, including the problems of constructing the precoding codebook and selecting the best precoder. This paper investigates precoding for a multicast channel in which a base station is se ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
This paper introduces a divide and conquer approach to the design of transmit and receive filters for communication over a Multiple Input Multiple Output (MIMO) Gaussian channel subject to an average power constraint. It involves conversion to a set of par ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
This paper relates the style of 16th century Flemish paintings by Goossen van der Weyden (GvdW) to the style of preliminary sketches or underpaintings made prior to executing the painting. Van der Weyden made underpaintings in markedly different styles for ...
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Journal ArticleIEEE Transactions on Wireless Communications · July 1, 2011
In this paper, we design MMSE-optimal training sequences for multi-user MIMO-OFDM systems with an arbitrary number of transmit antennas and an arbitrary number of training symbols. It addresses spectrally-efficient uplink transmission scenarios where the u ...
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Journal ArticleAdvances in Computational Mathematics · July 1, 2011
Fusion frame theory is an emerging mathematical theory that provides a natural framework for performing hierarchical data processing. A fusion frame can be regarded as a frame-like collection of subspaces in a Hilbert space, and thereby generalizes the con ...
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Journal ArticleIEEE Transactions on Information Theory · June 1, 2011
The Golden code is a full-rate full-diversity space-time code which has been incorporated in the IEEE 802.16 (WiMAX) standard. The worst case complexity of a tree-based sphere decoder for a square QAM constellation is O(N 3), where n is the size of the und ...
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Journal ArticleIEEE Transactions on Information Theory · May 1, 2011
A two-user interference channel is considered where each transmitter has access to a part of the information intended to the other destination. A primary objective is to maximize the information rates, by exploring the cooperation between the transmitters ...
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Journal ArticleIEEE Transactions on Signal Processing · May 1, 2011
The theory of compressed sensing suggests that successful inversion of an image of the physical world (broadly defined to include speech signals, radar/sonar returns, vibration records, sensor array snapshot vectors, 2-D images, and so on) for its source m ...
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Journal ArticleComputer Networks · January 7, 2011
We consider congestion control in a network with delay sensitive/ insensitive traffic, modelled by adding explicit delay terms to the utility function measuring user's happiness on the Quality of Service (QoS). A new Network Utility Maximization (NUM) prob ...
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Journal ArticleDigital Signal Processing: A Review Journal · January 1, 2011
In this work, multiple radar waveforms are simultaneously transmitted, emitted from different antennas. The goal is to process the returns in such a way that the overall ambiguity function is a sum of individual ambiguity functions, such that the sum bette ...
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Journal ArticleJournal of Machine Learning Research · December 1, 2010
The ability to detect weak distributed activation patterns in networks is critical to several applications, such as identifying the onset of anomalous activity or incipient congestion in the Internet, or faint traces of a biochemical spread by a sensor net ...
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Journal Article2010 IEEE Information Theory Workshop, ITW 2010 - Proceedings · December 1, 2010
Certain nonlinear binary codes can be constructed as binary images of Z4-linear codes under the Gray map. Examples include the second-order Reed-Muller code and the Kerdock and Preparata codes. In this paper, we consider a new quaternary code which is an a ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · December 1, 2010
In this paper, a new space-time signaling scheme is proposed for Orthogonal Frequency Division Multiplexing (OFDM) using complementary sequences derived from the rows of the DFT matrix. The autocorrelative properties of the complementary sequences allows m ...
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Journal Article2010 48th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2010 · December 1, 2010
This paper considers on-off random access channels where users transmit either a one or a zero to a base station. Such channels represent an abstraction of control channels used for scheduling requests in third-generation cellular systems and uplinks in wi ...
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Journal Article2010 48th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2010 · December 1, 2010
This paper studies non-asymptotic model selection and recovery of sparse signals in high-dimensional, linear inference problems. In contrast to the existing literature, the focus here is on the general case of arbitrary design matrices and arbitrary nonzer ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2010
The central goal of compressive sensing is to reconstruct a signal that is sparse or compressible in some basis using very few measurements. However reconstruction is often not the ultimate goal and it is of considerable interest to be able to deduce attri ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · November 19, 2010
We construct two families of deterministic sensing matrices where the columns are obtained by exponentiating codewords in the quaternary Delsarte-Goethals code DG(m,r). This method of construction results in sensing matrices with low coherence and spectral ...
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Journal ArticleIEEE Transactions on Information Theory · November 1, 2010
This paper introduces multidimensional generalizations of binary Reed-Muller codes where the codewords are projection operators, and the corresponding subspaces are widely separated with respect to the chordal distance on Grassmannian space. Parameters of ...
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Journal ArticleICUFN 2010 - 2nd International Conference on Ubiquitous and Future Networks · October 4, 2010
Driven by the emerging directions from the FCC and the broadband market, this paper aims at answering the fundamental question of how to use pricing as a lever to enable universal broadband coverage and effective network management in the United States. We ...
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Journal ArticleQuantum Information Processing · October 1, 2010
We introduce finite-level concatenation threshold regions for quantum fault tolerance. These volume thresholds are regions in an error probability manifold that allow for the implemented system dynamics to satisfy a prescribed implementation inaccuracy bou ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · August 23, 2010
This paper introduces the Reed Muller Sieve, a deterministic measurement matrix for compressed sensing. The columns of this matrix are obtained by exponentiating codewords in the quaternary second order Reed Muller code of length N. For k = O(N), the Reed ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · August 23, 2010
In this paper, we consider end-to-end secure communication in a large wireless network, where the locations of eavesdroppers are uncertain. Our framework attempts to bridge the gap between physical layer security under uncertain channel state information o ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · August 23, 2010
The problem of model selection arises in a number of contexts, such as compressed sensing, subset selection in linear regression, estimation of structures in graphical models, and signal denoising. This paper generalizes the notion of incoherence in the ex ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · August 23, 2010
Multiple-Input Multiple-Output (MIMO) systems improve the throughput and reliability of wireless communications. Perfect Channel State Information (CSI) is needed at the receiver to perform coherent detection and achieve the optimal gain of the system. In ...
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Journal Article · July 29, 2010
Beamforming is a widely used method of provisioning high quality wireless
channels that leads to high data rates and simple decoding structures. It
requires feedback of Channel State Information (CSI) from receiver to
transmitter, and the accuracy of this ...
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Journal Article2010 44th Annual Conference on Information Sciences and Systems, CISS 2010 · June 24, 2010
This paper describes a low-complexity approach for reconstructing average packet arrival rates and instantaneous packet counts at a router in a communication network, where the arrivals of packets in each flow follow a Poisson process. Assuming that the ra ...
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Journal ArticleProceedings - IEEE INFOCOM · June 15, 2010
This paper investigates pricing of Internet connectivity services in the context of a monopoly ISP selling broadband access to consumers. We first study the optimal combination of flat-rate and usage-based access price components for maximization of ISP re ...
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Journal ArticleIEEE Transactions on Communications · May 1, 2010
Providing real-time multimedia services over a besteffort network is challenging due to the stringent delay requirements in the presence of complex network dynamics. Multiple description (MD) coding is one approach to transmit the media over diverse (multi ...
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Journal ArticleIEEE Journal on Selected Topics in Signal Processing · April 1, 2010
Compressed Sensing aims to capture attributes of κ-sparse signals using very few measurements. In the standard compressed sensing paradigm, the N × C measurement matrix Φ is required to act as a near isometry on the set of all κ-sparse signals (restricted ...
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Journal ArticleStudies in Computational Intelligence · March 24, 2010
Video is becoming the dominant traffic over the Internet. To provide better Quality of Service (QoS) to the end users, while also achieve network resource efficiency, is an important problem for both network operators, content providers and consumers. In t ...
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Journal ArticleIEEE Transactions on Information Theory · March 1, 2010
This paper focuses on conditional optimization as a decoding primitive for high rate spacetime codes that are obtained by multiplexing in the spatial and code domains. The approach is a crystallization of the work of Hottinen which applies to spacetime cod ...
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Journal ArticleJournal of Communications and Networks · January 1, 2010
The problem of model selection arises in a number of contexts, such as subset selection in linear regression, estimation of structures in graphical models, and signal denoising. This paper studies non-asymptotic model selection for the general case of arbi ...
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Journal ArticleGLOBECOM - IEEE Global Telecommunications Conference · January 1, 2010
The use of beamforming to enable higher data rates in telecommunications is widely appreciated, but performance gains are typically calculated assuming delay-free feedback from the receiver and neglecting processing time. This paper introduces a mathematic ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2010
This paper provides a framework for designing space-time codes to take advantage of a small number of feedback bits from the receiver. The new codes are based on circulant matrices and simple conditions are derived that guarantee full rate and full diversi ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2010
In this paper, we present a method for detecting a point target using multiple antennas when the relative motion between the receivers and the target induces a non-negligible Doppler shift. As a key illustrative example, we consider a 4x4 system employing ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2010
Compressed sensing theory suggests that successful inversion of an image of the physical world from its modal parameters can be achieved at measurement dimensions far lower than the image dimension, provided that the image is sparse in an a priori known ba ...
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Journal Article2009 IEEE Information Theory Workshop, ITW 2009 · December 7, 2009
The sum capacity of a class of layered erasure onesided interference channels is developed under the assumption of no channel state information at the transmitters. Outer bounds are presented for this model and are shown to be tight for the following sub-c ...
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Journal ArticleIEEE Transactions on Signal Processing · December 1, 2009
Low complexity optimal (or nearly optimal) decoders for space-time codes have recently been under intensive investigation. For example, recent works by Sirianunpiboon and others show that the Silver code and the Golden code can be decoded optimally (or nea ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2009
In this paper, a new method of space-time processing is proposed for Orthogonal Frequency Division Multiplexing (OFDM) using complementary sequences derived from the rows of the DFT matrix. The autocorrelative properties of the complementary sequences allo ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2009
In this paper, we present a method for detecting a point target using multiple antennas when the relative motion between the receivers and the target induces a non-trivial Doppler shift. We consider a 4×4 system employing sets of unitary waveforms. In case ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2009
Multiple-Input Multiple-Output (MIMO) functionality has been shown to dramatically increase the capacity of wireless communication systems when the environment provides rich multipath scattering. In a predominantly Line-of-Sight (LOS) environment, the loss ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2009
This paper provides performance bounds for compressed sensing in the presence of Poisson noise using expander graphs. The Poisson noise model is appropriate for a variety of applications, including low-light imaging and digital streaming, where the signal- ...
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Journal ArticleIEEE Vehicular Technology Conference · December 1, 2009
Multiple-Input Multiple-Output (MIMO) functionality has been shown to dramatically increase the capacity of wireless communication systems when the environment provides rich multipath scattering. In a predominantly Line-of-Sight (LOS) environment, the loss ...
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Journal ArticleCAMSAP 2009 - 2009 3rd IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing · December 1, 2009
We present a new approach to radar imaging that exploits sparsity in the matched filter domain to enable high resolution imaging of targets in delay and Doppler. We show that the vector of radar cross-ambiguity values at any fixed test delay cell has a spa ...
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Journal Article2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009 · December 1, 2009
Graphics Processing Units (GPUs) with a few hundred extremely simple processors represent a paradigm shift for highly parallel computations. We use this emergent GPU architecture to provide a first demonstration of the feasibility of real time ML decoding ...
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Journal ArticleCAMSAP 2009 - 2009 3rd IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing · December 1, 2009
Compressed Sensing aims to capture attributes of a sparse signal using very few measurements. Candès and Tao showed that sparse reconstruction is possible if the sensing matrix acts as a near isometry on all k-sparse signals. This property holds with overw ...
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Journal Article2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009 · December 1, 2009
In this paper, we present a method for detecting a point target using multiple antennas when the relative motion between the receivers and the target induces a non-negligible Doppler shift. As a key illustrative example, we consider a 4 x 4 system employin ...
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Journal Article2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009 · December 1, 2009
We propose a simple method for downlink communications based on second order Reed-Muller sequences which generalize the Walsh sequences that are used in orthogonal CDMA. In our approach, coding occurs at the chip level (i.e. we use a spreading factor of 1) ...
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Journal ArticleProceedings of the 2009 International Conference on Electromagnetics in Advanced Applications, ICEAA '09 · December 1, 2009
Code diversity integrates space-time coding with beamforming by using a small number of feedback bits to select from a family of space-time codes. Different codes lead to different induced channels at the receiver, where Channel State information (CSI) is ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · November 19, 2009
The standard approach to quantum fault tolerance is to calculate error thresholds on basic gates in the limit of arbitrarily many concatenation levels. In contrast this paper takes the number of qubits and the target implementation accuracy as given, and p ...
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Journal ArticleIEEE International Conference on Communications · November 19, 2009
It is standard practice to integrate outer trellis codes with inner space-time block codes to increase coding gain, but the drawback is a decrease in rate. Jafarkhani and Seshadri [1] have introduced an alternative method of combining multiple inner orthog ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · November 19, 2009
The secrecy capacity of relay channels with orthogonal components is studied in the presence of additional passive eavesdropper nodes. The relay and destination receive signals from the source on two orthogonal channels such that the destination also recei ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · November 19, 2009
A fusion frame is a frame-like collection of subspaces in a Hilbert space. It generalizes the concept of a frame system for signal representation. In this paper, we study the existence and construction of fusion frames. We first introduce two general metho ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · November 19, 2009
The wiretap channel type II with an active eavesdropper is considered in this paper. Compared with the eavesdropper model considered in much of the literature, the eavesdropper considered here can not only overhear but also modify the signal transmitted ov ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · November 19, 2009
This paper provides new insight into the classical problem of determining both the capacity of the discrete-time channel with uniform output quantization and the capacity achieving input distribution. It builds on earlier work by Gallager and Witsenhausen ...
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Journal ArticleProceedings - IEEE INFOCOM · October 12, 2009
Pricing content-providers for connectivity to endusers and setting connection parameters based on the price is an evolving model on the Internet. The implications are heavily debated in telecom policy circles, and some advocates of "Network Neutrality" hav ...
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Journal ArticleInformation Theory and Applications Workshop, ITA 2009 · September 25, 2009
The secrecy capacity is developed for a class of relay channels with orthogonal components and a passive eavesdropper node. The relay and destination receive signals from the source on two orthogonal channels such that the destination also receives transmi ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 23, 2009
Perfect space-time block codes (STBCs) were first introduced by Oggier et al. to have full rate, full diversity and non-vanishing determinant. A maximum likelihood decoder based on the sphere decoder has been used for efficient decoding of perfect STBCs. H ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 23, 2009
We present a pilot-assisted method for estimating the frequency selective channel in a MIMO-OFDM system. The pilot sequence is designed using the DFT of the Golay complementary sequences. Novel exploitation of the perfect autocorrelation property of Golay ...
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Journal ArticleIEEE National Radar Conference - Proceedings · September 11, 2009
We present simple methods for constructing radar waveforms whose ambiguity functions are free of sidelobes inside a desired range or Doppler interval. We exploit the time-frequency duality between pulse amplitude modulation (PAM) and orthogonal frequency d ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · September 10, 2009
The standard approach to quantum fault tolerance is to calculate error thresholds on basic gates in the limit of arbitrarily many concatenation levels. In contrast this paper takes the number of qubits and the target implementation accuracy as given, and p ...
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Journal ArticleEurasip Journal on Wireless Communications and Networking · September 2, 2009
The secrecy capacity of relay channels with orthogonal components is studied in the presence of an additional passive eavesdropper node. The relay and destination receive signals from the source on two orthogonal channels such that the destination also rec ...
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Journal ArticleIEEE Transactions on Communications · July 23, 2009
We design a novel class of space-time codes, called linear diversity-embedding space-time block codes (LDE-STBC) where a high-rate STBC is linearly superimposed on a highdiversity STBC without requiring channel knowledge at the transmitter. In applying thi ...
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Journal ArticleRWS 2009 IEEE Radio and Wireless Symposium, Proceedings · July 21, 2009
We present a pilot-assisted method for estimating the frequency selective channel in a MIMO-OFDM (Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing) system. The pilot sequence is designed using the DFT (Discrete Fourier Transform) ...
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Journal ArticleIEEE Transactions on Wireless Communications · July 1, 2009
We consider a fading version of the dirty-paper problem, as proposed by Grover and Sahai. In this formulation, the various signals involved are complex-valued, and the interference (known only to the transmitter) is multiplied by a random complex-valued co ...
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Journal Article · June 30, 2009
Fusion frame theory is an emerging mathematical theory that provides a
natural framework for performing hierarchical data processing. A fusion frame
is a frame-like collection of subspaces in a Hilbert space, thereby
generalizing the concept of a frame for ...
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Journal ArticleIEEE Transactions on Information Theory · June 17, 2009
Results for Gaussian relay channels typically focus on maximizing transmission rates for given locations of the source, relay, and destination. We introduce an alternative perspective, where the objective is maximizing coverage for a given rate. The new ob ...
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Journal ArticleIEEE Transactions on Communications · June 16, 2009
Networks need to accommodate diverse applications with different Quality-of-Service (QoS) requirements. New ideas at the physical layer are being developed for this purpose, such as diversity embedded coding, which is a technique that combines high rates w ...
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Journal ArticleProceedings of the 2009 Australian Communications Theory Workshop, AusCTW 2009 · June 8, 2009
The performance of a multiple-input multipleoutput (MIMO) system depends strongly on the scattering environment and antenna spacing. The use of dual-polarized antennas is a promising alternative both in terms of diversity and effective use of space. In thi ...
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Journal Article2009 International Waveform Diversity and Design Conference Proceedings, WDD 2009 · April 23, 2009
We present a novel method of constructing a Doppler resilient pulse train of Golay complementary waveforms, for which the range sidelobes of the pulse train ambiguity function vanish inside a desired Doppler interval. This is accomplished by coordinating t ...
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Journal Article2009 International Waveform Diversity and Design Conference Proceedings, WDD 2009 · April 23, 2009
We present a pilot-assisted method for estimating the frequency selective channel in a MIMO-OFDM (Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing) system. The pilot sequence is designed using the DFT (Discrete Fourier Transform) ...
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Journal Article2009 6th IEEE Consumer Communications and Networking Conference, CCNC 2009 · April 9, 2009
The Peer-to-Peer (P2P) streaming has shown as an effective solution for wireline video applications, while for the wireless video streaming applications, the limited radio resource and battery energy are the main constraints on the way of P2P applications. ...
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Journal Article2009 6th IEEE Consumer Communications and Networking Conference, CCNC 2009 · April 9, 2009
With the advances in wireless technology and explosive growth of mobile devices and wireless networks, mobile TV is becoming a popular application. The main technical challenge to wireless video broadcast is to provide the best quality of service possible ...
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Journal ArticleIEEE Transactions on Wireless Communications · April 1, 2009
We propose a new full-rate space-time block code (STBC) for two transmit antennas which can be designed to achieve maximum diversity or maximum capacity while enjoying optimized coding gain and reduced-complexity maximum-likelihood (ML) decoding. The maxim ...
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Journal ArticleApplied and Computational Harmonic Analysis · March 1, 2009
Compressed sensing is a novel technique to acquire sparse signals with few measurements. Normally, compressed sensing uses random projections as measurements. Here we design deterministic measurements and an algorithm to accomplish signal recovery with com ...
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Chapter · January 1, 2009
In this chapter, we show that compressed learning, learning directly in the compressed domain, is possible. In particular, we provide tight bounds demonstrating that the linear kernel SVM's classifier in the measurement domain, with high probability, has t ...
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Chapter · January 1, 2009
Next-generation wireless systems aim to support both voice and high capacity flexible data services with limited bandwidth. Multiplicative and additive distortions inherent to the wireless medium make this difficult, and extensive research efforts are focu ...
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Journal ArticleIEEE Journal on Selected Topics in Signal Processing · 2009
The standard approach to the design of individual space-time codes is based on optimizing diversity and coding gains. This geometric approach leads to remarkable examples, such as perfect space-time block codes (Perfect space-time block codes. F. Oggier , ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 2009
Expander graphs have been recently proposed to construct efficient compressed sensing algorithms. In particular, it has been shown that any n-dimensional vector that is k-sparse can be fully recovered using O(k log n) measurements and only O(k log n) simpl ...
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Journal ArticleIEEE Transactions on Communications · January 1, 2009
In a MIMO multiple-access channel where users employ Space-Time Block Codes (STBC), interference cancellation can be used to suppress co-channel interference and recover the desired signal of each user at the receiver. Leveraging the special properties of ...
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Journal ArticleIEEE Signal Processing Magazine · January 1, 2009
Complementary waveforms developed by Golay are conceived to improve the sensitivity of far infrared spectrometry, which is similar to those developed by Tseng and Liu to analyze acoustic surface wave phenomena. In such a matrix, phase coded waveforms index ...
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Journal ArticleApplied and Computational Harmonic Analysis · January 1, 2009
We consider estimating a random vector from its measurements in a fusion frame, in presence of noise and subspace erasures. A fusion frame is a collection of subspaces, for which the sum of the projection operators onto the subspaces is bounded below and a ...
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Journal ArticleProceedings - 10th IEEE International Symposium on Multimedia, ISM 2008 · December 1, 2008
In this paper we will examine the effect of different parameters in the quality of real compressively sampled images in the compressed sensing framework. We will select a variety of different real images of different types and test the quality of the recov ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2008
In this work, multiple radar waveforms are simultaneously transmitted, emitted from different "virtual" antennas. The goal is to process the returns in such a way that the overall ambiguity function is a sum of ambiguity functions better approximating the ...
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Journal ArticleEuropean Signal Processing Conference · December 1, 2008
Space time signal processing starts with a system of linear equations where signals are multiplied by channel gains, and the standard criteria for the design of space time codes focus on differences between codewords at the transmitter. The value of algebr ...
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Journal ArticleGLOBECOM - IEEE Global Telecommunications Conference · December 1, 2008
To provide real-time multimedia services over a network is challenging due to the stringent delay requirements in the presence of complex network dynamics. Yet such services are beginning to be deployed over best effort networks. Multiple description (MD) ...
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Journal ArticleGLOBECOM - IEEE Global Telecommunications Conference · December 1, 2008
Internet is experiencing an explosive growth of video traffic. Given the limited network bandwidth resources, how to provide Internet users with good video playback quality is a key problem. For video clips competing bandwidth, we propose an approach of Co ...
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Journal ArticleIEEE Journal on Selected Topics in Signal Processing · December 1, 2008
Diversity embedded codes are high-rate space-time codes that have a high-diversity code embedded within them. They allow a form of communication where the high-rate code opportunistically takes advantage of good channel realizations while the embedded high ...
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Journal Article46th Annual Allerton Conference on Communication, Control, and Computing · December 1, 2008
We present a pilot-assisted method for estimating the frequency selective channel in a MIMO-OFDM (Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing) system. The pilot sequence is designed using the DFT (Discrete Fourier Transform) ...
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Journal Article46th Annual Allerton Conference on Communication, Control, and Computing · December 1, 2008
We present bounds on the minimum mean square error (MMSE) of LDPC codes at rates above capacity. One potential application for MMSE estimation involves cooperative communication. A relay following a compress-and-forward (CF) strategy could first compute an ...
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Journal ArticleIEEE Transactions on Information Theory · November 10, 2008
Designs for transmit alphabet constrained space-time codes naturally lead to questions about the design of rank distance codes. Recently, diversity embedded multilevel space-time codes for flat-fading channels have been designed from sets of binary matrice ...
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Journal Article2008 IEEE International Conference on Multimedia and Expo, ICME 2008 - Proceedings · October 23, 2008
For Internet based video broadcasting applications such as IPTV, the Peer-to-Peer (P2P) streaming scheme has been found to be an effective solution. An important issue in live broadcasting is to avoid playback buffer underflow. How to utilize the playback ...
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Journal ArticleIEEE Transactions on Information Theory · October 9, 2008
Space-time codes built out of Alamouti components have been adopted in wireless standards such as UMTS, IEEE 802.11n, and IEEE 802.16, where they facilitate higher data rates through multiplexing of parallel data streams and the addition of two or more ant ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · September 29, 2008
Advances in wireless technologies, such as WiMAX [1], allow high data rates and high reliability through the use of MIMO-OFDM. However, they are not optimally designed for broadcasting. The nature of the wireless medium may cause an entire frame to be in o ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · September 29, 2008
The standard approach to the design of individual space-time codes is based on optimizing diversity and coding gain. This geometric approach leads to remarkable examples, such as the Golden Code, for which the complexity of Maximum Likelihood (ML) decoding ...
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Journal ArticleCISS 2008, The 42nd Annual Conference on Information Sciences and Systems · September 22, 2008
This paper proposes a deterministic compressed sensing matrix that comes by design with a very fast reconstruction algorithm, in the sense that its complexity depends only on the number of measurements n and not on the signal dimension N. The matrix constr ...
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Journal ArticleCISS 2008, The 42nd Annual Conference on Information Sciences and Systems · September 22, 2008
We consider the linear minimum meansquared error (LMMSE) estimation of a random vector of interest from its fusion frame measurements in presence noise and subspace erasures. Each fusion frame measurement is a low-dimensional vector whose elements are inne ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 16, 2008
The use of complementary codes as a means of reducing radar range sidelobes is well-known, but lack of resilience to Doppler is often cited as a reason not to deploy them. This work describes techniques for providing Doppler resilience with an emphasis on ...
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Journal ArticleIEEE Transactions on Information Theory · September 15, 2008
We describe a method of constructing a sequence (pulse train) of phase-coded waveforms, for which the ambiguity function is free of range sidelobes along modest Doppler shifts. The constituent waveforms are Golay complementary waveforms which have ideal am ...
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Journal ArticleIEEE Transactions on Information Theory · August 1, 2008
This paper introduces a new rate-2, full-diversity space-time code for four transmit antennas and one receive antenna. The 4 × 4 codeword matrix consists of four 2 × 2 Alamouti blocks with entries from Q(i,√5), and these blocks can be viewed as quaternions ...
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Journal ArticleIEEE Transactions on Information Theory · April 1, 2008
This paper describes a fundamental correspondence between Boolean functions and projection operators in Hilbert space. The correspondence is widely applicable, and it is used in this paper to provide a common mathematical framework for the design of both a ...
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Journal ArticleIEEE Journal on Selected Areas in Communications · January 1, 2008
Service availability is one of the most closely scrutinized metrics in offering network services. It is important to cost effectively provision a managed and differentiated network with various service availability guarantees under a unified platform. In p ...
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Journal ArticleIEICE Transactions on Communications · January 1, 2008
We use the network utility maximization (NUM) framework to create an efficient and fair medium access control (MAC) protocol for wireless networks. By adjusting the parameters in the utility objective functions of NUM problems, we control the tradeoff betw ...
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Journal Article46th Annual Allerton Conference on Communication, Control, and Computing · January 1, 2008
We consider a basic model for two-hop transmissions of two information flows which interfere with each other. In this model, two sources simultaneously transmit to two relays (in the first hop), which then simultaneously transmit to two destinations (in th ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 2008
Rate and diversity impose a fundamental tradeoff in wireless communication. High-rate space-time codes come at a cost of lower reliability (diversity), and high reliability (diversity) implies a lower rate. However, wireless networks need to support applic ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 2007
This paper describes a common mathematical framework for the design of additive and non-additive Quantum Error Correcting Codes. It is based on a correspondence between boolean functions and projection operators. The new framework extends to operator quant ...
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Journal ArticleProceedings of the 2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks, ITW · December 1, 2007
Designs for transmit alphabet constrained space-time codes naturally lead to questions about the design of rank distance codes. Recently, diversity embedded multi-level space-time codes for flat fading channels have been designed by using sets of binary ma ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2007
While the use of complementary waveforms has been considered as a technique for providing essentially perfect range sidelobe performance in radar systems, its lack of resilience to Doppler is often cited as a reason not to deploy it. This work describes an ...
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Journal ArticleIEEE Workshop on Statistical Signal Processing Proceedings · December 1, 2007
We present a systematic way of constructing a Doppler resilient sequence of Golay complementary waveforms for radar, for which the composite ambiguity function maintains ideal shape at small Doppler shifts. The idea is to determine a sequence of Golay pair ...
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Journal ArticleProceedings of the 2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks, ITW · December 1, 2007
Space-time codes built out of Alamouti components have been adopted in wireless standards such as UMTS, IEEE 802.11n and IEEE 802.16 where they facilitate higher data rates through multiplexing of parallel data streams and the addition of two or more anten ...
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Journal ArticleProceedings of the 2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks, ITW · December 1, 2007
Results for Gaussian relay channels typically focus on maximizing transmission rates for given locations of the source, relay and destination. We consider an alternative approach, focusing on maximizing coverage for a given rate. This novel perspective ena ...
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Journal Article2007 IEEE Information Theory Workshop, ITW 2007, Proceedings · December 1, 2007
The Golden Code is incorporated in the IEEE 802.16 standard and is representative of a large class of space-time codes where performance is determined by the difficulty of solving an associated Diophantine approximation problem. This paper develops a new a ...
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Journal ArticleGLOBECOM - IEEE Global Telecommunications Conference · December 1, 2007
We study the congestion control in a network where the users may have different types of traffic, such as the traffic with fixed/variable rate, delay sensitive/insensitive, etc. To reflect the different requirements on delay by different applications, expl ...
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Journal ArticleProceedings - IEEE INFOCOM · September 4, 2007
Service availability is one of the most closely scrutinized metrics in offering network services. The network vendor can earn more revenue from the customers by guaranteeing higher service availability at the cost of higher operational expense. It is impor ...
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Journal ArticleProceedings - IEEE INFOCOM · September 4, 2007
Networks need to accommodate diverse applications with different Quality-of-Service (QoS) requirements. New ideas at the physical layer are being developed for this purpose, such as diversity embedded coding, which is a technique that combines high rates w ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 6, 2007
In this paper, we propose a method to exploit waveform agility in modern radars to improve performance in the challenging task of detecting small targets on the ocean surface in heavy clutter. The approach exploits the compound-Gaussian model for sea clutt ...
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Journal ArticleIEEE Transactions on Information Theory · August 1, 2007
With the advent of quantum key distribution (QKD) systems, perfect (i.e., information-theoretic) security can now be achieved for distribution of a cryptographic key. QKD systems and similar protocols use classical error-correcting codes for both error cor ...
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Journal ArticleIEEE Journal on Selected Areas in Communications · August 1, 2007
This paper reverse-engineers backoff-based random-access MAC protocols in ad-hoc networks. We show that the contention resolution algorithm in such protocols is implicitly participating in a non-cooperative game. Each link attempts to maximize a selfish lo ...
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Journal ArticleIEEE Transactions on Wireless Communications · July 1, 2007
This paper designs medium access control (MAC) protocols for wireless networks through the network utility maximization (NUM) framework. A network-wide utility maximization problem is formulated, using a collision/persistenceprobabilistic model and alignin ...
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Journal ArticleIEEE Journal on Selected Topics in Signal Processing · June 1, 2007
The dynamic adaptation of waveforms for transmission by active radar has been facilitated by the availability of waveform-agile sensors. In this paper, we propose a method to employ waveform agility to improve the detection of low radar-cross section (RCS) ...
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Journal ArticleIEEE Transactions on Communications · May 1, 2007
This paper presents pilot designs for consistent frequency-offset estimation of orthogonal frequency-division multiplexing systems in frequency-selective fading channels. We describe two design approaches, namely, consistency in the probabilistic sense and ...
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Journal ArticleIEEE Transactions on Information Theory · April 1, 2007
This paper describes a new radar primitive that enables instantaneous radar polarimetry at essentially no increase in signal processing complexity. This primitive coordinates transmission of distinct waveforms on orthogonal polarizations and applies a unit ...
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Journal ArticleMIMO Wireless Communications · January 1, 2007
Multiple-input multiple-output (MIMO) technology constitutes a breakthrough in the design of wireless communications systems, and is already at the core of several wireless standards. Exploiting multipath scattering, MIMO techniques deliver significant per ...
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Chapter · January 1, 2007
Next-generation wireless systems aim to support both voice and high capacity flexible data services with limited bandwidth. Multiplicative and additive distortions inherent to the wireless medium make this difficult, and extensive research efforts are focu ...
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Journal ArticleProceedings of the IEEE · January 1, 2007
Network protocols in layered architectures have historically been obtained on an ad hoc basis, and many of the recent cross-layer designs are also conducted through piecemeal approaches. Network protocol stacks may instead be holistically analyzed and syst ...
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Journal Article2006 4th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks, WiOpt 2006 · December 1, 2006
This paper reverse engineers backoff-based random-access MAC protocols in ad-hoc networks. We show that contention resolution algorithm in such protocols is implicitly participating in a non-cooperative game. Each link attempts to maximize a selfish local ...
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Journal ArticleConference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2006
Fully Polarimetric radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar transmitter and receiver on a pulse by p ...
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Journal ArticleEuropean Signal Processing Conference · December 1, 2006
We design a new rate-5/4 full-diversity orthogonal STBC for QPSK and 2 transmit antennas by enlarging the signalling set from the set of quaternions used in the Alamouti [1] code. Selective power scaling of information symbols is used to guarantee full-div ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 2006
The performance of space-time codes is evaluated in terms of diversity gain and coding gain, two measures which describe the worst-case pairwise error probability between codewords at high signal-to-noise ratio (SNR). We introduce the concept of effective ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 2006
This paper introduces a new full-rate, full-diversity space-time code for 4 transmit antennas. The 4 × 4 codeword matrix consists of four 2 × 2 Alamouti blocks with entries from Q(i, √5), and these blocks can be viewed as quaternions which in turn represen ...
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Journal ArticleProceedings - IEEE INFOCOM · December 1, 2006
The current framework of network utility maximization for rate allocation and its price-based algorithms assumes that each link provides a fixed-size transmission 'pipe' and each user's utility is a function of transmission rate only. These assumptions bre ...
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Journal ArticleProceedings - IEEE INFOCOM · December 1, 2006
This paper analyzes and designs medium access control (MAC) protocols for wireless ad-hoc networks through the network utility maximization (NUM) framework. We first reverse-engineer the current exponential backoff (EB) type of MAC protocols such as the BE ...
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Journal ArticleIEEE Vehicular Technology Conference · December 1, 2006
We study joint end-to-end congestion control and per-link medium access control (MAC) in ad-hoc wireless networks. We use a network utility maximization formulation, in which by adjusting the types of utility functions, we can accommodate multi-class servi ...
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Journal Article2006 IEEE Information Theory Workshop, ITW 2006 · November 21, 2006
Network protocols in layered architectures have historically been obtained primarily on an ad-hoc basis. Recent research has shown that network protocols may instead be holistically analyzed and systematically designed as distributed solutions to some glob ...
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Journal ArticleIEEE Journal on Selected Areas in Communications · May 1, 2006
The current framework of network utility maximization for rate allocation and its price-based algorithms assumes that each link provides a fixed-size transmission "pipe" and each user's utility is a function of transmission rate only. These assumptions bre ...
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Journal ArticleEurasip Journal on Applied Signal Processing · April 19, 2006
We investigate the theory of the finite Heisenberg-Weylgroup in relation to the development of adaptive radar and to theconstruction of spreading sequences and error-correcting codes incommunications. We contend that this group can form the basis forthe re ...
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Journal ArticleIEEE Communications Letters · March 1, 2006
We study joint end-to-end congestion control and per-link medium access control (MAC) in ad-hoc networks. We use a network utility maximization formulation, in which by adjusting the types of utility functions, we can accommodate multi-class services as we ...
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Journal ArticleIEEE Communications Letters · March 1, 2006
We design a new rate-5/4 full-diversity orthogonal space-time block code (STBC) for QPSK and 2 transmit antennas (TX) by enlarging the signalling set from the set of quaternions used in the Alamouti [1] code. Selective power scaling of information symbols ...
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Journal Article · January 1, 2006
Introduction The main impairment in wireless channels is fading or random fluctuation of the signal level. This signal fluctuation happens across time, frequency, and space. Diversity techniques provide the receiver with multiple independent looks at the s ...
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Journal Article · January 1, 2006
Introduction Information-theoretic analysis by Foschini (1996) and by Telatar (1999) shows that multiple antennas at the transmitter and receiver enable very high rate wireless communication. Space-time codes, introduced by Tarokh. (1998), improve the reli ...
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Journal Article2006 IEEE Conference on Information Sciences and Systems, CISS 2006 - Proceedings · January 1, 2006
Diversity embedded codes are opportunistic codes designed for the wireless fading channel. They are high-rate space-time codes which have embedded within them a high-diversity (low rate) code. In this paper, we focus on the application of diversity embedde ...
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Journal Article2006 IEEE Conference on Information Sciences and Systems, CISS 2006 - Proceedings · January 1, 2006
Network protocols in layered architectures have historically been obtained on an ad-hoc basis, and much of the recent cross-layer designs are conducted through piecemeal approaches. Network protocols may instead be holistically analyzed and systematically ...
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Journal ArticleProceedings - IEEE Military Communications Conference MILCOM · January 1, 2006
Consistent pilot designs [6] for carrier frequency offset (CFO) estimation eliminate ambiguity in the noise-free estimation metric trajectory regardless of the channel impulse response. Their importance is more pronounced in emergency and disaster situatio ...
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Journal ArticleProceedings - IEEE Military Communications Conference MILCOM · January 1, 2006
Network protocols in layered architectures have historically been obtained on an ad-hoc basis, and much of the recent cross-layer designs are conducted through piecemeal approaches. Network protocols may instead be holistically analyzed and systematically ...
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Journal ArticleIEEE International Conference on Communications · January 1, 2006
This paper presents pilot designs for consistent frequency offset estimation of OFDM systems in frequencyselective fading channels. We describe two design approaches, namely consistency in the probabilistic sense and absolute consistency. Existing preamble ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 2005
Two subspaces of a vector space are here called "nonintersecting" if they meet only in the zero vector. Motivated by the design of noncoherent multiple-antenna communications systems, we consider the following question. How many pairwise nonintersecting Mt ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 2005
We investigate the use of capacity and near-capacity achieving LPDC codes on the wire tap channel, where the dual conditions of reliable communications and security are required. We show that good codes for conventional channels (like BSC and BEC) also hav ...
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Journal Article2005 International Conference on Wireless Networks, Communications and Mobile Computing · December 1, 2005
We demonstrate the value of algebraic structure to cross-layer design of multiple-antenna wireless communication systems. At the network layer we will develop techniques for multiple access (many to one) and broadcast (one to many) communication where alge ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 2005
We present a family of Space-Time codes for the noncoherent MIMO channel. The codes are constructed via functions that can be considered as a generalization of boolean functions to commuting projection operators which arise in the theory of quantum stabili ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 2005
The current framework of network utility maximization for distributed rate allocation assumes fixed channel code rates. However, by adapting the physical layer channel coding, different rate-reliability tradeoffs can be achieved on each link and for each e ...
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Journal ArticleProceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms · July 1, 2005
Range-summable universal hash functions, also known as range-summable random variables, are binary-valued hash functions which can efficiently hash single values as well as ranges of values from the domain. They have found several applications in the area ...
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Conference43rd Annual Allerton Conference on Communication, Control and Computing 2005 · January 1, 2005
In this paper we consider encoder and decoder design for codes achieving perfect secrecy on the wiretap channel. We consider the special case of a noiseless main channel and binary erasure channel (BEC) as the wiretapper's channel and show that it is possi ...
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Conference43rd Annual Allerton Conference on Communication, Control and Computing 2005 · January 1, 2005
We present a family of Space-Time codes for the noncoherent MIMO channel. These space-time codes are strongly related to standard binary fist order Reed-Muller codes. In particular, their decoder can be built from several parallel decoders of first order R ...
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Conference43rd Annual Allerton Conference on Communication, Control and Computing 2005 · January 1, 2005
Diversity-embedded codes for fading channels are high-rate codes that are de-signed so that they have a high-diversity code embedded within them [3, 4]. This is equivalent to coding the data into two streams such that the high-priority stream has higher re ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2005
We investigate the theory of the finite discrete Heisenberg-Weyl group in relation to the development of adaptive radar. We contend that this group can form the basis for the representation of the radar environment in terms of operators on the space of wav ...
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ConferenceIEEE Vehicular Technology Conference · January 1, 2005
We 1 present a novel full-rate full-diversity orthogonal space-time block code for QPSK modulation and 4 transmit antennas based on quaternionic algebra. The code does not result in constellation expansion unlike other fullrate full-diversity codes in the ...
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ConferenceIEEE Vehicular Technology Conference · January 1, 2005
Rate and diversity impose a fundamental tradeoff in space-time coding. High-rate space-time codes come at a cost of lower diversity, and high reliability (diversity) implies a lower rate. In [2], [3], we 1 proposed a different point of view where we design ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · October 20, 2004
Codewords were constructed subject to the constraint that the elements of the codewords use symbols from a fixed, small constellation. The subspaces constructed remain nonintersecting when lifted to the complex field. The construction shows that the codewo ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · October 20, 2004
The construction and the analysis of a nonlinear 4×4 full rate, full-diversity orthogonal space-time block codes was discussed. The main aspect was the design, analysis and low complexity decoding of a full rate full diversity orthogonal STBC for four tran ...
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Journal ArticleIEEE International Conference on Communications · August 30, 2004
This paper designs space-time codes for standard PSK and QAM signal constellations that have flexible rate, diversity and require no constellation expansion. Central to this construction are binary partitions of the PSK and QAM constellations that appear i ...
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Journal ArticleProceedings of the IEEE · January 1, 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 i ...
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Journal ArticleConference Record / IEEE Global Telecommunications Conference · December 1, 2003
Rate and diversity impose a fundamental trade-off in space-time coding. High-rate space-time codes come at a cost of lower diversity, and high reliability (diversity) implies a lower rate. In this paper we explore a different point of view where we design ...
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Journal ArticleIEEE Transactions on Information Theory · October 1, 2003
In this paper, we study the multiple-access channel where users employ space-time block codes (STBC). The problem is formulated in the context of an intersymbol interference (ISI) multiple-access channel which occurs for transmission over frequency-selecti ...
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Journal ArticleIEEE International Conference on Communications · July 18, 2003
In this paper we study the multiple-access channel where users employ space-time block codes (STBC). The problem is formulated in the context of an inter-symbol interference (ISI) multiple-access channel. The algebraic structure of the STBC is utilized to ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · January 1, 2003
We study the design and decoding of high-rate space-time codes in two contexts. The first part of the paper examines the multiple-access channel (MAC) where users employ space-time block codes (STBC). The problem is formulated in the context of an inter-sy ...
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Journal ArticleIEEE Communications Magazine · September 1, 2002
We present an overview of research activities on space-time coding for broadband wireless transmission performed at AT&T Shannon Laboratory over the past two years. The emphasis is on physical layer modem algorithms such as channel estimation, equalization ...
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Journal ArticleIEEE Transactions on Information Theory · June 1, 2002
The concept of democracy was introduced in which the individual bits in a coarsely quantized representation of a signal were given equal weight in the approximation to the original signal. It was proved that such democratic representations could not achiev ...
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Journal ArticleIEEE Communications Letters · June 1, 2002
In this letter we introduce two space-time transmission schemes which allow full-rate and full-diversity noncoherent communications using two transmit antennas over fading frequency-selective channels. The first scheme operates in the frequency domain wher ...
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Journal ArticleIEEE Transactions on Vehicular Technology · July 1, 2001
A finite-length optimized-delay multi-input-multi-output (MIMO) mean-square-error decision-feedback equalizer for space-time block-coded transmissions over multipath-fadingchannels is presented. Alamouti's space-time block code with two transmit and two re ...
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Journal ArticleWireless Communications and Mobile Computing · 2001
The information capacity of wireless communication systems can be increased dramatically by employing multiple transmit and receive antennas [Foschini GJ, Gans MJ. On limits of wireless communications in a fading environment when using multiple antennas. W ...
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Journal ArticleConference Record of the Asilomar Conference on Signals, Systems and Computers · January 1, 2001
Space-Time Blocks Codes (STBC) make use of a rich algebraic structure to provide diversity gains with small decoding complexity. In this work, we show that the rich algebraic structure of STBC reduces the hardware and software complexity of interference ca ...
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Journal Article2000 IEEE Wireless Communications and Networking Conference · December 1, 2000
In this paper we estimate bit error probability bounds for finite-length delay-optimised multi-input multi-output (MIMO) equalizers. These equalizers shorten the impulse response memory of frequency-selective MIMO channels by minimizing the average energy ...
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Journal ArticleIEEE Transactions on Information Theory · May 1, 2000
Wireless systems are subject to a time-varying and unknown a priori combination of cochannel interference, fading, and Gaussian noise. It is well known that multiple antennas can provide diversity in space that allows system tradeoffs between interference ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1999
This paper investigates how closely randomly generated binary source sequences can be matched by convolutional code codewords. What distinguishes it from prior work is that a randomly chosen subsequence with density A is to be matched as closely as possibl ...
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Journal ArticleIEEE Journal on Selected Areas in Communications · March 1, 1999
We document the performance of space-time block codes [13], [14], which provide a new paradigm for transmission over Rayleigh fading channels using multiple transmit antennas. Data is encoded using a space-time block code, and the encoded data is split int ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1999
Tail-biting trellis representations of block codes are investigated. We develop some elementary theory, and present several intriguing examples, which we hope will stimulate further developments in this field. In particular, we construct a 16-state 12-sect ...
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Journal ArticleJournal of Algebraic Combinatorics · January 1, 1999
By using totally isotropic subspaces in an orthogonal space Ω+(2i, 2), several infinite families of packings of 2k-dimensional subspaces of real 2i -dimensional space are constructed, some of which are shown to be optimal packings. A certain Clifford group ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1999
The theory of space-time block coding is presented as a simple and elegant method for transmission using multiple transmit antennas in a wireless Rayleigh/Rician environment. These codes have a very simple maximum-likelihood decoding algorithm which is onl ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 1998
A 16-state tail-biting trellis for the binary (24,12,8) Golay code C 24 is exhibited. This tail-biting trellis is minimal. It has many other nice properties, and may be simpler to decode than the minimal conventional trellis for C24. Unwrapping this tail-b ...
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Journal ArticleConference Record of the Asilomar Conference on Signals, Systems and Computers · December 1, 1998
This paper presents a combined interference suppression and ML decoding scheme for space-time block codes that can effectively suppress interference from other co-channel users while providing each user with a diversity benefit. We consider a multiuser env ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1998
In 1948 Shannon developed fundamental limits on the efficiency of communication over noisy channels. The coding theorem asserts that there are block codes with code rates arbitrarily close to channel capacity and probabilities of error arbitrarily close to ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1998
We consider the design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas. Data is encoded by a channel code and the encoded data is split into n streams that are simu ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1998
When a block modulation code is concatenated with an errorcorrection code (ECC) in the standard way, the use of a modulation code with long blocklengths results in error propagation. This correspondence analyzes the performance of modified concatenation, w ...
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Journal ArticleIEEE Journal on Selected Areas in Communications · October 1, 1998
This paper presents the theory and practice of a new advanced modem technology suitable for high-data-rate wireless communications and presents its performance over a frequency-flat Rayleigh fading channel. The new technology is based on space-time coded m ...
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Conference1998 Information Theory Workshop, ITW 1998 · January 1, 1998
We introduce space-block codzng, a new paradigm for transmission over Rayleigh fading channels using multiple transmit antennas. Data is encoded using a space-block code and the encoded data is split into n streams which are simultaneously transmitted usin ...
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Journal ArticleApplied and Computational Harmonic Analysis · January 1, 1998
Invertible wavelet transforms that map integers to integers have important applications in lossless coding. In this paper we present two approaches to build integer to integer wavelet transforms. The first approach is to adapt the precoder of Laroia et al. ...
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Journal ArticleIEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC · December 1, 1997
We consider the design of channel codes for improving the data rate and/or the reliability of communications using multiple transmit antennas over a fading channel. It is assumed that the transmitter does not know the channel but seeks to choose a codebook ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1997
This paper describes how 2-adic numbers can be used to analyze the structure of binary cyclic codes and of cyclic codes defined over ℤ 2a, a ≥ 2, the ring of integers modulo 2 a. It provides a 2-adic proof of a theorem of McEliece that characterizes the po ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1997
An analysis of the Generalized Cross Constellation (GCC) is presented and a new perspective on its coding algorithm is described. We show how the GCC can be used to address generic sets of symbol points in any multidimensional space through an example base ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 1997
The unreasonable effectiveness of quantum computing is founded on coherent quantum superposition or entanglement which allows a large number of calculations to be performed simultaneously. This coherence is lost as a quantum system interacts with its envir ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1997
Invertible wavelet transforms that map integers to integers are important for lossless representations. In this paper, we present an approach to build integer to integer wavelet transforms based upon the idea of factoring wavelet transforms into lifting st ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 1997
The design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas is considered. A design criterion is provided and is then used to design space-time codes for high data r ...
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Journal ArticlePhysical Review Letters · January 20, 1997
A group theoretic framework is introduced that simplifies the description of known quantum error-correcting codes and greatly facilitates the construction of new examples. Codes are given which map 3 qubits to 8 qubits correcting 1 error, 4 to 10 qubits co ...
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Journal ArticleJournal of Algebraic Combinatorics · January 1, 1997
With the help of some new results about weight enumerators of self-dual codes over ℤ4 we investigate a class of double circulant codes over ℤ4, one of which leads to an extremal even unimodular 40-dimensional lattice. It is conjectured that there should be ...
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Journal ArticleIEEE International Conference on Communications · January 1, 1997
We consider the design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas. Here, data is encoded by a channel code and the encoded data is split into n streams that ar ...
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Journal ArticleIEEE International Conference on Communications · January 1, 1997
We revisit Space-Time Codes for a mobile communication system that employs multiple antennas at the base and optional antenna diversity at the mobile station. The realistic case when the channel state is not completely known is considered. It is assumed th ...
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Journal ArticleIEEE Vehicular Technology Conference · January 1, 1997
We consider the design of channel codes for improving the data rate and/or the reliability of communications over fading channels using multiple transmit antennas. Here, data is encoded by a channel code and the encoded data is split into n streams that ar ...
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Journal ArticleDesigns, Codes, and Cryptography · January 1, 1997
Certain nonlinear binary codes contain more codewords than any comparable linear code presently known. These include the Kerdock and Preparata codes, which exist for all lengths 4m ≥ 16. At length 16 they coincide to give the Nordstrom-Robinson code. This ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1996
Binary m-sequences are maximal-length sequences generated by shift registers of length m, that are employed in navigation, radar, and spread-spectrum communication. It is well known that given a pair of distinct /«-sequences, the crosscorrelation function ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1996
A family of quaternary (Z4-alphabet) sequences of length L = T -1, size M > L2 +3X+2, and maximum nontrivial correlation parameter Cmax < 2√L + 1 + 1 is presented. The sequence family always contains the four-phase family A. When r is odd, it includes the ...
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Journal ArticleIEEE Transactions on Information Theory · December 1, 1996
Certain nonlinear binary codes contain more code-words than any comparable linear code presently known. These include the Kerdock and Preparata codes that can be very simply constructed as binary images, under the Gray map, of linear codes over ℤ4 that are ...
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Journal ArticleElectro International, Conference Proceedings · January 1, 1996
Co-channel interference is a major impairment in wireless systems with channel (frequency and/or time) re-use. In practice the performance of Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) systems is limited by a few dom ...
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Journal ArticlePhysical Review A - Atomic, Molecular, and Optical Physics · January 1, 1996
A quantum error-correcting code is defined to be a unitary mapping (encoding) of k qubits (two-state quantum systems) into a subspace of the quantum state space of n qubits such that if any t of the qubits undergo arbitrary decoherence, not necessarily ind ...
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Journal ArticleDesigns, Codes and Cryptography · July 1, 1995
This paper presents some basic theorems giving the structure of cyclic codes of length n over the ring of integers modulo pa and over the p-adic numbers, where p is a prime not dividing n. An especially interesting example is the 2-adic cyclic code of leng ...
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Journal ArticleLinear Algebra and Its Applications · January 1, 1995
The Kerdock and Delsarte-Goethals codes can be very simply constructed as binary images under a certain natural map, called the Gray map, of linear codes over Z4, the integers modulo 4. We consider the Gray images of linear codes over Z4 obtained from the ...
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Journal ArticleIEEE Transactions on Vehicular Technology · January 1, 1995
To improve re-use of time/frequency slots in a cellular radio system, it is desirable for the average interference levels seen by all users to be made approximately equal. We provide constructions based on orthogonal latin squares that guarantee different ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1995
Binary m-sequences are maximal length sequences generated by shift registers of length m, that are employed in navigation, radar, and spread-spectrum communications systems, because of their crosscorrelation properties. It is well known that given a pair o ...
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Journal ArticleLinear Algebra and Its Applications · 1995
The Kerdock and Delsarte-Goethals codes can be very simply constructed as binary images under a certain natural map, called the Gray map, of linear codes over Z4, the integers modulo 4. We consider the Gray images of linear codes over Z4 obtained from the ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1995
The paper describes Markov methods for analyzing the expected and worst case performance of sequence-based methods of quantization. We suppose that the quantization algorithm is dynamic programming, where the current step depends on a vector of path metric ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1995
We present an analog of the well-known Weil-Carlitz-Uchiyama upper bound for exponential sums over finite fields for exponential sums over Galois rings. Some examples are given where the hound is tight. The bound has immediate application to the design of ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1995
A Markovian technique is described to calculate the exact performance of the Viterbi algorithm used as either a channel decoder or a source encoder for a convolutional code. The probability of information bit error and the expected Hamming distortion are c ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1995
We construct new self-dual and isodual codes over the integers modulo 4. The binary images of these codes under the Gray map are nonlinear, but formally self-dual. The construction involves Hensel lifting of binary cyclic codes. Quaternary quadratic residu ...
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Journal ArticleIEEE International Conference on Communications · January 1, 1995
Co-channel interference is a major impairment in wireless systems with channel re-use. In practice the performance of time division multiple access (TDMA) and frequency division multiple access (FDMA) systems is limited by a few dominant co-channel interfe ...
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Journal ArticleIEEE Vehicular Technology Conference · January 1, 1995
Cochannel interference is a major impairment in cellular systems. In practice the performance of time and frequency division multiple access (TDMA and FDMA) systems is limited by a few dominant cochannel interferers. Conventional channel coding techniques ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · January 1, 1995
An analysis of the Generalized Cross Constellation (GCC) is presented and a new perspective on its coding algorithm is described. We show how the GCC can be used to address generic sets of symbol points in any multidimensional space through an example base ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 1994
An upper bound for Weil-type exponential sums over Galois rings is presented together with some examples where the bound is tight. The bound may be regarded as the Galois-ring analogue of the well-known Weil-Carlitz-Uchiyama bound for exponential sums over ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · December 1, 1994
A nested chain of quaternary-sequence families having low correlation values is presented. The families are suitable for application in CDMA systems employing QPSK modulation. ...
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Journal ArticleNational Conference Publication - Institution of Engineers, Australia · December 1, 1994
We consider the problem of coding for a recording channel. Traditional magnetic or optical channels employ saturation recording, where the input to the channel is a two-level waveform. A new optical recording channel has been developed that supports unsatu ...
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Journal ArticleDesigns, Codes and Cryptography · October 1, 1994
We consider a variant of the classical problem of finding the size of the largest cap in the r-dimensional projective geometry PG(r, 3) over the field IF3 with 3 elements. We study the maximum size f(n) of a subset S of IF3n with the property that the only ...
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Journal ArticleTransactions of the American Mathematical Society · January 1, 1994
We consider, for a given complex parameter a, the nonassociative product defined on the tensor algebra of á-dimensional complex vector space by the left-normed bracketing is defined recursively to be the bracketing sequence The linear subspace spanned by a ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1994
Testing of high-speed voiceband modems has revealed a significant increase in distortion for points near the perimeter of a QAM signal constellation. This distortion increases with distance from the center of the constellation and limits performance at dat ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1994
Random overlapping pulse-position modulation (OPPM) sequences result in an unrecoverable error floor on both the probability of erroneous synchronization and the probability of symbol error when only chip synchronization is present It is known, however, th ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1994
Certain notorious nonlinear binary codes contain more codewords than any known linear code. These include the codes constructed by Nordstrom-Robinson, Kerdock, Preparata, Goethals, and Delsarte-Goethals. It is shown here that all these codes can be very si ...
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Journal ArticleIEEE International Symposium on Information Theory - Proceedings · January 1, 1994
An upper bound for Weil-type exponential sums over Galois rings is presented together with some examples where the bound is tight. The bound may be regarded as the Galois-ring analogue of the well-known Weil-Carlitz-Uchiyama bound for exponential sums over ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1994
We calculate the per-dimension mean squared error μ(S) of the two-state convolutional code C with generator matrix [1,1 + D], for the symmetric binary source S = [0,1], and for the uniform source S = [0,1]. When S = [0,1], the quantity μ(S) is the second m ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1993
In the last 10 years the invention of trellis coded modulation has revolutionized communication over bandlimited channels and is starting to be used in magnetic storage. Part of the reason is that sophisticated signal processing systems involving finite st ...
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Journal ArticleBulletin of the American Mathematical Society · January 1, 1993
The Nordstrom-Robinson, Kerdock, and (slightly modified) Pre-parata codes are shown to be linear over ℤ4, the integers mod 4. The Kerdock and Preparata codes are duals over ℤ4, and the Nordstrom-Robinson code is self-dual. All these codes are just extended ...
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Journal ArticleJournal of Algebraic Combinatorics: An International Journal · January 1, 1993
Shannon introduced the concept of zero-error capacity of a discrete memoryless channel. The channel determines an undirected graph on the symbol alphabet, where adjacency means that symbols cannot be confused at the receiver. The zero-error or Shannon capa ...
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Journal ArticleTransactions of the American Mathematical Society · January 1, 1993
Let 픅 be a family of k-subsets of a υ-set V, with 1 ≤ k ≤ υ/2. Given only the inner distribution of 픅, i.e., the number of pairs of blocks that meet in j points (with j = 0, 1, …, k), we are able to completely describe the regularity with which 픅 meets an ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1993
The Kerdock and extended Preparata codes are something of an enigma in coding theory since they are both Hamming-distance invariant and have weight enumerators that are MacWilliams duals just as if they were dual linear codes. In this paper, we explain, by ...
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Journal ArticleProceedings of the 1993 IEEE International Symposium on Information Theory · January 1, 1993
To improve re-use of time/frequency slots in a cellular radio system, it is desirable for the average interference levels seen by all users to be made approximately equal. We provide constructions based on orthogonal Latin squares that guarantee different ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1993
In many speech and image coding schemes. some of the coded bits are extremely sensitive to channel errors while some others exhibit very little sensitivity. In order to make the best use of channel redundancy, unequal error protection (UEP) codes are neede ...
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Journal ArticleIEEE Transactions on Information Theory · 1993
Asymptotic upper bounds on the minimum distance of trellis codes are derived. A universal bound and bounds specific to PSK and QAM signal sets are obtained. ...
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Journal ArticleProceedings of the 1993 IEEE International Symposium on Information Theory · January 1, 1993
Shannon introduced the concept of zero-error capacity of a discrete memoryless channel. The channel determines an undirected graph on the symbol alphabet, where adjacency means that symbols cannot be confused at the receiver. The zero-error or Shannon capa ...
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Journal ArticleProceedings of the 1993 IEEE International Symposium on Information Theory · January 1, 1993
In many speech and image coding schemes, some of the coded bits are extremely sensitive to channel errors while some others exhibit very little sensitivity. In order to make the best use of channel redundancy, unequal error protection (UEP) codes are neede ...
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Journal ArticleProceedings of the 1993 IEEE International Symposium on Information Theory · January 1, 1993
This talk describes methods for analyzing the expected and worst-case performance of sequence based methods of quantization. We suppose that the quantization algorithm is dynamic programming, where the current step depends on a vector of path metrics, whic ...
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Journal ArticleProceedings of the 1993 IEEE International Conference on Communications · January 1, 1993
Random OPPM sequences result in an unrecoverable error floor on both the probability of erroneous synchronization and the probability of symbol error when only chip synchronization is present. It is known, however, that for a given sequence length M, a sub ...
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Journal ArticleProceedings of the 1993 IEEE International Symposium on Information Theory · January 1, 1993
The output of a finite state machine is a collection of codewords that can be searched efficiently to find the optimum codeword with respect to any nonnegative measure that can be calculated on a symbol by symbol basis. Applications involving trellis codes ...
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Journal ArticleDiscrete Mathematics · September 1, 1992
We construct 2-state covering machines from binary linear codes with a sufficiently rich subcode structure. The goal is to trade multiple covering properties for increased redundancy. We explain why the expected covering properties of covering machines sho ...
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Journal ArticleDesigns, Codes and Cryptography · June 1, 1992
We obtain necessary conditions for the existence of a 2 - (ν, k, λ) design, for which the block intersection sizes s1, s2, ..., snsatisfy s1 ≡ s2 ≡ ... ≡ sn ≡ s (mod pe),where p is a prime and the exponent e is odd. These conditions are obtained from restr ...
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Journal ArticleCombinatorics, Probability and Computing · January 1, 1992
A family [formula omitted] of k-element sets of an n-set is called t-intersecting if any two of its members overlap in at least t-elements. The Erdős-Ko-Rado Theorem gives a best possible upper bound for such a family if n ≥ n0(k, t). One of the most excit ...
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Journal ArticleJournal of Combinatorial Theory, Series A · January 1, 1992
Given an [n, k]R code C, and a subcode H of C with codimension j, define SHj(C) = maxx∈F2n {d(x, H) + d(x, C H)}, and define the j-norm, Sj(C) to be the minimum value of SHj(C) as H ranges over the subcodes with codimension j. We prove that if k (n + 1) > ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1992
The problem of shaping signal constellations that are designed for the Gaussian channel is considered. The signal constellation consists of all points from some translate of a lattice A, that lie within a region $. The signal constellation is partitioned i ...
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ConferenceConference Record - Asilomar Conference on Signals, Systems and Computers · January 1, 1992
In the digital implementations of maximumlikelihood detectors based upon the Viterbi algorithm, bounds on the values of path metric differences are important parameters, and various techniques have been proposed for computing such bounds. This paper addres ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1991
There has been a great deal of recent interest in the covering radius of binary codes. We shall describe how good covering codes can be used to make high speed data transmission more reliable. ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1991
Let W1 = d, w2,…, wsbe the weights of the nonzero codewords in a binary linear [n, k, d] code C, and let w'1, w'2,…, w's' be the nonzero weights in the dual code CT. Let t be an integer in the range 0 < t < d such that there are at most d — t weights w'iwi ...
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Journal Article · December 1, 1990
Summary form only given. Let w1 = d, w2, ..., ws be the weights of the nonzero code words in a binary linear [n, k, d] code C, and let w1′, w2′, ..., ws′ be the nonzero weights in the dual code C⊥. Let t be an integer in the range 0 < t < d such that there ...
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Journal Article · December 1, 1990
Summary form only given, as follows. Many signaling schemes for the Gaussian channel are based on finite-dimensional lattices. The signal constellation consists of all lattice points within a region R, and the shape of this region determines the average si ...
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Journal ArticleDiscrete Mathematics · August 1, 1990
We obtain a new necessary condition for the existence of a 2-(υ, k, λ) design where the block intersection sizes s1,s2,...,sn satisfy s1≡s2≡...≡sn≡s( mod 2). This condition eliminates quasi-symmetric 2-(20, 10, 18) and 2-(60, 30, 58) designs. Quasi-symmetr ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1990
Many signaling schemes for the Gaussian channel are based on finite-dimensional lattices. The signal constellation consists of all lattice points within a region and the shape of this region determines the average signal power. Spherical signal constellati ...
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Journal ArticleIEEE Transactions on Computers · January 1, 1989
We analyze a model of a movable-head disk system with two read/write heads maintained a fixed distance d apart on each arm. Successive request-addresses are assumed to be independent random variables, uniformly distributed over the set of cylinders. The pu ...
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Journal ArticleIEEE Journal on Selected Areas in Communications · January 1, 1989
We describe a method of designing baseband line codes with prescribed spectral nulls in the transmitted spectrum. These codes have the important property that the transmitted power is adjustable (with a concomitant change in spectral shape, i.e., null widt ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1989
Known coset codes are adapted for use on partial response channels or to generate signals with spectral nulls. By the use of methods of coset precoding and running digital sum feedback, any desired tradeoff can be achieved between the power and spectra of ...
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Journal ArticleIEEE Transactions on Communications · January 1, 1989
Imai and Hirakawa have proposed a multilevel coding method based on binary block codes that admits a staged decoding procedure. This method has been extended to the design of codes for the Gaussian channel that admit multistage decoding procedures by Ginzb ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1989
A multilevel approach to the design of dc-free line codes is presented. The advantages of codes designed by this method over similar codes presented by Ferreira and Blaum are the improved run length/ accumulated charge parameters, higher transmission rate, ...
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Journal Article · December 1, 1988
Summary form only given, as follows. Imai and Hirakawa have proposed a multilevel coding method based on binary block codes that admits a staged decoding procedure. This method has been extended to the design of codes for the Gaussian channel by Ginzburg a ...
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Journal Article · December 1, 1988
Summary form only given, as follows. Known coset codes are adapted for use on partial response channels or to generate signals with spectral nulls. By use of methods of coset precoding and running digital sum feedback, any desired tradeoff can be achieved ...
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Journal ArticleProceedings - IEEE Military Communications Conference · December 1, 1988
The author designs multilevel trellis codes based on lattices and cosets that provide greater immunity to Gaussian noise and/or greater resistance to impulse noise than previous approaches. He shows how to calculate minimum-squared distance and path multip ...
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Journal Article · December 1, 1988
Summary form only given, as follows. The design of balanced error-correcting codes has received a lot of attention in recent literature. Besides their error-control capability, these codes also have power spectral densities that make them attractive for us ...
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Journal Article · December 1, 1988
Summary form only given, as follows. Any code C with covering radius R must satisfy a set of linear inequalities that involve the Lloyd polynomial LR(x); these generalize the sphere bound. The syndrome graphs associated with a linear code C help to keep tr ...
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Journal ArticleJournal of the ACM (JACM) · April 1, 1988
Two mathematical models dealing with optimal placement of directories on disk devices are analyzed. Storage addresses on the disk are approximated by points in the interval [0, 1]. Requests for information on the disk are represented by a sequence of file ...
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Journal ArticleEuropean Journal of Combinatorics · January 1, 1988
We apply duality in the Johnson scheme J(v, k) to give a very short proof of a theorem of Frankl and Füredi. We consider a family ℱ of k-subsets of a v-set such that ℱ is a 1-design and |x ∪ y| ⩾ λ > 0 for all x, y ∈ ℱ. We prove v ⩽ (k2 − k + λ)/λ with equ ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1988
Any code C with covering radius R must satisfy a set of linear inequalities that involve the Lloyd polynomial LR(x); these generalize the sphere bound. The “syndrome graphs” associated with a linear code C help to keep track of low weight vectors in the sa ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1988
A method is described for modifying classical N-dimensional trellis codes to provide baseband codes that combine a spectral null at dc with significant coding gain. The information rate of the classical code is decreased by one bit, and this extra redundan ...
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Journal ArticleJournal of Combinatorial Theory, Series A · January 1, 1988
A 2-design is said to be quasi-symmetric if there are two block intersection sizes. We obtain inequalities satisfied by the parameters of a quasi-symmetric design using linear programming techniques. The same methods apply to codes with covering radius 2 w ...
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Journal ArticleJournal of Combinatorial Theory, Series A · January 1, 1988
Let p be an odd prime. We derive new necessary conditions for the existence of 2 - (ν, k, λ) designs where the block intersection sizes s1, s2, ..., sn satisfy s1 ≡ s2 ≡ ... ≡ sn (mod p). The method is to define a nondegenerate scalar product on a 2m-dimen ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1987
A new technique is proposed for constructing trellis codes, which provides an alternative to Ungerboeck's method of “set partitioning.” The new codes use a signal constellation consisting of points from an n-dimensional lattice A, with an equal number of p ...
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Journal ArticleJournal of Combinatorial Theory, Series A · January 1, 1987
Gleason and Mallows and Sloane characterized the weight enumerators of maximal self-orthogonal codes with all weights divisible by 4. We apply these results to obtain a new necessary condition for the existence of 2 - (v, k, λ) designs where the intersecti ...
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Journal ArticleGraphs and Combinatorics · December 1, 1986
Codewords of weight 8 in the [24, 12] binary Golay code are called octads. A family ℱ of octads is said to be a regular intersecting family if ℱ is a 1-design and |x ∩ y| ≠ 0 for all x, y ∈ ℱ. We prove that if ℱ is a regular intersecting family of octads t ...
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Journal Article · December 1, 1986
Summary form only given. A technique is proposed for constructing multidimensional trellis codes that provides an alternative to Ungerboeck's method of 'set partitioning. ' The new codes use a signal constellation consisting of points from an n-dimensional ...
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Journal Article · December 1, 1986
Summary form only given. A. R. Calderbank et. al. have suggested a method of designing codes for channels with intersymbol interference, such as the magnetic recording channel. They considered an idealized model of the magnetic recording channel that leads ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1986
Calderbank, Heegard, and Ozarow [1] have suggested a method of designing codes for channels with intersymbol interference, such as the magnetic recording channel. These codes are designed to exploit intersymbol interference. The standard method is to minim ...
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Journal ArticleEuropean Journal of Combinatorics · January 1, 1986
Consider functions f1, . . . , fk defined on an n-element set I with the property that if x ∈ I then f1(x), . . . , fk(x) are all distinct. We shall say that the functions f1, . . . , fk never agree. Let ρ(f1, . . . , fk) be the size of the largest subset ...
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Journal ArticleProceedings of the London Mathematical Society · January 1, 1986
For each n and k, let Π(i, k) denote the poset of all partitions of n having every block size congruent to i mod k. Attach to Πn(i, k) a unique maximal or minimal element if it does not already have one, and denote the resulting poset Πn(i, k). Results of ...
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Journal ArticleIEEE Transactions on Information Theory · 1986
Motivated by an idealized model of the magnetic recording channel, codes were designed for a partial response channel with transfer function (1-D**N)/2 where the channel inputs are constrained to be plus or minus 1. Channel inputs are generated using a non ...
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Journal ArticleIEEE Transactions on Information Theory · 1986
Uniformly packed, linear e-error-correcting codes are considered. In particular, it is shown that the nonexistence of a uniformly packed left bracket 70,58,5 right bracket code C PERPEND is proved by examining geometries associated with the 3-weight code C ...
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Journal ArticleJournal of Combinatorial Theory, Series A · January 1, 1986
M. G. Kendall and B. Babington-Smith proved that if a tournament p′ is obtained from a tournament p by reversing the edges of a 3-cycle then p and p′ contain the same number of 3-cycles. This theorem is the basis of a cancellation argument used by D. Zeilb ...
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Journal ArticleEuropean Journal of Combinatorics · January 1, 1985
We consider codes in the Hamming association scheme Hn(q) with interesting metric properties. We describe how a uniformly packed linear code C determines a pair of dual subschemes. The existence of this pair of subschemes is used to establish restrictions ...
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Journal ArticleCommunications in Statistics. Stochastic Models · January 1, 1985
We analyze a service system in which two servers move independently on the surface of the n-dimensional sphere. Requests for service arrive independently and uniformly over the surface. the ith request is to be served completely before service of the (i+l) ...
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Journal ArticleAT&T Technical Journal · January 1, 1985
A trellis code is a “sliding window” method for encoding a binary data stream {ai}, ai = 0, 1, as a sequence of signal points drawn from Rn. The rule for assigning signal points depends on the state of the encoder. In this paper n = 4, and the signal point ...
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Journal ArticleMathematics of Operations Research · January 1, 1985
We analyze a service system in which two identical servers move one at a time along a linear array of N positions. Requests for service, each designating one of the N positions, join a first-in-first queue, where processing of the nth request does not begi ...
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Journal ArticleIEEE Transactions on Communications · January 1, 1985
A trellis code is a 'sliding window' method of encoding a binary data stream as a sequence of signal points. When a trellis code is used to encode data at the rate of k bits/channel symbol, each channel input depends not only on the most recent block of k ...
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Journal Article · December 1, 1984
Using a certain 4-dimensional lattice, a new family of codes has been constructed that has a very low error rate. Two particular codes in this family appear to be excellent candidates for use in modems operating at 9. 6 and 14. 4 kb/s, respectively, on dia ...
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Journal ArticlePhilips Journal of Research · December 1, 1984
Three-weight projective codes C are considered for which the restriction to C of the Hamming association scheme H//n(q) is an association scheme with three classes. Sufficient conditions are established and restrictions on the three weights of C are obtain ...
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Journal ArticleJournal of the ACM (JACM) · September 20, 1984
A mathematical model of computer disk storage devices having two movable read/write heads is studied. Storage addresses are approximated by points in the continuous interval [0, 1], and requests for information on the disk are processed first-come-first-se ...
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Journal ArticleIEEE Transactions on Information Theory · 1984
A trellis code is a 'sliding window' method of encoding a binary data stream as a sequence of real or complex numbers that are input to a noisy transmission channel. Ungerboeck has constructed simple trellis codes that provide the same noise immunity as is ...
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Journal ArticleDiscrete Mathematics · January 1, 1984
Consider the maximum length f(k) of a (lexicographically) increasing sequence of vectors in GF(2)k with the property that the sum of the vectors in any consecutive subsequence is nonzero modulo 2. We prove that 23 48 · 2k ≤ f(k) ≤ ( 1 2 + o(1))2k. A relate ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1984
A trellis code is a “sliding window” method of encoding a binary data stream as a sequence of real or complex numbers that are input to a noisy transmission channel. Ungerboeck has constructed simple trellis codes that provide the same noise immunity as is ...
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Journal ArticleBell System Technical Journal · January 1, 1983
A trellis code is a “sliding window” method of encoding a binary data stream into a sequence of real numbers that are input to a noisy transmission channel. When a trellis code is used to encode data at the rate of k bits/channel symbol, each channel input ...
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Journal ArticleIEEE Transactions on Information Theory · 1983
The author establishes a square root bound on the minimum weight in the quasi-cyclic binary codes constructed by V. K. Bhargava, S. E. Tavares, and S. G. S. Shiva. The proof rests on viewing the codes as ideas in a group algebra over GF. ...
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Journal ArticleJournal of Number Theory · January 1, 1983
This paper determines the parameters of all two-weight ternary codes C with the property that the minimum weight in the dual code C⊥ is at least 4. This yields a characterization of uniformly packed ternary [n, k, 4] codes. The proof rests on finding all i ...
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Journal ArticleThe Bell System technical journal · 1983
A trellis code is a 'sliding window' method of encoding a binary data stream into a sequence of real numbers that are input to a noisy transmission channel. When a trellis code is used to encode data at the rate of k bits/channel symbol, each channel input ...
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Journal ArticleIEEE Transactions on Information Theory · January 1, 1983
We establish a square root bound on the minimum weight in the quasi-cyclic binary codes constructed by Bhargava, Tavares, and Shiva. The proof rests on viewing the codes as ideals in a group algebra over GF (4). Theorem 6 answers a question raised by F. J. ...
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Journal ArticleJournal of the London Mathematical Society · January 1, 1982
We determine all uniformly packed [n, k, 4] codes over GF (2) and we derive a non-trivial necessary condition for the existence of uniformly packed [k, 4] codes over GF (q), where q 2 is a prime power. This condition allows us to classify uniformly packed ...
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Journal ArticleLinear Algebra and Its Applications · January 1, 1980
Let q be an odd prime power, and suppose q−1 (mod8), Let C(q) and C(q)∗ be the two extended binary quadratic residue codes (QR codes) of length q+1, and let T(q)={(a+x;b+x;a+b+x):a,b∈C(q),x∈C(q)∗}. We establish a square root bound on the minimum weight in ...
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