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Vahid Tarokh

Vahid Tarokh

Rhodes Family Distinguished Professor of Electrical and Computer Engineering
Electrical and Computer Engineering
vahid.tarokh@duke.edu
Box 90291, Durham, NC 27708
130 Hudson Hall, Durham, NC 27708

Selected Publications

Understanding and Robustifying Sub-domain Alignment for Domain Adaptation

Journal Article Transactions on Machine Learning Research · January 1, 2025 In unsupervised domain adaptation (UDA), aligning source and target domains improves the predictive performance of learned models on the target domain. A common method-ological improvement in alignment methods is to divide the domains and align sub-domains ... Cite

Data-driven target localization using adaptive radar processing and convolutional neural networks

Journal Article IET Radar, Sonar and Navigation · October 1, 2024 Leveraging the advanced functionalities of modern radio frequency (RF) modeling and simulation tools, specifically designed for adaptive radar processing applications, this paper presents a data-driven approach to improve accuracy in radar target localizat ... Full text Cite

Fundamental absorption bandwidth to thickness limit for transparent homogeneous layers.

Journal Article Nanophotonics (Berlin, Germany) · April 2024 Past work has considered the analytic properties of the reflection coefficient for a metal-backed slab. The primary result established a fundamental relationship for the minimal layer thickness to bandwidth ratio achievable for an absorber. There has yet t ... Full text Cite

Quickest Change Detection for Unnormalized Statistical Models

Journal Article IEEE Transactions on Information Theory · February 1, 2024 Classical quickest change detection algorithms require modeling pre-change and post-change distributions. Such an approach may not be feasible for various machine learning models because of the complexity of computing the explicit distributions. Additional ... Full text Cite

Recursive Least Squares With Minimax Concave Penalty Regularization for Adaptive System Identification

Journal Article IEEE Access · January 1, 2024 We develop a recursive least squares (RLS) type algorithm with a minimax concave penalty (MCP) for adaptive identification of a sparse tap-weight vector that represents a communication channel. The proposed algorithm recursively yields its estimate of the ... Full text Cite

Neural McKean-Vlasov Processes: Distributional Dependence in Diffusion Processes

Conference Proceedings of Machine Learning Research · January 1, 2024 McKean-Vlasov stochastic differential equations (MV-SDEs) provide a mathematical description of the behavior of an infinite number of interacting particles by imposing a dependence on the particle density. We study the influence of explicitly including dis ... Cite

Bayesian quickest change detection for unnormalized and score-based models

Journal Article Sequential Analysis · January 1, 2024 Score-based algorithms are proposed for the quickest detection of changes in unnormalized statistical models. These are models where the densities are known within a normalizing constant. These algorithms can also be applied to score-based models where the ... Full text Cite

REFORMA: Robust REinFORceMent Learning via Adaptive Adversary for Drones Flying under Disturbances

Conference Proceedings - IEEE International Conference on Robotics and Automation · January 1, 2024 In this work, we introduce REFORMA, a novel robust reinforcement learning (RL) approach to design controllers for unmanned aerial vehicles (UAVs) robust to unknown disturbances during flights. These disturbances, typically due to wind turbulence, electroma ... Full text Cite

Large Deviation Analysis of Score-Based Hypothesis Testing

Journal Article IEEE Access · January 1, 2024 Score-based statistical models play an important role in modern machine learning, statistics, and signal processing. For hypothesis testing, a score-based hypothesis test is proposed in Wu et al., (2022). We analyze the performance of this score-based hypo ... Full text Cite

Base Models for Parabolic Partial Differential Equations

Conference Proceedings of Machine Learning Research · January 1, 2024 Parabolic partial differential equations (PDEs) appear in many disciplines to model the evolution of various mathematical objects, such as probability flows, value functions in control theory, and derivative prices in finance. It is often necessary to comp ... Cite

Distributionally Robust Optimization as a Scalable Framework to Characterize Extreme Value Distributions

Conference Proceedings of Machine Learning Research · January 1, 2024 The goal of this paper is to develop distributionally robust optimization (DRO) estimators, specifically for multidimensional Extreme Value Theory (EVT) statistics. EVT supports using semi-parametric models called max-stable distributions built from spatia ... Cite

Random Linear Projections Loss for Hyperplane-Based Optimization in Neural Networks

Conference Proceedings of Machine Learning Research · January 1, 2024 Advancing loss function design is pivotal for optimizing neural network training and performance. This work introduces Random Linear Projections (RLP) loss, a novel approach that enhances training efficiency by leveraging geometric relationships within the ... Cite

Steering Decision Transformers via Temporal Difference Learning

Conference IEEE International Conference on Intelligent Robots and Systems · January 1, 2024 Decision Transformers (DTs) have been highly effective for offline reinforcement learning (RL) tasks, successfully modeling the sequences of actions in a given set of demonstrations. However, DTs may perform poorly in stochastic environments, which are pre ... Full text Cite

DynamicFL: Federated Learning with Dynamic Communication Resource Allocation

Conference Proceedings - 2024 IEEE International Conference on Big Data, BigData 2024 · January 1, 2024 Federated Learning (FL) is a collaborative machine learning framework that allows multiple users to train models utilizing their local data in a distributed manner. However, considerable statistical heterogeneity in local data across devices often leads to ... Full text Cite

PERCEIVING COPULAS FOR MULTIMODAL TIME SERIES FORECASTING

Conference Proceedings - Winter Simulation Conference · January 1, 2024 Transformers have demonstrated remarkable efficacy in forecasting time series. However, their dependence on self-attention mechanisms demands significant computational resources, thereby limiting their applicability across diverse tasks. Here, we propose t ... Full text Cite

GENERATIVE LEARNING FOR SIMULATION OF VEHICLE FAULTS

Conference Proceedings - Winter Simulation Conference · January 1, 2024 We develop a novel generative model to simulate vehicle health and forecast faults, conditioned on practical operational considerations. The model, trained on data from the US Army’s Predictive Logistics program, aims to support predictive maintenance. It ... Full text Cite

Neural network accelerated process design of polycrystalline microstructures

Journal Article Materials Today Communications · August 1, 2023 Computational experiments are exploited in finding a well-designed processing path to optimize material structures for desired properties. This requires understanding the interplay between the processing-(micro)structure–property linkages using a multi-sca ... Full text Cite

Region selection in Markov random fields: Gaussian case

Journal Article Journal of Multivariate Analysis · July 1, 2023 We consider the problem of model selection in Gaussian Markov fields in the sample deficient scenario. The benchmark information-theoretic results in the case of d-regular graphs require the number of samples to be at least proportional to the logarithm of ... Full text Cite

Multimodal Controller for Generative Models

Conference Lecture Notes in Networks and Systems · January 1, 2023 Class-conditional generative models are crucial tools for data generation from user-specified class labels. Existing approaches for class-conditional generative models require nontrivial modifications of backbone generative architectures to model condition ... Full text Cite

Subspace Perturbation Analysis for Data-Driven Radar Target Localization

Conference Proceedings of the IEEE Radar Conference · January 1, 2023 Recent works exploring data-driven approaches to classical problems in adaptive radar have demonstrated promising results pertaining to the task of radar target localization. Via the use of space-time adaptive processing (STAP) techniques and convolutional ... Full text Cite

Score-based Quickest Change Detection for Unnormalized Models

Conference Proceedings of Machine Learning Research · January 1, 2023 Classical change detection algorithms typically require modeling pre-change and post-change distributions. The calculations may not be feasible for various machine learning models because of the complexity of computing the partition functions and normalize ... Cite

Robust Quickest Change Detection for Unnormalized Models

Conference Proceedings of Machine Learning Research · January 1, 2023 Detecting an abrupt and persistent change in the underlying distribution of online data streams is an important problem in many applications. This paper proposes a new robust score-based algorithm called RSCUSUM, which can be applied to unnormalized models ... Cite

Inference and Sampling of Point Processes from Diffusion Excursions

Conference Proceedings of Machine Learning Research · January 1, 2023 Point processes often have a natural interpretation with respect to a continuous process. We propose a point process construction that describes arrival time observations in terms of the state of a latent diffusion process. In this framework, we relate the ... Cite

Transfer Learning for Individual Treatment Effect Estimation

Conference Proceedings of Machine Learning Research · January 1, 2023 This work considers the problem of transferring causal knowledge between tasks for Individual Treatment Effect (ITE) estimation. To this end, we theoretically assess the feasibility of transferring ITE knowledge and present a practical framework for effici ... Cite

PASTA: Pessimistic Assortment Optimization

Conference Proceedings of Machine Learning Research · January 1, 2023 We consider a class of assortment optimization problems in an offline data-driven setting. A firm does not know the underlying customer choice model but has access to an offline dataset consisting of the historically offered assortment set, customer choice ... Cite

Off-Policy Evaluation for Human Feedback

Conference Advances in Neural Information Processing Systems · January 1, 2023 Off-policy evaluation (OPE) is important for closing the gap between offline training and evaluation of reinforcement learning (RL), by estimating performance and/or rank of target (evaluation) policies using offline trajectories only. It can improve the s ... Cite

PRUNING DEEP NEURAL NETWORKS FROM A SPARSITY PERSPECTIVE

Conference 11th International Conference on Learning Representations, ICLR 2023 · January 1, 2023 In recent years, deep network pruning has attracted significant attention in order to enable the rapid deployment of AI into small devices with computation and memory constraints. Pruning is often achieved by dropping redundant weights, neurons, or layers ... Cite

CHARACTERISTIC NEURAL ORDINARY DIFFERENTIAL EQUATIONS

Conference 11th International Conference on Learning Representations, ICLR 2023 · January 1, 2023 We propose Characteristic-Neural Ordinary Differential Equations (C-NODEs), a framework for extending Neural Ordinary Differential Equations (NODEs) beyond ODEs. While NODE models the evolution of latent variables as the solution to an ODE, C-NODE models t ... Cite

Toward Data-Driven STAP Radar

Preprint · January 25, 2022 Link to item Cite

Identifying Latent Stochastic Differential Equations

Journal Article IEEE Transactions on Signal Processing · January 1, 2022 We present a method for learning latent stochastic differential equations (SDEs) from high dimensional time series data. Given a high-dimensional time series generated from a lower dimensional latent unknown Itô process, the proposed method learns the mapp ... Full text Cite

Online Action Change Detection for Automatic Vision-based Ground Control of Aircraft

Conference AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 · January 1, 2022 Classical action recognition algorithms require the user to pre-select the time window for the action by clipping the video or choosing the initial and final time frames. Recently, new deep learning algorithms have been developed to detect a key action fro ... Full text Cite

Dimension reduced turbulent flow data from deep vector quantisers

Journal Article Journal of Turbulence · January 1, 2022 Analysing large-scale data from simulations of turbulent flows is memory intensive, requiring significant resources. This major challenge highlights the need for data compression techniques. In this study, we apply a physics-informed Deep Learning techniqu ... Full text Cite

Fisher Task Distance and its Application in Neural Architecture Search

Journal Article IEEE Access · January 1, 2022 We formulate an asymmetric (or non-commutative) distance between tasks based on Fisher Information Matrices, called Fisher task distance. This distance represents the complexity of transferring the knowledge from one task to another. We provide a proof of ... Full text Cite

Toward Data-Driven STAP Radar

Conference Proceedings of the IEEE Radar Conference · January 1, 2022 Using an amalgamation of techniques from classical radar, computer vision, and deep learning, we characterize our ongoing data-driven approach to space-time adaptive processing (STAP) radar. We generate a rich example dataset of received radar signals by r ... Full text Cite

A Physics-Informed Vector Quantized Autoencoder for Data Compression of Turbulent Flow

Conference Data Compression Conference Proceedings · January 1, 2022 Analyzing large-scale data from simulations of turbulent flows is memory intensive, requiring significant resources. This major challenge highlights the need for data compression techniques. In this study, we apply a physics-informed Deep Learning techniqu ... Full text Cite

On The Energy Statistics of Feature Maps in Pruning of Neural Networks with Skip-Connections

Conference Data Compression Conference Proceedings · January 1, 2022 We propose a new structured pruning framework for compressing Deep Neural Networks (DNNs) with skip-connections, based on measuring the statistical dependency of hidden layers and predicted outputs. The dependence measure defined by the energy statistics o ... Full text Cite

Multi-Agent Adversarial Attacks for Multi-Channel Communications

Conference Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS · January 1, 2022 Recently Reinforcement Learning (RL) has been applied as an anti-adversarial remedy in wireless communication networks. However studying the RL-based approaches from the adversary's perspective has received little attention. Additionally, RL-based approach ... Cite

Score-Based Hypothesis Testing for Unnormalized Models

Journal Article IEEE Access · January 1, 2022 Unnormalized statistical models play an important role in machine learning, statistics, and signal processing. In this paper, we derive a new hypothesis testing procedure for unnormalized models. Our approach is motivated by the success of score matching t ... Full text Cite

Large deviations of convex polyominoes*

Journal Article Electronic Journal of Probability · January 1, 2022 Many open problems in machine learning, pattern recognition, and geometric analysis require enumeration of different types of lattice polygons, and in particular convex polyominoes. In this work, we develop a large deviation principle for convex polyominoe ... Full text Cite

Towards Deep Learning-Guided Multiuser SNR and Doppler Shift Detection for Next-Generation Wireless Systems

Conference IEEE Vehicular Technology Conference · January 1, 2022 In order to meet the ever-growing demand for data traffic, highly efficient multiple access schemes, such as OFDMA, are widely used in modern communication standards. In such multiple access schemes, adaptive modulation and coding (AMC) are used to optimiz ... Full text Cite

Semi-Empirical Objective Functions for MCMC Proposal Optimization

Conference Proceedings - International Conference on Pattern Recognition · January 1, 2022 Current objective functions used for training neural MCMC proposal distributions implicitly rely on architectural restrictions to yield sensible optimization results, which hampers the development of highly expressive neural MCMC proposal architectures. In ... Full text Cite

Modeling Extremes with d-max-decreasing Neural Networks

Conference Proceedings of the 38th Conference on Uncertainty in Artificial Intelligence, UAI 2022 · January 1, 2022 We propose a neural network architecture that enables non-parametric calibration and generation of multivariate extreme value distributions (MEVs). MEVs arise from Extreme Value Theory (EVT) as the necessary class of models when extrapolating a distributio ... Cite

Personalized Federated Recommender Systems with Private and Partially Federated AutoEncoders

Conference Conference Record - Asilomar Conference on Signals, Systems and Computers · January 1, 2022 Recommender Systems (RSs) have become increasingly important in many application domains, such as digital marketing. Conventional RSs often need to collect users' data, centralize them on the server-side, and form a global model to generate reliable recomm ... Full text Cite

BLASCHKE PRODUCT NEURAL NETWORK (BPNN): A PHYSICS-INFUSED NEURAL NETWORK FOR PHASE RETRIEVAL OF MEROMORPHIC FUNCTIONS

Conference ICLR 2022 - 10th International Conference on Learning Representations · January 1, 2022 Numerous physical systems are described by ordinary or partial differential equations whose solutions are given by holomorphic or meromorphic functions in the complex domain. In many cases, only the magnitude of these functions are observed on various poin ... Cite

TASK AFFINITY WITH MAXIMUM BIPARTITE MATCHING IN FEW-SHOT LEARNING

Conference ICLR 2022 - 10th International Conference on Learning Representations · January 1, 2022 We propose an asymmetric affinity score for representing the complexity of utilizing the knowledge of one task for learning another one. Our method is based on the maximum bipartite matching algorithm and utilizes the Fisher Information matrix. We provide ... Cite

Modeling Extremes with d-max-decreasing Neural Networks

Conference Proceedings of Machine Learning Research · January 1, 2022 We propose a neural network architecture that enables non-parametric calibration and generation of multivariate extreme value distributions (MEVs). MEVs arise from Extreme Value Theory (EVT) as the necessary class of models when extrapolating a distributio ... Cite

Inference and Sampling for Archimax Copulas

Conference Advances in Neural Information Processing Systems · January 1, 2022 Understanding multivariate dependencies in both the bulk and the tails of a distribution is an important problem for many applications, such as ensuring algorithms are robust to observations that are infrequent but have devastating effects. Archimax copula ... Cite

SemiFL: Semi-Supervised Federated Learning for Unlabeled Clients with Alternate Training

Conference Advances in Neural Information Processing Systems · January 1, 2022 Federated Learning allows the training of machine learning models by using the computation and private data resources of many distributed clients. Most existing results on Federated Learning (FL) assume the clients have ground-truth labels. However, in man ... Cite

GAL: Gradient Assisted Learning for Decentralized Multi-Organization Collaborations

Conference Advances in Neural Information Processing Systems · January 1, 2022 Collaborations among multiple organizations, such as financial institutions, medical centers, and retail markets in decentralized settings are crucial to providing improved service and performance. However, the underlying organizations may have little inte ... Cite

Characteristic Neural Ordinary Differential Equations

Journal Article · November 25, 2021 We propose Characteristic-Neural Ordinary Differential Equations (C-NODEs), a framework for extending Neural Ordinary Differential Equations (NODEs) beyond ODEs. While NODEs model the evolution of a latent variables as the solution to an ODE, C-NODE models ... Link to item Cite

Blaschke Product Neural Networks (BPNN): A Physics-Infused Neural Network for Phase Retrieval of Meromorphic Functions

Journal Article · November 25, 2021 Numerous physical systems are described by ordinary or partial differential equations whose solutions are given by holomorphic or meromorphic functions in the complex domain. In many cases, only the magnitude of these functions are observed on various poin ... Link to item Cite

Decentralized Multi-Target Cross-Domain Recommendation for Multi-Organization Collaborations

Journal Article · October 25, 2021 Recommender Systems (RSs) are operated locally by different organizations in many realistic scenarios. If various organizations can fully share their data and perform computation in a centralized manner, they may significantly improve the accuracy of recom ... Link to item Cite

Task Affinity with Maximum Bipartite Matching in Few-Shot Learning

Journal Article · October 5, 2021 We propose an asymmetric affinity score for representing the complexity of utilizing the knowledge of one task for learning another one. Our method is based on the maximum bipartite matching algorithm and utilizes the Fisher Information matrix. We provide ... Link to item Cite

Data from: Benchmarking deep learning architectures for artificial electromagnetic material problems

Dataset · August 25, 2021 Artificial electromagnetic materials (AEMs), including metamaterials, derive their electromagnetic properties from geometry rather than chemistry. With the appropriate geometric design, AEMs have achieved exotic properties not realizable with conventional ... Full text Cite

CNN-Based Joint SNR and Doppler Shift Classification Using Spectrogram Images for Adaptive Modulation and Coding

Journal Article IEEE Transactions on Communications · August 1, 2021 This paper proposes a novel convolutional neural network (CNN) based joint classification method to characterize the signal-to-noise power ratio (SNR) and Doppler shift using spectrogram images, in order to enable efficient adaptive modulation and coding ( ... Full text Cite

Semi-Empirical Objective Functions for MCMC Proposal Optimization

Journal Article · June 3, 2021 Current objective functions used for training neural MCMC proposal distributions implicitly rely on architectural restrictions to yield sensible optimization results, which hampers the development of highly expressive neural MCMC proposal architectures. In ... Link to item Cite

GAL: Gradient Assisted Learning for Decentralized Multi-Organization Collaborations

Journal Article · June 2, 2021 Collaborations among multiple organizations, such as financial institutions, medical centers, and retail markets in decentralized settings are crucial to providing improved service and performance. However, the underlying organizations may have little inte ... Link to item Cite

SemiFL: Semi-Supervised Federated Learning for Unlabeled Clients with Alternate Training

Journal Article · June 2, 2021 Federated Learning allows the training of machine learning models by using the computation and private data resources of many distributed clients. Most existing results on Federated Learning (FL) assume the clients have ground-truth labels. However, in man ... Link to item Cite

A Methodology for Exploring Deep Convolutional Features in Relation to Hand-Crafted Features with an Application to Music Audio Modeling

Journal Article · May 31, 2021 Understanding the features learned by deep models is important from a model trust perspective, especially as deep systems are deployed in the real world. Most recent approaches for deep feature understanding or model explanation focus on highlighting input ... Link to item Cite

Knowledge-Aided Data-Driven Radar Clutter Representation

Conference IEEE National Radar Conference - Proceedings · May 7, 2021 We use a knowledge-aided, data-driven, location-aware approach based on the RFView simulation software to model and estimate the effect of ground clutter in airborne radars. Using the RFView simulator, we produce many samples of potential clutter effects a ... Full text Cite

On Statistical Efficiency in Learning

Journal Article IEEE Transactions on Information Theory · April 1, 2021 A central issue of many statistical learning problems is to select an appropriate model from a set of candidate models. Large models tend to inflate the variance (or overfitting), while small models tend to cause biases (or underfitting) for a given fixed ... Full text Cite

Fisher Task Distance and Its Application in Neural Architecture Search

Journal Article · March 23, 2021 We formulate an asymmetric (or non-commutative) distance between tasks based on Fisher Information Matrices, called Fisher task distance. This distance represents the complexity of transferring the knowledge from one task to another. We provide a proof of ... Link to item Cite

Talaria: A Framework for Simulation of Permissioned Blockchains for Logistics and Beyond

Journal Article · March 3, 2021 In this paper, we present Talaria, a novel permissioned blockchain simulator that supports numerous protocols and use cases, most notably in supply chain management. Talaria extends the capability of BlockSim, an existing blockchain simulator, to include p ... Link to item Cite

Dimension Reduced Turbulent Flow Data From Deep Vector Quantizers

Journal Article Journal of Turbulence 2022 · March 1, 2021 Analyzing large-scale data from simulations of turbulent flows is memory intensive, requiring significant resources. This major challenge highlights the need for data compression techniques. In this study, we apply a physics-informed Deep Learning techniqu ... Link to item Cite

Compressing Deep Networks Using Fisher Score of Feature Maps

Conference Data Compression Conference Proceedings · March 1, 2021 In this paper, we propose a new structural technique for pruning deep neural networks with skip-connections. Our approach is based on measuring the importance of feature maps in predicting the output of the model using their Fisher scores. These scores sub ... Full text Cite

Improved Automated Machine Learning from Transfer Learning

Journal Article · February 27, 2021 In this paper, we propose a neural architecture search framework based on a similarity measure between some baseline tasks and a target task. We first define the notion of the task similarity based on the log-determinant of the Fisher Information matrix. N ... Link to item Cite

Generative Archimedean Copulas

Journal Article · February 22, 2021 We propose a new generative modeling technique for learning multidimensional cumulative distribution functions (CDFs) in the form of copulas. Specifically, we consider certain classes of copulas known as Archimedean and hierarchical Archimedean copulas, po ... Link to item Cite

Modeling Extremes with d-max-decreasing Neural Networks

Journal Article · February 17, 2021 We propose a novel neural network architecture that enables non-parametric calibration and generation of multivariate extreme value distributions (MEVs). MEVs arise from Extreme Value Theory (EVT) as the necessary class of models when extrapolating a distr ... Link to item Cite

Convergence Rate of Empirical Spectral Distribution of Random Matrices from Linear Codes

Journal Article IEEE Transactions on Information Theory · February 1, 2021 It is known that the empirical spectral distribution of random matrices obtained from linear codes of increasing length converges to the well-known Marchenko-Pastur law, if the Hamming distance of the dual codes is at least 5. In this paper, we prove that ... Full text Cite

Model linkage selection for cooperative learning

Journal Article Journal of Machine Learning Research · January 1, 2021 We consider the distributed learning setting where each agent or learner holds a specific parametric model and a data source. The goal is to integrate information across a set of learners and data sources to enhance the prediction accuracy of a given learn ... Cite

Fisher Auto-Encoders

Journal Article 24TH INTERNATIONAL CONFERENCE ON ARTIFICIAL INTELLIGENCE AND STATISTICS (AISTATS) · 2021 Cite

Task-aware neural architecture search

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2021 The design of handcrafted neural networks requires a lot of time and resources. Recent techniques in Neural Architecture Search (NAS) have proven to be competitive or better than traditional handcrafted design, although they require domain knowledge and ha ... Full text Cite

Flow parameter estimation based on on-board measurements of air vehicle traversing turbulent flows

Conference AIAA Scitech 2021 Forum · January 1, 2021 Inspired by principles from particle transport theory in fluid dynamics, we recently developed a new energy-efficient control approach via implicit model following (IMF) for air vehicles traversing turbulent flows. However, the control design requires prio ... Cite

On Statistical Efficiency in Learning.

Journal Article IEEE Trans. Inf. Theory · 2021 Full text Cite

Fisher Auto-Encoders

Conference Proceedings of Machine Learning Research · January 1, 2021 It has been conjectured that the Fisher divergence is more robust to model uncertainty than the conventional Kullback-Leibler (KL) divergence. This motivates the design of a new class of robust generative auto-encoders (AE) referred to as Fisher auto-encod ... Cite

Deep Pinsker and James-Stein Neural Networks for Decoding Motor Intentions From Limited Data.

Journal Article IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society · January 2021 Non-parametric regression has been shown to be useful in extracting relevant features from Local Field Potential (LFP) signals for decoding motor intentions. Yet, in many instances, brain-computer interfaces (BCIs) rely on simple classification methods, ci ... Full text Cite

HETEROFL: COMPUTATION AND COMMUNICATION EFFICIENT FEDERATED LEARNING FOR HETEROGENEOUS CLIENTS

Conference ICLR 2021 - 9th International Conference on Learning Representations · January 1, 2021 Federated Learning (FL) is a method of training machine learning models on private data distributed over a large number of possibly heterogeneous clients such as mobile phones and IoT devices. In this work, we propose a new federated learning framework nam ... Cite

Investigation of Input Signal Representation to CNN for Improving SNR Classification Accuracy

Conference IEEE Vehicular Technology Conference · January 1, 2021 With the increase in demand for wireless data traffic, high-speed communication systems are required in many environment. Adaptive modulation and coding is an important technique to realize this, but it requires feedback of communication environment inform ... Full text Cite

Generative Archimedean Copulas

Conference 37th Conference on Uncertainty in Artificial Intelligence, UAI 2021 · January 1, 2021 We propose a new generative modeling technique for learning multidimensional cumulative distribution functions (CDFs) in the form of copulas. Specifically, we consider certain classes of copulas known as Archimedean and hierarchical Archimedean copulas, po ... Cite

Generative Archimedean Copulas

Conference Proceedings of Machine Learning Research · January 1, 2021 We propose a new generative modeling technique for learning multidimensional cumulative distribution functions (CDFs) in the form of copulas. Specifically, we consider certain classes of copulas known as Archimedean and hierarchical Archimedean copulas, po ... Cite

Fundamental Limits in Model Selection for Modern Data Analysis

Chapter · January 1, 2021 With rapid development in hardware storage, precision instrument manufacturing, and economic globalization etc., data in various forms have become ubiquitous in human life. This enormous amount of data can be a double-edged sword. While it provides the pos ... Full text Cite

Benchmarking Data-driven Surrogate Simulators for Artificial Electromagnetic Materials

Conference Advances in Neural Information Processing Systems · January 1, 2021 Artificial electromagnetic materials (AEMs), including metamaterials, derive their electromagnetic properties from geometry rather than chemistry. With the appropriate geometric design, AEMs have achieved exotic properties not realizable with conventional ... Cite

HeteroFL: Computation and Communication Efficient Federated Learning for Heterogeneous Clients

Journal Article · October 2, 2020 Federated Learning (FL) is a method of training machine learning models on private data distributed over a large number of possibly heterogeneous clients such as mobile phones and IoT devices. In this work, we propose a new federated learning framework nam ... Link to item Cite

Deep Cross-Subject Mapping of Neural Activity

Journal Article · July 13, 2020 Objective. In this paper, we consider the problem of cross-subject decoding, where neural activity data collected from the prefrontal cortex of a given subject (destination) is used to decode motor intentions from the neural activity of a different subject ... Link to item Cite

GeoStat Representations of Time Series for Fast Classification

Journal Article · July 13, 2020 Recent advances in time series classification have largely focused on methods that either employ deep learning or utilize other machine learning models for feature extraction. Though successful, their power often comes at the requirement of computational c ... Link to item Cite

Projected Latent Markov Chain Monte Carlo: Conditional Sampling of Normalizing Flows

Journal Article · July 12, 2020 We introduce Projected Latent Markov Chain Monte Carlo (PL-MCMC), a technique for sampling from the high-dimensional conditional distributions learned by a normalizing flow. We prove that a Metropolis-Hastings implementation of PL-MCMC asymptotically sampl ... Link to item Cite

Perception-Distortion Trade-Off with Restricted Boltzmann Machines

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 1, 2020 In this work, we introduce a new procedure for applying Restricted Boltzmann Machines (RBMs) to missing data inference tasks, based on linearization of the effective energy function governing the distribution of observations. We compare the performance of ... Full text Cite

Supervised Encoding for Discrete Representation Learning

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 1, 2020 Classical supervised classification tasks search for a nonlinear mapping that maps each encoded feature directly to a probability mass over the labels. Such a learning framework typically lacks the intuition that encoded features from the same class tend t ... Full text Cite

Speech emotion recognition with dual-sequence LSTM architecture

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 1, 2020 Speech Emotion Recognition (SER) has emerged as a critical component of the next generation of human-machine interfacing technologies. In this work, we propose a new duallevel model that predicts emotions based on both MFCC features and mel-spectrograms pr ... Full text Cite

Learning Partial Differential Equations from Data Using Neural Networks

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 1, 2020 We develop a framework for estimating unknown partial differential equations (PDEs) from noisy data, using a deep learning approach. Given noisy samples of a solution to an unknown PDE, our method interpolates the samples using a neural network, and extrac ... Full text Cite

Robust Marine Buoy Placement for Ship Detection Using Dropout K-Means

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 1, 2020 Marine buoys aid in the battle against Illegal, Unreported and Unregulated (IUU) fishing by detecting fishing vessels in their vicinity. Marine buoys, however, may be disrupted by natural causes and buoy vandalism. In this paper, we formulate marine buoy p ... Full text Cite

Deep James-Stein Neural Networks for Brain-Computer Interfaces

Conference ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 1, 2020 Nonparametric regression has proven to be successful in extracting features from limited data in neurological applications. However, due to data scarcity, most brain-computer interfaces still rely on linear classifiers. This work leverages the robustness o ... Full text Cite

DRASIC: Distributed recurrent autoencoder for scalable image compression

Journal Article Data Compression Conference Proceedings · March 1, 2020 We propose a new architecture for distributed image compression from a group of distributed data sources. The work is motivated by practical needs of data-driven codec design, low power consumption, robustness, and data privacy. The proposed architecture, ... Full text Cite

Deep clustering of compressed variational embeddings

Journal Article Data Compression Conference Proceedings · March 1, 2020 Motivated by the ever-increasing demands for limited communication bandwidth and low-power consumption, we propose a new methodology, named joint Variational Autoencoders with Bernoulli mixture models (VAB), for performing clustering in the compressed data ... Full text Cite

Multimodal Controller for Generative Models

Journal Article · February 6, 2020 Class-conditional generative models are crucial tools for data generation from user-specified class labels. Existing approaches for class-conditional generative models require nontrivial modifications of backbone generative architectures to model condition ... Link to item Cite

Cross-subject decoding of eye movement goals from local field potentials.

Journal Article Journal of neural engineering · February 2020 ObjectiveWe consider the cross-subject decoding problem from local field potential (LFP) signals, where training data collected from the prefrontal cortex (PFC) of a source subject is used to decode intended motor actions in a destination subject. ... Full text Cite

Proximal gradient algorithm with momentum and flexible parameter restart for nonconvex optimization

Journal Article IJCAI International Joint Conference on Artificial Intelligence · January 1, 2020 Various types of parameter restart schemes have been proposed for proximal gradient algorithm with momentum to facilitate their convergence in convex optimization. However, under parameter restart, the convergence of proximal gradient algorithm with moment ... Cite

Sparse Representation-Based Denoising for High-Resolution Brain Activation and Functional Connectivity Modeling: A Task fMRI Study.

Journal Article IEEE access : practical innovations, open solutions · January 2020 In the field of neuroimaging and cognitive neuroscience, functional Magnetic Resonance Imaging (fMRI) has been widely used to study the functional localization and connectivity of the brain. However, the inherently low signal-to-noise ratio (SNR) of the fM ... Full text Cite

Proximal Gradient Algorithm with Momentum and Flexible Parameter Restart for Nonconvex Optimization

Conference PROCEEDINGS OF THE TWENTY-NINTH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE · 2020 Cite

On the information of feature maps and pruning of deep neural networks

Conference Proceedings - International Conference on Pattern Recognition · January 1, 2020 A technique for compressing deep neural models achieving competitive performance to state-of-the-art methods is proposed. The approach utilizes the mutual information between the feature maps and the output of the model in order to prune the redundant laye ... Full text Cite

Prediction in Online Convex Optimization for Parametrizable Objective Functions

Journal Article Proceedings of the IEEE Conference on Decision and Control · December 1, 2019 Many techniques for online optimization problems involve making decisions based solely on presently available information: fewer works take advantage of potential predictions. In this paper, we discuss the problem of online convex optimization for parametr ... Full text Cite

Restricted Recurrent Neural Networks

Journal Article Proceedings - 2019 IEEE International Conference on Big Data, Big Data 2019 · December 1, 2019 Recurrent Neural Network (RNN) and its variations such as Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU), have become standard building blocks for learning online data of sequential nature in many research areas, including natural language pr ... Full text Cite

A Distributed Online Convex Optimization Algorithm with Improved Dynamic Regret

Journal Article Proceedings of the IEEE Conference on Decision and Control · December 1, 2019 In this paper, we consider the problem of distributed online convex optimization, where a network of local agents aim to jointly optimize a convex function over a period of multiple time steps. The agents do not have any information about the future. Exist ... Full text Cite

Recurrent Neural Network-Assisted Adaptive Sampling for Approximate Computing

Conference Proceedings - 2019 IEEE International Conference on Big Data, Big Data 2019 · December 1, 2019 We propose an adaptive signal sampling approach that dynamically adjusts the sampling rate to approximate the local Nyquist rate of the signal. The proposed adaptive sampling approach consists of a recurrent neural network-based change detector that detect ... Full text Cite

Distributed Online Convex Optimization with Improved Dynamic Regret

Journal Article · November 12, 2019 In this paper, we consider the problem of distributed online convex optimization, where a group of agents collaborate to track the global minimizers of a sum of time-varying objective functions in an online manner. Specifically, we propose a novel distribu ... Link to item Cite

Bayesian Model Comparison with the Hyvärinen Score: Computation and Consistency

Journal Article Journal of the American Statistical Association · October 2, 2019 The Bayes factor is a widely used criterion in model comparison and its logarithm is a difference of out-of-sample predictive scores under the logarithmic scoring rule. However, when some of the candidate models involve vague priors on their parameters, th ... Full text Cite

Multi-Level Mean-Shift Clustering for Single-Channel Radio Frequency Signal Separation

Conference IEEE International Workshop on Machine Learning for Signal Processing, MLSP · October 1, 2019 Emerging wireless communication applications have led to a crowded radio frequency (RF) spectrum. Therefore, it is desired to develop signal separation techniques that can extract different RF signals from their mixtures. Existing signal separation approac ... Full text Cite

Minimax-optimal decoding of movement goals from local field potentials using complex spectral features.

Journal Article Journal of neural engineering · August 2019 ObjectiveWe consider the problem of predicting eye movement goals from local field potentials (LFP) recorded through a multielectrode array in the macaque prefrontal cortex. The monkey is tasked with performing memory-guided saccades to one of eig ... Full text Cite

Peak sidelobe level gumbel distribution of antenna arrays with random phase centers

Journal Article IEEE Transactions on Antennas and Propagation · August 1, 2019 The maximum value of an antenna array's sidelobe beampattern, or radiation pattern in the power domain, is an important parameter determining its performance. In this paper, when array antenna elements have random phase centers, we approximate the maximum ... Full text Cite

Sequential Detection of Regime Changes in Neural Data

Journal Article International IEEE/EMBS Conference on Neural Engineering, NER · May 16, 2019 The problem of detecting changes in firing patterns in neural data is studied. The problem is formulated as a quickest change detection (QCD) problem. Important algorithms from the literature are reviewed. A new algorithmic technique is discussed to detect ... Full text Cite

Asymptotically Optimal Prediction for Time-Varying Data Generating Processes

Journal Article IEEE Transactions on Information Theory · May 1, 2019 We develop a methodology (referred to as kinetic prediction) for predicting time series undergoing unknown changes in their data generating distributions. Based on Kolmogorov-Tikhomirov's {\varepsilon } -entropy, we propose a concept called {\varepsilon } ... Full text Cite

Estimation of the evolutionary spectra with application to stationarity test

Journal Article IEEE Transactions on Signal Processing · March 1, 2019 In this paper, we propose a new inference procedure for understanding non-stationary processes, under the framework of evolutionary spectra developed by Priestley. Among various frameworks of modeling non-stationary processes, the distinguishing feature of ... Full text Cite

Momentum Schemes with Stochastic Variance Reduction for Nonconvex Composite Optimization

Journal Article · February 7, 2019 Two new stochastic variance-reduced algorithms named SARAH and SPIDER have been recently proposed, and SPIDER has been shown to achieve a near-optimal gradient oracle complexity for nonconvex optimization. However, the theoretical advantage of SPIDER does ... Link to item Cite

Spiderboost and momentum: Faster stochastic variance reduction algorithms

Journal Article Advances in Neural Information Processing Systems · January 1, 2019 SARAH and SPIDER are two recently developed stochastic variance-reduced algorithms, and SPIDER has been shown to achieve a near-optimal first-order oracle complexity in smooth nonconvex optimization. However, SPIDER uses an accuracy-dependent stepsize that ... Cite

SGD converges to global minimum in deep learning via star-convex path

Journal Article 7th International Conference on Learning Representations, ICLR 2019 · January 1, 2019 © 7th International Conference on Learning Representations, ICLR 2019. All Rights Reserved. Stochastic gradient descent (SGD) has been found to be surprisingly effective in training a variety of deep neural networks. However, there is still a lack of under ... Cite

Gradient information for representation and modeling

Conference Advances in Neural Information Processing Systems · January 1, 2019 Motivated by Fisher divergence, in this paper we present a new set of information quantities which we refer to as gradient information. These measures serve as surrogates for classical information measures such as those based on logarithmic loss, Kullback- ... Cite

Restricted Recurrent Neural Networks.

Conference IEEE BigData · 2019 Cite

SGD converges to global minimum in deep learning via star-convex path

Conference 7th International Conference on Learning Representations, ICLR 2019 · January 1, 2019 Stochastic gradient descent (SGD) has been found to be surprisingly effective in training a variety of deep neural networks. However, there is still a lack of understanding on how and why SGD can train these complex networks towards a global minimum. In th ... Cite

Model Selection Techniques: An Overview

Journal Article IEEE Signal Processing Magazine · November 1, 2018 In the era of big data, analysts usually explore various statistical models or machine-learning methods for observed data to facilitate scientific discoveries or gain predictive power. Whatever data and fitting procedures are employed, a crucial step is to ... Full text Cite

Wavelet Shrinkage and Thresholding Based Robust Classification for Brain-Computer Interface

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018 A macaque monkey is trained to perform two different kinds of tasks, memory aided and visually aided. In each task, the monkey saccades to eight possible target locations. A classifier is proposed for direction decoding and task decoding based on local fie ... Full text Cite

Evolutionary Spectra Based on the Multitaper Method with Application to Stationarity Test

Journal Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018 In this work, we propose a new inference procedure for understanding non-stationary processes, under the framework of evolutionary spectra developed by Priestley. Among various frameworks of modeling non-stationary processes, the distinguishing feature of ... Full text Cite

A Penalized Method for the Predictive Limit of Learning

Conference ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018 Machine learning systems learn from and make predictions by building models from observed data. Because large models tend to overfit while small models tend to underfit for a given fixed dataset, a critical challenge is to select an appropriate model (e.g. ... Full text Cite

Sequential Event Detection Using Multimodal Data in Nonstationary Environments

Journal Article 2018 21st International Conference on Information Fusion, FUSION 2018 · September 5, 2018 The problem of sequential detection of anomalies in multimodal data is considered. The objective is to observe physical sensor data from CCTV cameras, and social media data from Twitter and Instagram to detect anomalous behaviors or events. Data from each ... Full text Cite

Asymptotically Pseudo-Independent Matrices

Journal Article · September 2, 2018 We show that the family of pseudo-random matrices recently discovered by Soloveychik, Xiang, and Tarokh in their work `Symmetric Pseudo-Random Matrices' exhibits asymptotic independence. More specifically, any two sequences of matrices of matching sizes fr ... Link to item Cite

Online Learning for Multimodal Data Fusion with Application to Object Recognition

Journal Article IEEE Transactions on Circuits and Systems II: Express Briefs · September 1, 2018 We consider online multimodal data fusion, where the goal is to combine information from multiple modes to identify an element in a large dictionary. We address this problem in the context of object recognition by focusing on tactile sensing as one of the ... Full text Cite

Classification of Local Field Potentials using Gaussian Sequence Model

Journal Article 2018 IEEE Statistical Signal Processing Workshop, SSP 2018 · August 29, 2018 A problem of classification of local field potentials (LFPs), recorded from the prefrontal cortex of a macaque monkey, is considered. An adult macaque monkey is trained to perform a memory based saccade. The objective is to decode the eye movement goals fr ... Full text Cite

Communication Complexity of Dual Decomposition Methods for Distributed Resource Allocation Optimization

Journal Article IEEE Journal on Selected Topics in Signal Processing · August 1, 2018 Dual decomposition methods are among the most prominent approaches for finding primal/dual saddle point solutions of resource allocation optimization problems. To deploy these methods in the emerging Internet of things networks, which will often have limit ... Full text Cite

Cyclostationary statistical models and algorithms for anomaly detection using multi-modal data

Journal Article 2018 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2018 - Proceedings · July 2, 2018 A framework is proposed to detect anomalies in multi-modal data. A deep neural network-based object detector is employed to extract counts of objects and sub-events from the data. A cyclostationary model is proposed to model regular patterns of behavior in ... Full text Cite

Supervised Learning Using Data-dependent Random Features with Application to Seizure Detection

Conference Proceedings of the IEEE Conference on Decision and Control · July 2, 2018 The randomized-feature technique has been successfully applied to large-scale supervised learning. Despite being significantly more efficient compared to kernel methods in terms of computational cost, random features can be improved from generalization (pr ... Full text Cite

Stationary Geometric Graphical Model Selection

Journal Article · June 9, 2018 We consider the problem of model selection in Gaussian Markov fields in the sample deficient scenario. In many practically important cases, the underlying networks are embedded into Euclidean spaces. Using the natural geometric structure, we introduce the ... Link to item Cite

Bridging AIC and BIC: A New Criterion for Autoregression

Scholarly Edition · June 1, 2018 To address order selection for an autoregressive model fitted to time series data, we propose a new information criterion. It has the benefits of the two well-known model selection techniques: The Akaike information criterion and the Bayesian information c ... Full text Cite

Convergence of Limited Communication Gradient Methods

Journal Article IEEE Transactions on Automatic Control · May 1, 2018 Distributed optimization increasingly plays a central role in economical and sustainable operation of cyber-physical systems. Nevertheless, the complete potential of the technology has not yet been fully exploited in practice due to communication limitatio ... Full text Cite

Analysis of Multistate Autoregressive Models

Journal Article IEEE Transactions on Signal Processing · May 1, 2018 In this paper, we consider the inference problem for a wide class of time-series models, referred to as multistate autoregressive models. The time series that we consider are composed of multiple epochs, each modeled by an autoregressive process. The numbe ... Full text Cite

Pseudo-Wigner Matrices

Journal Article IEEE Transactions on Information Theory · April 1, 2018 We consider the problem of generating pseudo-random matrices based on the similarity of their spectra to Wigner's semicircular law. We introduce the notion of an r -independent pseudo-Wigner matrix ensemble and prove the closeness of the spectra of its mat ... Full text Cite

Symmetric Pseudo-Random Matrices

Journal Article IEEE Transactions on Information Theory · April 1, 2018 We consider the problem of generating symmetric pseudo-random sign (±1) matrices based on the similarity of their spectra to Wigner's semicircular law. Using binary m-sequences (Golomb sequences) of lengths n=2m-1 , we give a simple explicit construction o ... Full text Cite

Optimal prediction of data with unknown abrupt change points

Conference 2017 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2017 - Proceedings · March 7, 2018 We develop a novel methodology for predicting time series under unknown abrupt changes in data generating distributions. Based on Kolmogorov and Tikhomirov's e entropy, we propose a concept called e-predictability that quantifies the size of a model class ... Full text Cite

Detecting structural changes in dependent data

Conference 2017 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2017 - Proceedings · March 7, 2018 In the era of big data, a frequently encountered task is to model and identify structural changes in the data generating process. It is quite challenging especially when data are dependent and massive, requiring computationally efficient analysis. To addre ... Full text Cite

Modeling nonlinearity in multi-dimensional dependent data

Conference 2017 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2017 - Proceedings · March 7, 2018 Given massive data that may be time dependent and multi-dimensional, how to efficiently explore the underlying functional relationships across different dimensions and time lags? In this work, we propose a methodology to sequentially and adaptively model n ... Full text Cite

Region Detection in Markov Random Fields: Gaussian Case

Journal Article · February 11, 2018 We consider the problem of model selection in Gaussian Markov fields in the sample deficient scenario. The benchmark information-theoretic results in the case of d-regular graphs require the number of samples to be at least proportional to the logarithm of ... Link to item Cite

Large Deviations of Convex Polyominoes

Journal Article · February 11, 2018 Enumeration of various types of lattice polygons and in particular polyominoes is of primary importance in many machine learning, pattern recognition, and geometric analysis problems. In this work, we develop a large deviation principle for convex polyomin ... Link to item Cite

On data-dependent random features for improved generalization in supervised learning

Journal Article 32nd AAAI Conference on Artificial Intelligence, AAAI 2018 · January 1, 2018 The randomized-feature approach has been successfully employed in large-scale kernel approximation and supervised learning. The distribution from which the random features are drawn impacts the number of features required to efficiently perform a learning ... Cite

On variability of renewable energy and online power allocation

Journal Article IEEE Transactions on Power Systems · January 1, 2018 As electric power system operators shift from conventional energy to renewable energy sources, power distribution systems will experience increasing fluctuations in supply. These fluctuations present the need to not only design online decentralized power a ... Full text Cite

CLASSIFICATION OF LOCAL FIELD POTENTIALS USING GAUSSIAN SEQUENCE MODEL

Conference 2018 IEEE STATISTICAL SIGNAL PROCESSING WORKSHOP (SSP) · 2018 Cite

Learning bounds for greedy approximation with explicit feature maps from multiple kernels

Journal Article Advances in Neural Information Processing Systems · January 1, 2018 Nonlinear kernels can be approximated using finite-dimensional feature maps for efficient risk minimization. Due to the inherent trade-off between the dimension of the (mapped) feature space and the approximation accuracy, the key problem is to identify pr ... Cite

Model Selection Techniques - An Overview.

Journal Article CoRR · 2018 Cite

SLANTS: Sequential Adaptive Nonlinear Modeling of Time Series

Journal Article IEEE Transactions on Signal Processing · October 1, 2017 We propose a method for adaptive nonlinear sequential modeling of time series data. Data are modeled as a nonlinear function of past values corrupted by noise, and the underlying nonlinear function is assumed to be approximately expandable in a spline basi ... Full text Cite

Multiple Change Point Analysis: Fast Implementation and Strong Consistency

Journal Article IEEE Transactions on Signal Processing · September 1, 2017 One of the main challenges in identifying structural changes in stochastic processes is to carry out analysis for time series with dependency structure in a computationally tractable way. Another challenge is that the number of true change points is usuall ... Full text Cite

On Sequential Elimination Algorithms for Best-Arm Identification in Multi-Armed Bandits

Journal Article IEEE Transactions on Signal Processing · August 15, 2017 We consider the best-arm identification problem in multi-armed bandits, which focuses purely on exploration. A player is given a fixed budget to explore a finite set of arms, and the rewards of each arm are drawn independently from a fixed, unknown distrib ... Full text Cite

The number of independent sets in hexagonal graphs

Conference IEEE International Symposium on Information Theory - Proceedings · August 9, 2017 We derive the tightest known bounds on η = 2ν, where ν is the growth rate of the logarithm of the number of independent sets on a hexagonal lattice. To obtain these bounds, we generalize a method proposed by Calkin and Wilf. Their original strategy cannot ... Full text Cite

Pseudo-wigner matrices from dual BCH codes

Conference IEEE International Symposium on Information Theory - Proceedings · August 9, 2017 We consider the problem of generating symmetric pseudo-random sign (±1) matrices based on the similarity of their spectra to Wigner's semicircular law. We introduce r-independent pseudo-Wigner ensembles and prove closeness of their spectra to the semicircu ... Full text Cite

Explicit symmetric pseudo-random matrices

Conference IEEE International Symposium on Information Theory - Proceedings · July 2, 2017 We consider the problem of generating symmetric pseudo-random sign (±1) matrices based on the similarity of their spectra to Wigner's semicircular law. Using binary m-sequences (Golomb sequences) of lengths n = 2m - 1, we give a simple explicit constructio ... Full text Cite

Nonlinear sequential accepts and rejects for identification of top arms in stochastic bandits

Journal Article 55th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2017 · July 1, 2017 We address the M-best-Arm identification problem in multi-Armed bandits. A player has a limited budget to explore K arms (M < K), and once pulled, each arm yields a reward drawn (independently) from a fixed, unknown distribution. The goal is to find the to ... Full text Cite

On the spectral norms of pseudo-wigner and related matrices

Journal Article 55th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2017 · July 1, 2017 We investigate the spectral norms of symmetric N × N matrices from two pseudo-random ensembles. The first is the pseudo-Wigner ensemble introduced in 'Pseudo-Wigner Matrices' by Soloveychik, Xiang and Tarokh and the second is its sample covariance-Type ana ... Full text Cite

Fundamental Limits of TOA/DOA and Inertial Measurement Unit-Based Wireless Capsule Endoscopy Hybrid Localization

Journal Article International Journal of Wireless Information Networks · June 1, 2017 In this paper, performance analysis of hybrid localization based on radio-frequency (RF) and inertial measurement unit (IMU) measurements for a single wireless capsule endoscopy (WCE) traveling the gastrointestinal tract is studied. Specifically, the multi ... Full text Cite

Analysis of a privacy-preserving PCA algorithm using random matrix theory

Conference 2016 IEEE Global Conference on Signal and Information Processing, GlobalSIP 2016 - Proceedings · April 19, 2017 To generate useful summarization of data while maintaining privacy of sensitive information is a challenging task, especially in the big data era. The privacy-preserving principal component algorithm proposed in [1] is a promising approach when a low rank ... Full text Cite

Robustness analysis for an online decentralized descent power allocation algorithm

Conference 2016 Information Theory and Applications Workshop, ITA 2016 · March 27, 2017 As independent service providers shift from conventional energy to renewable energy sources, the power distribution system will likely experience increasingly significant fluctuation in supply, given the uncertain and intermittent nature of renewable sourc ... Full text Cite

Robust interferometric imaging via prior-less phase recovery: Redundant spacing calibration with generalized-closure phases

Journal Article Monthly Notices of the Royal Astronomical Society · January 11, 2017 Atmospheric turbulence presents a fundamental challenge to Fourier phase recovery in optical interferometry. Typical reconstruction algorithms employ Bayesian inference techniques which rely on prior knowledge of the scene under observation. In contrast, r ... Full text Cite

Dictionary learning and sparse coding-based denoising for high-resolution task functional connectivity MRI analysis

Conference Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2017 We propose a novel denoising framework for task functional Magnetic Resonance Imaging (tfMRI) data to delineate the high-resolution spatial pattern of the brain functional connectivity via dictionary learning and sparse coding (DLSC). In order to address t ... Full text Cite

On Optimal Generalizability in Parametric Learning

Journal Article ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS 30 (NIPS 2017) · January 1, 2017 Link to item Cite

On optimal generalizability in parametric learning

Journal Article Advances in Neural Information Processing Systems · January 1, 2017 We consider the parametric learning problem, where the objective of the learner is determined by a parametric loss function. Employing empirical risk minimization with possibly regularization, the inferred parameter vector will be biased toward the trainin ... Cite

Scaling laws and phase transitions for target detection in MIMO radar

Conference 2016 IEEE Information Theory Workshop, ITW 2016 · October 21, 2016 The performance of MIMO radar has been a subject of intense study in the past decades. For such a system, however, the important phenomenon of phase transition has received little attention in the literature. In this paper, we study the phase transition on ... Full text Cite

Resolving phase ambiguities in the calibration of redundant interferometric arrays: Implications for array design

Journal Article Monthly Notices of the Royal Astronomical Society · October 1, 2016 We provide new results enabling robust interferometric image reconstruction in the presence of unknown aperture piston variation via the technique of redundant spacing calibration (RSC). The RSC technique uses redundant measurements of the same interferome ... Full text Cite

Convergence of limited communications gradient methods

Conference Proceedings of the American Control Conference · July 28, 2016 Distributed control and decision making increasingly play a central role in economical and sustainable operation of cyber-physical systems. Nevertheless, the full potential of the technology has not yet been fully exploited in practice due to communication ... Full text Cite

Transmit beamforming in Rayleigh product MIMO channels: Ergodic mutual information and symbol error rate

Conference 2016 IEEE International Conference on Communications, ICC 2016 · July 12, 2016 In this paper, we consider MIMO beamforming in the presence of Rayleigh product channels. Based on a derived largest eigenvalue distribution, the key performance metrics of the beamforming system are obtained, assuming perfect channel knowledge at the tran ... Full text Cite

Base camp quality of life standardization and improvement

Conference Proceedings - International Carnahan Conference on Security Technology · July 2, 2016 The United States (US) Army has over 66,000 soldiers engaged in contingency operations across the world. Current budgetary constraints and an uncertain global security environment require these operations to be executed as efficiently as possible. Base cam ... Full text Cite

An adaptive localization technique for wireless capsule endoscopy

Conference International Symposium on Medical Information and Communication Technology, ISMICT · June 23, 2016 Wireless capsule endoscopy (WCE) is an emerging technique to enhance Gastroenterologists information about the patient's gastrointestinal (G.I.) tract. Localization of capsule inside human body in this case is an active area of research. This can be though ... Full text Cite

Complementary lattice arrays for coded aperture imaging.

Journal Article Journal of the Optical Society of America. A, Optics, image science, and vision · May 2016 In this work, we propose the concept of complementary lattice arrays in order to enable a broader range of designs for coded aperture imaging systems. We provide a general framework and methods that generate richer and more flexible designs compared to the ... Full text Cite

Distributed resource allocation using one-way communication with applications to power networks

Conference 2016 50th Annual Conference on Information Systems and Sciences, CISS 2016 · April 26, 2016 Typical coordination schemes for future power grids require two-way communications. Since the number of end power-consuming devices is large, the bandwidth requirements for such two-way communication schemes may be prohibitive. Motivated by this observatio ... Full text Cite

Data-driven learning of the number of states in multi-state autoregressive models

Conference 2015 53rd Annual Allerton Conference on Communication, Control, and Computing, Allerton 2015 · April 4, 2016 In this work, we consider the class of multi-state autoregressive processes that can be used to model non-stationary time series of interest. In order to capture different autoregressive (AR) states underlying an observed time series, it is crucial to sele ... Full text Cite

Key Pre-Distributions From Graph-Based Block Designs

Journal Article IEEE Sensors Journal · March 15, 2016 With the development of wireless communication technologies which considerably contributed to the development of wireless sensor networks (WSNs), we have witnessed ever-increasing WSN-based applications which induced a host of research activities in both a ... Full text Cite

Order Selection of Autoregressive Processes Using Bridge Criterion

Conference Proceedings - 15th IEEE International Conference on Data Mining Workshop, ICDMW 2015 · January 29, 2016 A new criterion is introduced for determining the order of an autoregressive model fit to time series data. The proposed technique is shown to give a consistent and asymptotically efficient order estimation. It has the benefits of the two well-known model ... Full text Cite

Learning the Number of Autoregressive Mixtures in Time Series Using the Gap Statistics

Conference Proceedings - 15th IEEE International Conference on Data Mining Workshop, ICDMW 2015 · January 29, 2016 Using a proper model to characterize a time series is crucial in making accurate predictions. In this work we use time-varying autoregressive process (TVAR) to describe non-stationary time series and model it as a mixture of multiple stable autoregressive ... Full text Cite

Improving Target Localization and Tracking by Dynamically Prioritized Frequency Band Allocation for Wireless Sensor Networks in Urban Environments

Chapter · January 1, 2016 In a multi-modal wireless sensor network, sensors of different modalities (or types) cluster together to accomplish the tasks of sensing, fusion, and management of cluster resources and to meet the application goals. A distributed sensor network consists o ... Full text Cite

A novel cyber physical system for 3-D imaging of the small intestine in vivo

Journal Article IEEE Access · December 11, 2015 Small intestine is the longest organ in the gastrointestinal tract where much of the digestion and the food absorption take place. Wireless video capsule endoscope (VCE) is the first device taking 2-D pictures from the lesions and the abnormalities in the ... Full text Cite

In vivo and in situ measurement and modelling of intra-body effective complex permittivity.

Journal Article Healthcare technology letters · December 2015 Radio frequency tracking of medical micro-robots in minimally invasive medicine is usually investigated upon the assumption that the human body is a homogeneous propagation medium. In this Letter, the authors conducted various trial programs to measure and ... Full text Cite

Sequential learning of Multi-state autoregressive time series

Conference Proceeding of the 2015 Research in Adaptive and Convergent Systems, RACS 2015 · October 9, 2015 Modeling and forecasting streaming data has fundamental importance in many real world applications. In this paper, we present an online model selection technique that can be used to model non-stationary time series in a sequential manner. Multi-state autor ... Full text Cite

Comment on "Asymptotic Achievability of the Cramér-Rao Bound for Noisy Compressive Sampling"

Journal Article · September 14, 2015 In [1], we proved the asymptotic achievability of the Cram\'{e}r-Rao bound in the compressive sensing setting in the linear sparsity regime. In the proof, we used an erroneous closed-form expression of $\alpha \sigma^2$ for the genie-aided Cram\'{e}r-Rao b ... Link to item Cite

Sparse Signal Recovery from a Mixture of Linear and Magnitude-Only Measurements.

Journal Article IEEE signal processing letters · September 2015 We consider the problem of exact sparse signal recovery from a combination of linear and magnitude-only (phaseless) measurements. A k-sparse signal x ∈ ℂ n is measured as r = Bx and y = |Cx|, wher ... Full text Cite

Peak sidelobe level gumbel distribution for arrays of randomly placed antennas

Conference IEEE National Radar Conference - Proceedings · June 22, 2015 Extreme Value Theory (EVT) is used to analyze the peak sidelobe level distribution for array element positions with arbitrary probability distributions. Computations are discussed in the context of linear antenna arrays using electromagnetic energy. The re ... Full text Cite

Capacity of Hexagonal Checkerboard Codes

Journal Article · June 6, 2015 In this paper, we propose a new method to bound the capacity of checkerboard codes on the hexagonal lattice. This produces rigorous bounds that are tighter than those commonly known. ... Link to item Cite

Bayesian-based localization of wireless capsule endoscope using received signal strength.

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference · January 2014 In wireless body area sensor networking (WBASN) applications such as gastrointestinal (GI) tract monitoring using wireless video capsule endoscopy (WCE), the performance of out-of-body wireless link propagating through different body media (i.e. blood, fat ... Full text Cite

An augmented Lagrangian based compressed sensing reconstruction for non-Cartesian magnetic resonance imaging without gridding and regridding at every iteration.

Journal Article PloS one · January 2014 BackgroundNon-Cartesian trajectories are used in a variety of fast imaging applications, due to the incoherent image domain artifacts they create when undersampled. While the gridding technique is commonly utilized for reconstruction, the incohere ... Full text Cite

Compressed sensing reconstruction for undersampled breath-hold radial cine imaging with auxiliary free-breathing data.

Journal Article Journal of magnetic resonance imaging : JMRI · January 2014 PurposeTo improve compressed sensing (CS) reconstruction of accelerated breath-hold (BH) radial cine magnetic resonance imaging (MRI) by exploiting auxiliary data acquired between different BHs.Materials and methodsCardiac function is usu ... Full text Cite

Compressed sensing techniques for image reconstruction in optical interferometry

Conference Optics InfoBase Conference Papers · January 1, 2014 We develop a novel method of image reconstruction from bispectrum and magnitude observables of an optical interferometer using Compressed-Sensing techniques.We validate our method in simulation and with actual measurements from a Fizeau interferometer. © 2 ... Cite

The design of environmentally friendly networks using coordinated multi-point (CoMP) transmission

Conference 2014 IEEE 11th Consumer Communications and Networking Conference, CCNC 2014 · January 1, 2014 Full text Cite

An environmentally friendly approach to the relay-aided cellular network architecture

Conference 2014 IEEE 11th Consumer Communications and Networking Conference, CCNC 2014 · January 1, 2014 We solve the problem of environmentally friendly (i.e., energy-efficient) base station and relay-station planning for a simplified cooperative cellular network. We assume a two-hop transmission model based on the time-division multiplexing operation. We pr ... Full text Cite

Compressed sensing techniques for image reconstruction in optical interferometry

Conference Optics InfoBase Conference Papers · January 1, 2014 We develop a novel method of image reconstruction from bispectrum and magnitude observables of an optical interferometer using Compressed-Sensing techniques.We validate our method in simulation and with actual measurements from a Fizeau interferometer. © 2 ... Full text Cite

Distortion-based achievability conditions for joint estimation of sparse signals and measurement parameters from undersampled acquisitions

Conference IEEE International Symposium on Information Theory - Proceedings · December 19, 2013 In this paper, we consider an undersampling system model of the form y = A(T(x, θ)) + n, where x is a k-sparse signal, T(·, · is a (possibly non-linear) function specified by a parameter vector θ and acting on x, A is a sensing matrix, and n is additive me ... Full text Cite

Analysis of the impact of nonlinearity on the capacity of communication channels

Journal Article IEEE Transactions on Information Theory · November 4, 2013 We study the impact of nonlinearities on the transmission rate of a communication system by establishing lower and upper bounds on the channel capacity. Our analysis is based on a general transmission model that includes transmitter and receiver nonlineari ... Full text Cite

New Conditions for Sparse Phase Retrieval

Journal Article · October 4, 2013 We consider the problem of sparse phase retrieval, where a $k$-sparse signal ${\bf x} \in {\mathbb R}^n \textrm{ (or } {\mathbb C}^n\textrm{)}$ is measured as ${\bf y} = |{\bf Ax}|,$ where ${\bf A} \in {\mathbb R}^{m \times n} \textrm{ (or } {\mathbb C}^{m ... Link to item Cite

Accelerated aortic flow assessment with compressed sensing with and without use of the sparsity of the complex difference image.

Journal Article Magnetic resonance in medicine · September 2013 Phase contrast (PC) cardiac MR is widely used for the clinical assessment of blood flow in cardiovascular disease. One of the challenges of PC cardiac MR is the long scan time which limits both spatial and temporal resolution. Compressed sensing reconstruc ... Full text Cite

On the effects of frequency scaling over capacity scaling in underwater networks - Part I: Extended network model

Journal Article Wireless Personal Communications · August 1, 2013 In this two-part paper, information-theoretic capacity scaling laws are analyzed in an underwater acoustic network with n regularly located nodes on a square, in which both bandwidth and received signal power can be limited significantly. Parts I and II de ... Full text Cite

On the effects of frequency scaling over capacity scaling in underwater networks - Part II: Dense network model

Journal Article Wireless Personal Communications · August 1, 2013 This is the second in a two-part series of papers on information-theoretic capacity scaling laws for an underwater acoustic network. Part II focuses on a dense network scenario, where nodes are deployed in a unit area. By deriving a cut-set upper bound on ... Full text Cite

Energy-efficient base-station topologies for green cellular networks

Conference 2013 IEEE 10th Consumer Communications and Networking Conference, CCNC 2013 · April 15, 2013 We consider the problem of energy-efficient base-station (BS) planning for green cellular network design. There exist a number of criteria for greenness in the literature, but we focus only on the energy-normalized throughput. We first model energy consump ... Full text Cite

A peak power efficient cooperative diversity using star-QAM with coherent/noncoherent detection

Journal Article IEEE Transactions on Wireless Communications · April 1, 2013 In this paper, we propose a new simple relaying strategy based on bit-interleaved convolutionally coded star-quadrature amplitude modulation (QAM) along with coherent/noncoherent detection. Star-QAM is composed of multiple concentric circles of phase-shift ... Full text Cite

On frequency offset estimation for OFDM

Journal Article IEEE Transactions on Wireless Communications · February 8, 2013 This paper presents a comparative study of Schmidl-Cox (SC) and Morelli-Mengali (MM) algorithms for frequency offset estimation in OFDM, along with a new least squares (LS) and a new modified SC algorithm. All algorithms have comparable accuracy approachin ... Full text Cite

Spectral distribution of product of pseudorandom matrices formed from binary block codes

Journal Article IEEE Transactions on Information Theory · January 24, 2013 Let {\bf A} \in \{-1,1\}^{N-{a} \times n} and {\bf B} \in \{-1,1\}^{N-{b} \times n} be two matrices whose rows are drawn i.i.d. from the codewords of the binary codes {\cal C}a and {\cal C}b of length n and dual distances {d^{\prime}}a and {d^{\prime}}b, r ... Full text Cite

A highly scalable key pre-distribution scheme for wireless sensor networks

Journal Article IEEE Transactions on Wireless Communications · January 18, 2013 Given the sensitivity of the potential WSN applications and because of resource limitations, key management emerges as a challenging issue for WSNs. One of the main concerns when designing a key management scheme is the network scalability. Indeed, the pro ... Full text Cite

Analysis of network coded HARQ for multiple unicast flows

Journal Article IEEE Transactions on Communications · January 14, 2013 In this paper, we consider network coded (NCed) Hybrid-ARQ (HARQ) for multiple unicast flows. The main contribution of the paper is the derivation of throughput expressions for NCed HARQ with arbitrary number of users in identical i.i.d. channels amid pack ... Full text Cite

Near field resonator isolation system: Theory to implementation

Journal Article IEEE Transactions on Circuits and Systems I: Regular Papers · January 1, 2013 The absence of electromagnetic wave motivates various studies of new communication channels in near field regime. An approach studied here is based on resonant inductive coupling and the use of Resonator Isolation (RI) system. The main concept of the RI sy ... Full text Cite

Capacity analysis for Gaussian channels with memoryless nonlinear hardware

Conference IEEE International Conference on Communications · January 1, 2013 This paper presents the analysis of the impact of circuit nonlinearities on the transmission rate of a communication system. We consider a general transmission model that includes transmitter- and receiver-side nonlinearities, environmental thermal noise a ... Full text Cite

Compressed sensing reconstruction for whole-heart imaging with 3D radial trajectories: a graphics processing unit implementation.

Journal Article Magnetic resonance in medicine · January 2013 A disadvantage of three-dimensional (3D) isotropic acquisition in whole-heart coronary MRI is the prolonged data acquisition time. Isotropic 3D radial trajectories allow undersampling of k-space data in all three spatial dimensions, enabling accelerated ac ... Full text Cite

Rate assignment in wireless networks: Stability analysis and controller design

Journal Article IEEE Transactions on Control Systems Technology · January 1, 2013 In this brief, data-rate assignment in IS-856 uplink (reverse link) is studied. The problem is first formulated using an interference model, and then a dynamic control strategy is developed for efficient rate assignment. In the first step, the controller i ... Full text Cite

Semidefinite programming-based localization algorithm in networks with inhomogeneous media

Conference Proceeding of the 2012 ACM Research in Applied Computation Symposium, RACS 2012 · December 1, 2012 In this paper, we study the asymptotic properties of a semidefinite programming (SDP) based localization algorithm in a network with inhomogeneous RF transmission medium given incomplete and inaccurate pairwise distance measurements between sensorssensors ... Full text Cite

Energy harvesting cooperative communications

Conference IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC · December 1, 2012 In this paper, we propose a new cooperative wireless transmission in a scenario where the source salvages the energy during the relay's transmission considering the fact that the source does not need to retrieve the transmitted message. We also evaluate a ... Full text Cite

Bayesian source localization in networks with heterogeneous transmission medium

Journal Article Navigation, Journal of the Institute of Navigation · September 1, 2012 Precise positioning and tracking information in networks with a heterogeneous transmission medium presents a novel networking paradigm. Most of the localization algorithms are vulnerable to the variations of signal propagation speed, dielectric constant, a ... Full text Cite

Interference aware-coordinated beamforming in a multi-cell system

Journal Article IEEE Transactions on Wireless Communications · August 27, 2012 In this paper, we propose jointly optimized linear transceiver algorithms called interference aware-coordinated beamforming (IA-CBF) for a two-cell system where each base station is equipped with multiple transmit antennas. To generalize IA-CBF to more tha ... Full text Cite

A practical transmit beamforming strategy for closed-loop MIMO communication

Journal Article International Journal of Communication Systems · August 1, 2012 A new beamforming strategy is proposed for multiuser systems with N transmit antennas at the transmitter and M ≤ N single antenna receivers. The proposed scheme remarkably improves on the classical spatial division multiple access, and achieves the same da ... Full text Cite

Bounds on the capacity of discrete memoryless channels corrupted by synchronization and substitution errors

Journal Article IEEE Transactions on Information Theory · June 25, 2012 We study the capacity of discrete memoryless channels with synchronization errors and additive noise. We first show that with very large alphabets, their capacity can be achieved by independent and identically distributed input sources, and establish prove ... Full text Cite

Vertical spectrum sharing via distributed asynchronous interference avoidance in cognitive radio networks

Conference 2012 IEEE Consumer Communications and Networking Conference, CCNC'2012 · May 11, 2012 In this paper, we study the problem of distributed spectrum allocation under a vertical spectrum sharing scenario in a cognitive radio network. The secondary users share the spectrum licensed to the primary user by observing the activity statistics of the ... Full text Cite

DiBa: a data-driven Bayesian algorithm for sleep spindle detection.

Journal Article IEEE transactions on bio-medical engineering · February 2012 Although the spontaneous brain rhythms of sleep have commanded much recent interest, their detection and analysis remains suboptimal. In this paper, we develop a data-driven Bayesian algorithm for sleep spindle detection on the electroencephalography (EEG) ... Full text Cite

Accelerated phase contrast imaging using compressed sensing with complex difference sparsity

Journal Article Journal of Cardiovascular Magnetic Resonance · February 1, 2012 Full text Cite

Distributed dynamic spectrum allocation for secondary users in a vertical spectrum sharing scenario

Journal Article IEICE Transactions on Communications · January 1, 2012 In this paper, we study the problem of distributed spectrum allocation under a vertical spectrum sharing scenario in a cognitive radio network. The secondary users share the spectrum licensed to the primary user by observing the activity statistics of the ... Full text Cite

Guest editorial: Special issue on high mobility wireless communications

Journal Article Journal of Modern Transportation · January 1, 2012 Full text Cite

Spectral distribution of the product of two random matrices based on binary block codes

Conference 2011 49th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2011 · December 1, 2011 In this paper, we study the spectral distribution of the product of two random matrices based on binary block codes, and prove that if the dual distances of the underlying codes are large enough, the asymptotic spectral distribution will be close to a dete ... Full text Cite

New codes from dual BCH codes with applications in Low PAPR OFDM

Journal Article IEEE Transactions on Wireless Communications · December 1, 2011 Dual Bose-Ray-Chaudhuri (BCH) codes, despite their favorable peak to average power ratio (PAPR) properties, have not been used in coded orthogonal frequency division multiplexing (OFDM) systems. This is due to unavailability of a practical decoder and larg ... Full text Cite

Jointly optimized two-cell MIMO systems

Conference 2011 IEEE GLOBECOM Workshops, GC Wkshps 2011 · December 1, 2011 Jointly optimized interference aware coordinated beamforming (IA-CBF) algorithms for a two-cell system are investigated, where each base/mobile station is equipped with multiple transmit antennas. We first derive a minimum-mean-square-error IA-CBF algorith ... Full text Cite

Regularized recursive least squares for anomaly detection in sparse channel tracking applications

Conference Proceedings of the 2011 ACM Research in Applied Computation Symposium, RACS 2011 · December 1, 2011 In this paper, we study the problem of anomaly detection in sparse channel tracking applications via the l 1-regularized least squares adaptive filter (SPARLS). Anomalies arise due to unexpected adversarial changes in the channel and quick detection of the ... Full text Cite

Sidelobe level distribution computation for antenna arrays with arbitrary element distributions

Conference Conference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2011 This paper discusses the conditions in which the sidelobe level distribution can be calculated in closed form for arrays with randomly located antenna elements with arbitrary element probability distributions. By using the number of times a beampattern cro ... Full text Cite

Robust scalable physical layer network coding

Conference 2011 49th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2011 · December 1, 2011 We present a new method of physical layer network coding that transforms the received signal at a relay node before re-transmission by eliminating the unreliable components of the signal. This approach improves the physical layer network coding performance ... Full text Cite

Localization of mobile nodes based on inaccurate round-trip-time measurements using Bayesian inference

Conference Proceedings of the 2011 ACM Research in Applied Computation Symposium, RACS 2011 · December 1, 2011 In this paper, we present a Bayesian-based localization method to estimate the unknown location of a mobile station (MS) in a network given the known location of a set of base stations. In this study, the MS was covered by a base station if the signal to i ... Full text Cite

Compressed-sensing motion compensation (CosMo): a joint prospective-retrospective respiratory navigator for coronary MRI.

Journal Article Magnetic resonance in medicine · December 2011 Prospective right hemidiaphragm navigator (NAV) is commonly used in free-breathing coronary MRI. The NAV results in an increase in acquisition time to allow for resampling of the motion-corrupted k-space data. In this study, we are presenting a joint prosp ... Full text Cite

Information-theoretic limits of dense underwater networks

Conference Conference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2011 Information-theoretic throughput scaling laws are analyzed in an underwater acoustic network with n regularly located nodes on a unit square, in which both bandwidth and received signal power can be severely limited. A narrow-band model is assumed where th ... Full text Cite

Analog Transmission

Chapter · November 7, 2011 Full text Cite

A coding theory approach to noisy compressive sensing using low density frames

Journal Article IEEE Transactions on Signal Processing · November 1, 2011 We consider the compressive sensing of a sparse or compressible signal x ∈ R M. We explicitly construct a class of measurement matrices inspired by coding theory, referred to as low density frames, and develop decoding algorithms that produce an accurate e ... Full text Cite

Beam selection gain versus antenna selection gain

Journal Article IEEE Transactions on Information Theory · October 1, 2011 We consider beam selection using a fixed beamforming network (FBN) at a base station with M array antennas. In our setting, a Butler matrix is deployed at the RF stage to form M beams, and then the best beam is selected for transmission. We introduce some ... Full text Cite

Achievable rate regions and performance comparison of half duplex bi-directional relaying protocols

Journal Article IEEE Transactions on Information Theory · October 1, 2011 In a bi-directional relay channel, two nodes wish to exchange independent messages over a shared wireless half-duplex channel with the help of a relay. In this paper, we derive achievable rate regions for four new half-duplex protocols and compare these to ... Full text Cite

Blind identification of sparse channels and symbol detection via the em algorithm

Conference 17th DSP 2011 International Conference on Digital Signal Processing, Proceedings · September 29, 2011 In this paper, we address the problem of blind identification of sparse channels. For this purpose, the Expectation-Maximization is modified to accommodate channel sparsity. The resulting algorithm is applicable for linear and nonlinear channels. Computer ... Full text Cite

Low-dimensional-structure self-learning and thresholding: regularization beyond compressed sensing for MRI reconstruction.

Journal Article Magnetic resonance in medicine · September 2011 An improved image reconstruction method from undersampled k-space data, low-dimensional-structure self-learning and thresholding (LOST), which utilizes the structure from the underlying image is presented. A low-resolution image from the fully sampled k-sp ... Full text Cite

Adaptive algorithms for sparse system identification

Journal Article Signal Processing · August 1, 2011 In this paper, identification of sparse linear and nonlinear systems is considered via compressive sensing methods. Efficient algorithms are developed based on Kalman filtering and Expectation-Maximization. The proposed algorithms are applied to linear and ... Full text Cite

Near shannon limit and low peak to average power ratio turbo block coded OFDM

Journal Article IEEE Transactions on Communications · August 1, 2011 In this paper, we present an advanced solution for the long standing problem of large peak to average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. Although the design of low PAPR codewords has been extensively studied an ... Full text Cite

Cognitive networks achieve throughput scaling of a homogeneous network

Journal Article IEEE Transactions on Information Theory · August 1, 2011 Two distinct, but overlapping, networks that operate at the same time, space, and frequency is considered. The first network consists of n randomly distributed primary users, which form an ad hoc network. The second network again consists of m randomly dis ... Full text Cite

Improved capacity scaling in wireless networks with infrastructure

Journal Article IEEE Transactions on Information Theory · August 1, 2011 This paper analyzes the impact and benefits of infrastructure support in improving the throughput scaling in networks of n randomly located wireless nodes. The infrastructure uses multiantenna base stations (BSs), in which the number of BSs and the number ... Full text Cite

Group randomness properties of pseudo-noise and gold sequences

Conference 12th Canadian Workshop on Information Theory, CWIT 2011 · July 7, 2011 In this paper, we study the group randomness of pseudo-random sequences based on shortened first-order Reed-Muller codes and the Gold sequences. In particular, we characterize the empirical spectral distribution of random matrices from shortened first-orde ... Full text Cite

Optimum cognitive radio transmission scheme for reducing average interference power

Conference 12th Canadian Workshop on Information Theory, CWIT 2011 · July 7, 2011 Reducing interference induced by secondary users is one of the most challenging problems in spectrum sharing. In this paper, we derive the optimum transmission strategy that minimizes the average interference power created by cognitive radios at a given po ... Full text Cite

Service coverage for cognitive radio networks with cooperative relays in shadowed hotspot areas

Conference 2011 IEEE Wireless Communications and Networking Conference, WCNC 2011 · June 23, 2011 In this paper, we investigate the service coverage for interweaving cognitive radio networks with cooperative relays in shadowed areas within the metropolitan region. We highlight the influence of relays on the primary and secondary systems in severe shado ... Full text Cite

Low peak to average power ratio Turbo Block QPSK coded OFDM

Conference 2011 IEEE Consumer Communications and Networking Conference, CCNC'2011 · June 7, 2011 In this work, we propose a QPSK OFDM code that has both low peak to average power ratio and good bit error rate performance. We consider a Time-frequency Turbo Block code. This code is composed of the cosets of the first-order binary Reed-Muller (RM) code ... Full text Cite

Spectral distribution of random matrices from binary linear block codes

Journal Article IEEE Transactions on Information Theory · June 1, 2011 Let C be a binary linear block code of length n, dimension k and minimum Hamming distance d over GF(2)n. Let d⊥ denote the minimum Hamming distance of the dual code of C over GF(2)n. Let εGF(2)n {-1,1}n be the component-wise mapping ε(vi):=(-1)vi, for v=(v ... Full text Cite

Network error correction from matrix network coding

Conference 2011 Information Theory and Applications Workshop, ITA 2011 - Conference Proceedings · May 13, 2011 We present matrix network coding methods that are naturally amenable to a distributed implementation method, i.e., do not require the knowledge of network topology, and that are suitable for network error correction. First, the Singleton bound can be K-fol ... Full text Cite

On effects of antenna pointing accuracy for on-the-move satellite networks

Journal Article IEEE Transactions on Vehicular Technology · May 1, 2011 In this paper, we study the adjacent geostationary satellite interference to/from on-the-move platforms with motion-induced antenna pointing errors. First, using satellite geometry, we derive tight upper and lower bounds for the average uplink and downlink ... Full text Cite

Compressed sensing with wavelet domain dependencies for coronary MRI: a retrospective study.

Journal Article IEEE transactions on medical imaging · May 2011 Coronary magnetic resonance imaging (MRI) is a noninvasive imaging modality for diagnosis of coronary artery disease. One of the limitations of coronary MRI is its long acquisition time due to the need of imaging with high spatial resolution and constraint ... Full text Cite

Accelerated noncontrast-enhanced pulmonary vein MRA with distributed compressed sensing.

Journal Article Journal of magnetic resonance imaging : JMRI · May 2011 PurposeTo investigate the efficacy of distributed compressed sensing (CS) to accelerate free-breathing, electrocardiogram (ECG)-triggered noncontrast pulmonary vein (PV) magnetic resonance angiography (MRA).Materials and methodsFully samp ... Full text Cite

On the Order Optimality of Large-scale Underwater Networks

Journal Article · March 1, 2011 Capacity scaling laws are analyzed in an underwater acoustic network with $n$ regularly located nodes on a square, in which both bandwidth and received signal power can be limited significantly. A narrow-band model is assumed where the carrier frequency is ... Link to item Cite

Capacity- and Bayesian-based cognitive sensing with location side information

Journal Article IEEE Journal on Selected Areas in Communications · February 1, 2011 We investigate spectrum sensing by energy detection based on two different objective functions: a Bayesian sensing cost or the network weighted sum capacity. The Bayesian cost is a traditional detection measure which aims at minimizing a combination of the ... Full text Cite

Analysis of interference in air-to-ground CDMA cellular systems under idealized assumptions

Journal Article IEEE Transactions on Communications · January 1, 2011 In this paper, we study the air-to-ground cellular systems with no frequency reuse. We provide an analysis of the inter-cell interference under idealized assumptions: 3D hexagonal cell planning, a line of sight channel model with no shadowing and idealized ... Full text Cite

GADIA: A greedy asynchronous distributed interference avoidance algorithm

Journal Article IEEE Transactions on Information Theory · December 1, 2010 In this paper, the problem of distributed dynamic frequency allocation is considered for a canonical communication network, which spans several networks such as cognitive radio networks and digital subscriber lines (DSLs). A greedy asynchronous distributed ... Full text Cite

On the performance estimate for Turbo codes

Conference 2010 International Conference on Wireless Communications and Signal Processing, WCSP 2010 · December 1, 2010 Recently, the scaling law has been extended to approximate the waterfall performance for Turbo codes over the binary erasure channel. However, the waterfall approximation over other channels, such as the AWGN and Rayleigh fading channels, is still unknown ... Full text Cite

Multi-hop routing is order-optimal in underwater extended networks

Conference IEEE International Symposium on Information Theory - Proceedings · August 23, 2010 Capacity scaling laws are analyzed in an underwater acoustic network with n regularly located nodes. A narrowband model is assumed where the carrier frequency is allowed to scale as a function of n. In the network, we characterize an attenuation parameter ... Full text Cite

Analysis of network coded HARQ for multiple unicast flows

Conference IEEE International Conference on Communications · August 13, 2010 In this paper, we consider network coded (NCed) Hybrid-ARQ (HARQ) for multiple unicast flows. The main contribution of the paper is the derivation of throughput expression for NCed HARQ with arbitrary number of users in i.i.d. channels. We apply the result ... Full text Cite

SPARLS: The Sparse RLS Algorithm

Journal Article IEEE TRANSACTIONS ON SIGNAL PROCESSING · August 1, 2010 Full text Link to item Cite

SPARLS: The sparse RLS algorithm

Journal Article IEEE Transactions on Signal Processing · August 1, 2010 We develop a recursive L1-regularized least squares (SPARLS) algorithm for the estimation of a sparse tap-weight vector in the adaptive filtering setting. The SPARLS algorithm exploits noisy observations of the tap-weight vector output stream and produces ... Full text Cite

Random frames from binary linear block codes

Conference 2010 44th Annual Conference on Information Sciences and Systems, CISS 2010 · June 24, 2010 Let C be an [n, k, d] binary linear block code of length n, dimension k and minimum Hamming distance d over GF(2n). Let d⊥ denote the minimum Hamming distance of the dual code of Cover GF(2n). Let ε : GF(2n) → {-1, 1}n be the component-wise mapping ε(vi) : ... Full text Cite

An adaptive greedy algorithm with application to nonlinear communications

Journal Article IEEE Transactions on Signal Processing · June 1, 2010 Greedy algorithms form an essential tool for compressed sensing. However, their inherent batch mode discourages their use in time-varying environments due to significant complexity and storage requirements. In this paper two existing powerful greedy scheme ... Full text Cite

On Capacity Scaling of Underwater Networks: An Information-Theoretic Perspective

Journal Article · May 5, 2010 Capacity scaling laws are analyzed in an underwater acoustic network with $n$ regularly located nodes on a square. A narrow-band model is assumed where the carrier frequency is allowed to scale as a function of $n$. In the network, we characterize an atten ... Link to item Cite

A survey of error-correcting codes for channels with symbol synchronization errors

Journal Article IEEE Communications Surveys and Tutorials · March 1, 2010 We present a comprehensive survey of errorcorrecting codes for channels corrupted by synchronization errors. We discuss potential applications as well as the obstacles that need to be overcome before such codes can be used in practical systems. © 2010 IEEE ... Full text Cite

On the equivalence of interleavers for turbo codes using quadratic permutation polynomials over integer rings

Journal Article IEEE Communications Letters · March 1, 2010 It is known that the equivalence of interleavers for turbo codes using quadratic permutation polynomials (QPPs) over integer rings can be exactly determined by the so-called quadratic null polynomials (QNPs) over integer rings. For generating QNPs or highe ... Full text Cite

Shannon-theoretic limits on noisy compressive sampling

Journal Article IEEE Transactions on Information Theory · January 1, 2010 In this paper, we study the number of measurements required to recover a sparse signal in ℤM with L nonzero coefficients from compressed samples in the presence of noise. We consider a number of different recovery criteria, including the exact recovery of ... Full text Cite

An exponential model for evaluating error performance of turbo codes

Conference GLOBECOM - IEEE Global Telecommunications Conference · January 1, 2010 In this paper, an exponential model is proposed to approximate the error performance of Turbo codes within low and intermediate SNR region. Our analysis unveils that, the proposed exponential model offers a simple but effective method to approximate the wa ... Full text Cite

Low density frames for compressive sensing

Conference ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2010 We consider the compressive sensing of a sparse or compressible signal x ∈ ℝM. We explicitly construct a class of measurement matrices, referred to as the low density frames, and develop decoding algorithms that produce an accurate estimate x̂ even in the p ... Full text Cite

Adaptive algorithms for sparse nonlinear channel estimation

Conference IEEE Workshop on Statistical Signal Processing Proceedings · December 25, 2009 In this paper, we consider the estimation of sparse nonlinear communication channels. Transmission over the channels is represented by sparse Volterra models that incorporate the effect of Power Amplifiers. Channel estimation is performed by compressive se ... Full text Cite

TAS protocols of a PASD system with limited feedback information

Conference GLOBECOM - IEEE Global Telecommunications Conference · December 1, 2009 In a Protocol Assisted Switched Diversity (PASD) system, the time separated repetition blocks are accumulated in order to increase decoding reliability. In this paper, we consider transmit antenna selection (TAS) protocols in a PASD system. To minimize sys ... Full text Cite

Adaptive modulation and network coding with optimized precoding in two-way relaying

Conference GLOBECOM - IEEE Global Telecommunications Conference · December 1, 2009 We propose a precoding strategy which controls amplitude and phase of receiving signals to improve throughput for two-stage bidirectional relaying. We consider the case when the nodes know channel state information (CSI) and can adopt adaptive modulation t ... Full text Cite

An adaptive rate assignment strategy for CDMA2000 IS-856 subject to RAB delay

Conference GLOBECOM - IEEE Global Telecommunications Conference · December 1, 2009 In this paper, the problem of resource allocation in IS-856 uplink in the presence of time-delay is studied. A set of nonlinear adaptive controllers are designed to stabilize the wireless network and use the system resources efficiently. The controllers ob ... Full text Cite

Preface

Book · December 1, 2009 Full text Cite

Non-linear network coding in two-way relaying discrete channels

Conference 2009 International Conference on Wireless Communications and Signal Processing, WCSP 2009 · December 1, 2009 In this paper, we present optimal network coding which can maximize achievable rate region in two-way relaying discrete channels, where there are two communicating nodes and one relaying node. We focus on a low-complexity relaying protocol termed the detec ... Full text Cite

Cognitive networks achieve throughput scaling of a homogeneous network

Conference Final Proceedings of the 2009 7th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks, WiOpt 2009 · December 1, 2009 We study two distinct, but overlapping, networks which operate at the same time, space and frequency. The first network consists of n randomly distributed primary users, which form either an ad hoc network, or an infrastructure- supported ad hoc network in ... Full text Cite

Sphere packing optimization and EXIT chart analysis for multi-dimensional QAM signaling

Conference IEEE International Conference on Communications · November 19, 2009 We investigate on multi-dimensional QAM constellations optimized by sphere packing with the known densest lattices. We propose a greedy design method assisted by the sphere detection. It is demonstrated that the optimized constellations can significantly i ... Full text Cite

Denoising strategy for convolutionally-coded bidirectional relaying

Conference IEEE International Conference on Communications · November 19, 2009 In this paper, we present a forwarding strategy for two-stage bidirectional relaying in which trellis-coded modulation (TCM) is employed. We reveal that adaptive network coding cannot resolve distance shortening occurred at specific channel conditions when ... Full text Cite

Controller design for rate assignment in wireless networks

Conference IEEE International Conference on Communications · November 19, 2009 In this paper, data-rate assignment in IS-856 uplink (reverse link) is studied. The problem is first formulated in an interference model framework, and then a dynamic control strategy is developed for efficient rate assignment. In the first step, the contr ... Full text Cite

A class of Bi-directional multi-relay protocols

Conference IEEE International Symposium on Information Theory - Proceedings · November 19, 2009 In a bi-directional relay channel, two nodes wish to exchange independent messages over a shared wireless halfduplex channel with the help of relays. Recent work has considered information theoretic limits of the bi-directional relay channel with a single ... Full text Cite

Interference and noise reduction by beamforming in cognitive networks

Journal Article IEEE Transactions on Communications · November 6, 2009 We consider beamforming in a cognitive network with multiple primary users and a secondary user sharing the same spectrum. Each primary and secondary user consists of a transmitter and a receiver. In particular, we assume that the secondary transmitter has ... Full text Cite

Interference analysis between on-the-move users and GEO satellites

Conference IEEE Vehicular Technology Conference · October 12, 2009 We consider on the move satellite systems with geostationary satellites. Using the antenna pointing distribution of Weerackody and Gonzalez, we derive tight upper and lower bounds of the interference between adjacent satellites from/to the on-the-move plat ... Full text Cite

Rate of channel hardening of antenna selection diversity schemes and its implication on scheduling

Journal Article IEEE Transactions on Information Theory · October 8, 2009 For a multiple-antenna system, we find a simple and accurate expression for the asymptotic distribution of the antenna selection gain when the transmitter selects the transmit antenna with the strongest channel. We use this to estimate the underlying chann ... Full text Cite

Frequency-domain bit-flipping equalizer for wideband MIMO channels

Journal Article IEEE Transactions on Wireless Communications · October 1, 2009 We propose a low-complexity equalizer whose performance approaches that of the optimal maximum-likelihood estimators in wideband multiple-input multiple-output (MIMO) channels. The proposed algorithm makes use of a bit-flipping refinement procedure precede ... Full text Cite

A new construction of signature waveforms for multi-rate multi-cell QS-CDMA systems

Journal Article Wireless Personal Communications · September 1, 2009 In this paper, we propose a new construction of signature waveform sets based on Generalized Loosely Synchronization (GLS) sets and different chip waveforms. The new signature sets are applied into the multi-rate multi-cell quasi-synchronous CDMA (QS-CDMA) ... Full text Cite

Dual antenna selection algorithms and feedback strategies with reduced complexity for multiple-input multiple-output systems

Journal Article IET Microwaves, Antennas and Propagation · August 24, 2009 A simple antenna selection strategy for multiple-input multiple-output wireless systems with partial feedback is presented. In the proposed scheme, both transmit and receive antenna selection are done at the receiver, significantly reducing feedback inform ... Full text Cite

Peak power reduction of OFDM signals with sign adjustment

Journal Article IEEE Transactions on Communications · August 12, 2009 It has recently been shown that significant reduction in the peak to mean envelope power (PMEPR) can be obtained by altering the sign of each subcarrier in a multicarrier system with n subcarriers. However, finding the best sign not only requires a search ... Full text Cite

Scaling laws of single-hop cognitive networks

Journal Article IEEE Transactions on Wireless Communications · August 1, 2009 We consider a cognitive network consisting of n cognitive users uniformly distributed with constant density among primary users. Each user has a single transmitter and a single receiver, and the primary and cognitive users transmit concurrently. The cognit ... Full text Cite

Comparison of SPARLS and RLS algorithms for adaptive filtering

Conference 2009 IEEE Sarnoff Symposium, SARNOFF 2009 - Conference Proceedings · July 23, 2009 In this paper, we overview the Low Complexity Recursive ℒ1-Regularized Least Squares (SPARLS) algorithm proposed in [2], for the estimation of sparse signals in an adaptive filtering setting. The SPARLS algorithm is based on an Expectation-Maximization typ ... Full text Cite

On the primary exclusive region of cognitive networks

Journal Article IEEE Transactions on Wireless Communications · July 1, 2009 We study a cognitive network consisting of a single primary transmitter and multiple secondary, or cognitive, users. The primary transmitter, located at the center of the network, communicates with primary receivers within a disc called the primary exclusi ... Full text Cite

Optimized constellations for two-way wireless relaying with physical network coding

Journal Article IEEE Journal on Selected Areas in Communications · June 1, 2009 We investigate modulation schemes optimized for two-way wireless relaying systems, for which network coding is employed at the physical layer. We consider network coding based on denoise-and-forward (DNF) protocol, which consists of two stages: multiple ac ... Full text Cite

Downlink transmission rate-control strategies for closed-loop multiple-input multiple-output systems

Journal Article IET Communications · April 20, 2009 A novel downlink transmission rate-control and feedback reduction strategy for closed-loop multiple-input multiple-output (MIMO) multiple-input multiple-output wireless systems is presented. Unlike conventional systems that use signal to interference plus ... Full text Cite

Compressive Sensing Using Low Density Frames

Journal Article · March 3, 2009 We consider the compressive sensing of a sparse or compressible signal ${\bf x} \in {\mathbb R}^M$. We explicitly construct a class of measurement matrices, referred to as the low density frames, and develop decoding algorithms that produce an accurate est ... Link to item Cite

SPARLS: A Low Complexity Recursive $\mathcal{L}_1$-Regularized Least Squares Algorithm

Journal Article · January 6, 2009 We develop a Recursive $\mathcal{L}_1$-Regularized Least Squares (SPARLS) algorithm for the estimation of a sparse tap-weight vector in the adaptive filtering setting. The SPARLS algorithm exploits noisy observations of the tap-weight vector output stream ... Link to item Cite

Asymptotic achievability of the Cramér-Rao bound for noisy compressive sampling

Journal Article IEEE Transactions on Signal Processing · January 1, 2009 We consider a model of the form =Ax + n, where x ε CM is sparse with at most L nonzero coefficients in unknown locations, y ε CN is the observation vector, A CN×M is the measurement matrix and n ε CN is the Gaussian noise. We develop a Cramér-Rao bound on ... Full text Cite

Bi-directional half-duplex relaying protocols

Journal Article Journal of Communications and Networks · January 1, 2009 The bi-directional relay channel is the natural extension of a three-terminal relay channel where node a transmits to node b with the help of a relay r to allow for two-way communication between nodes a and b. That is, in a bi-directional relay channel, a ... Full text Cite

Denoising Strategy for Convolutionally-Coded Bidirectional Relaying

Conference 2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8 · January 1, 2009 Link to item Cite

TAS Protocols of a PASD system with limited feedback information

Conference GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8 · January 1, 2009 Link to item Cite

Controller Design for Rate Assignment in Wireless Networks

Conference 2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8 · January 1, 2009 Link to item Cite

Adaptive Modulation and Network Coding with Optimized Precoding in Two-Way Relaying

Conference GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8 · January 1, 2009 Link to item Cite

Sphere Packing Optimization and EXIT Chart Analysis for Multi-Dimensional QAM Signaling

Conference 2009 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-8 · January 1, 2009 Link to item Cite

An Adaptive Rate Assignment Strategy for CDMA2000 IS-856 Subject to RAB Delay

Conference GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8 · January 1, 2009 Link to item Cite

The impact of spectrum sensing time on the performance of the GADIA algorithm

Conference 2008 IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks, DySPAN 2008 · December 29, 2008 In this paper, we analyze the performance of the GADIA (Greedy Asynchronous Distributed Interference Avoidance) algorithm ([1], [2]) given the spectral sensing time of the various active agents. Under the assumption that the sensing time is small compared ... Full text Cite

Beam selection gain from butler matrices

Conference IEEE Vehicular Technology Conference · December 1, 2008 We consider a wireless transmission scenario, when a base station is endowed with a fixed beamforming network, where M antennas are employed at the base station to point beams to predetermined azimuthal angles. In our setting, a Butler matrix is deployed a ... Full text Cite

Interference reduction by beamforming in cognitive networks

Conference GLOBECOM - IEEE Global Telecommunications Conference · December 1, 2008 We consider beamforming in a cognitive network with multiple primary users and secondary users sharing the same spectrum. In particular, we assume that each secondary transmitter has Nt antennas and transmits data to its single- antenna receiver using beam ... Full text Cite

Denoising maps and constellations for wireless network coding in two-way relaying systems

Conference GLOBECOM - IEEE Global Telecommunications Conference · December 1, 2008 We investigate on the design of modulation schemes suited for two-way wireless relaying systems that apply network coding at the physical layer. We consider network coding based on denoise-and-forward (DNF), which consists of two stages: multiple access (M ... Full text Cite

On the peak to average power reduction of OFDM signals using reserved subcarriers

Conference IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC · December 1, 2008 Orthogonal Frequency Division Multiplexing (OFDM) is an attractive technique for high data rate transmissions in wireless and wireline systems. However OFDM signals suffer from high peak-to-mean envelope power (PMEPR). In this paper we consider the problem ... Full text Cite

Random array theory and collaborative beamforming

Chapter · December 1, 2008 In wireless sensor networks, the sensor nodes are often randomly situated, and each node is likely to be equipped with a single antenna. If these sensor nodes are able to synchronize, it is possible to beamform by considering sensor nodes as a random array ... Full text Cite

Two-way relaying with network coding for frequency-selective fading channels

Conference Conference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2008 In this paper, we present a design method of physical layer network coding for reliable two-way relaying in frequency- selective fading channels. We consider a two-stage protocol: At the first stage, two terminals simultaneously transmit data packets towar ... Full text Cite

Performance bounds for bidirectional coded cooperation protocols

Journal Article IEEE Transactions on Information Theory · November 10, 2008 In coded bidirectional cooperation, two nodes wish to exchange messages over a shared half-duplex channel with the help of a relay. In this correspondence, we derive performance bounds for this problem for each of three decode-and-forward protocols. The fi ... Full text Cite

Bi-directional half-duplex protocols with multiple relays

Journal Article · October 7, 2008 In a bi-directional relay channel, two nodes wish to exchange independent messages over a shared wireless half-duplex channel with the help of relays. Recent work has considered information theoretic limits of the bi-directional relay channel with a single ... Link to item Cite

Improved throughput scaling in wireless ad hoc networks with infrastructure

Conference IEEE International Symposium on Information Theory - Proceedings · September 29, 2008 We analyze the benefits of infrastructure support in improving the throughput scaling in networks of n randomly located wireless nodes. The infrastructure uses multi-antenna base stations (BSs), in which the number of BSs and the number of antennas at each ... Full text Cite

The primary exclusive region in cognitive networks

Conference 2008 5th IEEE Consumer Communications and Networking Conference, CCNC 2008 · September 23, 2008 In this paper, we consider a cognitive network in which a single primary transmitter communicates with primary receivers within an area of radius R 0, called the primary exclusive region (PER). Inside this region, no cognitive users may transmit. Outside t ... Full text Cite

Ground-to-air interference analysis in cellular ATG systems

Conference CISS 2008, The 42nd Annual Conference on Information Sciences and Systems · September 22, 2008 For air-to-ground cellular systems with no frequency reuse, we provide an analysis of the inter-cell interference under 3D hexagonal cell planning and a line of sight channel model with no shadowing and no fading assumptions. Based on this model, we provid ... Full text Cite

Noisy compressive sampling limits in linear and sublinear regimes

Conference CISS 2008, The 42nd Annual Conference on Information Sciences and Systems · September 22, 2008 The authors have recently established a set of results that characterize the number of measurements required to recover a sparse signal in ℂM with L non-zero coefficients from compressed samples in the presence of noise. These results indicate that for a n ... Full text Cite

A distributed asynchronous algorithm for spectrum sharing in wireless ad hoc networks

Conference CISS 2008, The 42nd Annual Conference on Information Sciences and Systems · September 22, 2008 We propose a distributed asynchronous spectrum allocation algorithm that achieves performance close to that of a centralized optimal algorithm. In our network model, nodes are grouped into a number of clusters. Each cluster chooses its transmission frequen ... Full text Cite

On the degrees-of-freedom of the MIMO interference channel

Conference CISS 2008, The 42nd Annual Conference on Information Sciences and Systems · September 22, 2008 The high signal-to-noise ratio capacity of the symmetric MIMO interference channel is characterized as a function of the interference-to-noise ratio. This work is a multiple antenna extension of the degrees of freedom expressions derived by Etkin et al. fo ... Full text Cite

Relay selection methods for wireless cooperative communications

Conference CISS 2008, The 42nd Annual Conference on Information Sciences and Systems · September 22, 2008 We study the problem of relay selection in a wireless cooperative network. Assuming a single source, a single destination, and N uniformly distributed candidate relays, we seek to select a set of cooperating relays to minimize the total transmission time o ... Full text Cite

Interference in air-to-ground cellular systems

Conference IEEE International Conference on Communications · September 12, 2008 Interference in cellular terrestrial systems has been extensively studied in the literature mainly through the use of simulations. The interference for CDMA cellular air-to-ground systems has been similarly evaluated through extensive simulations. However, ... Full text Cite

Cognitive sensing based on side information

Conference Proceedings of the 2008 IEEE Sarnoff Symposium, SARNOFF · August 14, 2008 We study a sensing algorithm for cognitive radios based on Bayesian energy detection while utilizing available side information. The side information available to the cognitive user can consist of: (i) spatial locations of the cognitive and primary receive ... Full text Cite

Comparison of bi-directional relaying protocols

Conference Proceedings of the 2008 IEEE Sarnoff Symposium, SARNOFF · August 14, 2008 In a bi-directional relay channel, two nodes wish to exchange independent messages over a shared wireless channel with the help of a relay. In this paper, we derive achievable rate regions for four new half-duplex protocols and compare these to four existi ... Full text Cite

Distributed dynamic frequency allocation in wireless networks under time-varying user activities

Conference Proceedings of the 2008 IEEE Sarnoff Symposium, SARNOFF · August 14, 2008 We propose a framework to analyze the performance of the distributed dynamic frequency allocation algorithm introduced in [1] in the presence of time-varying activity of clusters. In our network model, nodes are grouped into a number of clusters. Each clus ... Full text Cite

Iterative approach to base station positioning in cellular networks

Conference Proceedings of the 2008 IEEE Sarnoff Symposium, SARNOFF · August 14, 2008 We consider the problem of finding the optimal spatial configuration of a number of base stations in a cellular network. We propose a framework to approximately maximize the average Signal to Interference plus Noise Ratio (SINR), with respect to the positi ... Full text Cite

Achievable rate regions for bi-directional relaying

Journal Article · August 7, 2008 In a bi-directional relay channel, two nodes wish to exchange independent messages over a shared wireless half-duplex channel with the help of a relay. In this paper, we derive achievable rate regions for four new half-duplex protocols and compare these to ... Link to item Cite

On bounds and algorithms for frequency synchronization for collaborative communication systems

Journal Article IEEE Transactions on Signal Processing · August 1, 2008 Cooperative diversity systems are wireless communication systems designed to exploit cooperation among users to mitigate the effects of multipath fading. In fairly general conditions, it has been shown that these systems can achieve the diversity order of ... Full text Cite

A frame construction and a universal distortion bound for sparse representations

Journal Article IEEE Transactions on Signal Processing · June 1, 2008 We consider approximations of signals by the elements of a frame in a complex vector space of dimension N and formulate both the noiseless and the noisy sparse representation problems. The noiseless representation problem is to find sparse representations ... Full text Cite

An overview of scaling laws in ad hoc and cognitive radio networks

Journal Article Wireless Personal Communications · May 1, 2008 Currently, wireless communications are changing along the lines of three main thrusts. The first is the introduction of secondary spectrum licensing (SSL). Regulations on the usage of licensed spectra are being loosened, encouraging unused primary spectrum ... Full text Cite

Achievable rates and scaling laws for cognitive radio channels

Journal Article Eurasip Journal on Wireless Communications and Networking · February 5, 2008 Cognitive radios have the potential to vastly improve communication over wireless channels. We outline recent information theoretic results on the limits of primary and cognitive user communication in single and multiple cognitive user scenarios. We first ... Full text Cite

Introduction to the issue on signal processing and networking for dynamic spectrum access

Journal Article IEEE Journal on Selected Topics in Signal Processing · February 1, 2008 Full text Cite

Construction of block orthogonal Golay sequences and application to channel estimation of mimo-ofdm systems

Journal Article IEEE Transactions on Communications · January 1, 2008 In this paper, we construct a family of block orthogonal Golay sequences that have low peak-to-mean envelope power ratio (PMEPR) as well as blockwise orthogonal properties. We then present an application of the sequences to channel estimation of multiple-i ... Full text Cite

Cognitive radio networks: Highlights of information theoretic limits, models, and design

Journal Article IEEE Signal Processing Magazine · January 1, 2008 In recent years, the development of intelligent, adaptive wireless devices called cognitive radios, together with the introduction of secondary spectrum licensing, has led to a new paradigm in communications: cognitive networks. Cognitive networks are wire ... Full text Cite

Performance analysis of a PASD antenna system in Rayleigh fading channels

Conference IEEE Wireless Communications and Networking Conference, WCNC · January 1, 2008 In this paper, we analyze the performance of a communication system that employs Protocol Assisted Switched Diversity (PASD) antennas under Rayleigh fading channel conditions. The PASD system accumulates time-displaced blocks, each with the same informatio ... Full text Cite

A broadcast scheme for MIMO systems with channel state information at the transmitter

Journal Article IEICE Transactions on Communications · January 1, 2008 We propose a new broadcast strategy for a multiple-input multiple-output (MIMO) system with N transmit antennas at the transmitter and M≤N single antenna receivers. The proposed method, based on dirtypaper coding (DPC), spatially separates the M users but ... Full text Cite

Interference in a cognitive network with beacon

Conference IEEE Wireless Communications and Networking Conference, WCNC · January 1, 2008 We study a cognitive network consisting of multiple cognitive users communicating in the presence of a single primary user. The primary user is located at the center of the network, and the cognitive users are uniformly distributed within a circle around t ... Full text Cite

On the Peak to Average Power Reduction of OFDM Signals Using Reserved Subcarriers

Conference 2008 IEEE 19TH INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS · January 1, 2008 Link to item Cite

Beam Selection Gain from Butler Matrices

Conference 68TH IEEE VEHICULAR TECHNOLOGY CONFERENCE, FALL 2008 · January 1, 2008 Link to item Cite

Performance study of various sparse representation methods using redundant frames

Conference Forty-first Annual Conference on Information Sciences and Systems, CISS 2007 - Proceedings · December 1, 2007 Sparse representations have recently received wide attention because of their numerous potential applications. In this paper, we consider sparse representations of signals with at most L non-zero coefficients using a frame ℱ of size M in CN. We bound the a ... Full text Cite

Scaling laws of cognitive networks

Journal Article Proceedings of the 2nd International Conference on Cognitive Radio Oriented Wireless Networks and Communications, CrownCom · December 1, 2007 Opportunistic secondary spectrum usage has the potential to dramatically increase spectral efficiency and rates of a network of secondary cognitive users. In this work we consider a cognitive network: n pairs of cognitive transmitter and receiver wish to c ... Full text Cite

Antenna selection strategies for MIMO systems

Conference IEEE International Conference on Communications · December 1, 2007 Antenna selection strategies for multiple-input multiple-output (MIMO) wireless systems is presented. In our scheme, both transmit and receive antenna selection is done at the receiver, significantly reducing feedback information to the transmitter. Row/co ... Full text Cite

Information theoretic analysis of cognitive radio systems

Chapter · December 1, 2007 Cognitive radios have recently emerged as a prime candidates for exploiting the increasingly flexible licensing of wireless spectrum. Regulatory bodies have come to realize that most of the time, large portions of certain licensed frequency bands remain em ... Full text Cite

A new practical dirty-paper coding strategy in MIMO system

Conference Forty-first Annual Conference on Information Sciences and Systems, CISS 2007 - Proceedings · December 1, 2007 In this paper, we propose a new broadcast strategy for a MIMO system with N transmit antennas at the transmitter and M < N single antenna receivers. The proposed method spatially separates the M users but does not suffer from the power loss of classical SD ... Full text Cite

Training sequence design for wireless collaborative communication systems in frequency-selective fading

Conference Conference Record - Asilomar Conference on Signals, Systems and Computers · December 1, 2007 We consider a collaborative communication system consisting of several nodes jointly communicating to a common destination node. Once each node determines the message to send, a space-time code across the sources is used to transmit the signal to the desti ... Full text Cite

On sparsity, redundancy and quality of frame representations

Conference IEEE International Symposium on Information Theory - Proceedings · December 1, 2007 We consider approximations of signals by the elements of a frame in a complex vector space of dimension N and formulate both the noiseless and the noisy sparse representation problems. The noiseless representation problem is to find sparse representations ... Full text Cite

Coded bi-directional relaying in combat scenarios

Conference Proceedings - IEEE Military Communications Conference MILCOM · December 1, 2007 In this paper, we present three protocols for bidirectional coded cooperation. In coded bi-directional cooperation, two agents wish to communicate with each other in the presence of a relay node that may help. The first protocol is a two phase protocol whe ... Full text Cite

Channel hardening and the scheduling gain of antenna selection diversity schemes

Conference IEEE International Symposium on Information Theory - Proceedings · December 1, 2007 For a multiple antenna system, we compute the asymptotic distribution of antenna selection gain when the transmitter selects the transmit antenna with the strongest channel. We use this to asymptotically estimate the underlying channel capacity distributio ... Full text Cite

Fundamental limits of cognitive radio networks

Chapter · December 1, 2007 Cognitive radios have the potential to greatly improve spectral effi- ciency in wireless networks. In this chapter we explore the fundamental limits of communication in channels employing cognitive radios. We take an informationtheoretic approach, making u ... Full text Cite

A Distributed Dynamic Frequency Allocation Algorithm

Journal Article · November 20, 2007 We consider a network model where the nodes are grouped into a number of clusters and propose a distributed dynamic frequency allocation algorithm that achieves performance close to that of a centralized optimal algorithm. Each cluster chooses its transmis ... Link to item Cite

Performance bounds for Bi-directional coded cooperation protocols

Journal Article Proceedings - International Conference on Distributed Computing Systems · November 15, 2007 In coded bi-directional cooperation, two nodes wish to exchange messages over a shared half-duplex channel with the help of a relay. In this paper, we derive performance bounds for this problem for each of three protocols. The first protocol is a two phase ... Full text Cite

Performance of sparse representation algorithms using randomly generated frames

Journal Article IEEE Signal Processing Letters · November 1, 2007 We consider sparse representations of signals with at most L nonzero coefficients using a frame F of size M in CN. For any F, we establish a universal numerical lower bound on the average distortion of the representation as a function of the sparsity epsi; ... Full text Cite

On the Degrees of Freedom in Cognitive Radio Channels

Journal Article · July 12, 2007 After receiving useful peer comments, we would like to withdraw this paper. ... Link to item Cite

Design of an OFDM cooperative space-time diversity system

Journal Article IEEE Transactions on Vehicular Technology · July 1, 2007 In this paper, we propose a wireless system that realizes theoretical benefits of space-time cooperation. Specifically, we design a space-time cooperative system based on orthogonal frequency division multiplexing (OFDM), which we refer to as a cooperative ... Full text Cite

Reverse-link rate control algorithms with fairness guarantees for CDMA systems

Journal Article IEEE Transactions on Wireless Communications · April 1, 2007 We propose a set of distributed rate control algorithms for the reverse-link of CDMA systems using a pricing mechanism. In the derivation, we assume that the base station broadcasts a real-valued feedback in order to control the reverse activity level. In ... Full text Cite

Performance Bounds on Sparse Representations Using Redundant Frames

Journal Article · March 9, 2007 We consider approximations of signals by the elements of a frame in a complex vector space of dimension $N$ and formulate both the noiseless and the noisy sparse representation problems. The noiseless representation problem is to find sparse representation ... Link to item Cite

Comparison study of UWB indoor channel models

Journal Article IEEE Transactions on Wireless Communications · January 1, 2007 We compare three approaches for modeling the ultra-wideband (UWB) indoor channel delay profile, including the one adopted by the IEEE 802.15.3a Task Group. We do this using a large database we collected (and have reported on previously) spanning numerous i ... Full text Cite

MIMO-OFDM and its application

Journal Article Journal of Communications and Networks · January 1, 2007 Full text Cite

Adaptive frequency synchronization for collaborative communication systems

Conference Proceedings - International Conference on Distributed Computing Systems · January 1, 2007 Cooperative diversity systems are wireless communication systems designed to exploit cooperation among users to mitigate the effects of multipath fading. In fairly general conditions, it has been shown that these systems can achieve the diversity order of ... Full text Cite

Scaling Laws of Cognitive Networks.

Conference CrownCom · 2007 Cite

Cooperation, competition and cognition in wireless networks: From theory to implementation

Chapter · December 1, 2006 Nodes and/or clusters of a wireless network operating on the same frequency can operate using three different paradigms: 1) Competition: Traditionally, this is information theoretically casted in the framework of interference channels. 2) Cooperation: Sile ... Full text Cite

Approximating fluid schedules in crossbar packet-switches and Banyan networks

Journal Article IEEE/ACM Transactions on Networking · December 1, 2006 We consider a problem motivated by the desire to provide flexible, rate-based, quality of service guarantees for packets sent over input queued switches and switch networks. Our focus is solving a type of online traffic scheduling problem, whose input at e ... Full text Cite

Variable-rate two-phase collaborative communication protocols for wireless networks

Journal Article IEEE Transactions on Information Theory · September 1, 2006 The performance of two-phase collaborative communication protocols is studied for wireless networks. All the communication nodes in the cluster are assumed to share the same channel and transmit or receive collaboratively in a quasi-static Rayleigh flat-fa ... Full text Cite

Limits on communications in a cognitive radio channel

Journal Article IEEE Communications Magazine · June 1, 2006 In this article we review FCC secondary markets initiatives and how smart wireless devices could be used to increase spectral efficiency. We survey the current proposals for cognitive radio deployment, and present a new, potentially more spectrally efficie ... Full text Cite

Achievable rates in cognitive radio channels

Journal Article IEEE Transactions on Information Theory · May 1, 2006 Cognitive radio promises a low-cost, highly flexible alternative to the classic single-frequency band, single-protocol wireless device. By sensing and adapting to its environment, such a device is able to fill voids in the wireless spectrum and can dramati ... Full text Cite

On compound channels with side information at the transmitter

Journal Article IEEE Transactions on Information Theory · April 1, 2006 Costa has proved that for noncausally known Gaussian interference at a power constrained transmitter communicating over an additive white Gaussian noise channel there is no capacity loss when compared to a scenario where interference is not present. For th ... Full text Cite

Optimized nonuniform PSK for multiclass traffic and its application to space-time block codes

Journal Article IEEE Transactions on Communications · February 1, 2006 We construct nonuniform phase-shift keying (PSK) constellations that provide unequal error protection for multiclass traffic such as compressed voice and video data. Then closed-form expressions expression for the exact bit-error rate (BER) of the nonunifo ... Full text Cite

Complementary beamforming: New approaches

Journal Article IEEE Transactions on Communications · January 1, 2006 Smart antenna technology can greatly improve the coverage radius of wireless systems by focusing the transmitted signal (beam) toward desired users. However, beamforming has an important side effect as it creates a region, herein referred to as the complem ... Full text Cite

Distributed delay-aware rate control algorithm for the reverse-link of CDMA systems

Conference IEEE International Conference on Communications · January 1, 2006 We propose a new distributed rate control algorithm for the reverse link of CDMA systems. Specifically, when the statistics of packet arrivals are known locally to each access terminal (AT), this new algorithm aims to provide a means to control the relativ ... Full text Cite

Differential spatial multiplexing for two and three transmit antennas

Conference IEEE International Conference on Communications · January 1, 2006 In this paper, we construct a differential spatial multiplexing method that can trade-off spatial diversity for increased transmission rate in differential multi-input multi-output (MIMO) systems. To achieve a desired multiplexing gain while providing simp ... Full text Cite

Cognitive decomposition of wireless networks

Conference 1st International Conference on Cognitive Radio Oriented Wireless Networks and Communications 2006, CROWNCOM · January 1, 2006 In this paper, we provide a framework for a fundamental study of the communication limits of networks of cognitive devices. It is shown that all communication in a network of cognitive and non-cognitive devices can be cast into competitive, cognitive and c ... Full text Cite

Cognitive decomposition of wireless networks

Conference 2006 1ST INTERNATIONAL CONFERENCE ON COGNITIVE RADIO ORIENTED WIRELESS NETWORKS AND COMMUNICATIONS · January 1, 2006 Link to item Cite

Cognitive multiple access networks

Conference IEEE International Symposium on Information Theory - Proceedings · December 1, 2005 A cognitive radio can sense the transmission of other users in its environment and possibly extract the corresponding messages. It can use this information to transmit over the same channel while reducing interference from, and to other users. In this pape ... Full text Cite

Performance evaluation of MB-OFDM and DS-UWB systems for wireless personal area networks

Conference ICU 2005: 2005 IEEE International Conference on Ultra-Wideband, Conference Proceedings · December 1, 2005 Ultra-wideband (UWB) radio has been proposed for physical layer standard of the future high-speed wireless personal area networks (WFANs), One proposal is referred to as multi-band orthogonal frequency division multiplexing (MB-OFDM), and the other is dire ... Cite

Opportunistic beamforming based on multiple weighting vectors

Journal Article IEEE Transactions on Wireless Communications · November 1, 2005 In order to improve the throughput of the opportunistic beamforming, the authors generalize the opportunistic beamforming by using multiple random weighting vectors at each time slot. The base station chooses the best weighting vector and performs the oppo ... Full text Cite

Collaborative beamforming for distributed wireless ad hoc sensor networks

Journal Article IEEE Transactions on Signal Processing · November 1, 2005 The performance of collaborative beamforming is analyzed using the theory of random arrays. The statistical average and distribution of the beampattern of randomly generated phased arrays is derived in the framework of wireless ad hoc sensor networks. Each ... Full text Cite

Trading-off transmission rate with transmit diversity in differential detection

Conference IEEE Vehicular Technology Conference · October 17, 2005 In this paper we construct a method where rate can be trade-off for diversity in differential detection transmit diversity. Specifically, we show for the case 3 and 4 transmit and M receive anteanns, when using the PSK constellation, it is possible to doub ... Cite

Delay bounds for packetizing time-varying fluid policies with speedup and lookahead in single server systems

Conference Proceedings - IEEE INFOCOM · October 7, 2005 We consider an online, processor sharing system with a single server in a packet-switched network where the processor multiplexes packets from multiple input ports onto the same output link. Under a fluid model, in which incoming data is treated as infinit ... Full text Cite

Optimum opportunistic beamforming based on multiple weighting vectors

Conference IEEE International Conference on Communications · September 13, 2005 In order to improve the throughput of the opportunistic beamforming, we generalize the opportunistic beamforming by using multiple random weighting vectors at each time slot. The base station chooses the best weighting vector and performs the opportunistic ... Cite

Collaborative diversity enhancements for wireless communications

Conference IEEE International Conference on Communications · September 12, 2005 The use of the spatial dimension is known to greatly increase the reliability of quasi-static (non-ergodic) wireless channels. In this paper, we demonstrate that most of this gain can also be achieved through collaborative communications with single-antenn ... Cite

UWB delay profile models for residential and commercial indoor environments

Journal Article IEEE Transactions on Vehicular Technology · July 1, 2005 We present models for the ultrawideband (UWB) channel delay profile in indoor environments, based on the processing of two large sets of measured data. Both measurement sets are for a center frequency of 5 GHz, but the bandwidths are very different - 1.25 ... Full text Cite

Space-time diversity enhancements using collaborative communications

Journal Article IEEE Transactions on Information Theory · June 1, 2005 The use of the spatial dimension is known to greatly increase the reliability of quasi-static (i.e., nonergodic) wireless channels. In this paper, it is demonstrated that most of this gain can also be achieved through collaborative communications with sing ... Full text Cite

On the effects of phase estimation errors on collaborative beamforming in wireless ad hoc networks

Conference ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2005 The performance of collaborative beamforming is studied using the theory of random arrays in the framework of wireless sensor networks. With the application to ad hoc networks in mind, two scenarios, one denoted closed-loop and the other open-loop, are con ... Full text Cite

A signal processing application of randomized low-rank approximations

Conference 2005 IEEE/SP 13TH WORKSHOP ON STATISTICAL SIGNAL PROCESSING (SSP), VOLS 1 AND 2 · January 1, 2005 Link to item Cite

A signal processing application of randomized low-rank approximations

Conference IEEE Workshop on Statistical Signal Processing Proceedings · January 1, 2005 Low-rank approximations to linear operators find wide use in signal processing. In the discrete case, assuming the desired rank is known a priori, such approximations are generally calculated using the singular value decomposition. In this vein, randomized ... Full text Cite

Design and analysis of collaborative diversity protocols for wireless sensor networks

Conference IEEE Vehicular Technology Conference · December 1, 2004 We consider wireless sensor networks where all the sensor nodes share the same channel and transmit collaboratively in a quasi-static Rayleigh fading environment. Intuition suggests that collaborative communication can achieve a higher diversity gain than ... Cite

Time-hopping sequence design for narrowband interference suppression

Conference IEEE Vehicular Technology Conference · December 1, 2004 In this paper, we present a simple interference mitigation solution for coexistence of Ultra-Wideband (UWB) systems with other wireless systems. Specifically, we consider the design of time-hopping codes for UWB systems that deploy impulse radio architectu ... Cite

Collaborative beamforming in ad hoc networks

Conference 2004 IEEE Information Theory Workshop - Proceedings, ITW · December 1, 2004 The performance of collaborative beamforming is analyzed using the theory of random arrays. The statistical average and distribution of the beampatterns of randomly generated phased arrays are derived in the framework of wireless ad hoc sensor networks. Ea ... Cite

Universal bounds on buffer size for packetizing fluid policies in input queued, crossbar switches

Conference Proceedings - IEEE INFOCOM · November 22, 2004 In this paper, we consider a type of on-line, traffic scheduling problem in input queued, crossbar switches. The input to a problem, at each time step, is a set of desired traffic rates. These traffic rates in general cannot be exactly achieved since they ... Full text Cite

Measurement and modeling of an ultra-wide bandwidth indoor channel

Journal Article IEEE Transactions on Communications · October 1, 2004 This paper describes the results of frequency-domain channel sounding in residential environments. It consists of detailed characterization of complex frequency responses of ultra-wideband (UWB) signals having a nominal center frequency of 5 GHz. A path lo ... Full text Cite

Frequency synchronization in OFDM

Conference ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 27, 2004 We present an OFDM frequency synchronization scheme. The scheme uses periodic OFDM symbols, similarly to the algorithms proposed previously by Morelli and Mengali and Schmidl and Cox. The proposed scheme attains considerably higher accuracy than the scheme ... Cite

Multiple-antenna channel hardening and its implications for rate feedback and scheduling

Journal Article IEEE Transactions on Information Theory · September 1, 2004 Wireless data traffic is expected to grow over the next few years and the technologies that will provide data services are still being debated. One possibility is to use multiple antennas at base stations and terminals to get very high spectral efficiencie ... Full text Cite

Differential space time block codes using QAM for four transmit antennas

Conference IEEE International Conference on Communications · August 30, 2004 We develop differential space time block codes (STBC) using non-constant modulus constellations for four transmit antennas. The proposed method improves on the conventional differential STBC techniques because of the larger minimum distances of non-constan ... Cite

An Impulse Response Model For Residential Wireless Channels

Conference Conference Record / IEEE Global Telecommunications Conference · December 1, 2003 We present a statistical model for the Multipath Intensity Profile (MIP) that can be used to construct an impulse response of a residential wireless channel. The model incorporates relevant parameters such as distance, global rms delay spread and the corre ... Cite

Coexistence of Ultra-Wideband Systems with IEEE-802.1la Wireless LANs

Conference Conference Record / IEEE Global Telecommunications Conference · December 1, 2003 In this study we provide a physical layer based analysis of the coexistence issues of Ultra-Wideband (UWB) with other devices in the same spectrum. Specifically, we have focused on the UWB interference to and from devices using the Wireless Local Area Netw ... Cite

Differential space time block codes using QAM constellations

Conference IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC · December 1, 2003 We propose differential space time block codes (STBC) using quadrature amplitude modulation (QAM), which can not be utilized in the conventional differential STBC. Since QAM constellations have a larger minimum distance compared with phase shift keying (PS ... Full text Cite

Complementary beamforming

Conference IEEE Vehicular Technology Conference · December 1, 2003 We present complementary beamforming techniques which enable the formation of multiple directional beams to some users while guaranteeing a minimum power level to the rest of the users in the network. These techniques can be used for many different applica ... Cite

A New Construction of 16-QAM Golay Complementary Sequences

Journal Article IEEE Transactions on Information Theory · November 1, 2003 We present a new construction of 16-QAM Golay sequences of length n = 2m, The number of constructed sequences is (14 + 12m) (m!/2)4 m+1. When employed as a code in an orthogonal frequency-division multiplexing (OFDM) system; this set of sequences has a pea ... Full text Cite

Differential space time block codes using nonconstant modulus constellations

Journal Article IEEE Transactions on Signal Processing · November 1, 2003 We propose differential space time block codes (STBC) using nonconstant modulus constellations, e.g., quadrature amplitude modulation (QAM), which cannot be utilized in the conventional differential STBC. Since QAM constellations have a larger minimum dist ... Full text Cite

UWB path loss characterization in residential environments

Conference IEEE Radio Frequency Integrated Circuits Symposium, RFIC, Digest of Technical Papers · August 22, 2003 In this paper, we describe a simple method for measurement of the Ultra-Wideband Band (UWB) frequency response for evaluation of the path loss and impulse response of the UWB indoor channel. We propose a simple statistical path loss model for the residenti ... Cite

UWB path loss characterization in residential environments

Conference IEEE MTT-S International Microwave Symposium Digest · August 18, 2003 In this paper, we describe a simple method for measurement of the Ultra-Wideband Band (UWB) frequency response for evaluation of the path loss and impulse response of the UWB indoor channel We propose a simple statistical path loss model for the residentia ... Cite

Special issue on coding and signal processing for MIMO system

Journal Article Journal of Communications and Networks · June 2003 Full text Cite

Variable-rate space-time block codes in M-ary PSK systems

Journal Article IEEE Journal on Selected Areas in Communications · April 1, 2003 We consider a multiple antenna system when combined array processing with space-time coding is used. We present variable rate space-time block codes for two, three, and four transmit antennas and optimize the transmit power so that the average bit-error ra ... Full text Cite

Energy reduction in VLSI computation modules: An information-theoretic approach

Journal Article IEEE Transactions on Information Theory · April 1, 2003 We consider the problem of reduction of computation cost by introducing redundancy in the number of ports as well as in the input and output sequences of computation modules. Using our formulation, the classical "communication scenario" is the case when a ... Full text Cite

A multipath intensity profile model for residential environments

Conference IEEE Wireless Communications and Networking Conference, WCNC · January 1, 2003 We describe a statistical model for the multipath intensity profile (MIP) in residential environments. The work is based on over 300,000 frequency response measurements at 712 locations in 23 homes. We show that, for non-line-of-sight (NLS) path, the MIP i ... Full text Cite

An empirical indoor path loss model for ultra-wideband channels

Journal Article Journal of Communications and Networks · January 1, 2003 We present a statistical model for the path loss of ultra-wideband (UWB) channels in indoor environments. In contrast to our previously reported measurements, the data reported here are for a bandwidth of 6GHz rather than 1.25GHz; they encompass commercial ... Full text Cite

UWB indoor path loss model for residential and commercial buildings

Conference IEEE Vehicular Technology Conference · January 1, 2003 We present a statistical model for the path loss of ultra-wideband channels in indoor environments. In contrast to previous measurements, the data reported here are for a bandwidth of 6 GHz rather than 1.25 GHz; they encompass commercial buildings in addit ... Full text Cite

Invited - UWB path loss characterization in residential environments

Conference 2003 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 · January 1, 2003 Link to item Cite

UWB indoor delay profile model for residential and commercial environments

Conference IEEE Vehicular Technology Conference · January 1, 2003 We present a statistical model for the delay profile of ultra-wideband channels in indoor environments. Two kinds of profiles are defined, namely the multipath intensity profile (MIP) and the power delay profile (PDF). The MIP is he delay profile at a poin ... Full text Cite

Existence and construction of noncoherent unitary space-time codes

Journal Article IEEE Transactions on Information Theory · December 1, 2002 We consider transmission using N transmit and reception using M receive antennas in a wireless environment assuming that neither the transmitter nor the receiver knows the channel coefficients. For the scenario that the transmission employs noncoherent T × ... Full text Cite

Two constructions of 16-QAM Golay complementary sequences

Conference IEEE International Symposium on Information Theory - Proceedings · September 12, 2002 Two constructions of 16-quadrature amplitude modulation (QAM) Golay complementary sequences from 4-QAM complementary sequences were presented. These sequences can be applied as pilot sequences in future orthogonal frequency division miltiplexing (OFDM) sys ... Cite

Energy reduction and fundamental energy limits in digital VLSI circuits

Conference IEEE International Symposium on Information Theory - Proceedings · September 12, 2002 Energy reduction and fundamental energy limits in digital VLSI circuits were discussed. Bus was used to calculate the minimum cost of energy since its cost function is known. Results can be extended to units modelled as finite state machines and can also b ... Cite

Editorial

Journal Article Eurasip Journal on Applied Signal Processing · May 1, 2002 Full text Cite

Editorial

Journal Article EURASIP Journal on Advances in Signal Processing · March 18, 2002 Full text Cite

Applied Signal Processing: Editorial

Journal Article Eurasip Journal on Applied Signal Processing · March 1, 2002 Cite

Existence and construction of block interleavers

Conference IEEE International Conference on Communications · January 1, 2002 The necessary and sufficient conditions on the existence of (N1, N2) block interleavers of block size L, were established. The interleaver was found to exist on the condition that L ≥ N1N2. Explicit algebraic expressions were also provided. It was proved t ... Full text Cite

Space-time codes for wireless optical communications

Journal Article Eurasip Journal on Applied Signal Processing · January 1, 2002 A space-time channel coding technique is presented for overcoming turbulence-induced fading in an atmospheric optical heterodyne communication system that uses multiple transmit and receive apertures. In particular, a design criterion for minimizing the pa ... Full text Cite

Maximum achievable energy reduction using coding with applications to deep sub-micron buses

Conference Proceedings - IEEE International Symposium on Circuits and Systems · January 1, 2002 In this work we ask: How much can we reduce the power consumption in deep-sub-micron buses using coding techniques? We answer the question in two steps. First we give the minimum energy per information bit required for communicating through deep-sub-micron ... Cite

Autoregressive modeling of an indoor UWB channel

Conference 2002 IEEE Conference on Ultra Wideband Systems and Technologies, UWBST 2002 - Digest of Papers · January 1, 2002 Based on frequency domain measurements in the 4.375-5.625 GHz band a channel model for the frequency response of the indoor radio channel is introduced. In particular. a second-order Autoregressive (AR) model is proposed for frequency response generation o ... Full text Cite

A statistical path loss model for in-home UWB channels

Conference 2002 IEEE Conference on Ultra Wideband Systems and Technologies, UWBST 2002 - Digest of Papers · January 1, 2002 This paper describes a simple statistical model for evaluating the path loss in residential environments. It consists of detailed characterization of path loss model parameters of ultra-wideband band (UWB) signals having a nominal center frequency of 5 GHz ... Full text Cite

Variable rate sapce-time block codes in MPSK systems

Conference Conference Record of the Asilomar Conference on Signals, Systems and Computers · January 1, 2002 We consider a multiple antenna system when combined array processing with space-time coding is used [2]. We present variable rate space-time block codes for two, three, and four transmit antennas and optimize the transmit power so that the average BER is m ... Cite

A simple encodable/decodable OFDM QPSK code with low peak-to-mean envelope power ratio

Journal Article IEEE Transactions on Information Theory · November 1, 2001 We present a quadrature phase-shift keying (QPSK) coding scheme for multicarrier communications. The scheme supports simple encoding and extremely simple maximum-likelihood (ML) decoding algorithms for orthogonal frequency-division multiplexing (OFDM). Mor ... Full text Cite

A simple encodable/decodable OFDM QPSK code with low peak-to-mean envelope power ratio

Conference IEEE International Symposium on Information Theory - Proceedings · September 12, 2001 We present a QPSK coding scheme for use in multicarrier communications. The scheme supports simple encoding and extremely simple maximum likelihood (ML) decoding algorithms for orthogonal frequency division multiplexing (OFDM) applications. Moreover, all t ... Cite

Multiple transmit antenna differential detection from generalized orthogonal designs

Journal Article IEEE Transactions on Information Theory · September 1, 2001 We explicitly construct multiple transmit antenna differential encoding/decoding schemes based on generalized orthogonal designs. These constructions generalize the two transmit antenna differential detection scheme that we proposed before. ... Full text Cite

A construction of OFDM 16-QAM sequences having low peak powers

Journal Article IEEE Transactions on Information Theory · January 1, 2001 Using a realization of 16-QAM as set addition of two scaled versions of the 4-PSK constellation, we construct 16-QAM sequences having low peak-to-mean envelope power ratios (PMEPR) from 4-PSK Golay sequences. Various upper bounds on the peak envelope power ... Full text Cite

Space-time codes for wireless optical channels

Journal Article IEEE International Symposium on Information Theory - Proceedings · January 1, 2001 A space-time channel coding technique is presented for overcoming turbulence-induced fading in an atmospheric optical communication system that uses multiple transmit and receive apertures. In particular, a design criterion for minimizing the pairwise prob ... Full text Cite

A channel-shortening multiuser detector for DS-CDMA systems

Conference IEEE Vehicular Technology Conference · January 1, 2001 The multiple-access interference (MAI) encountered by Direct-Sequence Code-Division Multiple Access (DS-CDMA) users in a multipath environment is a key issue in the detection of mobile communication users. The MAI is one of the major reasons for the degrad ... Cite

On the existence and construction of good codes with low peak-to-average power ratios

Conference IEEE International Symposium on Information Theory - Proceedings · December 1, 2000 The peak-to-average power ratio PAPR(C) of a code C is an important characteristic of that code when it is used in OFDM communications. We establish bounds on the region of achievable triples (R, d, PAPR(C)) where R is the code rate and d is the minimum Eu ... Cite

On the existence and construction of good codes with low peak-to-average power ratios

Journal Article IEEE Transactions on Information Theory · September 1, 2000 The first lower bound on the peak-to-average power ratio (PAPR) of a constant energy code of a given length n, minimum Euclidean distance and rate is established. Conversely, using a nonconstructive Varshamov-Gilbert style argument yields a lower bound on ... Full text Cite

Differential detection scheme for transmit diversity

Journal Article IEEE Journal on Selected Areas in Communications · July 1, 2000 We present a transmission scheme for exploiting diversity given by two transmit antennas when neither the transmitter nor the receiver has access to channel state information. The new detection scheme can use equal energy constellations and encoding is sim ... Full text Cite

Correction to "Space-time block codes from orthogonal designs"

Journal Article IEEE Transactions on Information Theory · January 2000 Full text Cite

On the computation and reduction of the peak-to-average power ratio in multicarrier communications

Journal Article IEEE Transactions on Communications · January 1, 2000 For any code C defined over an equal energy constellation, it is first shown that at any time instance, the problem of determining codewords of C with high peak-to-average power ratios (PAPR) in a multicarrier communication system is intimately related to ... Full text Cite

Image clustering using fuzzy graph theory

Conference Proceedings of SPIE - The International Society for Optical Engineering · January 1, 2000 We propose an image clustering algorithm which uses fuzzy graph theory. First, we define a fuzzy graph and the concept of connectivity for a fuzzy graph. Then, based on our definition of connectivity we propose an algorithm which finds connected subgraphs ... Cite

Design of successively refinable trellis-coded quantizers

Journal Article IEEE Transactions on Information Theory · December 1, 1999 We propose successively refinable trellis-coded quantizers for progressive transmission. (Progressive transmission is an essential component of image and multimedia browsing systems.) A new trellis structure which is scalable is used in the design of our t ... Full text Cite

Universal bound on the performance of lattice codes

Journal Article IEEE Transactions on Information Theory · December 1, 1999 We present a lower bound on the probability of symbol error for maximum-likelihood decoding of lattices and lattice codes on a Gaussian channel. The bound is tight for error probabilities and signal-to-noise ratios of practical interest, as opposed to most ... Full text Cite

Multiple description trellis-coded quantization

Journal Article IEEE Transactions on Communications · December 1, 1999 We present a construction of multiple description trellis-coded quantizers. We use the tensor product of trellises to build a trellis which is applicable to multiple description coding. The problems of index assignment and set partitioning for the resultin ... Full text Cite

On the existence and construction of good codes with low peak-to-average power ratios

Journal Article HP Laboratories Technical Report · April 1, 1999 The first lower bound on the peak-to-average power ratio (PAPR) of a constant energy code of a given length n, minimum Euclidean distance and rate is established. Conversely, using a non-constructive Varshamov-Gilbert style argument yields a lower bound on ... Cite

Space-time block coding for wireless communications: Performance results

Journal Article IEEE 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 ... Full text Cite

A differential detection scheme for transmit diversity

Conference IEEE Wireless Communications and Networking Conference, WCNC · January 1, 1999 We present a transmission scheme for exploiting diversity given by two transmit antennas when neither the transmitter nor the receiver has access to channel state information. The new detection scheme can use PSK constellations and encoding is simple. At t ... Full text Cite

Space-time block coding-from a physical perspective

Conference IEEE Wireless Communications and Networking Conference, WCNC · January 1, 1999 Space-time block coding (STBC) is an effective transmit diversity scheme. It was presented previously by in terms of coding and decoding by Alamouti (see IEEE J. Select. Areas Commun., vol.16, no.8, p.1451-58, 1998) and by Tarokh, Jafarkhani and Calderbank ... Full text Cite

Space-time codes for high data rate wireless communication: performance criteria in the presence of channel estimation errors, mobility, and multiple paths

Journal Article IEEE Transactions on Communications · January 1, 1999 Space-time coding is a bandwidth and power efficient method of communication over fading channels that realizes the benefits of multiple transmit antennas. Specific codes have been constructed using design criteria derived for quasi-static flat Rayleigh or ... Full text Cite

Combined array processing and space-time coding

Journal Article IEEE Transactions on Information Theory · January 1, 1999 The information capacity of wireless communication systems may be increased by employing multiple transmit and receiver antennas. The goal of the system design is to exploit this capacity in a practical way. To increase data rate over wireless channels, sp ... Full text Cite

Algorithm for reducing the peak to average power ratio in a multicarrier communications system

Conference IEEE VTS 50th Vehicular Technology Conference, VTC 1999-Fall · January 1, 1999 One of the main implementation disadvantages of a multicarrier communication system is the possibly high peak to average power ratio of the transmitted signals. One proposed solution is given by Jones and Wilkinson. It is based on applying a specific phase ... Cite

Space-time block codes from orthogonal designs

Journal Article IEEE 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 ... Full text Cite

Recent progress in space-time block and trellis coding

Journal Article IEEE International Symposium on Information Theory - Proceedings · December 1, 1998 Techniques for transmission and reception over wireless channels using multiple transmit antennas are presented. © 1998 IEEE. ... Full text Cite

Multiple description trellis coded quantization

Conference IEEE International Conference on Image Processing · December 1, 1998 We present a construction of multiple description trellis coded quantizers. We use the tensor product of trellises to build a trellis which is applicable to multiple description coding. The problems of index assignment and set partitioning for the resultin ... Cite

Space-time coded OFDM for high data-rate wireless communication over wideband channels

Conference IEEE Vehicular Technology Conference · December 1, 1998 The space-time coded orthogonal frequency division multiplexing (OFDM) scheme is described to provide high data-rate wireless communication over wideband channels. Simulation results for a 4-PSK 16 state space-time coded OFDM system are presented. The prop ... Cite

A space-time coding modem for high-data-rate wireless communications

Journal Article IEEE 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 ... Full text Cite

Principal ratio combining for fixed wireles applications when transmitter diversity is employed

Journal Article IEEE Communications Letters · August 1, 1998 We present a near-optimal detection method for decoding codes appropriate to transmission using multiple transmit antennas in a fixed wireless environment. The method is a nontrivial generalization of maximum ratio combining. This reduces the decoding comp ... Full text Cite

The application of orthogonal designs to wireless communication

Conference 1998 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 ... Full text Cite

Successively refinable trellis coded quantization

Conference Data Compression Conference Proceedings · January 1, 1998 We propose successively refinable trellis coded quantizers which are suitable for progressive transmission. A new trellis structure which is scalable is used in the design of our trellis coded quantizers. A hierarchical set partitioning is used to preserve ... Cite

New detection schemes for transmit diversity with no channel estimation

Conference ICUPC 1998 - IEEE 1998 International Conference on Universal Personal Communications, Conference Proceedings · January 1, 1998 We present two new detection methods for the simple transmit diversity scheme proposed by Alamouti (see IEEE Journal on Selected Areas of Communications, Special Issue on Signal Processing for Wireless Communications, 1998). The new detection schemes requi ... Full text Cite

Trellis-coded modulation and transmit diversity: Design criteria and performance evaluation

Conference ICUPC 1998 - IEEE 1998 International Conference on Universal Personal Communications, Conference Proceedings · January 1, 1998 This paper presents the selection criteria for trellis codes used with the simple transmit diversity scheme proposed in Alamouti (1998) and reviewed in this paper. The optimum metrics for soft decision Viterbi decoding are derived and the asymptotic coding ... Full text Cite

Principal ratio combining for fixed wireless applications when transmitter diversity is employed

Conference ICUPC 1998 - IEEE 1998 International Conference on Universal Personal Communications, Conference Proceedings · January 1, 1998 We present a near-optimal detection method for decoding codes appropriate to transmission using multiple transmit antennas in a fixed wireless environment. The method is a non-trivial generalization of maximum ratio combining. This reduces the decoding com ... Full text Cite

Space-time codes for high data rate wireless communication: Performance criterion and code construction

Journal Article IEEE Transactions on Information Theory · January 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 ... Full text Cite

Existence of optimal prefix codes for infinite source alphabets

Journal Article IEEE Transactions on Information Theory · December 1, 1997 It is proven that for every random variable with a countably infinite set of outcomes and finite entropy there exists an optimal prefix code which can be constructed from Huffman codes for truncated versions of the random variable, and that the average len ... Full text Cite

Upper bounds on trellis complexity of lattices

Journal Article IEEE Transactions on Information Theory · December 1, 1997 Unlike block codes, n-dimensional lattices can have minimal trellis diagrams with an arbitrarily large number of states, branches, and paths. In particular, we show by a counterexample that there is no f(n), a function of n, such that all rational lattices ... Full text Cite

Upper bounds on trellis complexity of lattices

Conference IEEE International Symposium on Information Theory - Proceedings · December 1, 1997 Unlike block codes, n-dimensional lattices can have minimal trellis diagrams with an arbitrarily large number of states, branches, and paths. We show by a counter-example that there is no f(n), a function of n, such that all rational lattices of dimension ... Full text Cite

Sequential decoding of lattice codes

Conference IEEE International Symposium on Information Theory - Proceedings · December 1, 1997 We consider lattice tree-codes based on a lattice Λ having a finite trellis diagram T. Such codes are easy to encode and benefit from the structure of Λ . Sequential decoding of lattice tree-codes is studied, and the corresponding Fano (1963) metric is der ... Full text Cite

Space-time coded modulation for high data rate wireless communications

Conference Conference Record / IEEE Global Telecommunications Conference · December 1, 1997 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 ... Cite

Low-rate multi-dimensional space-time codes for both slow and rapid fading channels

Journal Article IEEE 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 ... Cite

Space-time codes for wireless communication

Journal Article IEEE 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 ... Full text Cite

Space-time codes for high data rate wireless communication: Performance criteria

Journal Article IEEE 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 ... Cite

Space-time codes for high data rate wireless communication: Mismatch analysis

Journal Article IEEE 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 ... Cite

Space-time codes for wireless communication: Code construction

Journal Article IEEE 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 ... Cite

Trellis complexity versus the coding gain of lattices I

Journal Article IEEE Transactions on Information Theory · December 1, 1996 The best possible tradeoff between the coding gain and trellis complexity for lattices is studied. Three trellis complexity functions are defined for lattices as a measure of minimum trellis decoding complexity per dimension required for achieving a coding ... Full text Cite

Trellis complexity versus the coding gain of lattices II

Journal Article IEEE Transactions on Information Theory · December 1, 1996 For an arbitrary rational lattice L with gain γ, the average number of states (respectively, branches) in any given trellis diagram of L is bounded below by a function of γ. It is proved that this function grows exponentially in γ. In the reverse direction ... Full text Cite

Trellis complexity versus the coding gain of lattices .2.

Conference IEEE TRANSACTIONS ON INFORMATION THEORY · November 1, 1996 Link to item Cite

On the trellis complexity of the densest lattice packings in ℝn

Journal Article SIAM Journal on Discrete Mathematics · January 1, 1996 An inequality relating the trellis complexity of lattices to their dimension and Hermite parameter is established. Using this inequality, a conjecture of Forney is proved indicating that the trellis complexity of the densest lattice packings in ℝn grows ex ... Full text Cite

A Constraint on the Existence of Simple Torsion-Free Lie Modules

Journal Article Proceedings of the American Mathematical Society · August 1995 Full text Cite

A constraint on the existence of simple torsion-free lie modules

Journal Article Proceedings of the American Mathematical Society · January 1, 1995 For any simple Lie algebra L with Cartan subalgebra H the classification of all simple H-diagonalizable. H-modules having a finite-dimensional weight space is known to depend on determining the simple torsion-free Lmodules of finite degree. It is further k ... Full text Cite

Trellis complexity versus the coding gain of lattices

Conference IEEE International Symposium on Information Theory - Proceedings · January 1, 1995 The growth of trellis diagrams of lattices versus their coding gain is studied. It is established that this growth exponentially in terms of the coding gain. ... Cite

Projected Latent Markov Chain Monte Carlo: Conditional Sampling of Normalizing Flows

Conference We introduce Projected Latent Markov Chain Monte Carlo (PL-MCMC), a technique for sampling from the exact conditional distributions learned by normalizing flows. As a conditional sampling method, PL-MCMC enables Monte Carlo Expectation Maximization (MC-EM) ... Cite

Task-Aware Neural Architecture Search”, International Conference on Acoustics, Speech, and Signal Processing

Conference The design of handcrafted neural networks requires a lot of time and resources. Recent techniques in Neural Architecture Search (NAS) have proven to be competitive or better than traditional handcrafted design, although they require domain knowledge and ha ... Cite