A5066172831- Wireless Communication Security Techniques
- Cooperative Communication and Network Coding
- Advanced Wireless Communication Techniques
- Neural Networks and Applications
- Error Correcting Code Techniques
- Blind Source Separation Techniques
- Cellular Automata and Applications
- Sparse and Compressive Sensing Techniques
- Advanced MIMO Systems Optimization
- Chaos-based Image/Signal Encryption
- Wireless Communication Networks Research
- Quantum Information and Cryptography
- Speech and Audio Processing
- Algorithms and Data Compression
- DNA and Biological Computing
- Advanced Data Compression Techniques
- Statistical Methods and Inference
- Advanced Optical Sensing Technologies
- Quantum Mechanics and Applications
- Distributed systems and fault tolerance
- Adversarial Robustness in Machine Learning
- Cloud Computing and Resource Management
- Quantum Computing Algorithms and Architecture
- Distributed Sensor Networks and Detection Algorithms
- Advanced Steganography and Watermarking Techniques
Massachusetts Institute of Technology
2016-2025
IIT@MIT
2011-2024
Tsinghua–Berkeley Shenzhen Institute
2024
Bar-Ilan University
2024
Association for Asian Studies
2018-2023
The Alan Turing Institute
2023
Moscow Institute of Thermal Technology
2021
Hebrew University of Jerusalem
2021
Rutgers, The State University of New Jersey
2019
Cornell University
2018-2019
We develop and analyze low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks. The underlying techniques exploit space available through cooperating terminals' relaying signals for one another. outline several strategies employed the radios, including fixed schemes such as amplify-and-forward decode-and-forward, selection adapt based upon channel measurements between terminals, incremental limited feedback from destination...
We develop and analyze space-time coded cooperative diversity protocols for combating multipath fading across multiple protocol layers in a wireless network. The exploit spatial available among collection of distributed terminals that relay messages one another such manner the destination terminal can average fading, even though it is unknown priori which will be involved. In particular, source initiates transmission to its destination, many relays potentially receive transmission. Those...
We consider the problem of embedding one signal (e.g., a digital watermark), within another "host" to form third, "composite" signal. The is designed achieve efficient tradeoffs among three conflicting goals maximizing information-embedding rate, minimizing distortion between host and composite signal, robustness embedding. introduce new classes methods, termed quantization index modulation (QIM) distortion-compensated QIM (DC-QIM), develop convenient realizations in what we refer as dither...
The role of multiple antennas for secure communication is investigated within the framework Wyner's wiretap channel. We characterize secrecy capacity in terms generalized eigenvalues when sender and eavesdropper have antennas, intended receiver has a single antenna, channel matrices are fixed known to all terminals, show that beamforming strategy capacity-achieving. In addition, we study masked scheme radiates power isotropically directions it attains near-optimal performance high SNR...
The capacity of the Gaussian wiretap channel model is analyzed when there are multiple antennas at sender, intended receiver and eavesdropper. associated matrices fixed known to all terminals. A computable characterization secrecy established as saddle point solution a minimax problem. converse based on Sato-type argument used in other broadcast settings, coding theorem codebooks. At high signal-to-noise ratio (SNR), shown be attained by simultaneously diagonalizing via generalized singular...
We develop energy-efficient transmission protocols for wireless networks that exploit spatial diversity created by antenna sharing: coordinated and/or processing several distributed radios. focus on single-user and examine possibilities the strategy employed assisting radio, or relay, including decoding forwarding as well amplifying forwarding. In each case, we receivers based upon maximum-likelihood maximum signal-to-noise ratio criteria, relate their structures, compare bit-error...
We derive performance limits for two closely related communication scenarios involving a wireless system with multiple-element transmitter antenna arrays: point-to-point partial side information at the transmitter, and broadcast multiple receivers. In both cases, ideal beamforming is impossible, leading to an inherently lower achievable as quality of degrades or number receivers increases. Expected signal-to-noise ratio (SNR) mutual are considered measures. case, we determine when...
We develop two variants of an energy-efficient cooperative diversity protocol that combats fading induced by multipath propagation in wireless networks, The underlying techniques build upon the classical relay channel and related work exploit space available at distributed antennas through coordinated transmission processing cooperating radios. While applicable to any setting, these protocols are particularly attractive ad-hoc or peer-to-peer which radios typically constrained employ a...
Lattice-reduction (LR) techniques are developed for enhancing the performance of multiple-input multiple-output (MIMO) digital communication systems. When used in conjunction with traditional linear and nonlinear detectors, LR substantially close gap to fundamental limits little additional system complexity. Results individual channels ensembles developed, illustrated detail case small (2 /spl times/ 2), uncoded, coherent For example, we show that, relative maximum likelihood bound, get us...
The role of the wavelet transformation as a whitening filter for 1/f processes is exploited to address problems parameter and signal estimations embedded in white background noise. Robust, computationally efficient, consistent iterative estimation algorithms are derived based on method maximum likelihood, Cramer-Rao bounds obtained. Included among these optimal fractal dimension estimators noisy data. Algorithms obtaining Bayesian minimum-mean-square estimates also together with an explicit...
We study a problem of broadcasting confidential messages to multiple receivers under an information-theoretic secrecy constraint. Two scenarios are considered: 1) all obtain common message; and 2) each receiver is independent message. Moreover, two models parallel channels fast-fading channels. For the case reversely degraded channels, one eavesdropper, arbitrary number legitimate receivers, we determine capacity for transmitting message, sum-capacity messages. assume that channel state...
This paper considers the problem of communication over a discrete memoryless channel (DMC) or an additive white Gaussian noise (AWGN) subject to constraint that probability adversary who observes outputs can detect is low. In particular, relative entropy between output distributions when codeword transmitted and no input provided must be sufficiently small. For DMC whose distribution induced by "off" symbol not mixture other symbols, it shown maximum amount information under this criterion...
Conventional quantum key distribution (QKD) typically uses binary encoding based on photon polarization or time-bin degrees of freedom and achieves a capacity at most one bit per photon. Under photon-starved conditions the rate detection events is much lower than generation rate, because losses in long distance propagation relatively recovery times available single-photon detectors. Multi-bit arrival can be beneficial such situations. Recent security proofs indicate high-dimensional robust...
It is demonstrated that 1/f fractal processes are, in a broad sense, optimally represented terms of orthonormal wavelet bases. Specifically, via useful frequency-domain characterization for processes, the expansion's role as Karhunen-Loeve-type expansion developed. As an illustration potential, it shown wavelet-based representations naturally lead to highly efficient solutions some fundamental detection and estimation problems involving processes.< <ETX...
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While so-called 1/f or scaling processes emerge regularly in modeling a wide range of natural phenomena, as yet no entirely satisfactory framework has been described for the analysis such processes. Orthonormal wavelet bases are used to provide new construction nearly from set uncorrelated random variables.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
We develop and analyze space-time coded cooperative diversity protocols for combating multipath fading across multiple protocol layers in a wireless network. The exploit spatial available among collection of distributed terminals that relay messages one another such manner the destination terminal can average fading, even though it is unknown priori which will be involved. In particular, source initiates transmission to its destination, many relays potentially receive transmission. Those...
Signal estimation from a sequential encoding in the form of quantized noisy measurements is considered. As an example context, this problem arises number remote sensing applications, where central site estimates information-bearing signal low-bandwidth digitized information received sensors, and may or not broadcast feedback to sensors. We demonstrate that use appropriately designed often easily implemented additive control input before quantization at sensor can significantly enhance...
Wyner's wiretap channel is generalized to the case when sender, receiver and eavesdropper have multiple antennas. We consider two cases: deterministic fading case. In case, matrices of intended are fixed known all nodes. experience block sender has only receiver's state information (CSI) statistical knowledge eavesdropper's channel. For a scheme based on generalized-singular-value-decomposition (GSVD) proposed shown achieve secrecy capacity in high signal-to-noise-ratio (SNR) limit. When one...
Multirate systems and filter banks have traditionally played an important role in source coding compression for contemporary communication applications, many of the key design issues such applications been extensively explored. We review developments on comparatively less explored multirate wavelets channel modulation some classes channels. Some representative examples emerging potential are described. One involves use highly dispersive, broadband wireless multiuser (spread spectrum CDMA)...
Signals generated by chaotic systems represent a potentially rich class of signals both for detecting and characterizing physical phenomena in synthesizing new classes communications, remote sensing, variety other signal processing applications. Since classical techniques analysis do not exploit the particular structure there is significant challenge an opportunity exploring algorithms matched to signals. The authors outline issues associated with synthesis In addition two examples are...
In cloud computing jobs consisting of many tasks run in parallel, the on slowest machines (straggling tasks) become bottleneck completion job. One way to combat variability machine response time is add replicas straggling and wait for earliest copy finish. Using theory extreme order statistics, we analyze how task replication reduces latency, its impact cost resources. We also propose a heuristic algorithm search best strategies when it difficult model empirical behavior execution use...
We show that walls, and other obstructions with edges, can be exploited as naturally-occurring "cameras" reveal the hidden scenes beyond them. In particular, we demonstrate methods for using subtle spatio-temporal radiance variations arise on ground at base of a wall's edge to construct one-dimensional video scene behind wall. The resulting technique used variety applications in diverse physical settings. From standard RGB recordings, use cameras recover 1-D videos number trajectories people...
In cloud computing systems, assigning a task to multiple servers and waiting for the earliest copy finish is an effective method combat variability in response time of individual reduce latency. But adding redundancy may result higher cost resources, as well increase queueing delay due traffic load. This work helps understanding when how gives cost-efficient reduction For general service distribution, we compare different strategies terms number redundant tasks they are issued canceled. We...