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Spectral Efficiency in the Wideband Regime

by Sergio Verdú , 2002
"... The tradeoff of spectral efficiency (b/s/Hz) versus energy -per-information bit is the key measure of channel capacity in the wideband power-limited regime. This paper finds the fundamental bandwidth--power tradeoff of a general class of channels in the wideband regime characterized by low, but nonz ..."
Abstract - Cited by 393 (29 self) - Add to MetaCart
The tradeoff of spectral efficiency (b/s/Hz) versus energy -per-information bit is the key measure of channel capacity in the wideband power-limited regime. This paper finds the fundamental bandwidth--power tradeoff of a general class of channels in the wideband regime characterized by low

Cooperative diversity in wireless networks: efficient protocols and outage behavior

by J. Nicholas Laneman, David N. C. Tse, Gregory W. Wornell - IEEE TRANS. INFORM. THEORY , 2004
"... We develop and analyze low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks. The underlying techniques exploit space diversity available through cooperating terminals’ relaying signals for one another. We outline several strategies ..."
Abstract - Cited by 2009 (31 self) - Add to MetaCart
the destination terminal. We develop performance characterizations in terms of outage events and associated outage probabilities, which measure robustness of the transmissions to fading, focusing on the high signal-to-noise ratio (SNR) regime. Except for fixed decode-and-forward, all of our cooperative diversity

Laplacian eigenmaps and spectral techniques for embedding and clustering.

by Mikhail Belkin , Partha Niyogi - Proceeding of Neural Information Processing Systems, , 2001
"... Abstract Drawing on the correspondence between the graph Laplacian, the Laplace-Beltrami op erator on a manifold , and the connections to the heat equation , we propose a geometrically motivated algorithm for constructing a representation for data sampled from a low dimensional manifold embedded in ..."
Abstract - Cited by 668 (7 self) - Add to MetaCart
in a higher dimensional space. The algorithm provides a computationally efficient approach to nonlinear dimensionality reduction that has locality preserving properties and a natural connection to clustering. Several applications are considered. In many areas of artificial intelligence, information

A Transmission Control Scheme for Media Access in Sensor Networks

by Alec Woo, David E. Culler , 2001
"... We study the problem of media access control in the novel regime of sensor networks, where unique application behavior and tight constraints in computation power, storage, energy resources, and radio technology have shaped this design space to be very different from that found in traditional mobile ..."
Abstract - Cited by 481 (11 self) - Add to MetaCart
computing regime. Media access control in sensor networks must not only be energy efficient but should also allow fair bandwidth allocation to the infrastructure for all nodes in a multihop network. We propose an adaptive rate control mechanism aiming to support these two goals and find that such a scheme

Simplified processing for high spectral efficiency wireless communication employing multi-element arrays

by Gerard J. Foschini, Glen D. Golden, Reinaldo A. Valenzuela, Peter W. Wolniansky - IEEE J. Select. Areas Commun , 1999
"... Abstract — We investigate robust wireless communication in high-scattering propagation environments using multi-element antenna arrays (MEA’s) at both transmit and receive sites. A simplified, but highly spectrally efficient space–time communication processing method is presented. The user’s bit str ..."
Abstract - Cited by 256 (4 self) - Add to MetaCart
Abstract — We investigate robust wireless communication in high-scattering propagation environments using multi-element antenna arrays (MEA’s) at both transmit and receive sites. A simplified, but highly spectrally efficient space–time communication processing method is presented. The user’s bit

Distributed Multiuser Power Control for Digital Subscriber Lines

by Wei Yu, George Ginis, John M. Cioffi , 2002
"... This paper considers the multiuser power control problem in a frequency-selective interference channel. The interference channel is modeled as a noncooperative game, and the existence and uniqueness of a Nash equilibrium are established for a two-player version of the game. An iterative water-fillin ..."
Abstract - Cited by 271 (23 self) - Add to MetaCart
allocation by offering an opportunity for loops to negotiate the best use of power and frequency with each other. When applied to the upstream power backoff problem in very-high bit-rate digital subscriber lines and the downstream spectral compatibility problem in asymmetric digital subscriber lines, the new

Achievable Rates in Cognitive Radio Channels

by Natasha Devroye, Patrick Mitran, Vahid Tarokh - IEEE Trans. Inf. Theory , 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 dramatically increase spectral efficiency. In this pape ..."
Abstract - Cited by 274 (46 self) - Add to MetaCart
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 dramatically increase spectral efficiency

Spectral segmentation with multiscale graph decomposition

by Timothée Cour, Florence Bénézit, Jianbo Shi - In CVPR , 2005
"... We present a multiscale spectral image segmentation algorithm. In contrast to most multiscale image processing, this algorithm works on multiple scales of the image in parallel, without iteration, to capture both coarse and fine level details. The algorithm is computationally efficient, allowing to ..."
Abstract - Cited by 185 (3 self) - Add to MetaCart
We present a multiscale spectral image segmentation algorithm. In contrast to most multiscale image processing, this algorithm works on multiple scales of the image in parallel, without iteration, to capture both coarse and fine level details. The algorithm is computationally efficient, allowing

Signal Space Diversity : A Power and Bandwidth Efficient Diversity Technique for the Rayleigh Fading Channel

by Joseph Boutros, Emanuele Viterbo - IEEE Trans. on Information Theory , 1998
"... Abstract—The increasing need for high data-rate transmissions over time- or frequency-selective fading channels has drawn attention to modulation schemes with high spectral efficiency such as QAM. With the aim of increasing the “diversity order” of the signal set we consider multidimensional rotated ..."
Abstract - Cited by 188 (27 self) - Add to MetaCart
Abstract—The increasing need for high data-rate transmissions over time- or frequency-selective fading channels has drawn attention to modulation schemes with high spectral efficiency such as QAM. With the aim of increasing the “diversity order” of the signal set we consider multidimensional

Cognitive multiple access via cooperation: Protocol design and performance analysis

by Ahmed K. Sadek, K. J. Ray Liu, Anthony Ephremides - IEEE Trans. on Information Theory , 2007
"... Abstract—In this paper, a novel cognitive multiple-access strategy in the presence of a cooperating relay is proposed. Exploiting an important phenomenon in wireless networks, source burstiness, the cognitive relay utilizes the periods of silence of the terminals to enable cooperation. Therefore, no ..."
Abstract - Cited by 77 (24 self) - Add to MetaCart
reveal that the proposed protocols provide significant performance gains over conventional relaying strategies such as selection and incremental relaying, specially at high spectral efficiency regimes. The rationale is that the lossless bandwidth property of the proposed protocols results in a graceful
Results 1 - 10 of 4,486