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Cognitive Radio: Brain-Empowered Wireless Communications

by Simon Haykin , 2005
"... Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment and use ..."
Abstract - Cited by 1541 (4 self) - Add to MetaCart
and uses the methodology of understanding-by-building to learn from the environment and adapt to statistical variations in the input stimuli, with two primary objectives in mind: • highly reliable communication whenever and wherever needed; • efficient utilization of the radio spectrum. Following

Packet Switching In Radio Channels: Part III -- Polling and . . .

by Fouad A. Tobagi, Leonard Kleinrock - IEEE TRANSACTIONS ON COMMUNICATIONS , 1976
"... Here we continue the analytic study of packet switching in radio channels which we reported upon in our two previous papers [ 11, [2]. Again we consider a population of terminals communicating with a central station over a packet-switched radio channel. The allocation of bandwidth among the contend ..."
Abstract - Cited by 517 (5 self) - Add to MetaCart
Here we continue the analytic study of packet switching in radio channels which we reported upon in our two previous papers [ 11, [2]. Again we consider a population of terminals communicating with a central station over a packet-switched radio channel. The allocation of bandwidth among

Matching pursuits with time-frequency dictionaries

by Stephane G. Mallat, Zhifeng Zhang - IEEE Transactions on Signal Processing , 1993
"... Abstract-We introduce an algorithm, called matching pursuit, that decomposes any signal into a linear expansion of waveforms that are selected from a redundant dictionary of functions. These waveforms are chosen in order to best match the signal structures. Matching pursuits are general procedures t ..."
Abstract - Cited by 1671 (13 self) - Add to MetaCart
to compute adaptive signal representations. With a dictionary of Gabor functions a matching pursuit defines an adaptive time-frequency transform. We derive a signal energy distribution in the time-frequency plane, which does not include interference terms, unlike Wigner and Cohen class distributions. A

Adaptive clustering for mobile wireless networks

by Chunhung Richard Lin, Mario Gerla - IEEE Journal on Selected Areas in Communications , 1997
"... This paper describes a self-organizing, multihop, mobile radio network, which relies on a code division access scheme for multimedia support. In the proposed network architecture, nodes are organized into nonoverlapping clusters. The clusters are independently controlled and are dynamically reconfig ..."
Abstract - Cited by 561 (11 self) - Add to MetaCart
This paper describes a self-organizing, multihop, mobile radio network, which relies on a code division access scheme for multimedia support. In the proposed network architecture, nodes are organized into nonoverlapping clusters. The clusters are independently controlled and are dynamically

Taming the Underlying Challenges of Reliable Multihop Routing in Sensor Networks

by Alec Woo, Terence Tong, David Culler - In SenSys , 2003
"... The dynamic and lossy nature of wireless communication poses major challenges to reliable, self-organizing multihop networks. These non-ideal characteristics are more problematic with the primitive, low-power radio transceivers found in sensor networks, and raise new issues that routing protocols mu ..."
Abstract - Cited by 781 (20 self) - Add to MetaCart
The dynamic and lossy nature of wireless communication poses major challenges to reliable, self-organizing multihop networks. These non-ideal characteristics are more problematic with the primitive, low-power radio transceivers found in sensor networks, and raise new issues that routing protocols

Capacity of Fading Channels with Channel Side Information

by Andrea J. Goldsmith , et al. , 1997
"... We obtain the Shannon capacity of a fading channel with channel side information at the transmitter and receiver, and at the receiver alone. The optimal power adaptation in the former case is "water-pouring" in time, analogous to water-pouring in frequency for time-invariant frequency-sele ..."
Abstract - Cited by 586 (20 self) - Add to MetaCart
We obtain the Shannon capacity of a fading channel with channel side information at the transmitter and receiver, and at the receiver alone. The optimal power adaptation in the former case is "water-pouring" in time, analogous to water-pouring in frequency for time-invariant frequency

RADAR: an in-building RF-based user location and tracking system

by Paramvir Bahl, Venkata N. Padmanabhan , 2000
"... The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF) based system for locating and tracking users inside buildings. RADAR operates by recording and ..."
Abstract - Cited by 2036 (14 self) - Add to MetaCart
The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF) based system for locating and tracking users inside buildings. RADAR operates by recording

Topology Control of Multihop Wireless Networks using Transmit Power Adjustment

by Ram Ramanathan , Regina Rosales-hain , 2000
"... We consider the problem of adjusting the transmit powers of nodes in a multihop wireless network (also called an ad hoc network) to create a desired topology. We formulate it as a constrained optimization problem with two constraints- connectivity and biconnectivity, and one optimization objective- ..."
Abstract - Cited by 688 (3 self) - Add to MetaCart
- maximum power used. We present two centralized algorithms for use in static networks, and prove their optimality. For mobile networks, we present two distributed heuristics that adaptively adjust node transmit powers in response to topological changes and attempt to maintain a connected topology using

Recognizing human actions: A local SVM approach

by Christian Schüldt, Ivan Laptev, Barbara Caputo - In ICPR , 2004
"... Local space-time features capture local events in video and can be adapted to the size, the frequency and the velocity of moving patterns. In this paper we demonstrate how such features can be used for recognizing complex motion patterns. We construct video representations in terms of local space-ti ..."
Abstract - Cited by 758 (20 self) - Add to MetaCart
Local space-time features capture local events in video and can be adapted to the size, the frequency and the velocity of moving patterns. In this paper we demonstrate how such features can be used for recognizing complex motion patterns. We construct video representations in terms of local space

GPS-Less Low Cost Outdoor Localization for Very Small Devices.

by Nirupama Bulusu , John Heidemann , Deborah Estrin - IEEE Personal Communications Magazine, , 2000
"... Abstract-Instrumenting the physical world through large networks of wireless sensor nodes, particularly for applications like environmental monitoring of water and soil, requires that these nodes be very small, light, untethered and unobtrusive. The problem of localization, i.e., determining where ..."
Abstract - Cited by 1000 (27 self) - Add to MetaCart
in these networks. In this paper, we review localization techniques and evaluate the effectiveness of a very simple connectivity-metric method for localization in outdoor environments that makes use of the inherent radio-frequency (RF) communications capabilities of these devices. A fixed number of reference points
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