Results 1 - 10 of 2,959

Blind Beamforming for Non Gaussian Signals

by Jean-François Cardoso, Antoine Souloumiac - IEE Proceedings-F , 1993
"... This paper considers an application of blind identification to beamforming. The key point is to use estimates of directional vectors rather than resorting to their hypothesized value. By using estimates of the directional vectors obtained via blind identification i.e. without knowing the arrray mani ..."
Abstract - Cited by 719 (31 self) - Add to MetaCart
range of parameters, even when the array is perfectly known to the informed beamformer. The key assumption blind identification relies on is the statistical independence of the sources, which we exploit using fourth-order cumulants. A computationally efficient technique is presented for the blind

Routing Techniques in Wireless Sensor Networks: A Survey

by Jamal N. Al-karaki, Ahmed E. Kamal - IEEE WIRELESS COMMUNICATIONS , 2004
"... Wireless Sensor Networks (WSNs) consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specifically designed for WSNs where energy awareness is an essential design issue. The focus, howeve ..."
Abstract - Cited by 741 (2 self) - Add to MetaCart
survey of different routing techniques. Overall, the routing techniques are classified into three categories based on the underlying network structure: flat, hierarchical, and location-based routing. Furthermore, these protocols can be classified into multipath-based, query-based, negotiation-based, Qo

The Cricket Location-Support System

by Nissanka B. Priyantha, Anit Chakraborty, Hari Balakrishnan , 2000
"... This paper presents the design, implementation, and evaluation of Cricket, a location-support system for in-building, mobile, locationdependent applications. It allows applications running on mobile and static nodes to learn their physical location by using listeners that hear and analyze informatio ..."
Abstract - Cited by 1058 (11 self) - Add to MetaCart
than U.S. $10. We describe the randomized algorithm used by beacons to transmit information, the use of concurrent radio and ultrasonic signals to infer distance, the listener inference algorithms to overcome multipath and interference, and practical beacon configuration and positioning techniques

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
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

Iterative (turbo) soft interference cancellation and decoding for coded CDMA

by Xiaodong Wang, H. Vincent Poor - IEEE Trans. Commun , 1999
"... Abstract — The presence of both multiple-access interference (MAI) and intersymbol interference (ISI) constitutes a major impediment to reliable communications in multipath code-division multiple-access (CDMA) channels. In this paper, an iterative receiver structure is proposed for decoding multiuse ..."
Abstract - Cited by 456 (18 self) - Add to MetaCart
Abstract — The presence of both multiple-access interference (MAI) and intersymbol interference (ISI) constitutes a major impediment to reliable communications in multipath code-division multiple-access (CDMA) channels. In this paper, an iterative receiver structure is proposed for decoding

Multipath Beamforming UWB Signal Design Based on Ternary Sequences

by Di Wu, Predrag Spasojević, Ivan Seskar
"... We study an adaptive transmission approach that exploits the increased phase coherence of ultra-wideband (UWB) channels with a “discrete ” number of reflectors relative to narrowband wireless channels. The proposed multipath beamforming technique suggests selecting a ternary or multilevel sequence f ..."
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We study an adaptive transmission approach that exploits the increased phase coherence of ultra-wideband (UWB) channels with a “discrete ” number of reflectors relative to narrowband wireless channels. The proposed multipath beamforming technique suggests selecting a ternary or multilevel sequence

Grassmannian beamforming for multiple-input multiple-output wireless systems

by David J. Love, Robert W. Heath, Jr., Thomas Strohmer - IEEE TRANS. INFORM. THEORY , 2003
"... Transmit beamforming and receive combining are simple methods for exploiting the significant diversity that is available in multiple-input and multiple-output (MIMO) wireless systems. Unfortunately, optimal performance requires either complete channel knowledge or knowledge of the optimal beamformi ..."
Abstract - Cited by 329 (38 self) - Add to MetaCart
beamforming vector which are not always realizable in practice. In this correspondence, a quantized maximum signal-to-noise ratio (SNR) beamforming technique is proposed where the receiver only sends the label of the best beamforming vector in a predetermined codebook to the transmitter. By using

On Beamforming with Finite Rate Feedback in Multiple Antenna Systems

by Krishna Kiran Mukkavilli, Ashutosh Sabharwal, Elza Erkip, Behnaam Aazhang , 2003
"... In this paper, we study a multiple antenna system where the transmitter is equipped with quantized information about instantaneous channel realizations. Assuming that the transmitter uses the quantized information for beamforming, we derive a universal lower bound on the outage probability for any f ..."
Abstract - Cited by 272 (14 self) - Add to MetaCart
is the number of feedback bits and t is the number of transmit antennas. The geometrical bounding technique, used in the proof of the lower bound, also leads to a design criterion for good beamformers, whose outage performance approaches the lower bound. The design criterion minimizes the maximum inner product

Techniques for Multipath and Interference Mitigation in Galileo Ground Stations

by Marc Barceló, Gonzalo Seco-granados, Jose Lopez Vicario, Marc Barcelo, Gonzalo Seco-granados, Felix Antreich, Joan Manuel Cebrian, Joan Picanyol, Francisco Amarillo , 2010
"... A novel look into digital beamforming ..."
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A novel look into digital beamforming

Broadband Beamforming

by Kalpana Seshadrinathan
"... Broadband wireless channels, where high data rates are transmitted, are extremely dispersive in nature. A fundamental challenge in the design of equalizers for the broadband case lies in reducing complexity. Broadband finite impulse response (FIR) beamformers employ a space-time antenna array which ..."
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reduces the multipath delay spread to narrowband levels. The beamformers should additionally preserve the whiteness of the channel noise at the beamformer output to allow for the application of trellis based equalizers. The power complementarity property has been used to address this issue
Results 1 - 10 of 2,959