References of "Ottersten, Björn 50002797"
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See detailCarrier Allocation for Hybrid Satellite-Terrestrial Backhaul Networks
Lagunas, Eva UL; Maleki, Sina UL; Lei, Lei UL et al

in ICC Workshop on Satellite Communications: Challenges and Integration in the 5G ecosystem, Paris, France, May 2017 (2017, May)

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See detailOn the Diversity of Partial Relaying Cooperation with Relay Selection in Finite-SNR Regime
Vu, Thang Xuan UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE International Conference on Communications (2017, May)

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See detailFinite-SNR analysis for partial relaying cooperation with channel coding and opportunistic relay selection
Vu, Thang Xuan UL; Duhamel, Pierre; Chatzinotas, Symeon UL et al

in EURASIP Journal on Advances in Signal Processing (2017)

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See detailSpectral-Efficient Model for Multiuser Massive MIMO: Exploiting User Velocity
Vu, Thang Xuan UL; Trinh, Anh Vu; Chatzinotas, Symeon UL et al

in IEEE international Conference on Communications (2017, May)

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See detailDiscrimination of Angle-Doppler Signatures using Arbitrary Phase Center Motion for MIMO Radars
Hammes, Christian UL; Nijsure, Yogesh UL; Shankar, Bhavani UL et al

in IEEE Radar Conf 2017 (2017, May)

A novel Phase Center Motion (PCM) based technique for discriminating angle-Doppler signatures within Multiple-Input-Multiple-Output (MIMO) radars using Frequency Modulated Continuous Wave (FMCW) has been ... [more ▼]

A novel Phase Center Motion (PCM) based technique for discriminating angle-Doppler signatures within Multiple-Input-Multiple-Output (MIMO) radars using Frequency Modulated Continuous Wave (FMCW) has been explored in this work. The PCM technique induces angle dependent Doppler shifts in the back-scattered signal, wherein a modified Doppler post processing for FMCW leads to joint angle-Doppler processing. Specifically, we intend to design unique spatialtemporal motion of the phase center on each individual MIMO radar channel in an effort to synthesize nearly orthogonal angle-Doppler signatures. Subsequently, we also develop a MIMO radar receiver design, which would be capable of discriminating between these induced angle-Doppler signatures. The asymptotic investigation provides a Bessel function characteristic. Simulation results demonstrate a significant side-lobe suppression of 8:5 dB for an individual PCM trajectory and 7 dB over distinct PCM trajectories, in an attempt towards realization of nearly orthogonal MIMO radar channels. [less ▲]

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See detailFaster-than-Nyquist Spatiotemporal Symbol-level Precoding in the Downlink of Multiuser MISO Channels
Alodeh, Maha UL; Spano, Danilo UL; Chatzinotas, Symeon UL et al

in The 42nd IEEE International Conference on Acoustics, Speech and Signal Processing (2017, March)

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See detailSpectral coexistence for next generation wireless backhaul networks
Sharma, Shree Krishna; Lagunas, Eva UL; Tsinos, Christos UL et al

in Access, Fronthaul and Backhaul Networks for 5G and Beyond (2017)

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See detailOn the Energy-Efficiency of Hybrid Analog-Digital Transceivers for Single- and Multi-carrier Large Antenna Array Systems
Tsinos, Christos UL; Maleki, Sina UL; Chatzinotas, Symeon UL et al

in IEEE Journal on Selected Areas In Communications (2017)

Hybrid Analog-Digital transceivers are employed with the view to reduce the hardware complexity and the energy consumption in millimeter wave/large antenna array systems by reducing the number of their ... [more ▼]

Hybrid Analog-Digital transceivers are employed with the view to reduce the hardware complexity and the energy consumption in millimeter wave/large antenna array systems by reducing the number of their Radio Frequency (RF) chains. However, the analog processing network requires power for its operation and it further introduces power losses, dependent on the number of the transceiver antennas and RF chains, that have to be compensated. Thus, the reduction in the power consumption is usually much less than it is expected and given that the hybrid solutions present in general inferior spectral efficiency than a fully digital one, it is possible for the former to be less energy efficient than the latter in several cases. Existing approaches propose hybrid solutions that maximize the spectral efficiency of the system without providing any insight on their energy requirements/efficiency. To that end, in this paper, a novel algorithmic framework is developed based on which energy efficient hybrid transceiver designs are derived and their performance is examined with respect to the number of RF chains and antennas. Solutions are proposed for fully and partially connected hybrid architectures and for both single- and multi-carrier systems under the Orthogonal Frequency Division Multiplexing (OFDM) modulation. Simulations and theoretical results provide insight on the cases where a hybrid transceiver is the most energy efficient solution or not. [less ▲]

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See detailCodebook-Based Hybrid Precoding for Millimeter Wave Multiuser Systems
He, S.; Wang, J.; Huang, Y. et al

in IEEE Transactions on Signal Processing (2017), 65(20), 5289-5304

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See detailMulti-cell interference coordination for multigroup multicast transmission
Tervo, O.; Pennanen, H.; Chatzinotas, Symeon UL et al

in 2017 European Conference on Networks and Communications (EuCNC) (2017)

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See detailDeformation Based Curved Shape Representation
Demisse, Girum UL; Aouada, Djamila UL; Ottersten, Björn UL

in IEEE Transactions on Pattern Analysis & Machine Intelligence (2017)

In this paper, we introduce a deformation based representation space for curved shapes in Rn. Given an ordered set of points sampled from a curved shape, the proposed method represents the set as an ... [more ▼]

In this paper, we introduce a deformation based representation space for curved shapes in Rn. Given an ordered set of points sampled from a curved shape, the proposed method represents the set as an element of a finite dimensional matrix Lie group. Variation due to scale and location are filtered in a preprocessing stage, while shapes that vary only in rotation are identified by an equivalence relationship. The use of a finite dimensional matrix Lie group leads to a similarity metric with an explicit geodesic solution. Subsequently, we discuss some of the properties of the metric and its relationship with a deformation by least action. Furthermore, invariance to reparametrization or estimation of point correspondence between shapes is formulated as an estimation of sampling function. Thereafter, two possible approaches are presented to solve the point correspondence estimation problem. Finally, we propose an adaptation of k-means clustering for shape analysis in the proposed representation space. Experimental results show that the proposed representation is robust to uninformative cues, e.g. local shape perturbation and displacement. In comparison to state of the art methods, it achieves a high precision on the Swedish and the Flavia leaf datasets and a comparable result on MPEG-7, Kimia99 and Kimia216 datasets. [less ▲]

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See detailEnhanced Trajectory-based Action Recognition using Human Pose
Papadopoulos, Konstantinos UL; Goncalves Almeida Antunes, Michel UL; Aouada, Djamila UL et al

in IEEE International Conference on Image Processing, Beijing 17-20 Spetember 2017 (2017)

Action recognition using dense trajectories is a popular concept. However, many spatio-temporal characteristics of the trajectories are lost in the final video representation when using a single Bag-of ... [more ▼]

Action recognition using dense trajectories is a popular concept. However, many spatio-temporal characteristics of the trajectories are lost in the final video representation when using a single Bag-of-Words model. Also, there is a significant amount of extracted trajectory features that are actually irrelevant to the activity being analyzed, which can considerably degrade the recognition performance. In this paper, we propose a human-tailored trajectory extraction scheme, in which trajectories are clustered using information from the human pose. Two configurations are considered; first, when exact skeleton joint positions are provided, and second, when only an estimate thereof is available. In both cases, the proposed method is further strengthened by using the concept of local Bag-of-Words, where a specific codebook is generated for each skeleton joint group. This has the advantage of adding spatial human pose awareness in the video representation, effectively increasing its discriminative power. We experimentally compare the proposed method with the standard dense trajectories approach on two challenging datasets. [less ▲]

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See detailUnsupervised Vanishing Point Detection and Camera Calibration from a Single Manhattan Image with Radial Distortion
Goncalves Almeida Antunes, Michel UL; Barreto, Joao P.; Aouada, Djamila UL et al

in IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2017 (2017)

The article concerns the automatic calibration of a camera with radial distortion from a single image. It is known that, under the mild assumption of square pixels and zero skew, lines in the scene ... [more ▼]

The article concerns the automatic calibration of a camera with radial distortion from a single image. It is known that, under the mild assumption of square pixels and zero skew, lines in the scene project into circles in the image, and three lines suffice to calibrate the camera up to an ambiguity between focal length and radial distortion. The calibration results highly depend on accurate circle estimation, which is hard to accomplish, because lines tend to project into short circular arcs. To overcome this problem, we show that, given a short circular arc edge, it is possible to robustly determine a line that goes through the center of the corresponding circle. These lines, henceforth called Lines of Circle Centres (LCCs), are used in a new method that detects sets of parallel lines and estimates the calibration parameters, including the center and amount of distortion, focal length, and camera orientation with respect to the Manhattan frame. Extensive experiments in both semi-synthetic and real images show that our algorithm outperforms state- of-the-art approaches in unsupervised calibration from a single image, while providing more information. [less ▲]

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See detailDynamic Spectrum Sharing in 5G Wireless Networks with Full-Duplex Technology: Recent Advances and Research Challenges
Sharma; Bogale; Le et al

in IEEE Communications Surveys and Tutorials (2017)

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See detailEnergy-efficient coordinated multi-cell multi-group multicast beamforming with antenna selection
Tervo, O.; Tran, L. N.; Pennanen, H. et al

in 2017 IEEE International Conference on Communications Workshops (ICC) (2017)

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See detailMulti-Target Localization in Asynchronous MIMO Radars Using Sparse Sensing
Sedighi, Saeid UL; Shankar, Bhavani UL; Maleki, Sina UL et al

Scientific Conference (2017)

Multi-target localization, warranted in emerging applications like autonomous driving, requires targets to be perfectly detected in the distributed nodes with accurate range measurements. This implies ... [more ▼]

Multi-target localization, warranted in emerging applications like autonomous driving, requires targets to be perfectly detected in the distributed nodes with accurate range measurements. This implies that high range resolution is crucial in distributed localization in the considered scenario. This work proposes a new framework for multi-target localization, addressing the demand for the high range resolution in automotive applications without increasing the required bandwidth. In particular, it employs sparse stepped frequency waveform and infers the target ranges by exploiting sparsity in target scene. The range measurements are then sent to a fusion center where direction of arrival estimation is undertaken. Numerical results illustrate the impact of range resolution on multi-target localization and the performance improvement arising from the proposed algorithm in such scenarios. [less ▲]

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See detailModelling and Performance Analysis of Cognitive Radio Systems from a Deployment Perspective
Kaushik, Ankit; Sharma, Shree Krishna; Chatzinotas, Symeon UL et al

in Handbook of Cognitive Radio (2017)

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See detailMIMO directional modulation M-QAM precoding for transceivers performance enhancement.
Kalantari, Ashkan UL; Tsinos, Christos UL; Soltanalian, Mojtaba UL et al

in MIMO directional modulation M-QAM precoding for transceivers performance enhancement. (2017)

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See detailFraud Detection by Stacking Cost-Sensitive Decision Trees
Correa Bahnsen, Alejandro; Villegas, Sergio; Aouada, Djamila UL et al

in Data Science for Cyber-Security (DSCS), London 25-27 September (2017)

Detailed reference viewed: 172 (3 UL)