The Experts below are selected from a list of 159816 Experts worldwide ranked by ideXlab platform
Farbod Kayhan - One of the best experts on this subject based on the ideXlab platform.
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GLOBECOM - On Low Complexity Detection for QAM Isomorphic Constellations
GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017Co-Authors: Farbod KayhanAbstract:Despite of the known gap from the Shannon's capacity, several standards are still employing QAM or star shape Constellations, mainly due to the existing low complexity detectors. In this paper, we investigate the low complexity detection for a family of QAM isomorphic Constellations. These Constellations are known to perform very close to the peak-power limited capacity, outperforming the DVB-S2X standard Constellations. The proposed strategy is to first remap the received signals to the QAM constellation using the existing isomorphism and then break the log likelihood ratio computations to two one dimensional PAM Constellations. Gains larger than 0.6 dB with respect to QAM can be obtained over the peak power limited channels without any increase in detection complexity. Our scheme also provides a systematic way to design Constellations with low complexity one dimensional detectors. Several open problems are discussed at the end of the paper.
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On Low Complexity Detection for QAM Isomorphic Constellations
arXiv: Information Theory, 2017Co-Authors: Farbod KayhanAbstract:Despite of the known gap from the Shannon's capacity, several standards are still employing QAM or star shape Constellations, mainly due to the existing low complexity detectors. In this paper, we investigate the low complexity detection for a family of QAM isomorphic Constellations. These Constellations are known to perform very close to the peak-power limited capacity, outperforming the DVB-S2X standard Constellations. The proposed strategy is to first remap the received signals to the QAM constellation using the existing isomorphism and then break the log likelihood ratio computations to two one dimensional PAM Constellations. Gains larger than 0.6 dB with respect to QAM can be obtained over the peak power limited channels without any increase in detection complexity. Our scheme also provides a systematic way to design Constellations with low complexity one dimensional detectors. Several open problems are discussed at the end of the paper.
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ASMS/SPSC - QAM to circular isomorphic Constellations
2016 8th Advanced Satellite Multimedia Systems Conference and the 14th Signal Processing for Space Communications Workshop (ASMS SPSC), 2016Co-Authors: Farbod KayhanAbstract:Employing high order Constellations is inevitable in order to achieve higher spectral efficiency in satellite communi- cation systems. In DVB-S2X standard, Constellations with up to 256 points have been included. However, optimizing such high order Constellations is a difficult task. In this paper we propose a very simple constellation design based on the radial map from QAM Constellations to non-uniform APSK Constellations. Our method provides a systematic way to generate a family of optimized high order Constellations. We show that gains larger than 0.5 dB can be obtained with respect to the DVB- S2X Constellations with 256 points. Even though the proposed Constellations are essentially sub-optimal (in terms of maximizing the mutual information), they provide a very competitive test benchmark for the performance of high order Constellations. Moreover, the proposed construction potentially allows for an efficient one-dimensional soft detection by an inverse mapping to the QAM. Finally, further optimization techniques are discussed.
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ASMS/SPSC - QAM to circular isomorphic Constellations
2016 8th Advanced Satellite Multimedia Systems Conference and the 14th Signal Processing for Space Communications Workshop (ASMS SPSC), 2016Co-Authors: Farbod KayhanAbstract:Employing high order Constellations is inevitable in order to achieve higher spectral efficiency in satellite communi- cation systems. In DVB-S2X standard, Constellations with up to 256 points have been included. However, optimizing such high order Constellations is a difficult task. In this paper we propose a very simple constellation design based on the radial map from QAM Constellations to non-uniform APSK Constellations. Our method provides a systematic way to generate a family of optimized high order Constellations. We show that gains larger than 0.5 dB can be obtained with respect to the DVB- S2X Constellations with 256 points. Even though the proposed Constellations are essentially sub-optimal (in terms of maximizing the mutual information), they provide a very competitive test benchmark for the performance of high order Constellations. Moreover, the proposed construction potentially allows for an efficient one-dimensional soft detection by an inverse mapping to the QAM. Finally, further optimization techniques are discussed.
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constellation design for memoryless phase noise channels
IEEE Transactions on Wireless Communications, 2014Co-Authors: Farbod Kayhan, Guido MontorsiAbstract:In this paper, we optimize the constellation sets to be used in communication systems affected by phase noise. The main objective is to find the constellation which maximizes the channel mutual information under given power constraints. For any given constellation, the average mutual information (AMI) and the pragmatic average mutual information (PAMI) of the channel are calculated approximately, assuming that both the additive noise and phase noise are memoryless. Then, a simulated annealing algorithm is used to optimize the constellation. When the objective function is the PAMI, the proposed algorithm jointly optimizes the constellation and the binary labeling. We focus on Constellations with 8, 16, 64 and 256 signals. The performances of the optimized Constellations are compared with conventional Constellations showing considerable gains in all system scenarios. In particular, it is shown that the optimized Constellations are much more robust with respect to the changes in the phase noise characteristics than the phase shift keying (PSK) modulation and quadrature amplitude modulation (QAM).
Paul Melotti - One of the best experts on this subject based on the ideXlab platform.
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new algorithmic approaches to point constellation recognition
Information Security Conference, 2014Co-Authors: Thomas Bourgeat, Julien Bringer, Herve Chabanne, Robin Champenois, Jeremie Clement, Houda Ferradi, Marc Heinrich, Paul MelottiAbstract:Point constellation recognition is a common problem with many pattern matching applications. Whilst useful in many contexts, this work is mainly motivated by fingerprint matching. Fingerprints are traditionally modelled as Constellations of oriented points called minutiae. The fingerprint verifier’s task consists in comparing two point Constellations. The compared Constellations may differ by rotation and translation or by much more involved transforms such as distortion or occlusion.
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new algorithmic approaches to point constellation recognition
arXiv: Computer Vision and Pattern Recognition, 2014Co-Authors: Thomas Bourgeat, Julien Bringer, Herve Chabanne, Robin Champenois, Jeremie Clement, Houda Ferradi, Marc Heinrich, Paul MelottiAbstract:Point constellation recognition is a common problem with many pattern matching applications. Whilst useful in many contexts, this work is mainly motivated by fingerprint matching. Fingerprints are traditionally modelled as Constellations of oriented points called minutiae. The fingerprint verifier's task consists in comparing two point Constellations. The compared Constellations may differ by rotation and translation or by much more involved transforms such as distortion or occlusion. This paper presents three new constellation matching algorithms. The first two methods generalize an algorithm by Bringer and Despiegel. Our third proposal creates a very interesting analogy between mechanical system simulation and the constellation recognition problem.
Houda Ferradi - One of the best experts on this subject based on the ideXlab platform.
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new algorithmic approaches to point constellation recognition
Information Security Conference, 2014Co-Authors: Thomas Bourgeat, Julien Bringer, Herve Chabanne, Robin Champenois, Jeremie Clement, Houda Ferradi, Marc Heinrich, Paul MelottiAbstract:Point constellation recognition is a common problem with many pattern matching applications. Whilst useful in many contexts, this work is mainly motivated by fingerprint matching. Fingerprints are traditionally modelled as Constellations of oriented points called minutiae. The fingerprint verifier’s task consists in comparing two point Constellations. The compared Constellations may differ by rotation and translation or by much more involved transforms such as distortion or occlusion.
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new algorithmic approaches to point constellation recognition
arXiv: Computer Vision and Pattern Recognition, 2014Co-Authors: Thomas Bourgeat, Julien Bringer, Herve Chabanne, Robin Champenois, Jeremie Clement, Houda Ferradi, Marc Heinrich, Paul MelottiAbstract:Point constellation recognition is a common problem with many pattern matching applications. Whilst useful in many contexts, this work is mainly motivated by fingerprint matching. Fingerprints are traditionally modelled as Constellations of oriented points called minutiae. The fingerprint verifier's task consists in comparing two point Constellations. The compared Constellations may differ by rotation and translation or by much more involved transforms such as distortion or occlusion. This paper presents three new constellation matching algorithms. The first two methods generalize an algorithm by Bringer and Despiegel. Our third proposal creates a very interesting analogy between mechanical system simulation and the constellation recognition problem.
Jeremie Clement - One of the best experts on this subject based on the ideXlab platform.
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new algorithmic approaches to point constellation recognition
Information Security Conference, 2014Co-Authors: Thomas Bourgeat, Julien Bringer, Herve Chabanne, Robin Champenois, Jeremie Clement, Houda Ferradi, Marc Heinrich, Paul MelottiAbstract:Point constellation recognition is a common problem with many pattern matching applications. Whilst useful in many contexts, this work is mainly motivated by fingerprint matching. Fingerprints are traditionally modelled as Constellations of oriented points called minutiae. The fingerprint verifier’s task consists in comparing two point Constellations. The compared Constellations may differ by rotation and translation or by much more involved transforms such as distortion or occlusion.
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new algorithmic approaches to point constellation recognition
arXiv: Computer Vision and Pattern Recognition, 2014Co-Authors: Thomas Bourgeat, Julien Bringer, Herve Chabanne, Robin Champenois, Jeremie Clement, Houda Ferradi, Marc Heinrich, Paul MelottiAbstract:Point constellation recognition is a common problem with many pattern matching applications. Whilst useful in many contexts, this work is mainly motivated by fingerprint matching. Fingerprints are traditionally modelled as Constellations of oriented points called minutiae. The fingerprint verifier's task consists in comparing two point Constellations. The compared Constellations may differ by rotation and translation or by much more involved transforms such as distortion or occlusion. This paper presents three new constellation matching algorithms. The first two methods generalize an algorithm by Bringer and Despiegel. Our third proposal creates a very interesting analogy between mechanical system simulation and the constellation recognition problem.
Daniele Mortari - One of the best experts on this subject based on the ideXlab platform.
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The 3-D lattice theory of Flower Constellations
Celestial Mechanics and Dynamical Astronomy, 2013Co-Authors: Jeremy J. Davis, Martín E. Avendaño, Daniele MortariAbstract:Flower Constellations (FCs) have been extensively studied for use in optimal constellation design. The Harmonic FCs (HFCs) subset, representing the symmetric configurations, have recently been reformulated into 2-D Lattice Flower Constellations (2D-LFCs), encompassing the complete set of HFCs. Elliptic orbits are generally avoided due to the deleterious effects of Earth’s oblateness on the constellation, but here we present a novel concept for avoiding this problem and enabling more effective global coverage utilizing elliptic orbits. This new 3D Lattice Flower Constellations (3D-LFCs) framework generalizes the 2D-LFCs, Walker Constellations, elliptical Walker Constellations, and many of Draim’s global coverage Constellations. Previous studies have shown FCs can provide improved performance in global navigation over existing Global Navigation Satellite Systems (GNSS). We found a 3D-LFC design that improved the average positioning accuracy by 3.5 % while reducing launch $$\varDelta v$$ Δ v requirements when compared to the existing Galileo GNSS constellation.
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Design of Flower Constellations for Telecommunication Services
Proceedings of the IEEE, 2011Co-Authors: Daniele Mortari, M. Cristina De Sanctis, Mark LucenteAbstract:Satellite constellation designers take into consideration the entire telecommunication network and their design choices are influenced by many factors including: number of satellites, orbital characteristics, coverage area, network interconnections, system cost, and complexity. When the satellite constellation design method does not include a large number of possible configurations, then the final result of the design process is a suboptimal solution. Flower Constellation (FC) design provides a relatively new design approach which can overcome this problem. The time evolution of the FC theory is here summarized and the fundamental mathematics allowing the constellation design is provided. In particular, the theory is applied to the design and optimization of Constellations maximizing the global coverage and the network connectivity via intersatellite links. Performance results are compared to the classical type of satellite Constellations, i.e., the Walker Constellations. The performance improvement provided by FC design with respect to Walker Constellation design is shown. Finally, considerations regarding the cost for deployment and orbital control are also provided.
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flower constellation set theory part i compatibility and phasing
IEEE Transactions on Aerospace and Electronic Systems, 2008Co-Authors: Daniele Mortari, Matthew P. WilkinsAbstract:Flower Constellations are special satellite Constellations whose satellites follow the same 3-dimensional space track with respect to assigned rotating reference frame. This paper presents the theoretical foundation of compatibility and phasing of the Flower Constellations. Compatibility is the synchronization property of a Flower Constellation with respect to a rotating reference frame while phasing dictates the satellite distribution property. Compatibility and phasing, which are ruled by a set of five independent integer parameters, constitute the two main properties of the Flower Constellations. In particular, the dual-compatible Flower Constellations theory, which allows a simultaneous synchronization of the Flower Constellation dynamics with two independent rotating reference frames, is introduced. Meaningful examples and potential applications are briefly discussed.
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Flower Constellations for Telemedicine Services
Satellite Communications and Navigation Systems, 2008Co-Authors: M. Cristina De Sanctis, Tommaso Rossi, Marina Ruggieri, Mark Lucente, Daniele Mortari, C. Bruccoleri, Dario IzzoAbstract:Flower Constellations are a particular set of satellite Constellations where every satellite covers the same repeating space track. When the flower Constellations are visualized on an Earth centred earth fixed reference frame, the relative orbits shows flower-shaped figures centered on the Earth. In this paper the shape and the position of a particular flower Constellations has been designed for the provision of telemedicine services. Once that performance metrics of the constellation have been defined and the service targets have been identified, the performance of the flower constellation have been compared with the well known polar and Walker Constellations. The particular properties of the flower Constellations allow an optimized coverage of a list of targets. It was found that the flower Constellations provide better performance in terms access availability and mean access time.
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Flower Constellation of Orbiters for Martian Communication
2007 IEEE Aerospace Conference, 2007Co-Authors: M. Cristina De Sanctis, Tommaso Rossi, Marina Ruggieri, Mark Lucente, Daniele Mortari, Dario IzzoAbstract:Flower Constellations are a particular set of satellite Constellations where every satellite covers the same repeating space track. When the Flower Constellations are visualized on an Earth centered Earth fixed reference frame, the relative orbits show flower-shaped figures centered on the Earth. This innovative type of constellation presents features useful to be used in several applications, such as telecommunications, navigation, Earth science and interferometric radar. Several missions are foreseen to explore Mars in the next years to collect data in order to enhance our knowledge of the red planet. This effort requires the development of a reliable orbital infrastructure to support telecommunications with orbiters, landers and rovers. In this paper, a novel telecommunication architecture is presented, based on the previously introduced Flower Constellations. We designed an optimized Flower Constellation for the coverage of sites/regions of interest of the Mars surface. We proved that our proposed constellation provides better performance with respect to a reference constellation called 4retro 111 in terms of access duration and average gap time.
