Directional Antenna System-Based DoA/RSS Estimation, Localization and Tracking in Future Wireless Networks: Algorithms and Performance Analysis

Location information plays an important role in many emerging technologies such as robotics, autonomous vehicles, and augmented reality. Already now the majority of smartphone owners use their devices' localization capabilities for a broad range of location-based services. Currently, location information in smartphones is mostly obtained in a device-centric approach, where the device to be localized, here referred to as the target node (TN), estimates its own location using, for example, the global positioning system (GPS). However, TNs with wireless communication capabilities can be localized based on their transmitted signals by a third party. In particular, localization can be implemented as a functionality of a wireless network. Depending on the application area and implementation, this network-centric approach has several advantages compared to device-centric localization, such as reducing the energy consumption within the TNs, enabling localization of non-cooperative TNs, and making location information available in the network itself. Current generation wireless networks are already capable of coarse localization. However, these existing localization capabilities do not suffice for the challenging demands of future applications. The majority of approaches moreover does not exploit the fact that an increasing number of base stations (BSs) and user devices are equipped with directional antennas. However, directional antennas enable direction of arrival (DoA) estimation that can, in turn, serve as the basis for advanced localization and location tracking. In this thesis, we thus study the application of directional antennas for localization and location tracking in future generation wireless networks. The contributions of this thesis can be grouped into two topics.First, this thesis provides a detailed study of DoA/received signal strength (RSS) estimation and localization with a group of directional antennas herein denoted as sectorized antennas. This group of antennas is of particular interest as it encompasses a broad range of directional antennas that can be implemented with a single RF front-end. Thus, the hardware complexity of sectorized antennas is low in comparison to the conventionally used antenna arrays that require multiple transceiver branches. However, at the same time this means that DoA estimation with sectorized antennas has to be implemented in a fundamentally different way. In order to address these differences, the study of sectorized antennas in this thesis includes the derivation of Cramer-Rao bounds (CRBs) for DoA/RSS estimation and localization, the proposal of three different DoA/RSS estimators, as well as numerical and analytical performance evaluations of DoA/RSS estimation and localization using sectorized antennas.Second, this thesis deals with localization based on the fusion of DoA and RSS estimates as well as DoA and time of arrival (ToA) estimates. It is shown that the combination of these estimates can result in a much increased localization performance compared to a localization based on one of these estimates alone. For the localization based on DoA/RSS estimates, a mechanism explaining this improvement is revealed by means of a CRB analysis. Thereafter, DoA/RSS-based fusion is further studied using an extended Kalman filter (EKF) as an example location tracking algorithm. Finally, an EKF is proposed that tracks the location of a TN by fusing DoA and ToA estimates. Apart from a significantly improved tracking performance, this joint DoA/ToA-EKF moreover provides estimates for the TN device clock offset and is able to localize the TN in situations where a classical DoA-only EKF fails to provide a location estimate altogether.Overall, this thesis thus provides insights into benefits of localization and location tracking using directional antennas, accompanied by specific DoA/RSS estimation, localization and location tracking solutions, as well as design guidelines for implementing localization systems in future generation wireless networks

Die strategischen Antworten Europas

Europa hat zwei Gesichter. Es gab Zeiten, da waren die Europäer vom Wunder der Integration verzaubert. Nach Jahrhunderten leidvoller Erfahrung kriegerischer Gegnerschaften, nach imperialen Verwüstungen, nach nationalistischen Eruptionen hatten die Völker des Kontinents den inneren Hebel gleichsam komplett gewendet. Diese europäische Erfolgsgeschichte setzt sich heute fort. Gleichzeitig aber erscheint die Erfolgsgeschichte Europas gegenwärtig wie die Beschreibung einer entfernten Epoche. Die Rückkehr nationaler Egoismen und eine Erosion der Zustimmung prägen vielfach die Wahrnehmung der Europäischen Union. In dieser Situation ist es hilfreich, das eigentliche Kernproblem der Integration in den Blick zu nehmen: das konzeptionelle Schisma zwischen den Mitgliedstaaten. Unvereinbare Perspektiven über die Zukunft des Kontinents prallen aufeinander. Vordergründig wird um Vertragstexte gestritten, im Kern geht es jedoch um antagonistische Zukunftsfixierungen. Ohne die Verständigung über die künftige politische Ordnung des Kontinents könnte das Europa der 25 und bald mehr Staaten erodieren, möglicherweise sogar zerfallen. Solange dies nicht offen angesprochen wird, kann es keine positive Klärung der Problemlage geben. Die zentrale strategische Frage zur Zukunft der EU bleibt bis heute unbeantwortet: Wozu neue Anstrengungen unternehmen, warum neue Kräfte mobilisieren? Die Antwort auf diese Frage liegt in den neuen Konstellationen und Bedingungen der Weltpolitik: Es geht um die künftige Gestaltungskraft Europas in einer neuen globalen Ordnung. Die Zukunft Europas wird zunehmend durch Entwicklungen außerhalb des alten Kontinents entschieden. Es droht die Gefahr einer schleichenden Marginalisierung Europas. Europa muss nicht nur auf diese Entwicklungen reagieren, es hat vielmehr das Potenzial, die Regeln der neuen ökonomischen und politischen Weltordnung nach seinen Vorstellungen mitzugestalten. Die Gestaltungsfähigkeit Europas und die Zukunft des europäischen Kontinents werden sich an der Frage entscheiden, ob es den Europäern gelingt, die "europäische Antwort" so zu erneuern, dass sie zukunftsfähig wird. Die Neubegründung Europas erfordert, dass sich der Kontinent nach innen sowie nach außen behauptet und sich gegenüber seinen Bürgern erklärt und rechtfertigt

Europe's strategic responses

"Europe has two faces. On the one hand, there was a time when Europeans were enchanted by the miracle of integration. After having experienced bitter centuries of war and enmity, imperial devastation, and outbursts of nationalism, the nations of Europe had begun to move in precisely the opposite direction.Yet, although the European success story continues to this day, it also resembles the description of a distant epoch. Perceptions of the European Union are increasingly characterized by a resurgence of national egoism and declining levels of public approval. In this situation it is helpful to recall the problem at the heart of the issue of integration, which is the conceptual schism among the member states. Contradictory and irreconcilable attitudes toward the future of Europe confront each other. The arguments are ostensibly about treaty texts, though deep down it is a matter of antagonistic views of the shape of things to come. If it proves impossible to reach some kind of agreement about the future political order of the continent, the Europe of 25 and soon more member states may well go into decline, and may possibly even fall apart. This problem cannot be resolved until the issue has been openly discussed. The principal strategic question concerning the future of the EU continues to remain unanswered.Why is there a need to undertake new efforts, why is it necessary to mobilize new powers? The answer to this question is linked to the new constellations and conditions of world politics. It has to do with Europe’s ability to shape developments in a new global order. Europe’s future is increasingly being determined by developments taking place beyond its borders. There is a danger that the old continent will gradually become marginalized. Europe must not only react to these developments, it also has the potential to inject its own ideas into the formulation of the rules governing the new economic and political world order. Both Europe's ability to exert its influence and the fate of the European continent depend on whether the Europeans will be able to renew the 'European answer' in a manner that enables them to respond effectively to future challenges. Providing Europe with a new raison d’être requires the EU to assert itself both internally and externally, and to clearly communicate the reasons for further European integration to citizens." (author's abstract

Despot/Despotie

Verwendung der Begriffe 'Despot' und 'Despotie' in verschiedenen FachdiskursenVersion 1.0 (29.04.2022; erhalten am 22.04.2022

Die strategischen Antworten Europas

Europa hat zwei Gesichter. Es gab Zeiten, da waren die Europäer vom Wunder der Integration verzaubert. Nach Jahrhunderten leidvoller Erfahrung kriegerischer Gegnerschaften, nach imperialen Verwüstungen, nach nationalistischen Eruptionen hatten die Völker des Kontinents den inneren Hebel gleichsam komplett gewendet. Diese europäische Erfolgsgeschichte setzt sich heute fort. Gleichzeitig aber erscheint die Erfolgsgeschichte Europas gegenwärtig wie die Beschreibung einer entfernten Epoche. Die Rückkehr nationaler Egoismen und eine Erosion der Zustimmung prägen vielfach die Wahrnehmung der Europäischen Union. In dieser Situation ist es hilfreich, das eigentliche Kernproblem der Integration in den Blick zu nehmen: das konzeptionelle Schisma zwischen den Mitgliedstaaten. Unvereinbare Perspektiven über die Zukunft des Kontinents prallen aufeinander. Vordergründig wird um Vertragstexte gestritten, im Kern geht es jedoch um antagonistische Zukunftsfixierungen. Die zentrale strategische Frage zur Zukunft der EU bleibt bis heute unbeantwortet: Wozu neue Anstrengungen unternehmen, warum neue Kräfte mobilisieren? Die Antwort auf diese Frage liegt in den neuen Konstellationen und Bedingungen der Weltpolitik: Es geht um die künftige Gestaltungskraft Europas in einer neuen globalen Ordnung. Die Zukunft Europas wird zunehmend durch Entwicklungen außerhalb des alten Kontinents entschieden. Es droht die Gefahr einer schleichenden Marginalisierung Europas. Europa muss nicht nur auf diese Entwicklungen reagieren, es hat vielmehr das Potenzial, die Regeln der neuen ökonomischen und politischen Weltordnung nach seinen Vorstellungen mitzugestalten. Der vorliegende Beitrag beleuchtet die Strategie der institutionellen Effizienz, die Strategie weltpolitischer Mitgestaltung sowie die Strategie für ein europäisches Selbstbewusstsein. (ICD2

Localization of the pre-squalene segment of the isoprenoid biosynthetic pathway in mammalian peroxisomes

Previous studies have indicated that the early steps in the isoprenoid/cholesterol biosynthetic pathway occur in peroxisomes. However, the role of peroxisomes in cholesterol biosynthesis has recently been questioned in several reports concluding that three of the peroxisomal cholesterol biosynthetic enzymes, namely mevalonate kinase, phosphomevalonate kinase, and mevalonate diphosphate decarboxylase, do not localize to peroxisomes in human cells even though they contain consensus peroxisomal targeting signals. We re-investigated the subcellular localization of the cholesterol biosynthetic enzymes of the pre-squalene segment in human cells by using new stable isotopic techniques and data computations with isotopomer spectral analysis, in combination with immunofluorescence and cell permeabilization techniques. Our present findings clearly show and confirm previous studies that the pre-squalene segment of the cholesterol biosynthetic pathway is localized to peroxisomes. In addition, our data are consistent with the hypothesis that acetyl-CoA derived from peroxisomal β-oxidation of very long-chain fatty acids and medium-chain dicarboxylic acids is preferentially channeled to cholesterol synthesis inside the peroxisomes without mixing with the cytosolic acetyl-CoA poo

Superconductivity in the Two-Band Hubbard Model in Infinite Dimensions

We study a two-band Hubbard model in the limit of infinite dimensions, using a combination of analytical methods and Monte-Carlo techniques. The normal state is found to display various metal to insulators transitions as a function of doping and interaction strength. We derive self-consistent equations for the local Green's functions in the presence of superconducting long-range order, and extend previous algorithms to this case. We present direct numerical evidence that in a specific range of parameter space, the normal state is unstable against a superconducting state characterized by a strongly frequency dependent order-parameter.Comment: 12 pages (14 figures not included, available upon request), Latex, LPTENS Preprint 93/1

Entanglement transmission and generation under channel uncertainty: Universal quantum channel coding

We determine the optimal rates of universal quantum codes for entanglement transmission and generation under channel uncertainty. In the simplest scenario the sender and receiver are provided merely with the information that the channel they use belongs to a given set of channels, so that they are forced to use quantum codes that are reliable for the whole set of channels. This is precisely the quantum analog of the compound channel coding problem. We determine the entanglement transmission and entanglement-generating capacities of compound quantum channels and show that they are equal. Moreover, we investigate two variants of that basic scenario, namely the cases of informed decoder or informed encoder, and derive corresponding capacity results.Comment: 45 pages, no figures. Section 6.2 rewritten due to an error in equation (72) of the old version. Added table of contents, added section 'Conclusions and further remarks'. Accepted for publication in 'Communications in Mathematical Physics