Dissertations / Theses on the topic 'NLOS'

Les avancées récentes dans le domaine de navigation par satellites (GNSS) ontconduit à une prolifération des applications de géolocalisation dans les milieux urbains. Pourde tels environnements, les applications GNSS souffrent d’une grande dégradation liée à laréception des signaux satellitaires en lignes indirectes (NLOS) et en multitrajets (MP). Cetravail de thèse propose une méthodologie originale pour l’utilisation constructive des signauxdégradés MP/NLOS, en appliquant des techniques avancées de traitement du signal ou àl’aide d’une assistance d’un simulateur 3D de propagation des signaux GNSS. D’abord, nousavons établi le niveau maximal réalisable sur la précision de positionnement par un systèmeGNSS "Stand-Alone" en présence de conditions MP/NLOS, en étudiant les bornes inférieuressur l’estimation en présence des signaux MP/NLOS. Pour mieux améliorer ce niveau deprécision, nous avons proposé de compenser les erreurs NLOS en utilisant un simulateur 3D dessignaux GNSS afin de prédire les biais MP/NLOS et de les intégrer comme des observationsdans l’estimation de la position, soit par correction des mesures dégradées ou par sélectiond’une position parmi une grille de positions candidates. L’application des approches proposéesdans un environnement urbain profond montre une bonne amélioration des performances depositionnement dans ces conditions
Recent trends in Global Navigation Satellite System (GNSS) applications inurban environments have led to a proliferation of studies in this field that seek to mitigatethe adverse effect of non-line-of-sight (NLOS). For such harsh urban settings, this dissertationproposes an original methodology for constructive use of degraded MP/NLOS signals, insteadof their elimination, by applying advanced signal processing techniques or by using additionalinformation from a 3D GNSS simulator. First, we studied different signal processing frameworks,namely robust estimation and regularized estimation, to tackle this GNSS problemwithout using an external information. Then, we have established the maximum achievablelevel (lower bounds) of GNSS Stand-Alone positioning accuracy in presence of MP/NLOSconditions. To better enhance this accuracy level, we have proposed to compensate for theMP/NLOS errors using a 3D GNSS signal propagation simulator to predict the biases andintegrate them as observations in the estimation method. This could be either by correctingdegraded measurements or by scoring an array of candidate positions. Besides, new metricson the maximum acceptable errors on MP/NLOS errors predictions, using GNSS simulations,have been established. Experiment results using real GNSS data in a deep urban environmentshow that using these additional information provides good positioning performance enhancement,despite the intensive computational load of 3D GNSS simulation

The advent of wireless location technology and the increase in location-based services, has meant the need to investigate efficient network-based location methods becoming of paramount importance. Therefore, the interest in wireless positioning techniques has been increasing over recent decades. Among mobile positioning techniques, the Time of Arrival (TOA) and Time Difference of Arrival (TDOA) look promising. For the purpose of dealing with such technologies, some classic algorithms such as least square, most likelihood and Taylor method have been used to solve the estimation, which distinguishes the location. However, in real practice, there are certain factors that influence the level of location accuracy. The two most significant factors are cellular topologies and non-line-of-sight (NLOS) effect. This thesis reviews existing approaches and suggests innovative methods for both line-of-sight (LOS) and NLOS scenarios. A simulation platform is designed to test and compare the performances of these algorithms. The results of the simulation compared with actual position measurements demonstrate that the innovative approaches have high positioning accuracy. Additionally, this thesis demonstrates different types of cellular topologies and develops a simulation to show how the cellular topology affects the positioning quality level. Finally, this thesis implements an experiment to exhibit how the innovative algorithms perform in the real world.

Specialists are expecting the knowledge of location will trigger yet another revolution in mobile services. Location-base services (LBS) have attracted many researchers and enterprises and one of the key aspects of LBS is positioning technology. Considering a wider and more complex field - ubiquitous computing, location is the fundamental element. This work focuses on some aspects of the new techniques of terrestrial positioning systems. Wireless LAN is one of the most popular systems used for positioning for indoor environments and public places. We have investigated the trilateration and fingerprinting approaches and the results showed the advantages of fingerprinting. A novel method to generate the fingerprints database based on Universal Kriging (UK) was developed, which can not only significantly decrease the training time, but also increase the accuracy of estimates. In mobile phone positioning systems, most techniques suffer from the non-line-of-sight (NLOS) propagation. We investigated the specifics of NLOS error, and proposed a method to mitigate the errors. Furthermore, a new algorithm named WSMM (wireless signal map matching) was discussed. Simulations and experiments verified the idea, and the accuracy of positioning can be improved greatly. Since fingerprinting technique can utilize rather than suffer from the NLOS propagation, it was also applied in mobile phone positioning system. Experiments showed both the deterministic approach and probabilistic approach can provide better results comparing with other techniques in suburban area. To achieve a robust positioning system and provide more useful information of the user, multisensor combination and data fusion are necessary. As the first step of future research, a mulitsensor synchronization system was developed. This system can promisingly achieve synchronization with error less than 0.4 ms, which is suitable for most land applications. Hence the main findings of this thesis are: (1) a novel method of yielding fingerprint database for both wireless LAN (WLAN) and mobile phone systems when using the fingerprinting technique for positioning; (2) a database method to mitigate NLOS error for mobile phone positioning systems; (3) a low cost synchronization system for integration of multiple sensors.

The use of ubiquitous network has made real time tracking of objects, animals and human beings easy through the use of radio frequency identification system (RFID). Localization techniques in RFID rely on accurate estimation of the read range between the reader and the tags. The tags consist of a small chip and a printed antenna which receives from and transmits information to the reader. The range information about the distance between the tag and the reader is obtained from the received signal strength indication (RSSI). Accuracy of the read range using RSSI can be very complicated especially in complicated propagation environment due to the nature and features of the environment. There are different kinds of localisation systems and they are Global Positioning System (GPS) which can be used for accurate outdoor localization; while technologies like artificial vision, ultrasonic signals, infrared and radio frequency signals can be employed for indoor localization. This project focuses on the location estimation in RFID Non Line-of-Sight (NLOS) environment using Real Time Localization System (RTLS) with passive tags, in carrying out passengers and baggage tracking at the airport. Indoor location radio sensing suffers from reflection, refraction and diffractions due to the nature of the environment. This unfavourable phenomenon called multipath leads to delay in the arrival of signal and the strength of signal received by receiving antenna within the propagation channel which in turns affects the RSSI, yielding inaccurate location estimation. RTLS based on time difference of arrival and error compensation technique and extended Kalman filter technique were employed in a NLOS environment to determine the location of tag. The better method for location estimation in a NLOS between the Kalman filtering and extended Kalman filtering is investigated. According to simulation results, the extended Kalman filtering technique is more suitable to be applied to RTLS.

Thesis (M.S. in Systems Technology (Command Control and Communications))--Naval Postgraduate School, June 1990.
Thesis Advisor(s): Caldwell, William J. "June 1990." Description based on title screen as viewed on October 16, 2009. Author(s) subject terms: NLOS Weapon System Description, NLOS Organization and Employment, NLOS Command and Control, NLOS Command and Control Testing. Includes bibliographical references (p. 63).

The global war on terror emphasizes the need for a weapon system that can improve the self-defense capability of the U.S Navy ship against small surface craft threats. This MSSE Capstone Project investigated the feasibility of integrating the Non-Line of Sight Launching System (NLOS-LS) onto U.S. Navy ships. In particular, the focus of the project was on the DDG-51 class ships. The NLOS-LS was originally designed to provide support to Army ground forces against over the horizon threats. The U.S. Navy recognizes the prospect of this weapon in an at-sea environment. The capability of the system has been proven through its developmental testing to date and illustrates the potential to the U.S. Navy for ship defense. System integration involves incorporating a stand-alone, land-based system onto a ship with an existing shipboard combat system. This report addresses the top-level integration issues, such as the physical installation and combat system integration, and provides recommendations related to some important concerns that include interface analysis, functional analysis, system behavior, and physical installation. This analysis concludes with a notional implementation for many issues and provides a risk analysis for those issues. It also identifies many integration areas requiring further research.

En autorisant de nouveaux services centrés sur l'utilisateur (navigation indoor contextuelle, surveillance/inventaire de biens personnels, etc.), les nouvelles fonctions de radiolocalisation sont en passe de modifier en profondeur les usages liés à la mobilité. Dans ce contexte, la technologie radio ultra large bande impulsionnelle (IR-UWB), qui permet en théorie d'apprécier le temps de vol des impulsions transmises à l'échelle de la nanoseconde et donc, la distance séparant l'émetteur du récepteur avec une précision de l'ordre de quelques dizaines de centimètres seulement, a été régulièrement mise en avant ces dix dernières années. En dépit de ces bonnes dispositions, l'obstruction des liens radio par le(s) corps ou les obstacles (murs, mobilier...) donne toutefois lieu à des erreurs significatives sur les distances mesurées, dégradant d'autant les performances de positionnement, en particulier en environnements fermés (ex. indoor). Dans le cadre de cette thèse, on se proposait d'exploiter une architecture intégrée de récepteur IR-UWB, permettant d'estimer la réponse du canal multi-trajets dans son ensemble, afin d'améliorer la fonction de localisation. Une étude détaillée de ce canal radio mobile, tel que perçu par le récepteur, a d'abord été menée, débouchant sur une interprétation déterministe (c'est-à-dire géométrique) de l'évolution temporelle relative des composantes multi-trajets, ainsi qu'à une modélisation de leur interférence mutuelle. En s'appuyant sur l'étude précédente, des algorithmes de détection, d'association et de suivi des impulsions reçues (ex. batterie de filtres de Kalman à hypothèses multiples) ont alors été proposés. Ces différentes propositions tirent profit des spécificités de l'architecture du récepteur, en visant d'une part, à exploiter la cohérence spatio-temporelle des composantes multi-trajets résolues en réception, et d'autre part, à minimiser l'effet néfaste de leurs collisions au sein de canaux mobiles particulièrement denses (ex. via une estimation de canal multi-bandes). Les solutions apportées permettent en particulier, pour chaque lien radio en situation de non-visibilité, de corriger le temps d'arrivée des trajets directs manquants à partir de trajets secondaires suivis, tout en autorisant l'utilisation d'une structure de filtre classique pour la poursuite du mobile (c'est-à-dire, alimenté par plusieurs liens radio ainsi "corrigés" vis-à-vis de différentes balises fixes). Ces développements algorithmiques ont d'abord été validés par le biais de simulations (à partir d'un outil semi-déterministe, incluant un modèle de récepteur complet), avant d'être appliqués à un jeu de données réelles, issues de dispositifs radio IR-UWB commercialisés par la société BeSpoon
By making possible unprecedented user-centric services (monitoring/smart inventory of personal goods, context-aware indoor navigation, etc.), new radiolocation capabilities are on the verge of modifying in depth mobility-based usages. In this context, the impulse radio - ultra wideband technology (IR-UWB), which theoretically enables to estimate the arrival time of transmitted pulses at the nanosecond scale and hence, the relative distance between a transmitter and a receiver within a few tens of centimeters, has been regularly put forward for the last past decade. In spite of these good intrinsic properties, the obstruction of radio links, either by the carrying body itself or by surrounding obstacles (walls, pieces of furniture. . . ), can result in significant errors on unitary range measurements, degrading the overall positioning performance accordingly, in particular in confined environments (e.g., indoor). In the frame of this PhD work, the main idea was to rely on an integrated IR-UWB receiver architecture, which has the capability to finely estimate the entire multipath profile, in order to improve the localization functionality. An in-depth study of the mobile multipath channel, as perceived by the previous receiver, has been conducted first, leading to the deterministic interpretation (i.e., from a geometric point of view) of the relative temporal evolution of multipath components, as well as to the modelling of their mutual interference. Based on these preliminary investigations, adapted multipath detection, association and tracking algorithms have been proposed (e.g., multi-hypothesis Kalman filters in parallel). All these proposals benefit from the receiver specificities, aiming at capturing the space-time correlation of multipath components under mobility, while minimizing harmful interference effects in dense channels (e.g., by means of combined multi-band channel estimations). In particular, for each non-line-of-sight link independently, the previous solutions allow to correct the estimated arrival time of the missing direct path out of the tracked secondary paths, while enabling the use of a conventional structure for the mobile tracking filter (i.e., fed by several "corrected" links with respect to distinct base stations). These algorithmic developments were first validated by means of simulations (using a semideterminist tool including a complete model of the receiver), before being applied to a measurement data set issued by IR-UWB devices commercialized by the BeSpoon company

The Federal Communications Commission (FCC) that regulates all wireless communication service providers has issued modified regulations that all service providers must select a method for providing position location (PL) information of a user, requesting for E-911 service, by October 2000. The wireless 911 rules adopted by the FCC are aimed both for improving the reliability of the wireless 911 services and for providing the enhanced features generally available for wireline calls. From the service providers' perspective, effective position location technologies must be utilized to meet the FCC rules. The Time-of-Arrival (TOA) and the Time-Difference-of-Arrival (TDOA) methods are the technology that can provide accurate PL information without necessitating excessive hardware or software changes to the existing cellular/PCS infrastructure. The TOA method works well when the mobile station (MS) is located close to the controlling base station. With certain corrections applied, the TOA method can perform reliably even in the presence of Non-Line-of-Sight (NLOS) condition. The TDOA method performs better when the MS is located at a significant distance from the controlling base station. However, under the NLOS environmental condition, the performance of the TDOA method degenerates significantly. The fusion of TOA and the TDOA method exhibits certain advantages that are not evident when only one of the methods is applied. This thesis investigates the performance of data fusion techniques for a PL system, that are able to merge independent estimates obtained from TOA and TDOA measurements. A channel model is formulated for evaluating PL techniques within a NLOS cellular environment. It is shown that NLOS propagation can introduce a bias into TDOA measurements. A correction method is proposed for removing this bias and new corrected data fusion techniques are compared with previous techniques using simulation method, yielding favorable results.
Master of Science

We consider time-of-arrival based robust geolocation in harsh line-of-sight/non-line-of-sight environments. Herein, we assume the probability density function (PDF) of the measurement error to be completely unknown and develop an iterative algorithm for robust position estimation. The iterative algorithm alternates between a PDF estimation step, which approximates the exact measurement error PDF (albeit unknown) under the current parameter estimate via adaptive kernel density estimation, and a parameter estimation step, which resolves a position estimate from the approximate log-likelihood function via a quasi-Newton method. Unless the convergence condition is satisfied, the resolved position estimate is then used to refine the PDF estimation in the next iteration. We also present the best achievable geolocation accuracy in terms of the Cramér-Rao lower bound. Various simulations have been conducted in both real-world and simulated scenarios. When the number of received range measurements is large, the new proposed position estimator attains the performance of the maximum likelihood estimator (MLE). When the number of range measurements is small, it deviates from the MLE, but still outperforms several salient robust estimators in terms of geolocation accuracy, which comes at the cost of higher computational complexity.

Les systèmes radar à synthèse d’ouverture (RSO) sont utilisés depuis de nombreuses années pour des applications militaires telles que la détection des cibles cachées. L’amélioration constante de la résolution de ces capteurs permet aujourd’hui d’accéder à un niveau de détail élevé dans la scène imagée. Cependant, l’interprétation de ces images demeure particulièrement compliquée dans le cas des milieux urbains. En effet, ces milieux particuliers sont sièges de nombreux phénomènes physiques et d’interactions multiples qui rendent la tâche de détection difficile et parfois erronée. C’est dans ce contexte que s’inscrit cette thèse. L’objectif est d’étudier la faisabilité de détection d’une cible en non visée directe du capteur à l’intérieur d’une scène simple et représentative du milieu urbain: le canyon urbain. Une étude sur la phénoménologie de propagation électromagnétique à l’intérieur des canyons urbains est menée à l’aide de mesures en environnement contrôlé à échelle réduite. Ces mesures ont permis la validation d’un outil électromagnétique commercial pour l’étude de la propagation d’une configuration à échelle réelle. Se basant sur les résultats de simulation du code électromagnétique validé, un outil maison, dédié à la prédiction des zones de détection d’une cible à l’intérieur d’un canyon urbain et à l’analyse de la signature électromagnétique correspondante, a été développé et validé. En outre, ce code contribue à l’interprétation complète de données radiométriques et interférométriques d’une scène urbaine réelle
Synthetic Aperture Radar (SAR) systems have been used since many years for military applications such as the detection of hidden targets. With improved resolutions of these systems, high level of details can be distinguished in the corresponding images. However, some difficulties are encountered when analyzing the SAR images of urban areas. In particular, in these areas, many physical phenomena and interactions occur that make the detection of a target a challenging task. In this framework, the goal of the thesis is to investigate the feasibility of detecting Non Line Of Sight targets inside a simple and representative scene: the urban canyon. A study of the electromagnetic (EM) phenomenology of propagation inside urban canyons has been performed using indoor data at a reduced scale. These data allowed the validation of an EM commercial tool that studies the EM propagation at a real scale. Based on the results of simulation of this code, an in-house code was developed dedicated to predict the detection of a target inside an urban canyon and to analyze the corresponding EM signature. Moreover, this code contributed to a full interpretation of InSAR data of a real complex urban scene with targets

This research study investigates the performance of multiple antenna system with space-time block coding on a software defined radio platform. The method is based on the measurement of average bit error rate at different antenna spacing in line-of-sight and non-line-of-sight wireless channel conditions. Theoretical analysis and measurements results conclude that optimal antenna array spacing at the receiver side can significantly improve the performance of the wireless link.

Abstract The multiple–input multiple–output (MIMO) technique, applying several transmit and receive antennas in wireless communications, has emerged as one of the most prominent technical breakthroughs of the last decade. Wideband MIMO parameter estimation and its applications to the MIMO orthogonal frequency division multiplexing (MIMO–OFDM) channel estimation and mobile positioning are studied in this thesis. Two practical MIMO channel models, i.e., correlated-receive independent-transmit channel and correlated-transmit-receive channel, and associated space-time parameter estimation algorithms are considered. Thanks to the specified structure of the proposed training signals for multiple transmit antennas, the iterative quadrature maximum likelihood (IQML) algorithm is applied to estimate the time delay and spatial signature for the correlated-receive independent-transmit MIMO channels. For the correlated-transmit-receive MIMO channels, the spatial signature matrix corresponding to a time delay can be further decomposed in such a way that the angle of arrival (AOA) and the angle of departure (AOD) can be estimated simultaneously by the 2-D unitary ESPRIT algorithm. Therefore, the combination of the IQML algorithm and the 2-D unitary ESPRIT algorithm provides a novel solution to jointly estimate the time delay, the AOA and the AOD for the correlated-transmit-receive MIMO channels. It is demonstrated from the numerical examples that the proposed algorithms can obtain good performance at a reasonable cost. Considering the correlated-receive independent-transmit MIMO channels, channel coefficient estimation for the MIMO–OFDM system is studied. Based on the parameters of the correlated-receive independent-transmit MIMO channels, the channel statistics in terms of the correlation matrix are developed. By virtue of the derived channel statistics, a joint spatial-temporal (JST) filtering based MMSE channel estimator is proposed which takes full advantage of the channel correlation properties. The mean square error (MSE) of the proposed channel estimator is analyzed, and its performance is also demonstrated by Monte Carlo computer simulations. It is shown that the proposed JST minimum mean square error (MMSE) channel estimator outperforms the more conventional temporal MMSE channel estimator in terms of the MSE when the signals in the receive antenna array elements are significantly correlated. The closed form bit error probability of the space-time block coded OFDM system with correlation at the receiver is also developed by taking the channel estimation errors and channel statistics, i.e., correlation at the receiver, into account. Mobile positioning in the non-line of sight (NLOS) scenarios is studied. With the knowledge of the time delay, the AOA and the AOD associated with each NLOS propagation path, a novel geometric approach is proposed to calculate the MS's position by only exploiting two NLOS paths. On top of this, the least squares and the maximum likelihood (ML) algorithms are developed to utilize multiple NLOS paths to improve the positioning accuracy. Moreover, the ML algorithm is able to estimate the scatterers' positions as well as those of the MSs. The Cramer-Rao lower bound related to the position estimation in the NLOS scenarios is derived. It is shown both analytically and through computer simulations that the proposed algorithms are able to estimate the mobile position only by employing the NLOS paths.

Position location has become one of the more important tasks for improving communication and networking performance for future commercial wireless systems. It is also the enabling technology for many control and sensing applications envisioned by the wireless sensor networks (WSN). Despite its meaningfulness and many algorithms being developed in the past several years, position location in harsh propagation environments remains to be a challenging issue, due mainly to the lack of sufficient infrastructure support and the prominent phenomenon of non-line-of-sight (NLOS) signal propagation. Recently, adopting the concept of collaborative position location has attracted much research interest due to its potential in overcoming the abovementioned two difficulties. In this work, we approach collaborative position location from two different angles. Specifically, we investigate the optimal performance of collaborative position location, which serves as a theoretical performance benchmark. In addition, we developed a computationally efficient algorithm for collaborative position location and incorporated an effective NLOS mitigation method to improve its performance in NLOS-dense environments. Overall, our work provides insight into both theoretical and practical aspects of collaborative position location.
Ph. D.

La RFID (Radio Frequency IDentification) est une technologie qui permet la communication entre un tag et un lecteur par ondes radios. Un tag est dit passif lorsqu’il utilise l’onde fournie par le lecteur pour transmettre une information à celui-ci. Cette technologie couvre aujourd’hui tous les domaines de l’industrie. D’après les statistiques, 13% des applications industrielles utilisant cette technologie sont liées au domaine du transport. Dans notre cas, l’objectif a été d’étudier théoriquement et expérimentalement le comportement des tags UHF RFID passifs dans les véhicules de transport terrestres. L’application visée est un système de maintenance de véhicule de transport terrestre intelligent capable de rendre compte de l’état de santé du véhicule lors de son retour sur une zone de dépôt. L’utilisation d’un seul lecteur RFID UHF situé à l’extérieur des véhicules à contrôler est envisagé afin de minimiser le coût de revient final du système. L’étude théorique a été réalisée à partir d’un logiciel de simulation développé en interne (SIMUEM3D) qui est basé sur ce que nous avons appelé "l’Optique Géométrique Modifiée (OGM)". Des mesures d’atténuation d’un signal sinusoïdal pur (CW) ainsi que de taux de lecture de tags RFID UHF ont été réalisées dans deux types de véhicules : un fourgon tôlé et une berline de tourisme. Le modèle numérique a été étalonné grâce à ces mesures. Des études paramétriques portant sur la position du lecteur, la vitesse du véhicule et la diversité spatiale ont été conduites. Des recommandations d’installation sont fournies pour permettre de collecter des informations de maintenance et de détection à l’intérieur de véhicules de transport terrestres
The RFID (Radio Frequency Identification) is a technology which allows communication between a tag and a reader by using radio waves. A tag is called “passive” when it uses the received energy supplied by the reader without using any battery. Many industrial domains are covered by this technology. From statistical datas, 13% of industrial applications belong to the transportation domain. In our case, the objective is to study theoretically and experimentally the behavior of passive UHF RFID tags located inside terrestrial vehicles. The targeted application is an intelligent maintenance and repair system which is able to provide the health of a vehicle that returns back on a storage area. The choice has been made to use only one UHF RFDI reader fixed outside of the monitored vehicles in order to minimize the total cost of the system. The theoretical study has been performed using a modelling tool developed internally (SIMUEM3D) and based on what we call the “Modified Geometrical Optics (MGO)”. Measurements of the attenuation of a sinusoidal signal (CW) and of the reading rate have been carried out in two kinds of vehicles : a cargo van and a passenger car. The numerical model has been calibrated with those measurements. Parametrical studies have been done dealing on the reader location, the vehicle speed and spatial diversity. Installation recommendations are given in order to guide the use of such a maintenance and detections system inside utility cars, tourism cars or even buses

"Precise Tracking of Things (PToT) using RF signals has posed a serious challenge in an indoor environment. The precision localization information is an enabler for better coordinated-tasks and is essential for a successful launch of many emerging applications. PToT relies on two principal components, a novel navigation (tracking) algorithm, and a hybrid 3D fingerprint database. In this dissertation, we begin by using the two widely known ranging techniques, Time Of Arrival (TOA) associated with Ultra-wideband (UWB) and Received Signal Strength (RSS) with WiFi signals. First, we use the theoretical models derived from empirical measurement of TOA and RSS to analyze the performance of hybrid (WiFi & UWB) cooperative localization accuracy in a multi-robot operation in a typical office environment. To measure the performance of this hybrid localization, we derive a mathematical formulation for the Crame ́r-Rao-Lower- Bound (CRLB). The hybrid method shows more accuracy over WiFi-only approach. In achieving more precision, we extend our work. Second, we introduce a novel approach, a Kernel Method Particle Filter (KMPF) for tracking and predicting the position by accessing the information created by hybrid 3D fingerprint database. We derive the mathematical and statistical framework for the Particle Filter based on the statistical assumptions about the behavior of channel models. We also describe the formation of one of the necessary PToT component, a 3D fingerprint database. We compare the performance of the KMPF against the CRLB using WiFi signal channel models."

Over the years, the Internet has become increasingly popular and people's dependence on it has increased dramatically. Whether it be to communicate to someone across the world, find blueprints, or check sports scores, the Internet has become a necessary resource for everyone. In emergency situations, this need increases further. After the terrorist attacks on the Pentagon, it took several days to restore communications. This is not an acceptable time frame when people's lives are at stake. Virginia Tech's Center for Wireless Telecommunication has developed a prototype of a rapidly deployable high bandwidth wireless communication system at 28 GHz (Local Multipoint Distribution Service frequency). This system provides a large bandwidth radio link to a disaster zone up to 5 km away and puts Ethernet speeds and 802.11 accesses to users within hours. Because of the possible variability in locations that the system can be deployed, it is necessary to find the most useable channel at the site as quickly as possible. In addition to 28GHz radio links, the system also has a built-in channel sounder that measures and captures the channel impulse response of the current channel. Until now, there has been limited research on the relationship between the channel impulse response and the usability of the channel quantified using bit error rate. This thesis examines several different channels captured by CWT's channel sounder and simulates the BER using Cadence's SPW with time-domain models of the channels. This thesis goes on further to show that BER greatly depends on the channel impulse response and the symbol rate.
Master of Science

Les applications des techniques radar au milieu urbain constituent un domaine émergent. Une des difficultés principales est liée à la complexité du milieu de propagation induit par les bâtiments présents dans la scène. En effet, la présence de ces bâtiments génère d’une part des zones d’ombre à l’intérieur desquelles une cible n’est pas en visibilité directe, et d’autre part de nombreux multi-trajets produits par les possibles réflexions et diffractions sur les surfaces environnantes. Ces multi-trajets sont souvent vus comme une gêne, limitant les capacités de détection en radar. Or ils peuvent aussi être exploités à l’avantage du radar afin de détecter et localiser des cibles situées dans les zones d’ombre (cible en NLOS). L’objectif de ce travail de thèse est donc la mise en place de méthodes de traitement du signal permettant la détection et la localisation d’une cible en NLOS en milieu urbain et l’application de ces techniques pour détecter et localiser une cible en NLOS à partir de signaux réels. Pour cela, nous avons proposé dans un premier temps deux solutions pour la détection et la localisation de la cible en exploitant les multi-trajets. Dans un deuxième temps, nous avons développé deux filtres particulaires pour pister une cible en milieu urbain en présence de multi-trajets. Ces algorithmes ont été appliqués aux données réelles issues d’une expérimentation et ont montré des résultats prometteurs : même avec une connaissance approximative de la géométrie de la scène, il a été possible de détecter, localiser et suivre une cible en exploitant uniquement l’information fournie par les retards des multi-trajets
The applications of radar techniques to the urban environment constitute an emerging subject. One of the main difficulties is related to the complexity of the propagation environment induced by the buildings present in the scene. Indeed, the presence of these buildings generates on the one hand shadow areas within which a target is not in line of sight, and on the other hand, many multipaths produced by reflections and diffractions on the surrounding surfaces. Classically, these multipaths are often seen as an inconvenience, limiting radar detection capabilities. However, these multipaths can also be exploited to the advantage of the radar to detect and locate targets located in the shadow areas (target in NLOS). The objective of this thesis work is therefore to develop signal processing methods allowing the detection and localization of a target located in shadow areas in urban environment and to apply these techniques for detecting and locating a target in NLOS from realistic or even real signals. For this, we first proposed two solutions for detection and localization of a target by exploiting multipath information. In a second step, we developed two particle filters to track a target in urban environment in the presence of multipaths. These algorithms have been applied to real data and showed promising results: even with an approximate knowledge of the geometry of the scene, it has been possible to detect, locate and track a target by exploiting only the information on multipath delays

By using existing radio network infrastructure, a user can be positioned even where GPS and other positioning technologies lack coverage. The LTE Positioning Protocol (LPP) supports user Reference Signal Time Difference (RSTD) reports based on the Time of Arrival (TOA) for a Positioning Reference Signal (PRS). In the current reporting format, only one RSTD for each base station is considered, but for indoor environments this is easily biased due to fading and multipath issues, resulting in a Non-Line of Sight (NLOS) bias. With a rich User Equipment (UE) feedback that can represent the multipath channel for each Base Station (BS), the positioning accuracy can be increased. This thesis develops and evaluates a UE reporting format representing multiple TDOA candidates, and a probabilistic positioning algorithm, in terms of positioning accuracy and amount of data reported. By modeling time measurements as Gaussian Mixture (GM), the time information can be compressed with arbitrary resolution and used in a Maximum-Likelihood (ML) estimation to find the position. Results were obtained through simulation in a radio network simulator and post-processing of simulation data in Matlab. The results suggest that several TOA candidates improve the positioning accuracy, but that the largest improvement comes from a noise based threshold by increasing LOS detectability reducing the NLOS bias, while suppressing noise. The results also suggest that the accuracy for the method can be further improved by combining multiple time measurement occasions.

At present, the current 4G systems provide a universal platform for broadband mobile services; however, mobile traffic is still growing at an unprecedented rate and the need for more sophisticated broadband services is pushing the limits on current standards to provide even tighter integration between wireless technologies and higher speeds. This has led to the need for a new generation of mobile communications: the so-called 5G. Although 5G systems are not expected to penetrate the market until 2020, the evolution towards 5G is widely accepted to be the logical convergence of internet services with existing mobile networking standards leading to the commonly used term “mobile internet” over heterogeneous networks, with several Gbits/s data rate and very high connectivity speeds. Therefore, to support highly increasing traffic capacity and high data rates, the next generation mobile network (5G) should extend the range of frequency spectrum for mobile communication that is yet to be identified by the ITU-R. The mm-wave spectrum is the key enabling feature of the next-generation cellular system, for which the propagation channel models need to be predicted to enhance the design guidance and the practicality of the whole design transceiver system. The present work addresses the main concepts of the propagation channel behaviour using ray tracing software package for simulation and then results were tested and compared against practical analysis in a real-time environment. The characteristics of Indoor-Indoor (LOS and NLOS), and indoor-outdoor (NLOS) propagations channels are intensively investigated at four different frequencies; 5.8 GHz, 26GHz, 28GHz and 60GHz for vertical polarized directional, omnidirectional and isotropic antennas patterns. The computed data achieved from the 3-D Shooting and Bouncing Ray (SBR) Wireless Insite based on the effect of frequency dependent electrical properties of building materials. Ray tracing technique has been utilized to predict multipath propagation characteristics in mm-wave bands at different propagation environments. Finally, the received signal power and delay spread were computed for outdoor-outdoor complex propagation channel model at 26 GHz, 28 GHz and 60GHz frequencies and results were compared to the theoretical models.

De nos jours, la capacité de suivre des objets et des personnes est cruciale pour un grand nombre d’applications, telles que les applications médicales (surveillance de patients) ou les applications indépendantes qui nécessitent une très grande précision et résolution dans le processus de positionnement. Par conséquent, l’objectif scientifique principal de cette thèse est de développer un système de suivi utilisant un système de radar multistatique UWB pour fournir une localisation 2D en temps réel de transpondeurs ou de balises actives. La localisation est réalisée en coordonnées polaires (distance et angle d’azimut) en fusionnant les principes d’interférométrie et de goniométrie, en supposant un canal de propagation à trajet direct, ou LoS entre la station et la cible. L’ILS conçu utilise une technique hybride en combinant les méthodes duplex UWB et de corrélation de phase pour les estimations de la distance radiale et de l’angle d’Azimut. L’ILS proposé comprend deux composants principaux, une station émettrice/réceptrice servant de LBS et un AT. Le LBS a une chaîne d’émission et deux chaînes de réception identiques et indépendantes. La localisation est effectuée en envoyant des impulsions UWB vers l’AT qui joue le rôle de transpondeur actif et retransmet le signal reçu¸ à son tour au LBS après l’avoir retardé. Cet ILS conçu¸ devrait offrir, dans les conditions LoS, une estimation de position avec une précision et une résolution élevées, tout en maintenant une faible complexité du système. Le système fonctionne avec une seule ancre et répond simultanément aux défis intérieurs tels que les trajets multiples, les fortes atténuations de signal, les réflexions, etc
Nowadays, the ability to track objects and people is crucial for a huge number of applications, such as medical applications (monitoring of patients) or independent applications that require a very high accuracy and resolution in the positioning process. Therefore, the main scientific objective of this thesis is to develop a tracking system using an UWB multistatic radar system to provide realtime 2D location of transponders or active tags. The localization is carried out in polar coordinates (distance and azimuth angle) by merging the interferometry and goniometry principles, assuming a propagation channel with a direct path, or LoS between the station and the target. The designed ILS incorporates a hybrid technique by combining the duplex UWB and the Phase Correlation methods for the radial-distance and the azimuth angle estimates. The proposed ILS consists of two main components, a transmitter /receiver (transceiver) station serving as a LBS and an AT. The LBS has one transmitting channel and two identical and independent receiving channels. The localization is performed by sending UWB pulses towards the AT which acts as an active transponder and retransmits in turn the received signal back to the LBS upon delaying it. This designed ILS is expected to offer, under LoS conditions, a position estimation with high accuracy and resolution while maintaining low system complexity. The system works with a single anchor, and simultaneously addresses indoor challenges such as multipaths, strong signal attenuations, reflections, etc

Mes travaux de recherche se déclinent suivant deux directions : Techniques avancées du traitement du signal pour la localisation de sources. Application à la localisation et poursuite de mobile en UMTS. Méthodes rapides et stables pour la poursuite des sous-espaces. Techniques avancées du traitement du signal pour la localisation de sources : Application à la localisation et poursuite de mobile en UMTS. Depuis que la FCC (Federal Communications Commission) a demandé aux opérateurs américains d'assurer la localisation de tout terminal appelant les services d'urgence (avec une précision de 125 m dans 67 \% des cas), les opérateurs s'intéressent de plus en plus à la localisation de mobile. Ils y voient un moyen de proposer de nouveaux services comme la tarification par zone, la recherche de services proches (hôtels, restaurants), etc. De plus, cela leur permettrait d'avoir un indicateur géographique du trafic, pratique pour l'optimisation de leur réseau. Toutefois, bien que le nombre d'applications possibles soit important, la localisation de mobile n'a été prévue dans aucun système radio-mobile. C'est pourquoi, depuis quelques années, les opérateurs en ont fait un de leur sujet prioritaire de recherche. Plusieurs idées ont ainsi été proposées comme l'utilisation d'un récepteur GPS (Global Positionning Satellite) donnant la position du mobile à partir des temps d'arrivée de signaux issus de trois satellites. Cette solution, bien qu'étant d'une grande précision, n'est pas pour autant optimale. En effet, elle nécessite non seulement une visibilité directe du mobile avec trois satellites (ce qui pose un problème pour la localisation à l'intérieur des bâtiments, des reliefs montagneux. . . ) mais représente également un coût non négligeable à la charge des opérateurs. C'est pourquoi, certains opérateurs préfèrent s'orienter vers les solutions n'utilisant que les signaux radio. C'est cette approche que nous avons choisi de présenter dans cette thèse. Trois classes de méthodes sont utilisées pour la localisation du mobile : La première approche concerne méthodes basées sur l'estimation de la distance entre le mobile et la station de base, obtenue à partir des mesures des temps d'arrivée (TOA). Ces méthodes peuvent aussi bien être envisagées en liaison montante qu'en liaison descendante. Trois mesures impliquant des stations de base (BS) différentes sont au minimum nécessaires pour déterminer la position du mobile. La seconde approche concerne les méthodes basées sur l'estimation des angles d'arrivées(AOA). Celles-ci nécessitent l'installation d'antennes complexes et ne peut donc être envisagées qu'en liaison montante. Chaque AOA estimé définit une demi-droite, de sommet la station de base concernée, sur laquelle se trouve le mobile. Deux mesures de AOAs sont donc nécessaires pour localiser le mobile. Enfin, la troisième approche concerne les méthodes dites conjointes utilisant simultanément l'estimation des angles et des retards. La localisation de mobile ne nécessite alors que l'écoute d'une seule BS. Quelque soit la méthode choisie, les solutions proposées seront différentes selon la norme considérée. En effet, au problème d'absence de trajet direct (Non Line Of Sight (NLOS)) qui est caractéristique de l'ensemble des systèmes radio-mobile, s'ajoute un problème inhérent au système UMTS-FDD : le problème d'écoute (Near-Far Effect (NFE)). Il correspond à la difficulté pour les stations de base (BS) et les mobiles (MS) d'écouter des mobiles ou des BSs éloignés, i. E. Appartenant à des cellules voisines. Il est lié au fait que dans les réseaux UMTS-FDD les stations de base (respectivement les mobiles) émettent simultanément et sur la même bande de fréquence. Mon travail de recherche s'est donc attaché à proposer pour les systèmes UMTS-FDD, des solutions de localisation réalisites, efficaces et qui tiennent compte de ces deux problèmes. Un simulateur UMTS-FDD, construit suivant la norme, a permis de valider l'ensemble des solutions proposées. Enfin, une méthode adaptative de poursuite de mobile en UMTS est proposée. Cette méthode utilise l'estimation adaptative des sous-espaces qui occupe une partie de la thèse. Méthodes rapides et stables pour la poursuite des sous-espaces. Dans cette partie nous nous sommes intéressés à développer des techniques adaptatives capables d'exécuter un suivi de sous-espaces. L'ingrédient principal commun dans toutes ces méthodologies sera l'hypothèse que le rang du sous-espace est connu. La littérature existante sur le suivi de sous-espace est extrêmement riche, offrant une grande variété des schémas avec différentes complexités du calcul. Les algorithmes adaptatifs de suivi de sous-espace sont de grande importance, puisqu'ils peuvent être employés dans de nombreuses applications comme les systèmes de télécommunication, le filtrage adaptatif, la direction des arrivées, le traitement des rangées d'antenne, les systèmes linéaires, etc. Nous nous concentrons sur le problème du suivi de sous-espace lui-même, où nous sommes concernées par estimer les vecteurs singuliers (Minor and Principal Componet Analysis, MCA and PCA) ou une base orthonormale pour le sous-espace d'intérêt (Minor and Principal Subspace Analysis, MSA and PSA. Nos algorithmes proposés sont capables d'estimer le sous-espace (MSA and PSA) correspondant aux plus grandes et plus petites valeurs singulières (et même les vectuers propres correpondant, MCA and PCA). Leur caractéristique principale est leur faible complexité informatique, qui est accompagnée de stabilité numérique, même dans le cas des plus petites valeurs singulières. On devrait mentionner que toutes les techniques existantes de même complexité visant à estimer les plus petites valeurs singulières sont numériquement instables. En conclusion, avec l'aide des simulations, nous démontrons la meilleure exécution de notre méthode contre d'autres schémas populaires de la même complexité
The purpose of this thesis is to provide solutions to challenges facing the wireless localization and tracking techniques, with a special focus on Non Line of Sight (NLoS) effect arising from the presence of obstacles between the mobile station and the base station. In the case of mobile tracking algorithms, adaptive component and subspace analysis are important tools frequently used for different parametric estimation. We present in the first part of this thesis, an extensive study of this subject and we propose fast and efficient subspace tracking methods. The document is structured in three parts gathering several chapters: Subspace Tracking for Signal Processing. Mobile Localization in Wireless Networks. Appendix. Part I: Subspace Tracking for Signal Processing. In the first part, various theoretical aspects for adaptive subspace tracking in signal processing are presented. We start first by a global introduction. In chapter 1, an overview of subspace tracking methods is illustrated. In chapter 2, we propose fast adaptive algorithms for minor and principal component analysis. We start first by proposing new fast methods using Householder Transformation for extracting the desired minor eigenvectors of a covariance matrix. The two proposed methods are referred to as; MCA Orthogonal OJA using Householder Transform (MCA-OOJAH) and MCA Orthogonal FRANS using Householder Transform (MCA-OFRANSH). We propose next a fast PCA algorithm using Givens Rotations for tracking the desired principal eigenvectors of a covariance matrix, we refer to this new algorithm as Principal Component extraction using the Orthogonal PAST method (PC-OPAST). Finally, we study the MCA case where we elaborate a fast MCA algorithm for positive Hermitian covariance matrix associated with time series. This latter method is referred to as Minor Component extraction using the YAST-PGS algorithm (MC-YAST-PGS). Theoretical Convergence analysis and numerical stability analysis are provided in this chapter. Simulation results are presented to assess the performance of our algorithms and compare them with other existing methods. Chapter 3 relates to subspace analysis. To this end, we propose fast adaptive algorithms for minor and principal subspace analysis. The first new method referred to as Fast Orthogonal OJA (FOOJA) estimates the minor or the principal desired subspace of a covariance matrix. Another fast MSA method (YAST-PGS) is proposed in this chapter to extract the desired minor subspace of a positive Hermitian covariance matrix associated with time series. Theoretical stability analysis and simulation results are provided to illustrate the tracking capacity of the proposed algorithms. In chapter 4, we present an application of the subspace tracking for mobile localization. Indeed, we propose an adaptive mobile localization method using Time Of Arrival (TOA) and Direction Of Arrival (DOA) estimates. Simulation results prove the good estimation and tracking performance of the proposed method in typical propagation environments. Part II: Mobile Localization in Wireless Networks. This part deals with mobile localization in wireless networks and more precisely in the UMTS-FDD mode. Before presenting our contributions, we show in chapter 5, a brief summary on the evolution of cellular systems, and an overview of UMTS positioning methods. In chapter 6, we present an efficient TOA estimation method using RAKE-CFAR technique that reduces the effect of the hearability problem on mobile positioning in UMTS-FDD mode. Realistic simulation results show the accuracy improvement provided by the proposed method over a simple Rake receiver. In chapter 7, a new Mobile Station (MS) localization method is provided using Round Trip Time (RTT) measurements in the UMTS-FDD mode. The new methods take into account possible large RTT error measurements caused by Non Line of Sight (NLoS). The mobile position is then obtained only from the three most reliable RTT among the set of all RTT estimates when available. This method is also efficient even if all RTT measurements correspond to the LoS case. More precisely, this algorithm allows the selection of the least ’noisy’ RTT when all measurements are of LoS type. Simulation results show the gain of positioning accuracy provided by the proposed algorithm. In chapter 8, we propose an adaptive Interactive Multiple Models (IMM) Unscented Kalman Filter (UKF) with an efficient RAKE-CFAR method for mobile tracking in NLoS situation. This new algorithm is based first on an efficient and adaptive TOA estimation method, and an IMM-UKF method in order to operate in Non-Line-of-Sight situations and to track manoeuvring mobile. Realistic simulation results are presented in the UMTS-FDD mode to show the tracking accuracy provided by our proposed algorithm. Part III: Appendix. The appendix provides in chapters 9 and 10 complete proofs of some results of Part I and II and contains some details about the UMTS simulator

La thèse a porté sur la localisation de mobile pour les systèmes UMTS-FDD. Il s'agit d'un sujet qui intéresse de plus en plus les opérateurs, notamment dans le cas de système UMTS-FDD où il existe très peu de réseaux réels. Les différentes approches permettant de localiser un émetteur ont ainsi été envisagées, et plus particulièrement, celles basées sur les mesures de puissances, celles basées sur les temps d'arrivée (TOA) en liaison descendante ou encore celles basées sur les angles d'arrivée (AOA) et sur toute combinaison AOA-TOA. Pour ces différentes approches, nous nous sommes intéressés aux deux principales sources d'erreur pouvant dégrader les performances de la localisation : - l'absence de trajet direct qui est une des caractéristiques des systèmesradio-mobile. - Le problème d'écoute, qui est inhérent au système UMTS-FDD. A ces deux problèmes, nous avons proposé des solutions pour les différentes approches de localisation, qui soient à la fois précises et faciles à mettre en oeuvre au niveau de la norme. Concernant le problème d'écoute, nous avons proposé les solutions suivantes : Pour la liaison montante, il était possible d'envisager les algorithmes de suppression d'interférences existants, basés sur la connaissance des signatures des différents utilisateurs, qui présentent l'avantage d'être beaucoup plus robustes que l'estimation RAKE. Pour la liaison descendante, le mobile neconnaissant pas les signatures des utilisateurs, d'autres solutions devaient être envisagées. La première idée pouvait être d'utiliser les Idle periods, solution standardisée, correspondant à l'introduction de périodes de silence durant lesquelles une seule BS est autorisée à émettre afin de permettre au mobile d'écouter des BSs éloignées. Cette solution réduisant la capacité du système, nous nous sommes ainsi intéressés à d'autres estimateurs plus robustes aux interférences que l'estimateur Rake. En particulier, nous avons étudié l'estimateur RAKE-SP qui consiste à réaliser une projection de l'estimation du canal sur l'espace signal de la matrice de covariance du canal. Les simulations réalisées ont permis de montrer l'efficacité de cette approche. Concernant le problème d'absence de trajet direct, nous avons proposé pour les TOAs (resp. Les AOAs), une méthode de sélection basée sur un critère de cohérence qui permet de sélectionner les 3 (resp. Les 2) mesures paraissant les fiables parmi l'ensemble des mesures disponibles pour effectuer la triangulation. Plus précisément, il s'agit de sélectionner les mesures donnant la position du mobile la plus cohérente avec les différentes mesures de TOAs, AOAs relatives à chaque BS. Les méthodes proposées ont été largement illustrées par de nombreuses expériences réalisées à partir du simulateur UMTS-FDD construit qui ont montré leur efficacité
Mobile location is a growing practice in cellular communication systems and many applications are already forecasted : localizing traffic in order to balancethe network, emergency interventions. . . The thesis has focused on the main approaches proposed in the literature to locate a mobile : strength measures, Time-Of-Arrival (TOA), Angle-Of-Arrival(AOA) or Joint AOA-TOA techniques. This study done within the framework of UMTS-FDD norm, has highlighted two main difficulties : - The first one is the near-far problem (NFE) which corresponds to the difficulty for a base-station (BS) (resp. Mobile) to hear far-located mobiles(resp. BS) because of the interference generated by close-located mobiles(resp. BS) which is particularly important in UMTS-FDD systems - The second one concerns the absence of LOS path (NLOS problem) in radio-mobile environments due to the presence of obstacles between the mobile and the BS. Solutions both efficient and simple have been proposed in order to reduce the impact of these problems on mobile localization

In questa tesi si è deciso di focalizzarsi sui segnali a onde millimetriche e banda-ultra larga (UWB), i quali rappresentano, con ogni probabilità, i componenti fondamentali delle future reti di 5° generazione(5G). Sono state eseguite delle misure per poter analizzare il comportamento di questi segnali in ambienti diversi utilizzando un drone. Lo scopo del mio elaborato consiste nella sincronizzazione delle missioni del drone con le operazioni di acquisizione degli strumenti di misura. Per poter realizzare il sistema di sincronizzazione è stato utilizzato il software di elaborazione di calcolo Matlab.

First-generation, line-of-sight (LOS) fixed broadband wireless access techniques have been around for several years. However, services based on this technology have been limited in scope to service areas where transceivers can communicate with their base stations, unimpeded by trees, buildings and other obstructions. This limitation has serious consequences in that the system can deliver only 50% to 70% coverage within a given cell radius, thus affecting earned revenue. Next generation broadband fixed wireless access techniques are aimed at achieving a coverage area greater than 90%. To achieve this target, these techniques must be based on a point-to-multipoint (PMP) cellular architecture with low base station antennas, thus possessing the ability to operate in true non-line-of-sight (NLOS) conditions. A possible limiting factor for these systems is link degradation due to interference. This thesis presents a new model to estimate the levels of co-channel interference for such systems operating within the 3.5 GHz multichannel multipoint distribution service (MMDS) band. The model is site-specific in that it uses statistical building/roof height distribution parameters obtained from practically modeling several metropolitan cities in the U.S. using geographic information system (GIS) tools. This helps to obtain a realistic estimate and helps analyze the tradeoff between cell radius and modulation complexity. Together, these allow the system designer to decide on an optimal location for placement of customer premises equipment (CPE) within a given cell area.
Master of Science

The past two decades have seen a surge in the number of applications requiring precise positioning data. Modern cellular networks offer many services based on the user's location, such as emergency services (e.g., E911), and emerging wireless sensor networks are being used in applications spanning environmental monitoring, precision agriculture, warehouse and manufacturing logistics, and traffic monitoring, just to name a few. In these sensor networks in particular, obtaining precise positioning data of the sensors gives vital context to the measurements being reported. While the Global Positioning System (GPS) has traditionally been used to obtain this positioning data, the deployment locations of these cellular and sensor networks in GPS-constrained environments (e.g., cities, indoors, etc.), along with the need for reliable positioning, requires a localization scheme that does not rely solely on GPS. This has lead to localization being performed entirely by the network infrastructure itself, or by the network infrastructure aided, in part, by GPS. In the literature, benchmarking localization performance in these networks has traditionally been done in a deterministic manner. That is, for a fixed setup of anchors (nodes with known location) and a target (a node with unknown location) a commonly used benchmark for localization error, such as the Cramer-Rao lower bound (CRLB), can be calculated for a given localization strategy, e.g., time-of-arrival (TOA), angle-of-arrival (AOA), etc. While this CRLB calculation provides excellent insight into expected localization performance, its traditional treatment as a deterministic value for a specific setup is limited. Rather than trying to gain insight into a specific setup, network designers are more often interested in aggregate localization error statistics within the network as a whole. Questions such as: "What percentage of the time is localization error less than x meters in the network?" are commonplace. In order to answer these types of questions, network designers often turn to simulations; however, these come with many drawbacks, such as lengthy execution times and the inability to provide fundamental insights due to their inherent ``block box'' nature. Thus, this dissertation presents the first analytical solution with which to answer these questions. By leveraging tools from stochastic geometry, anchor positions and potential target positions can be modeled by Poisson point processes (PPPs). This allows for the CRLB of position error to be characterized over all setups of anchor positions and potential target positions realizable within the network. This leads to a distribution of the CRLB, which can completely characterize localization error experienced by a target within the network, and can consequently be used to answer questions regarding network-wide localization performance. The particular CRLB distribution derived in this dissertation is for fourth-generation (4G) and fifth-generation (5G) sub-6GHz networks employing a TOA localization strategy. Recognizing the tremendous potential that stochastic geometry has in gaining new insight into localization, this dissertation continues by further exploring the union of these two fields. First, the concept of localizability, which is the probability that a mobile is able to obtain an unambiguous position estimate, is explored in a 5G, millimeter wave (mm-wave) framework. In this framework, unambiguous single-anchor localization is possible with either a line-of-sight (LOS) path between the anchor and mobile or, if blocked, then via at least two NLOS paths. Thus, for a single anchor-mobile pair in a 5G, mm-wave network, this dissertation derives the mobile's localizability over all environmental realizations this anchor-mobile pair is likely to experience in the network. This is done by: (1) utilizing the Boolean model from stochastic geometry, which statistically characterizes the random positions, sizes, and orientations of reflectors (e.g., buildings) in the environment, (2) considering the availability of first-order (i.e., single-bounce) reflections as well as the LOS path, and (3) considering the possibility that reflectors can either facilitate or block reflections. In addition to the derivation of the mobile's localizability, this analysis also reveals that unambiguous localization, via reflected NLOS signals exclusively, is a relatively small contributor to the mobile's overall localizability. Lastly, using this first-order reflection framework developed under the Boolean model, this dissertation then statistically characterizes the NLOS bias present on range measurements. This NLOS bias is a common phenomenon that arises when trying to measure the distance between two nodes via the time delay of a transmitted signal. If the LOS path is blocked, then the extra distance that the signal must travel to the receiver, in excess of the LOS path, is termed the NLOS bias. Due to the random nature of the propagation environment, the NLOS bias is a random variable, and as such, its distribution is sought. As before, assuming NLOS propagation is due to first-order reflections, and that reflectors can either facilitate or block reflections, the distribution of the path length (i.e., absolute time delay) of the first-arriving multipath component (MPC) is derived. This result is then used to obtain the first NLOS bias distribution in the localization literature that is based on the absolute delay of the first-arriving MPC for outdoor time-of-flight (TOF) range measurements. This distribution is shown to match exceptionally well with commonly assumed gamma and exponential NLOS bias models in the literature, which were only attained previously through heuristic or indirect methods. Finally, the flexibility of this analytical framework is utilized by further deriving the angle-of-arrival (AOA) distribution of the first-arriving MPC at the mobile. This distribution gives novel insight into how environmental obstacles affect the AOA and also represents the first AOA distribution, of any kind, derived under the Boolean model. In summary, this dissertation uses the analytical tools offered by stochastic geometry to gain new insights into localization metrics by performing analyses over the entire ensemble of infrastructure or environmental realizations that a target is likely to experience in a network.
Doctor of Philosophy
The past two decades have seen a surge in the number of applications requiring precise positioning data. Modern cellular networks offer many services based on the user's location, such as emergency services (e.g., E911), and emerging wireless sensor networks are being used in applications spanning environmental monitoring, precision agriculture, warehouse and manufacturing logistics, and traffic monitoring, just to name a few. In these sensor networks in particular, obtaining precise positioning data of the sensors gives vital context to the measurements being reported. While the Global Positioning System (GPS) has traditionally been used to obtain this positioning data, the deployment locations of these cellular and sensor networks in GPS-constrained environments (e.g., cities, indoors, etc.), along with the need for reliable positioning, requires a localization scheme that does not rely solely on GPS. This has lead to localization being performed entirely by the network infrastructure itself, or by the network infrastructure aided, in part, by GPS. When speaking in terms of localization, the network infrastructure consists of what are called anchors, which are simply nodes (points) with a known location. These can be base stations, WiFi access points, or designated sensor nodes, depending on the network. In trying to determine the position of a target (i.e., a user, or a mobile), various measurements can be made between this target and the anchor nodes in close proximity. These measurements are typically distance (range) measurements or angle (bearing) measurements. Localization algorithms then process these measurements to obtain an estimate of the target position. The performance of a given localization algorithm (i.e., estimator) is typically evaluated by examining the distance, in meters, between the position estimates it produces vs. the actual (true) target position. This is called the positioning error of the estimator. There are various benchmarks that bound the best (lowest) error that these algorithms can hope to achieve; however, these benchmarks depend on the particular setup of anchors and the target. The benchmark of localization error considered in this dissertation is the Cramer-Rao lower bound (CRLB). To determine how this benchmark of localization error behaves over the entire network, all of the various setups of anchors and the target that would arise in the network must be considered. Thus, this dissertation uses a field of statistics called stochastic geometry} to model all of these random placements of anchors and the target, which represent all the setups that can be experienced in the network. Under this model, the probability distribution of this localization error benchmark across the entirety of the network is then derived. This distribution allows network designers to examine localization performance in the network as a whole, rather than just for a specific setup, and allows one to obtain answers to questions such as: "What percentage of the time is localization error less than x meters in the network?" Next, this dissertation examines a concept called localizability, which is the probability that a target can obtain a unique position estimate. Oftentimes localization algorithms can produce position estimates that congregate around different potential target positions, and thus, it is important to know when algorithms will produce estimates that congregate around a unique (single) potential target position; hence the importance of localizability. In fifth generation (5G), millimeter wave (mm-wave) networks, only one anchor is needed to produce a unique target position estimate if the line-of-sight (LOS) path between the anchor and the target is unimpeded. If the LOS path is impeded, then a unique target position can still be obtained if two or more non-line-of-sight (NLOS) paths are available. Thus, over all possible environmental realizations likely to be experienced in the network by this single anchor-mobile pair, this dissertation derives the mobile's localizability, or in this case, the probability the LOS path or at least two NLOS paths are available. This is done by utilizing another analytical tool from stochastic geometry known as the Boolean model, which statistically characterizes the random positions, sizes, and orientations of reflectors (e.g., buildings) in the environment. Under this model, considering the availability of first-order (i.e., single-bounce) reflections as well as the LOS path, and considering the possibility that reflectors can either facilitate or block reflections, the mobile's localizability is derived. This result reveals the roles that the LOS path and the NLOS paths play in obtaining a unique position estimate of the target. Using this first-order reflection framework developed under the Boolean model, this dissertation then statistically characterizes the NLOS bias present on range measurements. This NLOS bias is a common phenomenon that arises when trying to measure the distance between two nodes via the time-of-flight (TOF) of a transmitted signal. If the LOS path is blocked, then the extra distance that the signal must travel to the receiver, in excess of the LOS path, is termed the NLOS bias. As before, assuming NLOS propagation is due to first-order reflections and that reflectors can either facilitate or block reflections, the distribution of the path length (i.e., absolute time delay) of the first-arriving multipath component (MPC) (or first-arriving ``reflection path'') is derived. This result is then used to obtain the first NLOS bias distribution in the localization literature that is based on the absolute delay of the first-arriving MPC for outdoor TOF range measurements. This distribution is shown to match exceptionally well with commonly assumed NLOS bias distributions in the literature, which were only attained previously through heuristic or indirect methods. Finally, the flexibility of this analytical framework is utilized by further deriving angle-of-arrival (AOA) distribution of the first-arriving MPC at the mobile. This distribution yields the probability that, for a specific angle, the first-arriving reflection path arrives at the mobile at this angle. This distribution gives novel insight into how environmental obstacles affect the AOA and also represents the first AOA distribution, of any kind, derived under the Boolean model. In summary, this dissertation uses the analytical tools offered by stochastic geometry to gain new insights into localization metrics by performing analyses over all of the possible infrastructure or environmental realizations that a target is likely to experience in a network.

Nowadays, satellite-based localization is a well-established technical solution to support several navigation tasks in daily life. Besides the application inside of portable devices, satellite-based positioning is used for in-vehicle navigation systems as well. Moreover, due to its global coverage and the availability of inexpensive receiver hardware it is an appealing technology for numerous applications in the area of Intelligent Transportation Systems (ITSs). However, it has to be admitted that most of the aforementioned examples either rely on modest accuracy requirements or are not sensitive to temporary integrity violations. Although technical concepts of Advanced Driver Assistance Systems (ADASs) based on Global Navigation Satellite Systems (GNSSs) have been successfully demonstrated under open sky conditions, practice reveals that such systems suffer from degraded satellite signal quality when put into urban areas. Thus, the main research objective of this thesis is to provide a reliable vehicle positioning concept which can be used in urban areas without the aforementioned limitations. Therefore, an integrated probabilistic approach which preforms fault detection & exclusion, localization and multi-sensor data fusion within one unified Bayesian framework is proposed. From an algorithmic perspective, the presented concept is based on a probabilistic data association technique with explicit handling of outlier measurements as present in urban areas. By that approach, the accuracy, integrity and availability are improved at the same time, that is, a consistent positioning solution is provided. In addition, a comprehensive and in-depth analysis of typical errors in urban areas within the pseudorange domain is performed. Based on this analysis, probabilistic models are proposed and later on used to facilitate the positioning algorithm. Moreover, the presented concept clearly targets towards mass-market applications based on low-cost receivers and hence aims to replace costly sensors by smart algorithms. The benefits of these theoretical contributions are implemented and demonstrated on the example of a real-time vehicle positioning prototype as used inside of the European research project GAlileo Interactive driviNg (GAIN). This work describes all necessary parts of this system including GNSS signal processing, fault detection and multi-sensor data fusion within one processing chain. Finally, the performance and benefits of the proposed concept are examined and validated both with simulated and comprehensive real-world sensor data from numerous test drives.

Positioning is recognized as an important feature of fifth generation (\abbrFiveG) cellular networks due to the massive number of commercial use cases that would benefit from access to position information. Radio based positioning has always been a challenging task in urban canyons where buildings block and reflect the radio signal, causing multipath propagation and non-line-of-sight (NLOS) signal conditions. One approach to handle NLOS is to use data-driven methods such as machine learning algorithms on beam-based data, where a training data set with positioned measurements are used to train a model that transforms measurements to position estimates.  The work is based on position and radio measurement data from a 5G testbed. The transmission point (TP) in the testbed has an antenna that have beams in both horizontal and vertical layers. The measurements are the beam reference signal received power (BRSRP) from the beams and the direction of departure (DOD) from the set of beams with the highest received signal strength (RSS). For modelling of the relation between measurements and positions, two non-linear models has been considered, these are neural network and random forest models. These non-linear models will be referred to as machine learning algorithms.  The machine learning algorithms are able to position the user equipment (UE) in NLOS regions with a horizontal positioning error of less than 10 meters in 80 percent of the test cases. The results also show that it is essential to combine information from beams from the different vertical antenna layers to be able to perform positioning with high accuracy during NLOS conditions. Further, the tests show that the data must be separated into line-of-sight (LOS) and NLOS data before the training of the machine learning algorithms to achieve good positioning performance under both LOS and NLOS conditions. Therefore, a generalized likelihood ratio test (GLRT) to classify data originating from LOS or NLOS conditions, has been developed. The probability of detection of the algorithms is about 90\% when the probability of false alarm is only 5%.  To boost the position accuracy of from the machine learning algorithms, a Kalman filter have been developed with the output from the machine learning algorithms as input. Results show that this can improve the position accuracy in NLOS scenarios significantly.
Radiobasserad positionering av användarenheter är en viktig applikation i femte generationens (5G) radionätverk, som mycket tid och pengar läggs på för att utveckla och förbättra. Ett exempel på tillämpningsområde är positionering av nödsamtal, där ska användarenheten kunna positioneras med en noggrannhet på ett tiotal meter. Radio basserad positionering har alltid varit utmanande i stadsmiljöer där höga hus skymmer och reflekterar signalen mellan användarenheten och basstationen. En ide att positionera i dessa utmanande stadsmiljöer är att använda datadrivna modeller tränade av algoritmer baserat på positionerat testdata – så kallade maskininlärningsalgoritmer. I detta arbete har två icke-linjära modeller - neurala nätverk och random forest – bli implementerade och utvärderade för positionering av användarenheter där signalen från basstationen är skymd.% Dessa modeller refereras som maskininlärningsalgoritmer. Utvärderingen har gjorts på data insamlad av Ericsson från ett 5G-prototypnätverk lokaliserat i Kista, Stockholm. Antennen i den basstation som används har 48 lober vilka ligger i fem olika vertikala lager. Insignal och målvärdena till maskininlärningsalgoritmerna är signals styrkan för varje stråle (BRSRP), respektive givna GPS-positioner för användarenheten. Resultatet visar att med dessa maskininlärningsalgoritmer positioneras användarenheten med en osäkerhet mindre än tio meter i 80 procent av försöksfallen. För att kunna uppnå dessa resultat är viktigt att kunna detektera om signalen mellan användarenheten och basstationen är skymd eller ej. För att göra det har ett statistiskt test blivit implementerat. Detektionssannolikhet för testet är över 90 procent, samtidigt som sannolikhet att få falskt alarm endast är ett fåtal procent.\newline \newline%För att minska osäkerheten i positioneringen har undersökningar gjorts där utsignalen från maskininlärningsalgoritmerna filtreras med ett Kalman-filter. Resultat från dessa undersökningar visar att Kalman-filtret kan förbättra presitionen för positioneringen märkvärt.

Dissertation (Ph.D.)--Worcester Polytechnic Institute.
Keywords: Ray Tracing; Wideband Measurement; Dynamic Modeling of Ranging Error; ToA-Based Indoor Localization; NLoS Identification. Includes bibliographical references (leaves 147-159).

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica.
Made available in DSpace on 2013-03-04T19:47:54Z (GMT). No. of bitstreams: 1 313758.pdf: 2236026 bytes, checksum: b96b29cf2037d52a2d1bf72f2088b483 (MD5)
Este trabalho de pesquisa trata da modelagem estocástica de algoritmos adaptativos com sinal de entrada normalizado. Particularmente, visa se obter um modelo estocástico mais preciso para o algoritmo NLMS (normalized least-mean-square) do que os até então disponíveis na literatura. O modelo aqui proposto considera um problema de identificação de sistema com planta estacionária, apresenta solução analítica e contempla diferentes tipos de sinais de entrada gaussianos (complexos, reais, correlacionados e não correlacionados). A partir das expressões que descrevem o comportamento médio do algoritmo, são derivadas expressões para o valor do erro quadrático médio em excesso em regime permanente e o desajuste. Tais expressões possibilitam uma melhor compreensão de como e quais parâmetros afetam o desempenho do algoritmo em regime permanente. Além disso, considerando sinal de entrada branco, relações que permitem ajustar (através do passo de adaptação) a velocidade de convergência e o erro em regime permanente dos algoritmos NLMS e LMS são apresentadas. Resultados de simulação para diferentes cenários de operação são mostrados, atestando a precisão do modelo proposto frente a outros modelos da literatura.

Adaptive LMS equalizers are widely used in digital communication systems for their simplicity in implementation. Conventional adaptive filtering theory suggests the upper bound of the performance of such equalizer is determined by the performance of a Wiener filter of the same structure. However, in the presence of a narrowband interferer the performance of the LMS equalizer is better than that of its Wiener counterpart. This phenomenon, termed a non-Wiener effect, has been observed before and substantial work has been done in explaining the underlying reasons. In this work, we focus on the Bit Error Rate (BER) performance of LMS equalizers. At first a model – the Gaussian Mixture (GM) model – is presented to estimate the BER performance of a Wiener filter operating in an environment dominated by a narrowband interferer. Simulation results show that the model predicts BER accurately for a wide range of SNR, ISR, and equalizer length. Next, a model similar to GM termed the Gaussian Mixture using Steady State Weights (GMSSW) model is proposed to model the BER behavior of the adaptive NLMS equalizer. Simulation results show unsatisfactory performance of the model. A detailed discussion is presented that points out the limitations of the GMSSW model, thereby providing some insight into the non-Wiener behavior of (N)LMS equalizers. An improved model, the Gaussian with Mean Square Error (GMSE), is then proposed. Simulation results show that the GMSE model is able to model the non-Wiener characteristics of the NLMS equalizer when the normalized step size is between 0 and 0.4. A brief discussion is provided on why the model is inaccurate for larger step sizes.
Master of Science

There has recently been a strong drive towards next-to-leading order (NLO) accuracy in Monte Carlo event generators. This thesis is concerned with the implementation of a framework for NLO calculations within the matrix element generator AMEGIC++, which forms part of the Monte Carlo event generator Sherpa. An interface is presented for the connection of one-loop matrix elements to Sherpa, conforming with the Binoth Les Houches Accord. Automated Catani-Seymour dipole subtraction is presented for the cases of QCD corrections for processes involving massive final state particles, and the supersymmetric partners of quarks and gluons, namely squarks and gluinos. Similar dipole subtraction techniques are also applied to the case of photonic corrections. An automated implementation of on-shell subtraction, relevant for separating real-emission NLO corrections from leading order production and decay processes, is also presented. With the completion of this work, the event generator Sherpa, when interfaced to suitable one-loop code, is equipped to calculate all necessary components of QCD and electroweak NLO calculations.

This thesis is on a new method for improving the convergence speed of the normalised least mean square (NLMS) algorithm when the input is a coloured signal, such as speech, that can be decorrelated using linear prediction. The proposed method gives a significant improvement in the convergence speed and requires very little additional computation in terms of arithmetic operations and memory space. It is also very easy to implement. An important aspect of the proposed method is its inherent stability irrespective of the order of the prediction-error filter or the manner in which it is adapted. This allows the proposed method to be used without any restrictions beyond those of the conventional NLMS algorithm. Following the stability analysis, a further improvement to the basic proposed method is suggested. This improvement is restricted to the cases where the input signal is decorrelated by a prediction-error filter of up to order two. The proposed method finds immediate application in acoustic echo cancellation in hands-free telephones where the impulse response of the system (echo path) to be identified is very long and the identification has to be done in real time. Such an application requires an algorithm with low computational complexity and a fast rate of convergence. In general, the proposed method can be used where the input coloured signal can be decorrelated using linear prediction.

The immune system has evolved to fight off numerous pathogens. The first line of defense against these pathogens are innate immune cells. Innate immune cells ingest pathogens and a family of cytosolic proteins, NOD-like receptors (NLR) and AIM2-like receptors (ALRs), recognize conserved sequences on pathogens. Recognition of pathogens by NLRs and ALRs alerts the immune system to the presence of an invader and subsequent control of infection. NLRs and ALRs also recognize endogenous cell danger signals that are released during cell stress. Pathogens and tumor cells are capable of growing in a host with limited detection by the immune system. This evasion leads to a suboptimal immune response to both the bacteria and cancer cells resulting in enhanced infection and tumor growth. We investigated how the bacteria Francisella tularensis escapes recognition by the AIM2 receptor. We identified a novel gene important in bacterial folate metabolism that helps the bacteria escape immune recognition. The identification of this gene will help in the development of treatments for F. tularensis infection. In addition, we investigated the role of the NLRC4 receptor in a mouse model of melanoma. We found that mice lacking NLRC4 developed significantly larger tumors and had a diminished immune response compared to mice that expressed NLRC4. We also observed decreased expression of NLRC4 in metastatic melanoma tissue in humans. Thus demonstrating that NLRC4 is important for initiating an immune response to melanoma and down regulating expression of NLRC4 is a way for the tumor to evade the immune response.

Innate immune activation is thought to play a central role in IBD pathogenesis because genetic polymorphisms in NOD2 and NLRP3, cytosolic innate immune receptors belonging to the NLR family, have been associated with IBD susceptibility. However, the mechanisms through which NLR mutations predispose to IBD remain unclear. The aim of this project was to dissect the functional roles of different NLRs in intestinal inflammation. Using the well-established DSS-induced colitis model as well as experimental models of IBD based on infection with Helicobacter hepaticus, we found that Nod2 expression was significantly increased at the peak of intestinal inflammation, and remained elevated throughout the resolution process. This observation suggests a possible role for Nod2 in the resolution of inflammation. Conversely, upon infection with the acute intestinal pathogen Citrobacter rodentium, Nlrp3-/- mice suffered from increased bacterial colonization as early as 3 days post infection, resulting in exacerbated intestinal inflammation and severe weight loss. Analysis of irradiation bone marrow chimeras showed that the protection required Nlrp3 activation in the non-haematopoietic compartment. Furthermore, this protective mechanism was independent of the inflammasome-associated cytokines IL-1β or IL-18. Therefore, this study implicates Nlrp3 activation in intestinal tissue cells as having a crucial role in controlling pathogenic bacterial colonization, providing a potential mechanism by which NLRP3 polymorphisms could lead to increased susceptibility to IBD.

The presented work describes new concepts of fast switching elements based on principles of photonics. The waveguides working in visible and infra-red ranges are put in a basis of these elements. And as materials for manufacturing of waveguides the transparent polymers, dopped by molecules of the dyes possessing second order nonlinear-optical properties are proposed. The work shows how nonlinear-optical processes in such structures can be implemented by electro-optical and opto-optical control circuit signals. In this paper we consider the complete cycle of fabrication of several types of integral photonic elements. The theoretical analysis of high-intensity beam propagation in media with second-order optical nonlinearity is performed. Quantitative estimations of necessary conditions of occurrence of the nonlinear-optical phenomena of the second order taking into account properties of used materials are made. The paper describes the various stages of manufacture of the basic structure of the integrated photonics: a planar waveguide. Using the finite element method the structure of the electromagnetic field inside the waveguide in different modes was analysed. A separate part of the work deals with the creation of composite organic materials with high optical nonlinearity. Using the methods of quantum chemistry, the dependence of nonlinear properties of dye molecules from its structure were investigated in details. In addition, the paper discusses various methods of inducing of an optical nonlinearity in dye-doping of polymer films. In the work, for the first time is proposed the use of spatial modulation of nonlinear properties of waveguide according Fibonacci law. This allows involving several different nonlinear optical processes simultaneously. The final part of the work describes various designs of integrated optical modulators and switches constructed of organic nonlinear optical waveguides. A practical design of the optical modulator based on Mach-Zehnder interferometer made by a photolithography on polymer film is presented.
Die vorliegende Arbeit beschreibt neue Konzepte für schnelle photonische Schaltelemente. Diese Elemente basieren auf optischer Wellenleitung im sichtbaren und nahen infraroten Spektralbereich. Die Arbeit ist auf organische Wellenleiter aus transparenten, farbstoffdotierten Polymeren fokussiert, welche Chromophore mit besonders großen optischen Nichtlinearitäten zweiter Ordnung enthalten. Insbesondere wird dargestellt, wie nichtlineare optische Prozesse in derartigen Bauelementen genutzt werden können, wenn man elektrische oder optische Steuersignale einsetzt. Es wird der gesamte Her-stellungszyklus verschiedener integrierter photonischer Bauelemente betrachtet. Die Arbeit umfasst weiterhin eine detaillierte theoretische Analyse der Wellenausbreitung in Medien mit großer nichtlinearer optischer Suszeptibilität zweiter Ordnung bei hoher Lichtintensität. Unter Annahme optischer Materialkonstanten, welche den experimentell ermittelten Werten entsprechen, erfolgte eine quantitative Abschätzung für das Auftreten von Szenarien, bei denen messbare Abwei-chungen der Strahlausbreitung vom linearen Regime auftreten, z:B. das Auftreten von zeitlichen, räumlichen und spektralen Satteliten zu den im Material propagierenden Laserpulsen. Es gelang, we-sentliche Aspekte der Strahlpropagationsprozesse durch Anwendung von Jacobi-Integralfunktionen in geschlossener mathematischer Form darzustellen. Darüber hinausgehende theoretische Untersuchungen nutzten die Finite-Elemente-Methode, um die Verteilung des elektromagnetischen Feldes im Inneren optischer Wellenleiter für verschiedene Pro-pagationsmoden zu analysieren. Ein weiterer Teil der Arbeit beschäftigt sich mit organischen Kompositmaterialen, welche große opti-sche Nichtlinearitäten aufweisen. Mittels quantenchemischer Verfahren erfolgte eine detaillierte Un-tersuchung der Zusammenhänge zwischen der molekularen Struktur und den linearen sowie den nichtlinearen optischen Eigenschaften der untersuchten Farbstoffmoleküle und Polymere. In Bezug auf die Probenpräparation sind unterschiedliche Verfahren zur Schichtbildung und zur molekularen Orientierung miteinander verglichen und bewertet worden, da letztere eine Voraussetzung für das Auftreten nichtlinearer optischer Prozesse zweiter Ordnung bildet. Die Untersuchungen erstreckten sich auf Vakuumaufdampfschichten aus niedermolekularen Chromophoren und auf Polymerschich-ten, welche durch Vakuumabscheidung sowie durch Spincoating oder andere Flüssigphasenabschei-dungsverfahren hergestellt worden sind. Auf orientierenden Substraten (z.B. geriebene Schichten aus Polytetrafluoräthylen) konnte eine spontane Orientierung der deponierten Chromophore nachgewie-sen werden. Die Chromophore in Polymerschichten wurden durch Coronapolung orientiert. In der Arbeit ist zum ersten Mal vorgeschlagen worden, eine räumliche Modulation der nichtlinearen optischen Eigenschaften durch gezielte lokale Coronapolung oder andere Orientierungstechniken derart zu generieren, dass die Abfolge gepolter Domänen dem Bildungsgesetz einer modifizierten Fibonacci-Reihe mit gebrochen rationalen Zahlen gehorcht. Der Vorteil von optischen Wellenleitern mit dieser Struktur darin, dass diese mehrere unterschiedli-che nichtlineare optische Prozesse gleichzeitig unterstützen und somit eine Vielzahl neuartiger Phä-nomene auftreten kann, welche man in neuartigen photonischen Bauelementen, z.B. für die optische Informations- und Kommunikationstechnik nutzen kann. Der letzte Teil der Arbeit beschreibt den Aufbau verschiedener integrierter optischer Modulatoren und Schalter, die sich mit Hilfe das neu entwickelten Verfahrens herstellen lassen. Zukünftige Entwicklungen in der Photonik, insbesondere der optischen Informations- und Kommuni-kationstechnik werden im abschließenden Teil der Arbeit diskutiert.

The study of rogue waves is a booming topic mainly in oceanography but also in other fields. In this thesis I construct via Darboux transform a multi-parametric family of smooth quasi-rational solutions of the nonlinear Schödinger equation that present a behavior of rogue waves. For a general choice of parameters the second-order solutions give a model of "three sisters" (three higher than expected waves in a row) while for a particular choice of parameters we obtain the solutions given by Akhmediev et al. in a serie of articles in 2009. Then these solutions allow me to construct rational solutions of the KP-I equation that describe waves in shallow water.

Plant immunity is usually initiated with two types of immune receptors: 1) pattern recognition receptors (PRRs) recognize the conserved molecular features of pathogens (pathogen-associated molecular patterns, PAMPs) and trigger PTI (PAMP-triggered immunity) and; 2) nucleotide-binding/leucine-rich repeats (NLRs) serve as intracellular immune receptors with the ability to recognize the presence of relatively diverse pathogen effectors and trigger ETI (effector-triggered immunity). The Arabidopsis thaliana mutant snc1 contains a gain-of-function mutation in a Toll/interleukin-1 (TIR)-type NLR (TNL) gene and displays a dwarf morphology. Here, I report on the results of a snc1-influencing plant E3 ligase reverse genetic (SNIPER) screen that looked for snc1 plants with altered dwarfism in the presence of overexpressed E3 ligases. Six SNIPER genes were identified with four snc1-suppressors and two snc1-enhancers. SNIPER1/2/3 were selected for further characterization. The analysis of SNIPER1/2 is incomplete, thus is not included in this thesis. Chapter 3 describes SNIPER3, previously known as SAUL1 (Senescence-Associated E3 Ubiquitin Ligase 1) or PUB44 (Plant U-box 44), which encodes a U-box-type E3 ligase. Our data suggests that SAUL1 plays a dual role in plant immunity: on one hand, SAUL1 positively regulates basal resistance; on the other hand, SAUL1 suppresses a typical TNL immune receptor SUSA1 (Suppressor of saul1) to prevent its autoimmunity. ADR1, ADR1-L1 and ADR1-L2 are three homologous coiled-coil (CC)-type NLRs (CNLs), which were previously shown to work as helper NLRs. Chapter 4 further explores the specificity of the genetic requirement of ADR1s for typical TNLs, SNC1 and CHS2 (CHILLING SENSITIVE 2). Among the three ADR1 members, ADR1 is the leading contributor while ADR1-L1 is the least. Moreover, loss-of-function mutation of ADR1-L1 leads to over compensation of the transcript expression level of ADR1 and ADR1-L2 and results in the enhancement of snc1-mediated immunity. Overall, the studies I completed as part of my Ph.D. thesis expand our knowledge of the roles of E3 ligases and ADR1s in plant defense and help us to better understand the sophisticated regulatory mechanisms of plant innate immunity.
Science, Faculty of
Botany, Department of
Graduate

La leucémie lymphoïde chronique (LLC) est une hémopathie maligne caractérisée par l’accumulation, dans le sang et les organes lymphoïdes secondaires, de lymphocytes B matures résistants à l’apoptose. Le microenvironnement tumoral de la LLC au sein des organes lymphoïdes secondaires, et notamment les « Nurse-Like Cells » (NLCs), joue un rôle majeur dans la promotion de la survie et de la prolifération des cellules leucémiques. Au cours de cette étude, la surexpression du récepteur de la neurotensine NTSR2, un récepteur couplé aux protéines G, a été caractérisée. Il est activé de façon constitutive dans les cellules leucémiques circulantes, et son activation dépend de son interaction avec le récepteur à activité tyrosine kinase TrkB suite à la liaison de son ligand, le BDNF, tous deux également surexprimés. L’activation de NTSR2-TrkB par le BDNF entraine une signalisation de survie par les voies Src et Akt, aboutissant à la surexpression des protéines anti-apoptotiques Bcl-2 et Bcl-XL. L’inhibition du récepteur NTSR2 dans ces cellules fait diminuer leur viabilité. En présence des NLCs, les expressions de NTSR2, TrkB, BDNF, et de la sortiline, protéine de transport des neurotrophines et des récepteurs Trk, est accentuée. Les NLCs produisent elle-même du BDNF, activent la voie de signalisation Src, et leur rôle protecteur des cellules leucémiques est BDNF-dépendant. L’ensemble de ces travaux met en évidence un rôle capital de NTSR2-TrkB-BDNF dans la signalisation de survie des cellules leucémiques circulantes et au sein du microenvironnement tumoral de la LLC, et pourrait ainsi constituer une nouvelle cible thérapeutique potentielle
Chronic lymphocytic leukemia (CLL) is a malignant hemopathy characterized by the accumulation of apoptosis resistant mature B lymphocytes in peripheral blood and secondary lymphoid organs. In these secondary lymphoid organs, the tumor microenvironment, notably Nurse-like Cells (NLCs), plays a major role in leukemic cells survival and proliferation promotion. In this study, an overexpression of neurotensin receptor NTSR2, a G-protein coupled receptor, was identified. NTSR2 is constitutively activated in circulating leukemic cells and its activation depends on its interaction with tyrosine kinase activity receptor TrkB upon binding of its ligand, BDNF. Activation of NTSR2-TrkB by BDNF induces survival signaling by Src and Akt pathways, and in term anti-apoptotic proteins Bcl-2 and Bcl-XL overexpression. Inhibition of NTSR2 in those cells impacts their viability. In the presence of NLCs, expressions of NTSR2, TrkB, BDNF, and sortilin, a neurotrophin and Trk receptor transport regulator, are enhanced. NLCs produce BDNF, stimulate Src activation, and their protective role on leukemic cells is BDNF-dependent. Taken together, this study highlights a key role of NTSR2-TrkB-BDNF in leukemic cells survival signaling, both in the circulation or in the tumor microenvironment, and might thus constitute a potential new therapeutic target