Analysis of the sum rate for massive MIMO using 10 GHz measurements

Orientador: Gustavo FraidenraichTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Este trabalho apresenta um conjunto de contribuições para caracterização e modelagem de canais reais de rádio abordando aspectos relacionados com as condições favoráveis de propagação para sistemas massive MIMO. Discutiremos como caracterizar canais de rádio em um ambiente real, processamento de dados e análise das condições favoráveis de propagação. Em uma segunda parte, focamos na determinação teórica de alguns aspectos da tecnologia de massive MIMO utilizando propriedades de distribuições matriciais Wishart. Inicialmente, apresentamos uma contribuição sobre a aplicação do algoritmo ESPRIT, para estimar parâmetros de um conjunto de dados multidimensional. Obtivemos dados por varredura em frequência de um Analisador Vetorial de Rede e os adaptamos para o algoritmo ESPRIT. Mostramos como remover a influência do ganho de padrão de antenas e como utilizar um gerador de modelo de canal baseado nas medidas reais de canal de rádio. As medidas foram feitas na frequência de 10.1 GHz com largura de faixa de 500 MHz. Utilizando um gerador de modelo de canal, fomos além do universo das simulações por distribuições Gaussianas. Introduzimos o conceito de propagação favorável e analisamos condições de linha-de-visada usando arranjos lineares uniformes e arranjos retangulares uniformes de antena. Como novidade da pesquisa, mostramos os benefícios de explorar um número extra de graus de liberdade devido à escolha dos formatos de arranjo de antenas e ao aumento do número de elementos. Esta propriedade é observada ao analisarmos a distribuição dos autovalores de matrizes Gramianas. Em seguida, estendemos o mesmo raciocínio para as matrizes de canal geradas a partir de informações reais e verificamos se as propriedades ainda permaneceriam válidas. Na segunda parte deste trabalho, incluímos mais de uma antena no terminal móvel e calculamos a probabilidade de indisponibilidade para várias configurações de antenas e número arbitrário de usuários. Esboçamos inicialmente a formulação para a informação mútua e, em seguida, calculamos os resultados exatos em uma situação com dois usuários e duas antenas, tanto na estação base (EB) como nos terminais de usuário(TU). Visto que as formulações para a derivação exata dos casos com mais antenas e mais usuários mostrou-se muito intrincada, propusemos uma aproximação Gaussiana para simplificar o problema. Esta aproximação foi validada por simulações Monte Carlo para diferentes relações sinal/ruídoAbstract: This thesis presents a set of contributions for channel modeling and characterization of real radio channels delineating aspects related with the favorable propagation for massive MIMO systems. We will discuss about how to proceed for characterizing radio channels in an real environment , data processing, and analysis of favorable conditions. In a second part, we focused on determination of some theoretical aspects of the Massive MIMO technology using properties of Wishart distribution matrices. We initially present a contribution on the application of ESPRIT algorithm for estimating a multidimensional set of measured data. We have obtained data by frequency sweep carried out by a vector network analyzer(VNA) and adapted it to fit in the ESPRIT algorithm. We show how to remove antenna pattern gain using virtual antenna arrays and how to use a channel model generator based on radio channel measurements of real environments. The measurements were conducted at the frequency of 10.1 GHz and 500 MHz bandwidth. By using a channel model generator, we have explored beyond the simulation of Gaussian Distributions. We will introduce the concept of favorable propagation and analyze the line-of-sight conditions using ULA and URA array shapes. As a research novelty, we will show the benefits of exploiting an extra degree of freedom due to the choice of the antenna shapes and amount of antenna elements. We observe these properties through the distribution of the Gramian Matrices. Next, we extend the same rationale to channel matrices generated from real channels and we verify that the properties are still valid. In a second part of the research work, we included more than one antenna in the mobile terminals and calculated the outage probability for several antenna configurations and arbitrary number users. We introduce a formulation for mutual information and then we calculate exact results in a case with two users with two antennas in both Base Station (BS) and User Terminals (UT). Since the formulations to the exact derivation for cases with more antennas and users seems to be intricate, we propose a Gaussian approximation solution to simplify the problem. We validated this approximation with Monte Carlo simulations for different signal-to-noise ratiosDoutoradoTelecomunicações e TelemáticaDoutor em Engenharia Elétrica248416/2013-8CNPQCAPE

A study of poststenotic shear layer instabilities

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Photo- and Redox-Driven Artificial Molecular Motors

Directed motion at the nanoscale is a central attribute of life, and chemically driven motor proteins are nature's choice to accomplish it. Motivated and inspired by such bionanodevices, in the past few decades chemists have developed artificial prototypes of molecular motors, namely, multicomponent synthetic species that exhibit directionally controlled, stimuli-induced movements of their parts. In this context, photonic and redox stimuli represent highly appealing modes of activation, particularly from a technological viewpoint. Here we describe the evolution of the field of photo- and redox-driven artificial molecular motors, and we provide a comprehensive review of the work published in the past 5 years. After an analysis of the general principles that govern controlled and directed movement at the molecular scale, we describe the fundamental photochemical and redox processes that can enable its realization. The main classes of light- and redox-driven molecular motors are illustrated, with a particular focus on recent designs, and a thorough description of the functions performed by these kinds of devices according to literature reports is presented. Limitations, challenges, and future perspectives of the field are critically discussed

Advanced capabilities for planar X-ray systems

Mención Internacional en el título de doctorThe past decades have seen a rapid evolution towards the use of digital detectors in radiology and a more flexible robotized movement of the system components, X-ray tube and detector. This evolution opened the possibility for incorporating advanced capabilities in these planar X-ray systems, and for providing new valuable diagnostic information compared to the previous technology. Some of the current challenges for radiography are to obtain more quantitative images and to reduce the inherent superposition of tissues because of the 2D nature of the technique. Dual energy radiography, based on the acquisition of two images at different source voltages, enables a separate characterization of soft tissue and bone structures. Its benefits over conventional radiography have been proven in different applications, since it improves information content without adding significant extra acquisition time or radiation dose. In a different direction, a really disruptive advance would be to obtain 3D imaging with systems designed just for planar images. The incorporation of tomographic capabilities into these systems would have to deal with the acquisition of a limited number of projections, with non-standard geometrical configurations. This thesis presents original contributions in these two directions: dual energy radiography and 3D imaging with X-ray systems designed for planar imaging. The work is framed in a line of research of the Biomedical Imaging and Instrumentation Group from the Bioengineering and Aerospace Department of University Carlos III de Madrid working jointly with the University Hospital Gregorio Marañón, focused on the advance of radiology systems. This research line is carried out in collaboration with the group of Computer Architecture, Communications and Systems (ARCOS), from the same university, the Imaging Research Laboratory (IRL) of the University of Washington and the research center CREATIS, France. The research has a clear focus on technology transfer to the industry through the company Sedecal, a Spanish multinational among the 10 best world companies in the medical imaging field. The first contribution of this thesis is a complete novel protocol to incorporate dual energy capabilities that enable quantitative planar studies. The proposal is based on the use of a preliminary calibration with a very simple and low-cost phantom formed by two parts that represent soft tissue and bone equivalent materials. This calibration is performed automatically with no strict placement requirements. Compared to current Dual-energy X-ray Absorptiometry (DXA) systems, 1) it provides real mass-thickness values directly, enabling quantitative planar studies instead of relative comparisons, and 2) it is based on an automatic preliminary calibration without the need of interaction of an experienced technician. The second contribution is a novel protocol for the incorporation of tomographic capabilities into X-ray systems originally intended for planar imaging. For this purpose, we faced three main challenges. First, the geometrical trajectory of equipment follows non-standard circular orbits, thus posing severe difficulties for reconstruction. To handle this, the proposed protocol comprises a new geometrical calibration procedure that estimates all the system parameters per-projection. Second, the reconstruction of a limited number of projections from a reduced angular span leads to severe artifacts when using conventional reconstruction methods. To deal with these limited-view data, the protocol includes a novel advanced reconstruction method that incorporates the surface information of the sample, which can be extracted with a 3D light surface scanner. These data are introduced as an imposed constraint following the Split Bregman formulation. The restriction of the search space by exploiting the surface-based support becomes crucial for a complete recovery of the external contour of the sample and surroundings when the angular span is extremely reduced. The modular, efficient and flexible design followed for its implementation allows for the reconstruction of limited-view data with non-standard trajectories. Third, the optimization of the acquisition protocols has not yet explored with these systems. This thesis includes a study of the optimum acquisition protocols that allowed us to identify the possibilities and limitations of these planar systems. Using the surface-constrained method, it is possible to reduce the total number of projections up to 33% and the angular span down to 60 degrees. The contributions of this thesis open the way to provide depth and quantitative information very valuable for the improvement of radiological diagnosis. This could impact considerably the clinical practice, where conventional radiology is still the imaging modality most used, accounting for 80-90% of the total medical imaging exams. These advances open the possibility of new clinical applications in scenarios where 1) the reduction of the radiation dose is key, such as lung cancer screening or Pediatrics, according to the ALARA criteria (As Low As Reasonably Achievable), 2) a CT system is not usable due to movement limitations, such as during surgery or in an ICU and 3) where costs issues complicate the availability of CT systems, such as rural areas or underdeveloped countries. The results of this thesis has a clear application in the industry, since it is part of a proof of concept of the new generation of planar X-ray systems that will be commercialized worldwide by the company SEDECAL (Madrid, Spain).Los últimos años están viendo un rápido avance de los sistemas de radiología hacia el uso de detectores digitales y a una mayor flexibilidad de movimientos de los principales componentes del sistema, el tubo de rayos X y el detector. Esta evolución abre la posibilidad de incorporar capacidades avanzadas en sistemas de imagen plana por rayos X proporcionando nueva información valiosa para el diagnóstico. Dos retos en radiografía son obtener imágenes cuantitativas y reducir la superposición de tejidos debida a la naturaleza proyectiva de la técnica. La radiografía de energía dual, basada en la adquisición de dos imágenes a diferente kilovoltaje, permite obtener imágenes de tejido blando y hueso por separado. Los beneficios de esta técnica que aumenta la cantidad de información sin añadir un tiempo de adquisición o de dosis de radiación extra significativos frente al uso de radiografía convencional, han sido demostrados en diferentes aplicaciones. En otra dirección, un avance realmente disruptivo sería la obtención de imagen 3D con sistemas diseñados únicamente para imagen plana. La incorporación de capacidades tomográficas en estos sistemas tendría que lidiar con la adquisición de un número limitado de proyecciones siguiendo trayectorias no estándar. Esta tesis presenta contribuciones originales en esas dos direcciones: radiografía de energía dual e imagen 3D con sistemas de rayos X diseñados para imagen plana. El trabajo se encuadra en una línea de investigación del grupo de Imagen Biomédica e Instrumentación del Departamento de Bioingeniería e Ingeniería Aerospacial de la Universidad Carlos III de Madrid junto con el Hospital Universitario Gregorio Marañon, centrada en el avance de sistemas de radiología. Esta línea de investigación se desarollada en colaboración con el grupo Computer Architecture, Communications and Systems (ARCOS), de la misma universidad, el grupo Imaging Research Laboratory (IRL) de la Universidad de Washington y el centro de investigación CREATIS, de Francia. Se trata de una línea de investigación con un claro enfoque de transferencia tecnológica a la industria a través de la compañía SEDECAL, una multinacional española de entre las 10 líderes del mundo en el campo de la radiología. La primera contribución de esta tesis es un protocolo completo para incorporar capacidades de energía dual que permitan estudios cuantitativos de imagen plana. La propuesta se basa en una calibración previa con un maniquí simple y de bajo coste formado por dos materiales equivalentes de tejido blando y hueso respectivamente. Comparado con los sistemas actuales DXA (Dual-energy X-ray Absorptiometry), 1) proporciona valores reales de tejido atravesado, 2) se basa en una calibración automática que no requiere la interacción de un técnico con gran experiencia. La segunda contribución es un protocolo nuevo para la incorporación de capacidades tomográficas en sistemas de rayos X originariamente diseñados para imagen plana. Para ello, nos enfrentamos a tres principales dificultades. En primer lugar, las trayectorias que pueden seguir la fuente y el detector en estos sistemas no constituyen órbitas circulares estándares, lo que plantea retos importantes en la caracterización geométrica. Para solventarlo, el protocolo propuesto incluye una calibración geométrica que estima todos los parámetros geométricos del sistema para cada proyección. En segundo lugar, la reconstrucción de un número limitado de proyecciones adquiridas en un rango angular reducido da lugar a artefactos graves cuando se reconstruye con algoritmos convencionales. Para lidiar con estos datos de ángulo limitado, el protocolo incluye un nuevo método avanzado de reconstrucción que incorpora la información de superficie de la muestra, que se puede se obtener con un escáner 3D. Esta información se impone como una restricción siguiendo la formulación de Split Bregman, para compensar la falta de datos. La restricción del espacio de búsqueda a través de la explotación del soporte basado en superficie, es crucial para una recuperación completa del contorno externo de la muestra cuando el rango angular es extremadamente pequeño. El diseño modular, eficiente y flexible de la implementación propuesta permite reconstruir datos de ángulo limitado obtenidos con posiciones de fuente y detector no estándar. En tercer lugar, hasta la fecha, no se ha explorado la optimización del protocolo de adquisición con estos sistemas. Esta tesis incluye un estudio de los protocolos óptimos de adquisición que permitió identificar las posibilidades y limitaciones de estos sistemas de imagen plana. Gracias al método de reconstrucción basado en superficie, es posible reducir el número total de proyecciones hasta el 33% y el rango angular hasta 60 grados. Las contribuciones de esta tesis abren la posibilidad de proporcionar información de profundidad y cuantitativa muy valiosa para la mejora del diagnóstico radiológico. Esto podría impactar considerablemente en la práctica clínica, donde la radiología convencional es todavía la modalidad de imagen más utilizada, abarcando el 80- 90% del total de los exámenes de imagen médica. Estos avances abren la posibilidad de nuevas aplicaciones clínicas en escenarios donde 1) la reducción de la dosis de radiación es clave, como en screening de cáncer de pulmón, de acuerdo con el criterio ALARA (As Low As Reasonably Achievable), 2) no se puede usar un sistema TAC por limitaciones de movimiento como en cirugía o UCI, o 3) el coste limita la disponibilidad de sistemas TAC, como en zonas rurales o en países subdesarrollados. Los resultados de esta tesis presentan una clara aplicación industrial, ya que son parte de un prototipo de la nueva generación de sistemas planos de rayos X que serán distribuidos mundialmente por la compañía SEDECAL.This thesis has been developed as part of several research projects with public funding: - DPI2016-79075-R. ”Nuevos escenarios de tomografía por rayos X”, IP: Mónica Abella García, Ministerio de Economía y Competitividad, 01/01/2017-31/12/2019, 147.620 e. - ”Nuevos escenarios de tomografía por rayos X (NEXT) DPI2016-79075-R. Ministerio de Economía”, Industria y Competitividad. (Universidad Carlos III de Madrid). 30/12/2016-29/12/2019. 147.620 e. (…) - FP7-IMI-2012 (GA-115337), ”PreDict-TB: Model-based preclinical development of anti-tuberculosis drug combinations”. FP7-IMI - Seventh Framework Programme (EC-EFPIA). Unión Europea. (Universidad Carlos III de Madrid). 01/05/2012-31/10/2017. (…) - TEC2013-47270-R, ”Avances en Imagen Radiológica (AIR)”, Ministerio de Economía y Competitividad”, 01/01/2014-31/12/2016. IP: Mónica Abella Garcia and Manuel Desco Menéndez. 160.204 e (…) - RTC-2014-3028-1, ”Nuevos Escenarios Clínicos con Radiología Avanzada (NECRA)”, Ministerio de Economía y Competitividad, 01/06/2014-31/12/2016 IP: Mónica Abella García. 2014-2016. 219.458,96 e - IDI-20130301, ”Nuevo sistema integral de radiografía (INNPROVE: INNovative image PROcessing in medicine and VEterinary)”, IP: Mónica Abella García and Manuel Desco Menéndez. Ministerio de Economía y Competitividad. Subcontratación CDTI, 14/01/2013-31/03/2015. Total: 1.860.629e (UC3M: 325.000e). (Art. 83) - IPT-2012-0401-300000 INNPACTO 2012, ”Tecnologías para Procedimientos Intraoperatorios Seguros y Precisos. XIORT. MINECO. (Universidad Carlos III de Madrid). 01/01/2013-31/12/2015.Programa Oficial de Doctorado en Ingeniería MatemáticaPresidente: Doménec Ros Puig.- Secretario: Cyril Riddell.- Vocal: Yannick Boursie

Position location in wireless MIMO communication systems

Motivation and objectives -- Contributions -- Organization of the thesis -- Wireless communication channels -- Overview of wireless position location systems -- Fundamentals of array signal processing -- Mimo and space-time processing -- Bidirectional mimo channel model -- The system model -- The bidirectional beamforming MIMO channel -- Joint estimation of multipath parameters for Mimo systenms -- The proposed maximum likelihood multipath parameter estimation algorithms -- The proposed subspace-based multipath parameter estimation algorithm -- The cramer-rao lower bound -- Position location of mobile terminal in mimo systems -- The proposed hybrid TDOA/AOA/AOD location method for Mimo systems -- Analysis of the proposed location method for MIMO systems

Investigating the functional roles of occipital face area and lateral occipital cortex with transcranial magnetic stimulation

This thesis investigates the causal role of two extra-striate visual regions, the lateral occipital (LO) cortex and the occipital face area (OFA), in certain visual processes. Firstly, I examined whether these areas are causally implicated in the perception of bilateral visual symmetry. Despite the ubiquitous presence of this feature in the external world, the neural basis underlying its detection is not fully known. In Studies I and II,this issue was explored by disrupting the activity of LO and OFA with fMRI-guided transcranial magnetic stimulation (TMS) while participants discriminated between symmetric and nonsymmetric dot configurations and between perfectly symmetric and normal (i.e. somewhat non symmetric) faces. The results showed that rightOFA plays a causal role in detection of symmetry in both configurations of dots and faces whereas LO exclusively in the former, with the rightLO showing greater involvement relative to the homologous region in the left hemisphere. As symmetry is extracted in a holistic manner (i.e. through a parallel global analysis of the stimulusrather than via a serial point-by-point comparisonof the local elements), Study III examined whether rightOFA is involved, more generally, in visual detection based on holistic encoding and, if so, whether its role is restricted to faces or extends also to non-face stimuli. To examine this issue, rightOFA and rightLO were stimulated with fMRI-guided TMS meanwhile participants were asked to detect Mooney faces and non-face images, a class of stimuli which are known to be perceived through holistic processes. The results showed that rightOFA is causally involved in detection of both Mooney faces and objects. Taken together, this thesis sheds new light on the functions of LO and OFA in visual perception. Firstly, it demonstrates that both of these regions are causally involved in holistic processes, including detection of symmetry. Secondly, it is shownthat OFA s role in holistic processing extends to both face and non-face stimuli, suggesting that this region is not strictly face-selective.Tässä väitöskirjatyössä tutkitaan kahden myöhäisen näköaivokuoren alueen (lateral occipital cortex (LO) ja occipital face area (OFA)) kausaalista roolia tietyissä visuaalisissa prosesseissa. Ensiksi tutkittiin, osallistuvatko nämä alueet kausaalisesti bilateraalisen symmetrian havaitsemiseen. Huolimatta siitä, että symmetriaa on läsnä kaikkialla ympäröivässä maailmassa, sen havaitsemisen hermostollinen perusta ei ole vielä täysin tunnettu. Osatutkimuksissa I ja II asiaa tutkittiin häiritsemällä koehenkilöiden aivojen aktiivisuutta alueilla LO ja OFA fMRI-ohjatun trankraniaalisen magneettistimulaation (TMS) avulla, samalla kun he erottelivat symmetrisiä ja epäsymmetrisiä pistekuvioita sekä täysin symmetrisiä ja normaaleja (jonkin verran epäsymmetrisiä) kasvoja toisistaan. Tulokset osoittivat, että oikeanpuoleisella OFA:lla on kausaalinen rooli sekä pistekuvioiden että kasvojen symmetrian havaitsemisessa, kun taas LO:lla pelkästään edellisessä. Oikeanpuoleisen LO:n osallistumisen havaittiin olevan lisäksi voimakkaampaa suhteessa vastaavaan alueeseen vasemmassa aivopuoliskossa. Koska symmetria havaitaan holistisesti (havaitun ärsykkeen globaalin rinnakkaisen analyysin perusteella paikallisen piste pisteeltä vertailun sijaan), III osatyössä selvitettiin osallistuuko oikeanpuoleinen OFA yleisemmin visuaaliseen havaitsemiseen holistiseen enkoodaukseen perustuen, ja onko sen rooli rajoittunut pelkästään kasvoärsykkeisiin. Tämän tutkimiseksi oikeanpuoleista OFA:ta ja LO:ta stimuloitiin fMRI-ohjatulla TMS:lla koehenkilöiden tarkkaillessa n.k. Mooney kasvoja ja kuvia, joita molempia tiedetään prosessoitavan holistisesti. Tulokset osoittivat, että oikeanpuoleinen OFA osallistuu kausaalisesti sekä Mooney kasvojen että objektien tarkasteluun. Tämä väitöskirja laajentaa ymmärrystä LO ja OFA alueiden toiminnasta visuaalisessa havaitsemisessa. Ensiksi, se demonstroi, että molemmat näistä alueista osallistuvat kausaalisesti holistiseen prosessointiin, sisältäen myös symmetrian havaitsemisen. Toiseksi, työssä osoitetaan, että OFA:n rooli holistisessa prosessoinnissa käsittää sekä kasvo- että muut ärsykkeet, ehdottaen että alue ei ole tiukasti kasvoselektiivinen