This work focuses on fixing measurement inaccuracies to which models and figures of merit are susceptible in two wireless communication environments: power amplifier and multipath. To emulate or rate the performance of these environments, models and figures of merit, respectively, are often used. The usefulness of a model depends on how accurately and efficiently it emulates its real-world counterpart. The usefulness of a figure of merit depends on how accurately it represents system behavior. Most discussions on the challenges and trade-offs faced in modeling nearly always focus on the complexity of the device or channel of interest and the resultant difficulty in describing it. Similarly, figures of merit are meant only to summarize the performance of the device or channel. At some point, either in generation or verification of a model or figure of merit, there is a dependence on measured data. Though the complexity and performance of the device or channel are challenges by themselves, there are other significant sources of distortion that must be minimized to avoid errors in the measured data. For this work, the unique distortion of power amplifier and multipath environments is considered, and then errors in measurement which would obscure these distortions are eliminated. Specifically, three measurement issues are addressed: 1) identifying measurement setup artifacts, 2) achieving consistent measurement results and 3) reducing variations in the environment. This work contributes to increasing the accuracy of microwave measurements used in the modeling of nonlinear high-power amplifiers and used in figures of merit for power amplifiers and multipath channels.

In this dissertation an in-depth study was conducted into the design, implementation and evaluation of a QPSK-based receiver structure for application in a UMTS WCDMA environment. The novelty of this work lies with the specific receiver architecture aimed to optimise the BER performance when possibly sparse data streams are transmitted. This scenario is a real possibility according to Verd´u et al [1] and Hagenauer et al [2–6]. A novel receiver structure was conceptualised, developed and evaluated in both narrowband and wideband scenarios, where it was found to outperform conventional receivers when a sparse data stream is transmitted. In order to reach the main conclusions of this study, it was necessary to develop a realistic simulation platform. The developed platform is capable of simulating a communication system meeting the physical layer requirements of the UMTS WCDMA standard. The platform can also perform narrowband simulations. A flexible channel emulator was developed that may be configured to simulate AWGN channel conditions, frequency non-selective fading (either Rayleigh or Rician with a configurable LOS component and Doppler spread), or a full multipath scenario where each path has a configurable LOS component, Doppler spread, path gain and path delay. It is therefore possible to even simulate a complex, yet realistic, COST207-TU channel model. The platform is also capable of simulating MUI. Each interfering user has a unique and independent multipath fading channel, while sharing the same bandwidth. Finally, the entire platform executes all simulations in baseband for improved simulation times. The research outputs of this work are summarised below: <ul> <li>A parameter, the sparseness measure, was defined in order to quantify the level by which a data stream differs from an equiprobable data stream.</li> <li>A novel source model was proposed and developed to simulate data streams with a specified amount of sparseness.</li> <li>An introductory investigation was undertaken to determine the effect of simple FEC techniques on the sparseness of an encoded data stream.</li> <li>Novel receiver structures for both narrowband and wideband systems were proposed, developed and evaluated for systems where possibly sparse data streams may be transmitted.</li> <li>Analytic expressions were derived to take the effect of sparseness into account in communication systems, including expressions for the joint PDF of a BPSK branch, the optimal decision region of a detector in AWGN conditions as well as the BER performance of a communication system employing the proposed optimal receiver in both AWGN channel conditions as well as in flat fading channel conditions.</li> <li>Numerous BER performance curves were obtained comparing the proposed receiver structure with conventional receivers in a variety of channel conditions, including AWGN, frequency non-selective fading and a multipath COST207-TU channel environment, as well as the effect of MUI</li></ul>. AFRIKAANS : In hierdie verhandeling word ’n in-diepte studie gedoen rakende die ontwerp, implementasie en evaluasie van ’n KPSK-gebaseerde ontvanger struktuur wat in ’n UMTS WKVVT omgewing gebruik kan word. Die bydrae van hierdie werk lˆe in die spesifieke ontvanger argitektuur wat daarop mik om die BFT werksverrigting te optimeer wanneer yl data strome versend word. Hierdie is ’n realistiese moontlikheid volgens Verd´u et al [1] en Hagenauer et al [2–6]. ’n Nuwe ontvanger struktuur is gekonsepsualiseer, ontwikkel en evalueer vir beide noueband en wyeband stelsels, waar dit gevind is dat dit beter werksverrigting lewer as tradisionele ontvangers wanneer yl data strome versend word. Dit was nodig om ’n realistiese simulasie platform te ontwikkel om die belangrikste gevolgtrekkings van hierdie studie te kan maak. Die ontwikkelde platform is in staat om ’n kommunikasie stelsel te simuleer wat aan die fisiese laag vereistes van die UMTS WKVVT standaard voldoen. Die platform kan ook noueband stelsels simuleer. ’n Aanpasbare kanaal simulator is ontwikkel wat opgestel kan word om SWGR kanaal toestande, plat duining (beide Rayleigh of Ricies met ’n verstelbare siglyn komponent en Doppler verspreiding), sowel as ’n veelvuldige pad omgewing (waar elke unieke pad ’n verstelbare siglyn komponent, Doppler verspreiding, pad wins en pad vertraging het) te emuleer. Dit is selfs moontlik om ’n komplekse, maar steeds realistiese COST207-TU kanaal model te simuleer. Die platform het ook die vermo¨e om VGS te simuleer. Elke steurende gebruiker het ’n unieke en onafhanklike veelvuldige pad deinende kanaal, terwyl dieselfde bandwydte gedeel word. Laastens, alle simulasies van die platvorm word in basisband uitgevoer wat verkorte simulasie periodes verseker. Die navorsingsuitsette van hierdie werk kan as volg opgesom word: <ul> <li>’n Parameter, die ylheidsmaatstaf, is gedefin¨ýeer om dit moontlik te maak om die vlak waarmee die ylheid van ’n datastroom verskil van ’n ewekansige stroom te versyfer.</li> <li>’n Nuwe bronmodel is voorgestel en ontwikkel om datastrome met ’n spesifieke ylheid te emuleer.</li> <li>’n Inleidende ondersoek is onderneem om vas te stel wat die effek van VFK tegnieke op die ylheid van ’n enkodeerde datastroom is.</li> <li>Nuwe ontvanger strukture is voorgestel, ontwikkel en evalueer vir beide noueband en wyeband stelsels waar yl datastrome moontlik versend kan word.</li> <li>Analitiese uitdrukkings is afgelei om die effek van ylheid in ag te neem in kommunikasie stelsels. Uitdrukkings vir onder andere die gedeelte WDF van ’n BFVK tak, die optimale beslissingspunt van ’n detektor in SWGR toestande, sowel as die BFT werksverrigting van ’n kommunikasie stelsel wat van die voorgestelde optimale ontvangers gebruik maak, hetsy in SWGR of in plat duinende kanaal toestande.</li> <li>Talryke BFT werksverrigting krommes is verkry wat die voorgestelde ontvanger struktuur vergelyk met die konvensionele ontvangers in ’n verskeidenheid kanaal toestande, insluitend SWGR, plat duinende kanale en ’n veelvuldige pad COST207-TU kanaal omgewing, sowel as in die teenwoordigheid van VGS.</li></ul></p Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted

Since the frantic race towards the Shannon bound [1] commenced in the early 1950’s, linear block codes have become integral components of most digital communication systems. Both binary and non-binary linear block codes have proven themselves as formidable adversaries against the impediments presented by wireless communication channels. However, prior to the landmark 1974 paper [2] by Bahl et al. on the optimal Maximum a-Posteriori Probability (MAP) trellis decoding of linear block codes, practical linear block code decoding schemes were not only based on suboptimal hard decision algorithms, but also code-specific in most instances. In 1978 Wolf expedited the work of Bahl et al. by demonstrating the applicability of a block-wise Viterbi Algorithm (VA) to Bahl-Cocke-Jelinek-Raviv (BCJR) trellis structures as a generic optimal soft decision Maximum-Likelihood (ML) trellis decoding solution for linear block codes [3]. This study, largely motivated by code implementers’ ongoing search for generic linear block code decoding algorithms, builds on the foundations established by Bahl, Wolf and other contributing researchers by thoroughly evaluating the VA decoding of popular binary and non-binary linear block codes on realistic narrowband and wideband digital communication platforms in lifelike mobile environments. Ideally, generic linear block code decoding algorithms must not only be modest in terms of computational complexity, but they must also be channel aware. Such universal algorithms will undoubtedly be integrated into most channel coding subsystems that adapt to changing mobile channel conditions, such as the adaptive channel coding schemes of current Enhanced Data Rates for GSM Evolution (EDGE), 3rd Generation (3G) and Beyond 3G (B3G) systems, as well as future 4th Generation (4G) systems. In this study classic BCJR linear block code trellis construction is annotated and applied to contemporary binary and non-binary linear block codes. Since BCJR trellis structures are inherently sizable and intricate, rudimentary trellis complexity calculation and reduction algorithms are also presented and demonstrated. The block-wise VA for BCJR trellis structures, initially introduced by Wolf in [3], is revisited and improved to incorporate Channel State Information (CSI) during its ML decoding efforts. In order to accurately appraise the Bit-Error-Rate (BER) performances of VA decoded linear block codes in authentic wireless communication environments, Additive White Gaussian Noise (AWGN), flat fading and multi-user multipath fading simulation platforms were constructed. Included in this task was the development of baseband complex flat and multipath fading channel simulator models, capable of reproducing the physical attributes of realistic mobile fading channels. Furthermore, a complex Quadrature Phase Shift Keying (QPSK) system were employed as the narrowband communication link of choice for the AWGN and flat fading channel performance evaluation platforms. The versatile B3G multi-user multipath fading simulation platform, however, was constructed using a wideband RAKE receiver-based complex Direct Sequence Spread Spectrum Multiple Access (DS/SSMA) communication system that supports unfiltered and filtered Complex Spreading Sequences (CSS). This wideband platform is not only capable of analysing the influence of frequency selective fading on the BER performances of VA decoded linear block codes, but also the influence of the Multi-User Interference (MUI) created by other users active in the Code Division Multiple Access (CDMA) system. CSS families considered during this study include Zadoff-Chu (ZC) [4, 5], Quadriphase (QPH) [6], Double Sideband (DSB) Constant Envelope Linearly Interpolated Root-of- Unity (CE-LI-RU) filtered Generalised Chirp-like (GCL) [4, 7-9] and Analytical Bandlimited Complex (ABC) [7, 10] sequences. Numerous simulated BER performance curves, obtained using the AWGN, flat fading and multi-user multipath fading channel performance evaluation platforms, are presented in this study for various important binary and non-binary linear block code classes, all decoded using the VA. Binary linear block codes examined include Hamming and Bose-Chaudhuri-Hocquenghem (BCH) codes, whereas popular burst error correcting non-binary Reed-Solomon (RS) codes receive special attention. Furthermore, a simple cyclic binary linear block code is used to validate the viability of employing the reduced trellis structures produced by the proposed trellis complexity reduction algorithm. The simulated BER performance results shed light on the error correction capabilities of these VA decoded linear block codes when influenced by detrimental channel effects, including AWGN, Doppler spreading, diminished Line-of-Sight (LOS) signal strength, multipath propagation and MUI. It also investigates the impact of other pertinent communication system configuration alternatives, including channel interleaving, code puncturing, the quality of the CSI available during VA decoding, RAKE diversity combining approaches and CSS correlation characteristics. From these simulated results it can not only be gathered that the VA is an effective generic optimal soft input ML decoder for both binary and non-binary linear block codes, but also that the inclusion of CSI during VA metric calculations can fortify the BER performances of such codes beyond that attainable by classic ML decoding algorithms. / Dissertation (MEng(Electronic))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / unrestricted

PLC - power line communication is not new. It has been known for many years. But It never be used in massive scale. There were only sporadic applications, for example ripple control system HDO used in the Czechoslovakia. PLC currently experiencing a renaissance thanks to the advent of Smart Grid. PLC offering relatively low bit rates and relatively unreliable transmission, but these disadvantages compensates very low costs to build a communication infrastructure and it offers specific functionalities for Smart Grid. The question is whether the declared parameters will be met in the real world. This thesis tries to find an answer.

SLAM (Simultaneous Localization And Mapping) has been a very active and almost ubiquitous problem in the field of mobile and autonomous robotics for over two decades. For many years, filter-based methods have dominated the SLAM literature, but a change of paradigms could be observed recently. Current state of the art solutions of the SLAM problem are based on efficient sparse least squares optimization techniques. However, it is commonly known that least squares methods are by default not robust against outliers. In SLAM, such outliers arise mostly from data association errors like false positive loop closures. Since the optimizers in current SLAM systems are not robust against outliers, they have to rely heavily on certain preprocessing steps to prevent or reject all data association errors. Especially false positive loop closures will lead to catastrophically wrong solutions with current solvers. The problem is commonly accepted in the literature, but no concise solution has been proposed so far. The main focus of this work is to develop a novel formulation of the optimization-based SLAM problem that is robust against such outliers. The developed approach allows the back-end part of the SLAM system to change parts of the topological structure of the problem\'s factor graph representation during the optimization process. The back-end can thereby discard individual constraints and converge towards correct solutions even in the presence of many false positive loop closures. This largely increases the overall robustness of the SLAM system and closes a gap between the sensor-driven front-end and the back-end optimizers. The approach is evaluated on both large scale synthetic and real-world datasets. This work furthermore shows that the developed approach is versatile and can be applied beyond SLAM, in other domains where least squares optimization problems are solved and outliers have to be expected. This is successfully demonstrated in the domain of GPS-based vehicle localization in urban areas where multipath satellite observations often impede high-precision position estimates.

Les applications multimédias, dans les réseaux de capteurs sans fil, véhiculent des données volumineuses, qui nécessitent un taux de transmission élevé et un traitement intensif et par conséquent une consommation d'énergie importante. Transmettre efficacement ces flux hétérogènes, tout en assurant leur fiabilité et garantir les exigences de QoS, avec les ressources limitées disponibles, en particulier dans les contextes critiques, demeure un verrou scientifique ouvert. C’est pourquoi, dans le cadre de cette thèse, nous nous sommes intéressés aux aspects liés : au routage, à la tolérance aux pannes et à la gestion des interférences dans les RCMSF.Compte tenu, du très faible nombre de protocoles de routage, qui ont approché la phase expérimentale et encore moins ceux qui l’ont abordé pendant la transmission des données en temps réel, nous avons développé dans ce contexte, un protocole routage géographique baptisé GNMFT (Geographic Non-interfering Multipath Fault-tolerant),En premier lieu, nous avons amélioré le mode de sélection des nœuds, utilisé par le transfert glouton, pour faire face au problème du Minimum-local, où une fonction objective multicritères (distance, énergie et puissance de réception) relative au choix du prochain saut a été définie. Puis, nous avons introduit une phase d’optimisation des chemins construits afin d’éliminer les boucles et une approche adaptative gérant les transmissions simultanées des différents trafics.Par la suite, nous nous sommes orientés vers la tolérance aux pannes, pour assurer la fiabilité des données transmises ainsi que la connectivité du réseau. A cet effet, nous avons modélisé le nombre des paquets perdus durant la livraison des paquets et proposé deux mécanismes : un curatif pour réparer les défaillances soudaines et un préventif afin d’anticiper l’épuisement des batteries. Les deux mécanismes sont combinés avec une stratégie de basculement dynamique lors de la construction des chemins alternatives.En dernier lieu, nous avons présenté un modèle d’interférence et un troisième mécanisme qui limite les interactions entre les liens adjacents. De plus, nous avons défini également un modèle de perte de chemins dans un environnement multi-paires (source,sink) et nous avons calculé le coefficient de probabilité d’erreurs basée sur une fonction de distance qui sépare les flux de données. Une nouvelle métrique a été ajouté dans la fonction objective, relative à la somme des bruits des nœuds actifs qui interférent sur les nœuds du ForwardingSet du nœud courant.Les résultats obtenus montrent l’efficacité des approches proposées qui ont été étudiées et validées à la fois par simulation et sur un banc d’essai expérimental. / Multimedia applications in WSNs convey large data (image, audio and video) that requires high transmission rate and intensive treatment and therefore high energy consumption. Effectively transmit these heterogeneous flows, while ensuring their reliability and guaranteeing QoS requirements, with the limited resources available, especially in critical contexts, remains an open scientific problem. That is why, in this thesis, we are interested in aspects related to : routing, fault tolerance and interference management in WMSNs.Given the very low number of routing protocols, that have approached the experimental phase and still less those who approached it during data transmission in real time, we developed in this context, a geographic routing protocol baptised GNMF (Geographic Non-interfering Multipath Fault-tolerant),First, we improved node's selection mode used by the greedy-forwarding, to deal with local minimum problem, where a multi-criteria objective function (distance, energy and reception power) related to next-hop choice has been defined. Then, we introduced an optimization phase of built paths to eliminate loops and an adaptive approach to manage simultaneous traffic transmissions.After that, we oriented towards fault tolerance, to ensure transmitted data reliability and network connectivity. To this end, we modeled the number of lost packets during package delivery and proposed two mechanisms. The curative is used when sudden failures occurs and the preventive to anticipate batteries depletion. Both are combined with a dynamic failover strategy during alternative paths construction.Finally, we presented an interference model and a third mechanism that limits interactions between adjacent links. In addition, we also defined a path loss model in a multipairs environment (source, sink) and computed the error probability coefficient based on a distance function that separates the data flows. A new metric has been added in the objective function, related to noise sum of the active nodes that interferes on forwarding set nodes of the current node.Obtained results show the effectiveness of the proposed approaches that have been studied and validated both by simulation and on an experimental testbed.

The statistics of the amplitude, time and angle of arrival of multipaths in an indoor environment are all necessary components of multipath models used to simulate the performance of spatial diversity in receive antenna configurations. The model presented by Saleh and Valenzuela, was added to by Spencer et. al., and included all three of these parameters for a 7 GHz channel. A system was built to measure these multipath parameters at 2.4 GHz for multiple locations in an indoor environment. Another system was built to measure the angle of transmission for a 6 GHz channel. The addition of this parameter allows spatial diversity at the transmitter along with the receiver to be simulated. The process of going from raw measurement data to discrete arrivals and then to clustered arrivals is analyzed. Many possible errors associated with discrete arrival processing are discussed along with possible solutions. Four clustering methods are compared and their relative strengths and weaknesses are pointed out. The effects that errors in the clustering process have on parameter estimation and model performance are also simulated.

[ES] Las redes inalámbricas interiores son una parte integral de las comunicaciones actuales. Debido a la alta demanda de confiabilidad y la enorme densidad de redes interiores, algunas de ellas están migrando hacia las frecuencias de onda milimétrica (mmW), donde están disponibles mayor ancho de banda y rendimiento. Diseñar la red para la banda mmW ofrece soluciones a algunos problemas presentes en frecuencias m 'as bajas pero también plantea nuevos desafíos. Esta Tesis se centra en particular en casos de uso de conferencias en entornos grandes. La principal funcionalidad de la red de conferencias es realizar conferencias. Principalmente, esto significa transmitir señales de audio desde los participantes y fuentes de audio a otros participantes. Por lo tanto, se presenta el conjunto de requisitos para el diseño y despliegue de la red resultantes de los estándares de la conferencia, tipos de datos, estructura de los datos transmitidos, propagación en ambientes interiores y fenómenos físicos relacionados con la longitud de onda. Las soluciones de conferencias inalámbricas existentes se proporcionan en frecuencias Wi-Fi, es decir, 2,4 GHz y 5 GHz. Sin embargo, su objetivo no es conectar a los participantes de la conferencia a Internet, sino crear una red que cumpla con los requisitos de la conferencia basada en la funcionalidad proporcionada en la familia de estándares 802.11. La enmienda 802.11ay se proporciona para la comunicación en la banda de frecuencia de 60 GHz. Para permitir una fácil transición de las redes de conferencias inalámbricas hacia mmW, se estudia la enmienda 802.11ay y el canal de radio de 60 GHz. Se considera que el estándar es inadecuado para el tipo y la cantidad de datos enviados en las redes de conferencias inalámbricas. Está diseñado para trabajar con grandes cantidades de datos, mientras que los datos principales en las redes de conferencias son audio en tiempo real. Enviar tramas de datos con esa poca información introduce una sobrecarga significativa debido a los datos del pre 'ambulo en PPDU. Sin embargo, se considera que algunas de sus características merecen una mayor exploración. Al estudiar el caso de uso de la conferencia, es importante centrarse en las configuraciones dedicadas a las conferencias, es decir, la influencia de las propiedades de los materiales interiores, la forma y el tamaño del entorno, y el tipo y ubicación de la antena en la propagación. Para el canal de radio de 60 GHz se estudia el efecto multitrayecto, lo que lleva a la creación del modelo de predicción RMS DS. Además, se muestra que la directividad en esta banda proporciona una gran ventaja si se utiliza la transmisión LoS o si el reflector conocido ayuda a dirigir el haz en la dirección de receptor (RX). Además, esta Tesis también se centra en frecuencias distintas a 60 GHz, precisamente 27 GHz y 28 GHz, las frecuencias introducidas en el Rango de Frecuencia 2 (FR2) 5G NR. Para esta Tesis se realizaron varias campañas de medición en diferentes ambientes, como el auditorio, el aula grande, la sala de reuniones y la sala de seminarios. Los resultados resaltan la importancia de conocer el entorno para optimizar el despliegue de la red. El ray tracing (RT) se utiliza para profundizar la comprensión del comportamiento de los canales de radio medidos. Se identifica el origen de los componentes de trayectorias múltiples y los objetos que son reflectores de mayor impacto. Además, las simulaciones de entornos disponibles se realizan para frecuencias, configuraciones de antenas y configuraciones de mobiliario distintas a las de las mediciones realizadas. Se midieron e introdujeron en el simulador RT los valores de las pérdidas de transmisión y reflexión introducidas por objetos presentes en entornos grandes en frecuencias de 26-40 GHz y 55-65 GHz para permitir resultados m 'as precisos de las simulaciones. La comparación entre mediciones y simulaciones muestra la utilidad de las simulaciones RT en el análisis de canales de radio. / [CA] Les xarxes sense fil d'interior són una part integral de les comunicacions actuals. A causa de l'alta demanda de fiabilitat i la gran densitat de xarxes interiors, algunes d'elles migren cap a les freqüències de les ones mil·límetres (mmW), on hi ha una amplada de banda i un rendiment més grans disponibles. Dissenyar la xarxa per a la banda mmW ofereix solucions a alguns problemes presents en freqüències més baixes però també planteja nous reptes. Aquesta tesi se centra especialment en casos d'ús de conferències en entorns grans. La principal funcionalitat de la xarxa de conferències és la realització de conferències. Principalment, això significa transmetre senyals d'àudio dels participants i fonts d'àudio a altres participants. Per tant, es presenta el conjunt de requisits per al disseny i desplegament de la xarxa resultant dels estàndards de conferència, els tipus de dades, l'estructura de les dades transmeses, la propagació en entorns interiors i els fenòmens físics relacionats amb la longitud d'ona. Les solucions de conferències sense fil existents es proporcionen en freqüències Wi-Fi, és a dir, 2,4 GHz i 5 GHz. Tanmateix, no pretenen connectar els participants de la conferència a Internet, sinó crear una xarxa que compleixi els requisits de la conferència basada en la funcionalitat proporcionada a la família d'estàndards 802.11. L'esmena 802.11ay es proporciona per a la comunicació a la banda de freqüència de 60 GHz. Per permetre una fàcil transició de les xarxes de conferències sense fil cap al mmW, s'estudia l'esmena 802.11ay i el canal de ràdio de 60 GHz. Es considera que l'estàndard és inadequat per al tipus i la quantitat de dades enviades a les xarxes de conferències sense fil. Està dissenyat per treballar amb grans quantitats de dades, mentre que les dades principals de les xarxes de conferències són àudio en temps real. L'enviament de trames de dades amb aquesta poca informació introdueix una sobrecàrrega important a causa de les dades del preàmbul a PPDU. No obstant això, es considera que algunes de les seves característiques mereixen una exploració més detallada. Mentre s'estudia el cas d'ús de la conferència, és important centrar-se en les configuracions dedicades a les conferències, és a dir, la influència de les propietats dels materials interiors, la forma i la mida de l'entorn, i el tipus i col·locació d'antena en la propagació. Per al canal de ràdio de 60 GHz, s'estudia l'efecte multicamí, que condueix a la creació del model de predicció RMS DS. A més, es demostra que la directivitat en aquesta banda dóna un gran avantatge si s'utilitza la transmissió LoS o si el reflector conegut ajuda a dirigir el feix en la direcció de receptor (RX). A més, aquesta Tesi també se centra en freqüències diferents de 60 GHz, precisament 27 GHz i 28 GHz, les freqüències introduïdes en el rang de freqüències 2 (FR2) 5G NR. Per a aquesta Tesi s'han realitzat diverses campanyes de mesura en diferents entorns, com ara l'auditori, l'aula gran, la sala de reunions i la sala de seminaris. Els resultats posen de manifest la importància de conèixer l'entorn per tal d'optimitzar el desplegament de la xarxa. El ray tracing (RT) s'utilitza per aprofundir en la comprensió del comportament dels canals de ràdio mesurats. S'identifica l'origen dels components multipath i els objectes que són reflectors més impactants. A més, es realitzen simulacions dels entorns disponibles per a freqüències, configuracions d'antenes i configuracions de mobles diferents de les de les mesures realitzades. Es van mesurar els valors de les pèrdues de transmissió i reflexió introduïdes per objectes presents en entorns grans en freqüències de 26-40 GHz i 55-65 GHz i es van introduir al simulador RT per permetre els resultats més precisos de les simulacions. La comparació entre mesures i simulacions mostra la utilitat de les simulacions RT en l'anàlisi de canals de ràdio. / [EN] Indoor wireless networks are an integral part of today's communications. Due to the high demand for reliability and the huge density of indoor networks, some of them are migrating towards the Millimeter Wave (mmW) frequencies, where larger bandwidth and throughput are available. Designing the network for the mmW band offers solutions to some problems present in lower frequencies but also poses new challenges. This Thesis focuses in particular on conference use cases in large environments. The main functionality of the conference network is to conduct conferences. Primarily, this means transmitting audio signals from participants and audio sources to other participants. Therefore, the set of requirements for the network design and deployment resulting from conference standards, data types, structure of transmitted data, propagation in indoor environments, and physical phenomena related to the wavelength are presented. Existing wireless conference solutions are provided in Wi-Fi frequencies, that is 2.4 GHz and 5 GHz. However, they do not aim to connect conference participants to the Internet but to create a network fulfilling the conference requirements based on the functionality provided in 802.11 standards family. The 802.11ay amendment is provided for communication in the 60 GHz frequency band. To allow an easy transition of wireless conference networks towards the mmW, the 802.11ay amendment and the 60 GHz radio channel are studied. The standard is found to be inadequate for the type and amount of data sent in the wireless conference networks. It is designed to work with large amounts of data, whereas the primary data in conference networks is real-time audio. Sending data frames with that little information introduces significant overhead due to the preamble data in Physical Protocol Data Unit (PPDU). Nevertheless, some of its features are considered worth further exploration. While studying the conference use case, it is important to focus on setups dedicated to the conferences, that is, the influence of indoor materials properties, the environment's shape and size, and antenna type and placement on the propagation. For the 60 GHz radio channel, the multipath effect is studied, which leads to the creation of the Root Mean Square Delay Spread (RMS DS) prediction model. Moreover, it is shown that directivity in this band gives a great advantage if the Line of Sight (LoS) transmission is used or the known reflector helps to steer the beam into the direction of the receiver. Furthermore, this Thesis also focuses on frequencies other than 60 GHz, precisely 27 GHz and 28 GHz, the frequencies introduced in Frequency Range 2 (FR2) Fifth Generation (5G) New Radio (NR). Several measurement campaigns were performed for this Thesis in different environments, such as the auditory, the large classroom, the meeting room, and the seminar room. The results highlight the importance of knowing the environment in order to optimize network deployment. The Ray Tracing (RT) is used to deepen the understanding of the measured radio channels' behaviour. The origin of multipath components and the objects that are most impactful reflectors are identified. Moreover, the simulations of available environments are performed for frequencies, antenna setups, and furniture configurations other than those in performed measurements. Values of transmission and reflection losses introduced by objects present in large environments in frequencies 26-40 GHz and 55-65 GHz were measured and introduced into the RT simulator to allow the most precise results of simulations. Comparison between measurements and simulations shows the usefulness of RT simulations in radio channel analysis. / This thesis was partly founded by the H2020 Marie Sklodowska-Curie Actions Program within Project Grant No. 766231 WAVECOMBE - ITN - 2017. Measurement campaigns in Gdansk University of Technology were partially funded by the COST Action CA20120, ”Intelligence-Enabling Radio Commu- nications for Seamless Inclusive Interactions” (INTERACT) under the Short Term Scientific Mission No. CA20120-2146922e. / Drozdowska, MK. (2024). Intelligent Design of mmWave Conference Networks in Built Environments [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/211182

This thesis aims to contribute to the developments of wireless communication systems. The work generally consists of three parts: the first part is a discussion on general digital communication systems, the second part focuses on wireless channel modelling and fading mitigation techniques, and in the third part we discuss the possible application of advanced digital signal processing, especially time-frequency representation and blind source separation, to wireless communication systems. The first part considers general digital communication systems which will be incorporated in later parts. Today's wireless communication system is a subbranch of a general digital communication system that employs various techniques of A/D (Analog to Digital) conversion, source coding, error correction, coding, modulation, and synchronization, signal detection in noise, channel estimation, and equalization. We study and develop the digital communication algorithms to enhance the performance of wireless communication systems. In the Second Part we focus on wireless channel modelling and fading mitigation techniques. A modified Jakes' method is developed for Rayleigh fading channels. We investigate the level-crossing rate (LCR), the average duration of fades (ADF), the probability density function (PDF), the cumulative distribution function (CDF) and the autocorrelation functions (ACF) of this model. The simulated results are verified against the analytical Clarke's channel model. We also construct frequency-selective geometrical-based hyperbolically distributed scatterers (GBHDS) for a macro-cell mobile environment with the proper statistical characteristics. The modified Clarke's model and the GBHDS model may be readily expanded to a MIMO channel model thus we study the MIMO fading channel, specifically we model the MIMO channel in the angular domain. A detailed analysis of Gauss-Markov approximation of the fading channel is also given. Two fading mitigation techniques are investigated: Orthogonal Frequency Division Multiplexing (OFDM) and spatial diversity. In the Third Part, we devote ourselves to the exciting fields of Time-Frequency Analysis and Blind Source Separation and investigate the application of these powerful Digital Signal Processing (DSP) tools to improve the performance of wireless communication systems.

Most transportation problems arise from individual travel decisions. In response, transportation researchers had been studying individual travel behavior – a growing trend that requires activity data at individual level. Global positioning systems (GPS) and geographical information systems (GIS) have been used to capture and process individual activity data, from determining activity locations to mapping routes to these locations. Potential applications of GPS data seem limitless but our tools and methods to make these data usable lags behind. In response to this need, this dissertation presents a GIS-based toolkit to automatically extract activity episodes from GPS data and derive information related to these episodes from additional data (e.g., road network, land use). The major emphasis of this dissertation is the development of a toolkit for extracting information associated with movements of individuals from GPS data. To be effective, the toolkit has been developed around three design principles: transferability, modularity, and scalability. Two substantive chapters focus on selected components of the toolkit (map-matching, mode detection); another for the entire toolkit. Final substantive chapter demonstrates the toolkit’s potential by comparing route choice models of work and shop trips using inputs generated by the toolkit. There are several tools and methods that capitalize on GPS data, developed within different problem domains. This dissertation contributes to that repository of tools and methods by presenting a suite of tools that can extract all possible information that can be derived from GPS data. Unlike existing tools cited in the transportation literature, the toolkit has been designed to be complete (covers preprocessing up to extracting route attributes), and can work with GPS data alone or in combination with additional data. Moreover, this dissertation contributes to our understanding of route choice decisions for work and shop trips by looking into the combined effects of route attributes and individual characteristics. / Dissertation / Doctor of Philosophy (PhD)