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Resolved, 2023/2024, 1r quadrimestre

Resolved, 2023/2024, 1r quadrimestre

The TFG focuses on the research and development of spatial localization and sensing techniques assisted by Intelligent Reflective Surfaces (IRS) within the context of 6G communication networks. Given the increase in operating frequencies in 6G networks, which include millimeter-wave bands, the project addresses the challenges and opportunities of high-frequency communication. The use of passive IRS is considered a solution to enhance system coverage and multiplexing capacity, and its potential for localization and sensing applications is also explored. The project aims to model and simulate a complete system consisting of a base station, an IRS, and multiple transmitting objects. It involves the development of strategies to control the reflection elements of the IRS and the design of estimators to determine the position and power of transmitting objects based on reflected signals., El TFG se centra en la investigación y desarrollo de técnicas de localización espacial y detección asistida por Superficies Reflectantes Inteligentes (IRS) en el contexto de las redes de comunicación 6G. Dado el aumento en las frecuencias de operación en las redes 6G, que incluyen bandas milimétricas, el proyecto aborda los desafíos y oportunidades de la comunicación a alta frecuencia. El uso de IRS pasivas se considera una solución para mejorar la cobertura y la capacidad de multiplexación del sistema, y también se explora su potencial para aplicaciones de localización y detección. El proyecto tiene como objetivo modelar y simular un sistema completo que consta de una estación base, un IRS y múltiples objetos emisores, desarrollar estrategias para controlar los elementos de reflexión del IRS, y diseñar estimadores para determinar la posición y la potencia de los objetos emisores en función de las señales reflejadas., El TFG es centra en la investigació i desenvolupament de tècniques de localització espacial i detecció assistida per Superfícies Reflectores Intel·ligents (IRS) en el context de les xarxes de comunicació 6G. Donat l'augment de les freqüències d'operació a les xarxes 6G, que inclouen bandes mil·limètriques, el projecte aborda els reptes i oportunitats de la comunicació a alta freqüència. L'ús d'IRS passives es considera una solució per millorar la cobertura i la capacitat de multiplexació del sistema, i també s'explora el seu potencial per a aplicacions de localització i detecció. El projecte té com a objectiu modelar i simular un sistema complet que consta d'una estació base, un IRS i múltiples objectes emissors, desenvolupar estratègies per controlar els elements de reflexió de l'IRS, i dissenyar estimadors per determinar la posició i la potència dels objectes emissors en funció de les senyals reflectides.

Pacing and Beta-Blockers in Repetitive Polymorphic VT. An 18-year-old woman presented with recurrent exercise-induced syncopal episodes and severe systolic dysfunction. ECG monitoring disclosed repetitive polymorphic ventricular complexes, paroxysms of bidirectional ventricular tachycardia, and nonsustained bursts of slow polymorphic ventricular tachycardia that increased in length and rate during exercise. Ventricular arrhythmias were refractory to medical treatment, which included verapamil and beta-blockers. Addition of permanent atrial pacing to beta-blocker therapy suppressed the arrhythmias and reversed systolic impairment in the following months., Depto. de Medicina, Fac. de Medicina, TRUE, pub

The aim of this work is to analyse how the adaptation to certain speakers of a Speech Emotion Recognition (SER) system improves its performance by contrasting several variations of the adaptation procedure. The initial focus is on constructing a robust SER system using a deep neural network (DNN), which serves as the baseline model. This DNN is trained to recognize emotions present in speech signals. To further optimize the system's accuracy and efficacy, adaptation techniques are employed. These techniques involve adapting the baseline model to specific speakers, accounting for individual variations in speech patterns and emotions. This is implemented by further training the baseline model with different adaptation datasets. Finally, the performance of the adapted SER systems is evaluated and compared to the baseline to see which variations give better results and extract conclusions on which factors are more influential in the final performance of the adapted model., El objetivo de este trabajo es analizar cómo la adaptación a ciertos hablantes de un sistema de Reconocimiento de Emociones en el Discurso (SER, por sus siglas en inglés), mejora su rendimiento. El análisis se lleva a cabo contrastando diversas variaciones del procedimiento de adaptación. El enfoque inicial se centra en la construcción de un sistema SER robusto utilizando una red neuronal profunda (DNN, por sus siglas en inglés), que sirve como modelo de referencia. Esta DNN se entrena para reconocer emociones presentes en el discurso. Para optimizar aún más la precisión y eficacia del sistema, se emplean técnicas de adaptación. Estas técnicas implican adaptar el modelo de referencia a hablantes específicos, para así tener en cuenta las variaciones individuales en los patrones de habla y emociones. Esto se lleva a cabo mediante un entrenamiento adicional del modelo de referencia con diferentes conjuntos de datos. Finalmente, se evalúa el rendimiento de los sistemas SER adaptados y se comparan con el modelo de referencia para determinar qué variaciones proporcionan mejores resultados y extraer conclusiones sobre qué factores son más influyentes en el rendimiento final del modelo adaptado., L'objectiu d'aquest treball és analitzar com l'adaptació a certs parlants d'un sistema de Reconeixement d'Emocions en el Discurs (SER, per les seves sigles en anglès) millora el seu rendiment. L'anàlisi es realitza contrastant diverses variacions del procediment d'adaptació. L'enfocament inicial es centra en la construcció d'un sistema SER robust utilitzant una xarxa neuronal profunda (DNN, per les seves sigles en anglès), que serveix com a model de referència. Aquesta DNN s'entrena per reconèixer emocions presents en el discurs. Per optimitzar encara més la precisió i eficàcia del sistema, es fan servir tècniques d'adaptació. Aquestes tècniques impliquen adaptar el model de referència a parlants específics, per tal de tenir en compte les variacions individuals en els patrons de parla i emocions. Això es duu a terme mitjançant un entrenament addicional del model de referència amb diferents conjunts de dades. Finalment, s'avalua el rendiment dels sistemes SER adaptats i es comparen amb el model de referència per determinar quines variacions proporcionen millors resultats i extreure conclusions sobre quins factors són més influents en el rendiment final del model adaptat.

Receive spatial modulation (RSM) has been proposed as an effective transmission technology for next-generation wireless communications systems because of its reduced complexity and low energy consumption at the receiver end. Compared to conventional multiple-input multiple-output (MIMO) transceivers, which require one radio-frequency (RF) chain and analog-to-digital converter (ADC) per receive antenna, RSM can be implemented with one amplitude detector per antenna and a single RF chain, with mild performance degradation in terms of spectral efficiency (SE). However, its implementation using zero-forcing precoders is inadequate in mmWave channels due to the lack of propagation scattering and, hence, rank deficiency in the channel matrix. This has been only partially solved in the past using receiver antenna selection (RAS), which requires additional receive antennas. On the other hand, using reconfigurable intelligent surfaces (RIS), which can effectively create scatter and enhance the channel matrix rank, is an affordable solution that can also cope with shadowing situations and the higher path losses associated with mmWave bands. We propose using a RIS in a single-user MIMO communication with RSM to improve the downlink transmission. This paper shows that RIS-assisted RSM communication is more than a good option in mm Wave channels in terms of bit error rate due to the multipath induced in the channel and the link budget boosting., This work has been funded through the project ROUTE56 (Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación, PID2019-104945GB-I00 / MCIN / AEI / 10.13039/501100011033) and the grants 22CO1/008248 and 2021 SGR 01033 (AGAUR, Generalitat de Catalunya)., Peer Reviewed, Postprint (author's final draft)

Reconfigurable intelligent surfaces (RISs) have become a promising candidate for the development of future mobile systems. In the context of massive machine-type communications (mMTC), a RIS can be used to support the transmission from a group of sensors to a collector node. Due to the short data packets, we focus on the design of the RIS for maximizing the weighted sum and minimum rates in the finite blocklength regime. Under the assumption of non-orthogonal multiple access, successive interference cancelation is considered as a decoding scheme to mitigate interference. Accordingly, we formulate the optimizations as non-convex problems and propose two suboptimal solutions based on gradient ascent (GA) and sequential optimization (SO) with semi-definite relaxation (SDR). In the GA, we distinguish between Euclidean and Riemannian gradients. For the SO, we derive a concave lower bound for the throughput and maximize it sequentially applying SDR. Numerical results show that the SO can outperform the GA and that strategies relying on the optimization of the classical Shannon capacity might be inadequate for mMTC networks., This work was supported by the project ROUTE56 (PID2019-104945GB-I00 / MCIN / AEI / 10.13039/501100011033) funded by the Agencia Estatal de Investigación (Spanish Ministry of Science and Innovation); and the FPI grant BES-2017-079994, funded by the Spanish Ministry of Science, Innovation, and Universities., Peer Reviewed, Postprint (author's final draft)

In this work, we present a knowledge graph in a UI linked to a novel hybrid data framework, primarily designed to facilitate the communication between human agents and artificial intelligence entities., En este trabajo, presentamos un gráfico de conocimiento en una interfaz de usuario vinculada a un novedoso framework de datos híbrido, diseñado principalmente para facilitar la comunicación entre agentes humanos y entidades de inteligencia artificial., En aquest treball, us presentem un gràfic de coneixement en una interfície d'usuari vinculada a un nou framework de dades híbrid, dissenyat principalment per facilitar la comunicació entre agents humans i entitats d'intel·ligència artificial.

During these past years, the internet has had an enormous importance in current society. Large amounts of information are shared on this virtual agora, in which people interacts all across the globe at full speed. Nevertheless, not only it is crucial to guarantee this communication, but also its security an truthfulness. For this reason, some algorithms, for both Digital Signature and Encryption purposes, have been conceived. Since now, RSA, DSA or ECC have guaranteed this security. These systems, based on complex problems in which classical computers cannot solve, have been useful for most applications. Nevertheless, these communications will not be longer secure. These algorithms have been proof to be broken using Quantum Computers. Even though these computers will not be available until a couple of decades, a change in the long term should be done. In order to solve this problem, the mathematical community has investigated and conceived a large amount of algorithms, in which some of them are still under test and analysis. Nonetheless, not only is the security of communications uncertain, but also its integrity. Digital Signatures Schemes, which enable to demonstrate the identity of a person or a group, are based on these algorithms. For example, Personal Identity Cards or PDF Documents as a property deed will be impossible on the long term. Although some advancements have been done, due to the newness and constant development of this field, not too much implementation has been done. The main aim of this thesis is to study, create, develop and analyse a program which enables Digital Signature Scheme on PDFs using different Post Quantum (PQ) Algorithms, mainly CRYSTALS-Dilithium, Falcon and SPHINCS+. This implementations will be done based on different standards and technologies used for standard algorithms. Moreover, other multiple signature schemes as Composite or multiple signerInfos are going to be implemented and studied., Durante estos los últimos años, el internet ha tenido una enorme importancia en la sociedad actual. Grandes cantidades de información son compartidas en esta agora virtual, donde la gente interactua por todo el globo a toda velocidad. Sin embargo, no solo es crucial garantizar la comunicación en si, si no también su seguridad y veracidad. Por esta razon, varios algoritmos, tanto para firma digital como encriptación, se han concebido. Hasta ahora, RSA, DSA o ECC han garantizado esta seguridad. Estos sistemas, basados en problemas complejos de los cuales un ordenador clásico no puede resolver, han sido útiles para la mayoría de los usos. Sin embargo, estas comunicaciones ya no se podran considerar seguras al largo plazo. Ha sido probado que estos algoritmos se pueden romper usando ordenadores cuánticos. Aunque estos ordenadores no estarán disponibles hasta un par de decadas, varias investigaciones se han hecho al respecto. La comunidad matemática ha investigado y concevido algunos de estos algoritmos, y aún varios de ellos estan bajo test y analisis. Sin embargo, no solo la seguridad de las comunicaciones es incierta, si no su propia integridad. Los esquemas de firma digital, los cuales son capaces de demostrar la identidad de una persona o un grupo, estan basados en estos algoritmos. Por ejemplo, Carnets de Identidad o Documentos PDF como las escrituras de una propiedad serían imposibles al largo plazo. Aunque varios avances se han hecho a respecto, debido a su novedad y constante desarrollo en este campo, no se ha llevado a cabo mucha implementación. El objetivo principal de esta tesis es estudiar, crear, desarrollar y analizar un programa que permita la firma digital en PDFs utilizando diferentes algoritmos Post Cuánticos (PQ), principalmente CRYSTALS-Dilithium, Falcon y SPHINCS+. Estas implementaciones se harán basándose en diferentes estándares y tecnologías utilizadas para algoritmos estándares. Además, se implementarán y estudiarán otros sistemas de firma múlti, Durant aquests últims anys, l'internet ha tingut una enorme importància en la societat actual. Grans quantitats d'informació són compartides en aquesta agora virtual, on la gent interactua per tot el globus a tota velocitat. No obstant això, no sols és crucial garantir la comunicació en si, si no també la seva seguretat i veracitat. Per aquesta raó, diversos algorismes, tant per a signatura digital com encriptació, s'han concevut. Fins ara, RSA, DSA o ECC han garantit aquesta seguretat. Aquests sistemes, basats en problemes complexos dels quals un ordinador clàssic no pot resoldre, han estat útils per a la majoria d'aplicacions. No obstant això, aquestes comunicacions ja no es podran considerar segures al llarg termini. Ha estat provat que aquests algorismes es poden trencar amb ordinadors quàntics. Encara que aquests ordinadors no estaran disponibles fins a un parell de decades, un canvi a llarg termini es tindrá que fer. La comunitat matemàtica ha investigat i concevut una gran quantitat d'aquests algorismes, on encara diversos d'ells estan baix test i analisis. Tanmateix, no solament la seguretat de les comunicacions es incerta, sino la seva propia integritat. Els esquemes de firma digital, els quals son capaços de demostrar l'identitat d'una persona o un grup, estan basats en aquests algorismes. Per exemple, els carnets d'identitat o documents PDF com les escritures d'una propietat son impossibles al llarg termini. Encara que alguns avanços s'han fet al respecte, a causa de la seva novetat i constant desenvolupament en aquest camp, no s'ha dut a terme molta implementació. L'objectiu principal d'aquesta tesi és estudiar, crear, desenvolupar i analitzar un programa que permeti la firma digital en PDFs utilitzant diferents algorismes Post Quàntics (PQ), principalment CRYSTALS-Dilithium, Falcon i SPHINCS+. Aquestes implementacions es faran basant-se en diferents estàndards i tecnologies utilitzades per a algorismes estàndard. A més, s'implementaran i estudiaran altr

The arrival of new wireless technologies have allowed us to push the requirements of wireless communications systems to stricter levels in terms of data rate, bit error rate, energy efficiency or spectral efficiency. Some of these technologies are receive spatial modulation (RSM) or transmit beamforming (TxBF) in millimeter-wave (mmWave) bands. However, they require a large amount of energy consumption (radiofrequency (RF) chains and analog-to-digital converters (ADC) at each antenna) and may suffer a performance degradation due to the lack of channel scattering, shadowing situations and higher path losses. The use of a reconfigurable intelligent surface (RIS) is a viable technology that mitigates these problem with low-cost passive elements, at virtually no additional energy consumption. This study proposes the use of RIS in a single user (SU) multiple-input multiple-output (MIMO) communication with RSM and TxBF to improve a downlink (DL) transmission in fifth-generation (5G) mmWave. It shows that having RIS assisting the communication is more than good option for mmWave communications where there is no multipath as it can improve the transmission rate in TxBF in shadowed areas. However, it is the transmissions with RSM that get the most benefit from the use of RIS in terms of bit error rate., La llegada de las nuevas tecnologías inalámbricas nos ha permitido llevar los requisitos de los sistemas de comunicaciones inalámbricas a niveles más estrictos en términos de tasa de datos, tasa de error de bits, eficiencia energética o eficiencia espectral. Algunas de estas tecnologías son RSM o TxBF en bandas milimétricas (mmWave). Sin embargo, requieren una gran cantidad de consumo de energía (cadenas de radiofrecuencia (RF) y convertidores analógico a digital (ADC) en cada antena) y pueden sufrir una degradación del rendimiento debido a la falta de dispersión de canales, situaciones de shadowing y mayores pérdidas de propagación. El uso de una superficie reconfigurable inteligente (RIS) es una tecnología viable que mitiga estos problemas con elementos pasivos de bajo costo, prácticamente sin consumo de energía adicional. Este estudio propone el uso de RIS en una comunicación SU-MIMO con RSM y TxBF para mejorar una transmisión DL en 5G mmWave. Demuestra que tener RIS asistiendo a la comunicación es más que una buena opción para las comunicaciones mmWave donde no hay propagación multicamino, ya que puede mejorar la tasa de transmisión en TxBF en áreas con shadowing. Sin embargo, son las transmisiones con RSM las que obtienen mayor beneficio del uso de RIS en términos de tasa de error de bit., L'arribada de les noves tecnologies sense fil ens ha permès portar els requisits dels sistemes de comunicacions sense fil a nivells més estrictes en termes de taxa de dades, taxa d'error de bits, eficiència energètica o eficiència espectral. Algunes d'aquestes tecnologies són RSM o TxBF en bandes mil·limètriques (mmWave). No obstant això, requereixen una gran quantitat de consum d'energia (cadenes de radiofreqüència (RF) i convertidors de senyal analògica a digital (ADC) a cada antena) i poden patir una degradació del rendiment a causa de la manca de dispersió de canals, situacions de shadowing i majors pèrdues de propagació. L'ús d'una superfície reconfigurable intel·ligent (RIS) és una tecnologia viable que mitiga aquests problemes amb elements passius de baix cost, pràcticament sense consum d'energia addicional. Aquest estudi proposa l'ús de RIS en una comunicació SU-MIMO amb RSM i TxBF per millorar una transmissió DL a 5G mmWave. Demostra que tenir RIS assistint a la comunicació és més que una bona opció per a les comunicacions mmWave on no hi ha propagació multicamí, ja que pot millorar la taxa de transmissió a TxBF en àrees amb shadowing. Tot i això, són les transmissions amb RSM les que obtenen major benefici de l'ús de RIS en termes de taxa d'error de bit.

La tecnología Reconfigurable Intelligent Surface (RIS) se postula como una clara candidata a revolucionar las comunicaciones inalámbricas a partir del 6G y las siguientes generaciones de comunicaciones móviles. Una RIS es un conjunto de elementos, normalmente reflectores, distribuidos en una superficie. Sus elementos pueden cambiar rápidamente sus propiedades de radiación o reflexión. El uso más estudiado de la RIS es como reflector para crear una LoS (acrónimo inglés de Line of Sight) alternativa cuando la conexión directa entre BS (acrónimo inglés de Base Station) se bloquea. Esta tesis pretende descubrir las posibilidades de la RIS como modulador instalándola directamente en la BS. Dada la dificultad de cálculo de los campos reflejados, se usa una RIS basada en elementos radiantes, concretamente antenas tipo patch. Dado el tamaño físico de la RIS y el uso de longitudes de ondas milimétricas, es altamente probable que el receptor se encuentre en régimen de campo cercano del array y no sean aplicables los conceptos de campo lejano para un array. Siguiendo estas líneas de estudio se simulan varios experimentos para verificar la capacidad de la RIS para soportar técnicas de Multiple Input Multiple Output (MIMO) con un único usuario., La tecnologia Reconfigurable Intelligent Surface (RIS) es posiciona com una clara candidata a revolucionar les comunicacions inalàmbriques a partir del 6G i les següents generacions de comunicacions mòbils. Una RIS és un conjunt d’elements distribuïts en una superfície. Els seus elements poden canviar ràpidament les seves propietats de radiació o reflexió. El seu ús mes estudiat és com a reflector per crear una Line of Sight (LoS) alternativa quan la connexió directe entre la base station (BS) es bloqueja. Aquesta tesis pretén descobrir les possibilitats de la RIS com a modulador instal·lant-la directament a la BS. Donada la dificultat de càlcul dels camps reflectits, es utilitza una RIS basada en elements radiants, concretament antenes tipus patch. A causa de les dimensions de la RIS y de l’ús de longituds d’ones mil·limètriques, és altament probable que el receptor es trobi a la regió de camp proper de l’array i no siguin aplicables els conceptes de far field per a un array. Seguint aquestes línies d’estudi, es simulen diversos experiments per verificar la capacitat de la RIS per suportar tècniques de Multiple Input Multiple Output (MIMO) amb un únic usuari., Reconfigurable Intelligent Surface (RIS) technology is a clear candidate to revolutionise wireless communications from 6G and beyond. A RIS is a set of elements distributed on a surface. Its elements can rapidly change their radiation or reflection properties. The most studied use of the RIS is as a reflector to create an alternative LoS (Line of Sight) when the direct connection between BS (Base Station) is blocked. This thesis aims to discover the possibilities of the RIS as a modulator by installing it directly in the BS. Given the difficulty of calculating the reflected fields, a RIS based on radiating elements (patch antennas) is used. Given the physical size of the RIS and the use of millimetre wavelengths, it is highly probable that the receiver is in the near field array’s region so that the far field concepts for an array are not applicable. Based on this study, several experiments are simulated to verify the capability of the RIS to support Multiple Input Multiple Output (MIMO) techniques with a single user.

The analysis of an electrical fault in an industrial machine goes through several tests to narrow down the actual problem from a mechatronic subsystem. The process itself brings along an economic and time inversion which in some cases can affect the timeline. This study aims to determine the presence of anomalies in a strip encoder in order to avoid electrical issues in future performances. Specifically, it investigates whether the data collected from an optical encoder is reliable. To imitate the output signal from the encoder, an FPGA was used to reproduce it using VHDL language. With the help of the Cmod A7 buttons, the PCB emulates an encoder and stores the data into the RAM for its subsequent analysis. The result of the sequence is done by a neural networks process code with Python. These results suggest whether the data?s collection has any damages or it can be considered meaningful., El análisis de una falla eléctrica en una máquina industrial pasa por varias pruebas para acotar el problema real de un subsistema mecatrónico. El proceso en sí trae consigo una inversión económica y e inversión de tiempo que en algunos casos puede afectar a un calendario establecido. Este estudio tiene como objetivo determinar la presencia de anomalías en un "encoder strip" con el fin de evitar problemas eléctricos en futuras actuaciones. Específicamente, investiga si los datos recopilados de un codificador óptico son confiables. Para imitar la señal de salida del codificador se utilizó una FPGA para reproducirla en lenguaje VHDL. Con la ayuda de los botones de Cmod A7, la PCB emula un codificador y almacena los datos en la RAM para su posterior análisis. El resultado se procesa mediante redes neuronales con Python. Estos resultados sugieren si la recopilación de datos tiene algún daño o si puede considerarse significativa., L'anàlisi d'una falla elèctrica en una màquina industrial passa per diverses proves per reduir el problema real d'un subsistema mecatrònic. El procés en si comporta una inversió econòmica i temporal que en alguns casos pot afectar el cronograma. Aquest estudi pretén determinar la presència d'anomalies en un "encoder strip" per tal d'evitar problemes elèctrics en futures actuacions. Concretament, investiga si les dades recollides d'un codificador òptic són fiables. Per imitar el senyal de sortida del codificador, es va utilitzar un FPGA per reproduir-lo mitjançant el llenguatge VHDL. Amb l'ajuda dels botons del Cmod A7, la PCB emula un codificador i emmagatzema les dades a la memòria SRAM per a la seva anàlisi posterior. El resultat es procesa mitjançant xarxes neuronals amb Python. Aquests resultats suggereixen si la recollida de dades té algun dany o es pot considerar significativa.

Designers of millimeter wave (mmWave) cellular systems need to evaluate line-of-sight (LOS) maps to provide good service to users in urban scenarios. In this letter, we derive estimators to obtain LOS maps in scenarios with potential blocking elements. Applying previous stochastic geometry results, we formulate the optimal Bayesian estimator of the LOS map using a limited number of actual measurements at different locations. The computational cost of the optimal estimator is derived and is proven to be exponential in the number of available data points. An approximation is discussed, which brings the computational complexity from exponential to quasi-linear and allows the implementation of a practical estimator. Finally, we compare numerically the optimal estimator and the approximation with other estimators from the literature and also with an original heuristic estimator with good performance and low computational cost. For the comparison, both synthetic layouts and a real layout of Chicago have been used., The work presented in this paper has been funded through the project ROUTE56 - PID2019-104945GB-I00 (funded by Agencia Estatal de Investigacion, Ministerio de Ciencia e Innovación, MCIN / AEI / 10.13039/501100011033)., Peer Reviewed, Postprint (author's final draft)

2021/2022, 2n quadrimestre

In the last few years, a lot of effort has been put into the development of the fifth generation of cellular networks (5G). Given the vast heterogeneity of devices coexisting in these networks, new approaches have been sought to meet all requirements (e.g., data rate, coverage, delay, etc.). Within that framework, massive machine-type communications (mMTC) emerge as a promising candidate to enable many Internet of Things applications. mMTC define a type of systems where large sets of simple and battery-constrained devices transmit short data packets simultaneously. Unlike other 5G use cases, in mMTC, a low cost and power consumption are extensively pursued. Due to these specifications, typical humantype communications (HTC) solutions fail in providing a good service. In this dissertation, we focus on the design of energy-driven techniques for extending the lifetime of mMTC terminals. Both uplink (UL) and downlink (DL) stages are addressed, with special attention to the traffic models and spatial distribution of the devices. More specifically, we analyze a setup where groups of randomly deployed sensors send their (possibly correlated) observations to a collector node using different multiple access schemes. Depending on their activity, information might be transmitted either on a regular or sporadic basis. In that sense, we explore resource allocation, data compression, and device selection strategies to reduce the energy consumption in the UL. To further improve the system performance, we also study medium access control protocols and interference management techniques that take into account the large connectivity in these networks. On the contrary, in the DL, we concentrate on the support of wireless powered networks through different types of energy supply mechanisms, for which proper transmission schemes are derived. Additionally, for a better representation of current 5G deployments, the presence of HTC terminals is also included. Finally, to evaluate our propo, En els últims anys, s'han dedicat molts esforços al desenvolupament de la cinquena generació de telefonia mòbil (5G). Donada la gran heterogeneïtat de dispositius coexistint en aquestes xarxes, s'han buscat nous mètodes per satisfer tots els requisits (velocitat de dades, cobertura, retard, etc.). En aquest marc, les massive machine-type communications (mMTC) sorgeixen com a candidates prometedores per fer possible moltes aplicacions del Internet of Things. Les mMTC defineixen un tipus de sistemes en els quals grans conjunts de dispositius senzills i amb poca bateria, transmeten simultàniament paquets de dades curts. A diferència d'altres casos d'ús del 5G, en mMTC es persegueix un cost i un consum d'energia baixos. A causa d'aquestes especificacions, les solucions típiques de les human-type communications (HTC) no aconsegueixen proporcionar un bon servei. En aquesta tesi, ens centrem en el disseny de tècniques basades en l'energia per allargar la vida útil dels terminals mMTC. S'aborden tant les etapes del uplink (UL) com les del downlink (DL), amb especial atenció als models de trànsit i a la distribució espacial dels dispositius. Més concretament, analitzem un escenari en el qual grups de sensors desplegats aleatòriament, envien les seves observacions (possiblement correlades) a un node col·lector utilitzant diferents esquemes d'accés múltiple. Depenent de la seva activitat, la informació es pot transmetre de manera regular o esporàdica. En aquest sentit, explorem estratègies d'assignació de recursos, compressió de dades, i selecció de dispositius per reduir el consum d'energia en el UL. Per millorar encara més el rendiment del sistema, també estudiem protocols de control d'accés al medi i tècniques de gestió d'interferències que tinguin en compte la gran connectivitat d'aquestes xarxes. Per contra, en el DL, ens centrem en el suport de les wireless powered networks mitjançant diferents mecanismes de subministrament d'energia, per als quals es deriven esquemes de, En los últimos años, se han dedicado muchos esfuerzos al desarrollo de la quinta generación de telefonía móvil (5G). Dada la gran heterogeneidad de dispositivos coexistiendo en estas redes, se han buscado nuevos métodos para satisfacer todos los requisitos (velocidad de datos, cobertura, retardo, etc.). En este marco, las massive machine-type communications (mMTC) surgen como candidatas prometedoras para hacer posible muchas aplicaciones del Internet of Things. Las mMTC definen un tipo de sistemas en los cuales grandes conjuntos de dispositivos sencillos y con poca batería, transmiten simultáneamente paquetes de datos cortos. A diferencia de otros casos de uso del 5G, en mMTC se persigue un coste y un consumo de energía bajos. A causa de estas especificaciones, las soluciones típicas de las human-type communications (HTC) no consiguen proporcionar un buen servicio. En esta tesis, nos centramos en el diseño de técnicas basadas en la energía para alargar la vida ´útil de los terminales mMTC. Se abordan tanto las etapas del uplink (UL) como las del downlink (DL), con especial atención a los modelos de tráfico y a la distribución espacial de los dispositivos. Más concretamente, analizamos un escenario en el cual grupos de sensores desplegados aleatoriamente, envían sus observaciones (posiblemente correladas) a un nodo colector utilizando diferentes esquemas de acceso múltiple. Dependiendo de su actividad, la información se puede transmitir de manera regular o esporádica. En este sentido, exploramos estrategias de asignación de recursos, compresión de datos, y selección de dispositivos para reducir el consumo de energía en el UL. Para mejorar todavía más el rendimiento del sistema, también estudiamos protocolos de control de acceso al medio y técnicas de gestión de interferencias que tengan en cuenta la gran conectividad de estas redes. Por el contrario, en el DL, nos centramos en el soporte de las wireless powered networks mediante diferentes mecanismos de suministro de, Postprint (published version)

With the arrival of 5G networks, higher frequencies need to be used at the mmWave bands in order to find available and broad enough spectral bands. At these high frequencies, with very short wavelengths, any obstacle between the transmitter and the receiver will block the transmission. Furthermore, multipath transmission is not feasible since reflections produce a high reduction in the signal level. For this reason, free line-of-sight (LOS) is needed to achieve successful transmission. This study will provide a complete performance analysis at the network level considering multiple base stations, based on a statistical model of the positions of the base stations, of the blocking objects, and the shapes and sizes of these objects. The aim of this project is to develop a complete analysis of the effect of blocking elements such as buildings, which create no-line-of-vision (nLOS) regions and, therefore, lack of coverage., Con la llegada de las redes 5G, es necesario utilizar frecuencias más altas en las bandas de ondas milimétricas para encontrar bandas espectrales disponibles y lo suficientemente amplias. A estas altas frecuencias, con longitudes de onda muy cortas, cualquier obstáculo entre el transmisor y el receptor bloqueará la transmisión. Además, la transmisión multicamino no es factible, ya que las reflexiones provocan una gran reducción en el nivel de la señal. Por esta razón, se necesita una línea de visión directa (LOS) para lograr una transmisión exitosa. Este estudio proporcionará un análisis completo a nivel de red considerando múltiples estaciones base, basado en un modelo estadístico de la posición de cada una de ellas, de los objetos de bloqueo y las formas y tamaños de éstos. El objetivo de este proyecto es desarrollar un análisis completo del efecto de los elementos de bloqueo, como edificios, que crean regiones sin línea de visión (nLOS) y, consecuentemente, sin cobertura., Amb l'arribada de les xarxes 5G, s'han d'utilitzar freqüències més altes a les bandes d'ones mil·limètriques per trobar bandes espectrals prou amples i disponibles. A aquestes freqüències tan altes, amb longituds d'ona molt curtes, qualsevol obstacle entre lemissor i el receptor bloquejarà la transmissió. A més, la transmissió multicamí no és factible, ja que les reflexions produeixen una gran reducció del nivell del senyal. Per aquest motiu, es necessita una línia de visió directa (LOS) per aconseguir una transmissió exitosa. Aquest estudi proporcionarà una anàlisi completa a nivell de xarxa considerant múltiples estacions base, a partir d'un model estadístic de la posició de cadascuna, dels objectes de bloqueig i de les formes i dimensions d'aquests objectes. L'objectiu d'aquest projecte és desenvolupar una anàlisi completa de l'efecte dels elements de bloqueig com els edificis, que creen regions sense línia de visió (nLOS) i, conseqüentment, sense cobertura.

The millimeter waves (mmWave) bands, considered to support the forthcoming generation of mobile communications technologies, have a well-known vulnerability to blockages. Recentworks in the literature analyze the blockage probability considering independence or correlation among the blocking elements of the different links. In this letter, we characterize the effect of blockages and their correlation on the ergodic capacity. We carry out the analysis for urban scenarios, where the considered blocking elements are buildings that are primarily parallel to the streets.We also present numerical simulations based on actual building features of the city of Chicago to validate the obtained expressions., This work was supported by Agencia Estatal De Investigación, Ministerio De Ciencia e Innovación, MCIN / AEI / 10.13039/501100011033 through the Project ROUTE56 - PID2019-104945GB-I00., Peer Reviewed, Postprint (author's final draft)

In this paper, we address the design of multi-user multiple-input single-output (MU-MISO) precoders for indoor visible light communication (VLC) systems. The goal is to minimize the transmitted optical power per light emitting diode (LED) under imperfect channel state information (CSI) at the transmitter side. Robust precoders for imperfect CSI available in the literature include noisy and outdated channel estimation cases. However, to the best of our knowledge, no work has considered adding robustness against channel quantization. In this paper, we fill this gap by addressing the case of imperfect CSI due to the quantization of VLC channels. We model the quantization errors in the CSI through polyhedric uncertainty regions. For polyhedric uncertainty regions and positive real channels, as is the case of VLC channels, we show that the robust precoder against channel quantization errors that minimizes the transmitted optical power while guaranteeing a target signal to noise plus interference ratio (SNIR) per user is the solution of a second order cone programming (SOCP) problem. Finally, we evaluate its performance under different quantization levels through numerical simulations., This work has been funded by the Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación (Gobierno de España), MCIN/AEI/10.13039/501100011033, through the project ROUTE56 PID2019-104945GB-I00., Peer Reviewed, Postprint (published version)

Coexistence between human-type and machine-type communications is essential in future cellular networks. The former demands high data rates whereas long battery lifetimes are crucial for the latter. In this paper, we consider a setup where clusters of sensors and a set of user terminals (UTs) are served by a multiple-antenna base station (BS) that transfers power and data accordingly. Depending on the type of UT communication, half or full-duplex, data and energy are transmitted through the same signals (i.e., simultaneous wireless information and power transfer) or through separate signals, respectively. In addition, sensors also harvest energy from the signals transmitted by UTs and other active sensors. Thanks to the BS multi-antenna technology, block diagonalization is used to eliminate all the interference in the downlink. Based on that, in this paper we design transmission schemes that maximize the throughput for the UTs while guaranteeing a sufficient and fair amount of received power among all sensors in the network., The work presented in this paper was carried out within the framework of the project ROUTE56 (PID2019-104945GB-I00 / AEI / 10.13039/501100011033) and the FPI grant BES-2017-079994, both funded by the Spanish Ministry of Science and Innovation (Agencia Estatal de Investigación); and the grant 2017 SGR 578, funded by the Catalan Government (AGAUR, Departament de Recerca i Universitats, Generalitat de Catalunya)., Peer Reviewed, Postprint (author's final draft)

This paper presents an estimation approach within the framework of uplink massive machine-type-communications (mMTC) that considers the energy limitations of the devices. We focus on a scenario where a group of sensors observe a set of parameters and send the measured information to a collector node (CN). The CN is responsible for estimating the original observations, which are spatially correlated and corrupted by measurement and quantization noise. Given the use of Gaussian sources, the minimum mean squared error (MSE) estimation is employed and, when considering temporal evolution, the use of Kalman filters is studied. Based on that, we propose a device selection strategy to reduce the number of active sensors and a quantization scheme with adjustable number of bits to minimize the overall payload. The set of selected sensors and quantization levels are, thus, designed to minimize the MSE. For a more realistic analysis, communication errors are also included by averaging the MSE over the error decoding probabilities. We evaluate the performance of our strategy in a practical mMTC system with synthetic and real databases. Simulation results show that the optimization of the payload and the set of active devices can reduce the power consumption without compromising the estimation accuracy., The work presented in this paper has been carried out within the framework of the project ROUTE56 (PID2019-104945GB-I00/ AEI/10.13039/501100011033) funded by the Agencia Estatal de Investigación (Spanish Ministry of Science and Innovation); the FPI grant BES-2017-079994, funded by the Spanish Ministry of Science, Innovation and Universities; and the grant 2017 SGR 578, funded by the Catalan Government (AGAUR, Departament de Rercerca i Universitats, Generalitat de Catalunya)., Peer Reviewed, Postprint (author's final draft)

Resolved

Within the framework of 5G, blockage effects occurring in the mmWave band are critical. Previous works describe the effects of blockages in isolated and multiple links for simple blocking objects, modeled with mathematical tools such as stochastic geometry and random shape theory. Our study uses these tools to characterize a scenario with N links, including the possible correlation among them in terms of blocking for several models of blocking objects. We include numerical evaluations highlighting that assuming independence among the links’ blocking elements is a too-brief simplification and does not accurately describe the real scenario. This paper also applies the formulation developed for the case of N links to optimize the relay positioning in mmWave cells for coverage enhancement, that is, to minimize the communication failure probability. We also show that both link budget and blockages affect the optimum positioning of the relays as they are both essential for successful transmission., The work presented in this paper has been funded through the projects 5G&B-RUNNER-UPC (Agencia Estatal de Investigación and Fondo Europeo de Desarrollo Regional, TEC2016-77148-C2-1-R / AEI/FEDER, UE) and ROUTE56 (Agencia Estatal de Investigación, PID2019- 104945GB-I00 / AEI / 10.13039/501100011033); and the grant 2017 SGR 578 (Catalan Government—Secretaria d’Universitats i Recerca, Departament d’Empresa i Coneixement, Generalitat de Catalunya, AGAUR)., Peer Reviewed, Postprint (published version)

2019/2020, 2n quadrimestre

In Guayaquil-Ecuador, Av. Pedro Menéndez Gilbert is a main road with a designed capacity of 9000 vehicles/h, currently presenting traffic congestion problems, which affects its users. In order to propose possible solutions to the mobility problem, the research carried out aimed to analyze alternatives that would improve the level of service. The data collection method consisted of observation, with fieldwork at the entrance and exit intersections of a 900-m-long section. Manual counts and vehicle categorization were carried out for one week, as well as counting the distribution times of the traffic lights. The intersections were characterized in their geometry, traffic flows and traffic light system. Based on a previous study, a 5-year increase from 135,170 vehicles to 190,424 vehicles was projected. It was found that the main causes of congestion are the distribution of the alternating times of the signal cycle, and the blockage that occurs by the Metrovía feeder and collector buses. It is concluded that the main solution is the updating and proper adjustment of the traffic light system, as well as the opening of a pre-existing exit road, prior to the intersection, and control of the blockage produced by the Metrovía units, En Guayaquil-Ecuador, la Av. Pedro Menéndez Gilbert es una vía principal diseñada para una capacidad de 9000 veh/h presentando en la actualidad problemas de congestionamiento vial, lo cual afecta a sus usuarios. Con el fin de proponer posibles soluciones a la problemática de movilidad, la investigación realizada tuvo como objetivo analizar alternativas que permitan mejorar el nivel de servicio. El método de toma de datos consistió en la observación, con un trabajo de campo en las intersecciones de entrada y salida de un tramo de 900 m de longitud. Se realizaron conteos manuales y categorización de vehículos durante una semana, así como conteo de tiempos de reparto de los semáforos. Se caracterizaron las intersecciones en su geometría, flujos de tráfico y sistema de semáforos. Sobre la base de un estudio previo se proyectó un incremento a 5 años de 135170 a 190424 vehículos. Se comprobó que las causas principales del congestionamiento son la distribución de los tiempos de reparto del ciclo semafórico, y el atascamiento que se produce por los buses alimentadores y colectores de la Metrovía. Se concluye que la solución principal es la actualización y ajuste adecuado del sistema semafórico, así como la apertura de una vía de salida prexistente, anterior a la intersección, y control del atascamiento producido por las unidades de la Metrovía

In the millimeter waves (mmWave) bands considered for 5G and beyond, the use of very high frequencies results in the interruption of communication whenever there is no line of sight between the transmitter and the receiver. Blockages have been modeled in the literature so far using tools such as stochastic geometry and random shape theory. Using these tools, in this paper, we characterize the lengths of the segments in line-of-sight (LOS) and in non-line-of-sight (NLOS) statistically in an urban scenario where buildings (with random positions, lengths, and heights) are deployed in parallel directions configuring streets., This work has been funded through the projects 5G&B-RUNNER-UPC (Agencia Estatal de Investigacion and Fondo Europeo de Desarrollo Regional, TEC2016-77148-C2-1-R / AEI/FEDER, UE) and ROUTE56 (Agencia Estatal de Investigacion, PID2019-104945GB-I00 / AEI / 10.13039/501100011033); and the grant 2017 SGR 578 (AGAUR, Generalitat de Catalunya)., Peer Reviewed, Postprint (published version)

©2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., Machine-type-communications (MTC) are being crucial in the development of next generation mobile networks. Given that MTC devices are usually battery constrained, wireless power transfer (WPT) and energy harvesting (EH) have emerged as feasible options to enlarge the lifetime of the devices, leading to wireless powered networks. In that sense, we consider a setup where groups of sensors are served by a base station (BS), which is responsible for the WPT. Additionally, EH is used to collect energy from the wireless signals transmitted by other sensors. To characterize the energy obtained from both procedures, we model the sporadic activity of sensors as Bernoulli random variables and their positions with repulsive Matérn cluster processes. This way, the random activity and spatial distribution of sensors are introduced in the analysis of the energy statistics. This analysis can be useful for system design aspects such as energy allocation schemes or optimization of idle-active periods, among others. As an example of use of the developed analysis, we include the design of a WPT scheme under a proportional fair policy., The work presented in this paper was carried out within the framework of the project 5G&B RUNNER-UPC (TEC2016-77148-C2-1-R (AEI/FEDER, UE)), the research network RED2018-102668-T Red COMONSENS and the FPI grant BES-2017-079994, funded by the Spanish Ministry of Science, Innovation and Universities; and the grant 2017 SGR 578, funded by the Catalan Government (AGAUR, Secretaria d’Universitats i Recerca, Departament d’Empresa i Coneixement, Generalitat de Catalunya)., Peer Reviewed, Postprint (author's final draft)

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., Machine-type-communications (MTC) are crucial in the evolution of mobile communication systems. Within this context, we distinguish the so-called massive MTC (mMTC), where a large number of devices coexist in the same geographical area. In the case of sensors, a high correlation in the collected information is expected. In this letter, we evaluate the impact of correlation on the entropy of a set of quantized Gaussian sources. This model allows us to express the sensed data with the data correlation matrix. Given the nature of mMTC, these matrices may be well approximated as rank deficient. Accordingly, we exploit this singularity to design a technique for switching off several sensors that maximizes the entropy under power-related constraints. The discrete optimization problem is transformed into a convex formulation that can be solved numerically., This work is supported by the project 5G&B RUNNER-UPC (TEC2016-77148-C2-1-R (AEI/FEDER, UE)) and the research network RED2018-102668-T Red COMONSENS (funded by the Spanish Ministry of Science,Innovation and Universities), the fellowship FPI BES-2017-079994, and the grant 2017 SGR 578 (funded by the Catalan Government - AGAUR)., Peer Reviewed, Postprint (author's final draft)

In this paper, we design linear precoders for the downlink of a visible light communication (VLC) system that simultaneously serves multiple users. Instead of using phosphor-coated white light-emitting diodes (PWLEDs), we focus on Red-Green-Blue light-emitting diodes (RGB-LEDs) that allow modulating three separate data streams on the three primary colors of the RGB-LEDs. For this system, we design a zero-forcing (ZF) precoder that maximizes the weighted sum rate for a multilevel pulse amplitude modulation (M-PAM). The precoding design in RGB-based systems presents some challenges due to the system constraints, such as the limited power, the non-negative amplitude constraints per light-emitting diode (LED), and the need to guarantee white light emission while transmitting with RGB-LEDs. For comparison purposes, we also consider the ZF design for a PWLED-based system and evaluate the performance of both a PWLED- and an RGB-based system., The work has been supported by the Secretaria d’Universitats i Recerca Departament d’Empresa i Coneixement (AGAUR) of the Generalitat de Catalunya SGR grant 2017-SGR-578 and has been funded by the Agencia Estatal de Investigacion (AEI)/Fondo Europeo de Desarrollo Regional (FEDER) through the project TEC2016-77148-C2-1-R (AEI/FEDER, UE)., Peer Reviewed, Postprint (published version)

A large number of rural communities in developing countries do not have access to communications services, unlike urban areas where these services have rapidly grown. This connectivity gap is mainly caused by the urban-oriented business models of traditional operators, which are not cost-effective in regions that are characterized by isolation, low population density, and scarcity of resources. This paper analyzes a feasible and sustainable strategy to deploy mobile communications services (voice and data) in isolated communities in developing countries with less than 1000 inhabitants by combining appropriate low-cost technologies and an innovative business model fostered by recent regulation. This innovative model is based on the legal figure of the SRO (Small Rural Operator), which is specifically oriented to reach small communities in isolated rural areas. The results are based on a real deployment in 6 communities of the Peruvian Amazon, which was carried out by a consortium of universities, NGOs (Non-Government Organizations), and cellular operators. This deployment allowed us to obtain practical information on the cost structure of mobile networks in isolated areas, characterize the rural demand and the revenues associated with it, and understand how the business model of traditional operators could be adapted. This information permitted us to propose, implement and validate the SRO approach. The paper shows the results of this research and provides some lessons learned. The main conclusion is that the recent Peruvian regulation opened a niche market for SROs who want to offer services in isolated communities with less than 1000 inhabitants., This work has been funded by the Development Bank of Latin America (CAF), the Spanish Agency for International Development (AECID) and by the European Commission FP7 program through project TUCAN3G (IST-601102 STP)., Peer Reviewed, Postprint (published version)