Дисертації з теми "Beamforming 5G"

The growing traffic and global bandwidth shortage for broadband cellular communi-cation networks has motivated to explore the underutilized millimeter wave frequencyspectrum for future communications. Fifth generation (5G) is the key to empow-ering new services and use cases for people, businesses, and society at large. Withunprecedented speed and flexibility, 5G carries more data with greater reliability andresponsiveness than ever before. As 5G new radio (NR) begins to take full advantageof the high-band spectrum, i.e, the millimeter wave frequencies, new challenges arecreated. While millimeter waves offer broader bandwidth and high spatial resolution,the drawback is that the millimeter waves experience higher attenuation due to pathloss and are more prone to absorption, interference and weather conditions, thereforelimiting cell coverage.This thesis is an attempt to increase the 5G cell coverage by implementing ananalogue beamforming router in a cell. Beamforming router acts like a relay, whichextends the range of the 5G cell whenever needed, according to the position of theUser Equipment (UE) based on the information received from the gNodeB (gNB,logical 5G radio node). This thesis is investigating the downlink Signal-to-Noise Ratio(SNR) gain and thus possible increase in the data rate. Simulation and validation ofthe overall performance is done using MATLAB. The outcome of this study may beused to increase the 5G cell coverage if it is implemented in a real.

The energy and data rate requirements for the next generation cellular networks urge the need for innovative solutions. Inspired by its massive bandwidth, millimeter wave (mmWave) band is thought-out to be one of the key elements to meet the aspirations. However, mmWave links are known to have short coverage distance due to the propagation losses introduced at high frequencies. The proposed solutions to overcome the transmission challenges include using large arrays with improved directivity, adopting smaller cells, and relying on cooperative networks to extend the mmWave link and avoid shadowing areas. This work aims to improve the connectivity of the mmWave link in the outdoor environments. One of the cost effective methods is to increase the array gain by using Analogue Beamforming (ABF). The performance of the ABF system in the presence of phase quantization error has been analytically investigated. The study also includes comparing three different channel sounding techniques, namely: exhaustive search, side-to-side search, and n-tier search. The time overhead related to each method and their energy consumption are calculated. The numerical results assist in determining the optimum search period to obtain a reasonable spectral efficiency using minimal power consumption. The results also help identify the minimum number of quantization bits required to produce about ninety percent of the optimistic results. In order to extend the coverage further, relay networks are considered an essential component in mmWave communications. The performance of a single hybrid beamforming full-duplex relay system and multi-relay networks were investigated. The design algorithms for the processors in the network are proposed based on the greedy pursuit approach. The performance of the proposed algorithms is analysed under various scenarios. The analysis highlights the influence of the array size, the number of RF chains, and the length of the channel sounding period. The performance of the proposed systems is compared from both the spectral efficiency and power consumption prospects. The results also establish that the number of antennas at the source and the relay receiver arrays have a superior impact on the system performance than the sizes of the array at the destination and the relay transmitter.

This work arises from the desire to reduce latency during the initial access phase in 5G networks. Millimeter wave (mmWave) bands are a key technology since they provide a great availability of bandwidth, essential to deliver the continuously increasing demand of data without saturating the conventional bands (below 6 GHz). Despite the great advantages this band can offer, at these frequencies the propagation characteristics, mainly in terms of attenuation and penetration losses, are significantly different from those in the conventional bands, thereby highly directional transmissions are crucial. The main goal of this thesis is to identify an intelligent sweeping pattern making use of contextual information extracted from MDT (Minimization of Drive Test) data provided by Telecom Italia, which enable a collection of user equipment (UE) radio measurements combined with GPS coordinates. MDT data represents a fundamental tool to create a historical database containing information regarding the most populated area in terms of data traffic, at different times of the day. Else, these data are employed to develop a dual-slope model accounting for the propagation effects in each cell of Corticella, a fraction of the municipality of Bologna: this allows to plainer define the reference environment over which the initial access optimization algorithm applies. Afterwards, the historical database is used to choose the sequence of beams to be followed by the base station (gNB) and it is constantly updated according to the new collected information.

This thesis is about the researching for 5th generation (5G) communication system, which focus on the improvement of 3D beamforming technology in the antenna array using in the Full Dimension Multiple-Input Multiple-Output (FD-MIMO) system and Millimeter-wave (mm-wave) system. When the 3D beamforming technology has been used in 5G communication system, the beam needs a weighting matrix to direct the beam to cover the UEs, but some compromises should be considered. If the narrow beams are used to transmit signals, then more energy is focused in the desired direction, but this has a restricted coverage area to a single or few User Equipments (UEs). If the BS covers multiple UEs, then multiple beams need to be steered towards more groups of UEs, but there is more interference between these beams from their side lobes when they are transmitted at same time. These challenges are waiting to be solved, which are about interference between each beam when the 3D beamforming technology is used. Therefore, there needs to be one method to decrease the generated interference between each beam through directing the side lobe beams and nulls to minimize interference in the 3D beamforming system. Simultaneously, energy needs to be directed towards the desired direction. If it has been decided that one beam should covera cluster of UEs, then there will be a range of received Signal to Interference plus Noise Ratio (SINR) depending on the location of the UEs relative to the direction of the main beam. If the beam is directed towards a group of UEs then there needs be a clustering method to cluster the UEs. In order to cover multiple UEs, an improved K-means clustering algorithm is used to cluster the multiple UEs into different groups, which is based on the cosine distance. Itcan decrease the number of beams when multiple UEs need be covered by multiple beams at same time. Moreover, a new method has been developed to calculate the weighting matrix for beamforming. It can adjust the values of weighting matrix according to the UEs' location and direct the main beam in a desired direction whilst minimizing its side lobes in other undesired directions. Then the minimum side lobe beamforming system only needs to know the UEs' location and can be used to estimate the Channel State Information (CSI) of UEs. Therefore, the scheme also shows lower complexity when compared to the beamforming methods with pre-coding. In order to test the improved K-means clustering algorithm and the new weighting method that can enhance the performance for 3D beamforming system, the two simulation systems are simulated to show the results such as 3D beamforming LTE system and mm-wave system.

Recent advances in the telecommunications industry and the resulting applicationssuch as autonomous vehicles, vehicle surveillance and traffic safetyhas increased the demand for accurate and robust vehicle positioning systems.Existing Global Navigation Satellite System (GNSS) based positioning techniquesface significant performance loss in the tunnels and urban canyons.Recent researches have shown that radio-based positioning techniques are theoreticallypromising to make an accurate navigation system to fill the GNSSgaps. Fifth generation of mobile communication (5G) will utilize wide bandwidthstogether with beamforming enabled by antenna arrays to provide higherdata rates to mobile users. These features make 5G a favorable candidate forhigh accuracy positioning. On the other hand, sensor fusion is commonly employedto develop more robust and accurate navigation systems for vehicles. Inthis work, the range and angle measurements from 5G base stations are fusedwith the acceleration measurements by the means of the extended Kalman filterto generate position estimates for a moving car. The accuracy of this positioningsystem is studied with centimeter wave (cmWave) and millimeter wave(mmWave) 5G cellular networks which are set up by practical parameters. Towardsthat, the positioning system is tested in a simulation-based experimentwhere a car is moving on a highway and the 5G base stations are deployedalongside of it. Based on that, a detailed analysis of the Kalman filter’s rootmean squared error (RMSE) and the 5G’s different parameters and limitingfactors such as the line of sight (LOS) blockage is carried out. Our numericalresults show that vehicles connected to 5G can benefit from this system to enhancethe robustness and accuracy of their navigation system.
De senaste framstegen inom telekommunikationsindustrin och de resulterandeapplikationerna som autonoma fordon, fordonsövervakning och trafiksäkerhethar ökat efterfrågan på exakta fordonspositioneringssystem. ExisterandeGlobal Navigation Satellite System (GNSS) baserade positioneringsteknikerhar en betydande prestandaförlust i tunnlar och urbana kanjoner. Forskninghar visat att radiobaserade positioneringstekniker har mindre distributionskostnaderoch kan vara mer exakta än satellitbaserade navigationssystem.I den femte generation av mobilkommunikation (5G) används tekniker sommillimeterWave (mmWave) och multiple-input multiple-output (MIMO) därradio-terminaler består av stora matrisantenner och arbetar med stora bandbredder.Dessa funktioner gör 5G-system gynnsamma för positionering medhög noggrannhet. Å andra sidan har informationsfusion av Inertial NavigationSystems (INS) och andra positioneringstekniker vanligen använts för attutveckla mer robusta och exakta spårningssystem. I denna studie föreslår viett INS/5G-positioneringssystem för att spåra landfordon baserat på Kalmanfiltret. Vi adresserar systempositioneringsgränserna i termer av 5G nya radio(NR) subsystem och en detaljerad analys av beroendet av rotmedelfelteradkvadratfel (RMSE) för olika systemparametrar som utförs. Systemet testas iett enkelt simuleringsbaserat experiment som består av en rak motorväg medbasstationerna placerade bredvid det. Slutligen visar våra numeriska resultatatt det föreslagna systemet är i stånd att lokalisera ett UE-monterat fordon medsub-meter lägesfel även i närvaro av hård siktlinje blockering.

Nei prossimi anni è previsto un aumento del traffico dati, e la quinta generazione cellulare 5G dovrà fare affidamento su nuove tecnologie, come le onde millimetriche e il massive-MIMO, per soddisfare tale richiesta. Lo spettro di frequenze sotto i 6 GHz risulta infatti sovra-utilizzato, e le frequenze relative alle onde millimetriche promettono di garantire alte velocità di trasmissione dei dati, grazie alla grande disponibilità di banda, specialmente attorno ai 60 GHz. Nonostante questo aspetto favorevole, si ha però un elevato path loss e la difficoltà nel penetrare gli ostacoli. Per ovviare a tali problemi, l'utilizzo di tecniche di beamforming, ottenibili grazie all'uso congiunto di frequenze a onde millimetriche e massive-MIMO, permette di direzionare il pattern dell'antenna nelle direzioni spaziali desiderate, e di compensare il path loss grazie all'aumento della direttività. Considerando un sistema cellulare 5G, una comunicazione di tipo direttivo impone che i beam dell'utente e della stazione radio base debbano essere allineati per garantire la comunicazione, introducendo possibili ritardi nella fase di accesso iniziale. Di conseguenza, lo studio di algoritmi ad-hoc, progettati per velocizzare questa fase rappresenta un sfida importante per l'ottimizzazione dei futuri sistemi 5G. Nell'ottica quindi di velocizzare l'accesso iniziale nelle reti 5G, in questa tesi prima di tutto mostriamo gli approcci proposti nello stato dell'arte, mettendo in evidenza gli aspetti che possono essere migliorati. Successivamente viene spiegato il simulatore che abbiamo implementato su Matlab, e infine viene introdotto un nuovo algoritmo. In particolare, l'algoritmo proposto si basa sulla memoria degli utenti visti per settore e sull'utilizzo di diverse configurazioni dei beam. Questi due aspetti combinati tra loro risultano innovativi rispetto allo stato dell'arte. I risultati numerici ottenuti dimostrano la bontà della tecnica proposta negli scenari 5G considerati.

[ES] La tecnologia en fases de paquets es va convertir en dècades enrere en la indústria del radar. Avui en dia, la matriu de fases o la formació de bigues s'està convertint en una necessitat per a la comunicació digital. L'explotació d'un sistema de transmissió de feixos ajudarà a reduir el consum total d'energia de les estacions base i dels equips d'usuaris. També permetrà al servei oferir dades molt més elevades i millorar la qualitat del servei. La investigació sobre la comunicació digital i la comunicació requereix una antena i un maquinari compatible. El maquinari hauria de ser capaç de gestionar diferents escenaris i enfocaments per a problemes de comunicació mòbil. Hi ha diversos sistemes utilitzats per a la investigació de la formació de bigues, especialment per a la comunicació mòbil. Aquests sistemes pateixen de diverses deficiències. Són cares d'implementar, no adaptatives i fixades a una arquitectura relacionada amb determinat algorisme de generació de feixos o amb un nombre d'elements d'array fix. En aquesta tesi es proposa un nou sistema de matrius per fases. Aquest sistema es podria explotar per a la investigació en problemes de comunicació mòbil o radar. Està compost per una xarxa d'antenes planes de 8x1, canals de conversió de RF a banda base i processador de banda base. Es fa una estimació de la transformació de fases i de la DOA en mostres digitals de banda base. Això proporciona al sistema dinàmica quant als algorismes provats. Amb aquesta finalitat, es fan servir juntes SDR àgils per adquirir senyals de la matriu d'antenes i convertir-les en fluxos de dades digitals. Els fluxos de dades es processen després en un processador de banda base basat en FPGA. A més de ser baixos en costos i assequibles per part de petits instituts d'investigació i investigacions independents, el sistema es pot ajustar per portar més elements de matriu d'antenes. La matriu monopola plana de 8x1 està dissenyada, simulada i mesurada. Es combinen i descriuen les característiques d'impedància i de radiació. Els SDR s'introdueixen i es calibren per al funcionament de diversos elements i s'introdueixen els mètodes de calibratge per incerteses de fase i amplitud. El rendiment global del sistema es prova mitjançant diferents algorismes de formulació de feixos i algorismes de direcció d'estimació d'arribada. Els resultats de la mesura mostren que el sistema és fiable. S'aconsegueix un model de beamformació amb bona resolució i un rebuig elevat de la interferència. La estimació de la direcció d'arribada és precisa.
[CA] La tecnología de matriz en fase hizo una rotación en la industria del radar hace décadas. Hoy en día, la matriz en fase, o formación de haz, se está convirtiendo en una necesidad para la comunicación digital. La explotación de la formación de haz ayudaría a reducir el consumo de energía general de las estaciones base y el equipo del usuario. También permitirá que el servicio brinde datos mucho más altos y mejore la calidad del servicio. La investigación sobre la formación y comunicación de haces digitales requiere un conjunto de antenas y hardware compatible. El hardware debe ser capaz de manejar diferentes escenarios y enfoques para problemas de comunicación móvil. Hay varios sistemas utilizados para la investigación de conformación de haz, especialmente para la comunicación móvil. Estos sistemas sufren de varias deficiencias. Son costosos de implementar, no adaptativos y fijos a una arquitectura relacionada con cierto algoritmo de conformación de haz o con un número de elementos de arreglo fijo. En esta tesis, se propone un nuevo sistema matricial por fases. Este sistema podría ser explotado para la investigación en comunicaciones móviles o problemas de radar. Está compuesto por un conjunto de antenas planas de 8x1, canales de conversión de RF a banda base y procesador de banda base. La formación de haz y la estimación de DOA se realizan en muestras digitales de banda base. Esto proporciona al sistema dinamismo con respecto a los algoritmos probados. Para ese propósito, las tarjetas SDR ágiles se utilizan para adquirir señales de la red de antenas y convertirlas en flujos de datos digitales. Los flujos de datos se procesan en un procesador de banda base basado en FPGA. Además de ser de bajo costo y asequible para los pequeños institutos de investigación e investigaciones independientes, el sistema se puede ajustar para llevar más elementos de la red de antenas. El conjunto monopolo plano 8x1 está diseñado, simulado y medido. La correspondencia de impedancia y las características de radiación se representan y describen. Los SDR se introducen y se calibran para la operación de elementos múltiples y se introducen los métodos de calibración para las incertidumbres de fase y amplitud. El rendimiento general del sistema se prueba mediante diferentes algoritmos de conformación de haz y algoritmos de estimación de la dirección de llegada. Los resultados de las mediciones muestran que el sistema es confiable. Se logra una conformación de haz con buena resolución y alto rechazo de interferencia. Dirección de estimación de la llegada es precisa.
[EN] Phased array technology made a turnover in radar industry decades ago. Nowadays, phased array, or beamforming, is becoming a necessity for digital communication. Exploiting beamforming would help in reducing the overall power consumption of base stations and user equipment. It will also enables the service to provide much higher datarates and enhance the quality of service. Research on digital beamforming and communication requires antenna array and compatible hardware. The hardware should be capable of handling different scenarios and approaches for mobile communication problems. There are several systems used for beamforming research especially for mobile communication. These systems suffer from several deficiencies. They are either expensive to implement, not adaptive and fixed to an architecture related to certain beamforming algorithm or with fixed array elements number. In this thesis, a new phased array system is proposed. This system could be exploited for research in mobile communication or radar problems. It is composed of 8x1 planar antenna array, RF to baseband conversion channels and base band processor. Beamforming and DOA estimation is done on base band digital samples. This provides the system with dynamicity regarding tested algorithms. For that purpose, agile SDR boards are used to acquire signals from antenna array and convert them to digital data streams. Data streams are then processed in an FPGA based base band processor. In addition to being low in cost and affordable by small research institutes and freelancing researches, the system can be adjusted to carry more antenna array elements. The 8x1 planar monopole array is designed, simulated and measured. Impedance matching and radiation characteristics are plotted and described. SDRs are introduced and calibrated for multi-element operation and calibration method for phase and amplitude uncertainties are introduced. Overall system performance is tested by different beamforming algorithms and direction of arrival estimation algorithms. Measurement results show that the system is reliable. Beamforming with good resolution and high interference rejection is achieved. Direction of arrival estimation is accurate.
Haroun, MH. (2019). 8×1 Antenna Array System for Uplink Beamforming in LTE-A and 5G NR [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/129852
TESIS

In recent years, satellite communication systems, in particular LEO constellations, have been subject of increased attention in the new space race; this is substantiated by the numerous industrial endeavors aiming at providing high-speed broadband access anywhere at anytime, E.G., SpaceX Starlink. In 5G systems, there has been an increased focus to integrate a non-terrestrial component into the broader wireless communication infrastructure. It is expected that this trend will continue in the future. Satellites can provide coverage in areas where a terrestrial infrastructure is congested or unavailable; however, their energy resources are limited and due to the sidelobes in the multiple beam coverage, co-channel interference arises. Here, beamforming is an effective remedy for both problems. In this thesis, a distributed beamforming solution is investigated and compared with classic centralized methods. The distributed solution benefits from the fact that beamforming is not performed in a centralized manner in a single satellite, but is done collectively. So, if one satellite malfunctions, others can still provide coverage. Lastly, numerical simulations performed in MATLAB substantiate the advantages of distributed beamforming approach.

Afin de répondre à la demande croissante du nombre d'objets connectés et de débits de données plus élevés, la cinquième génération de réseau mobile (5G) va être déployée.Pour répondre à ces défis, la 5G utilisera le beamforming pour améliorer la qualité de transmission et étendre la couverture du réseau. En raison du manque de spectre RF disponible en dessous de 6 GHz, l'industrie de la téléphonie mobile étudie actuellement les bandes de fréquences millimétriques en particulier autour de 28 GHz. L'utilisation de la technologie CMOS pour les applications 5G apparait prometteuse pour le marché de masse que vise la 5G, d'autant qu'aujourd'hui la miniaturisation des transistors CMOS permet un fonctionnement compétitif aux fréquences millimétriques. Pour répondre à toutes les attentes de la 5G notamment en termes de fiabilité, de nouvelles idées en rupture, avec le self-healing et le self-contained, permettent d’utiliser au maximum les avantages de la technologie CMOS tout en proposant un fonctionnement fiable pou rl’amplificateur. Dans le cadre du self-healing et du self-contained, plusieurs circuits son tintégrés sur silicium tel qu'un amplificateur intégrant un détecteur de puissance totalement non invasif pour le self-healing et un amplificateur équilibré pour le selfcontained
In order to meet the growing demand for more connected objects and higher data rates,the fifth generation of mobile network (5G) will be deployed. To address thesechallenges, the 5G will use beamforming to improve the transmission quality and extendthe network coverage. Due to the lack of available RF spectrum below 6 GHz, the mobileindustry is studying millimeter wave frequency bands in particular around 28 GHz. Theuse of CMOS technology for 5G applications is promising for the 5G mass market,especially nowadays the miniaturization of CMOS transistors allows competitiveoperation at millimeter frequencies. To meet all the expectations of the 5G especially interms of reliability, new breakthrough ideas, with the self-healing and the selfcontained,allow to use all the benefits of CMOS technology to the maximum whileoffering reliable operation for the amplifier. Within the framework of self-healing andself-contained, several circuits are integrated on silicon such as an amplifier integratedwith a totally non-invasive power detector for self-healing and a balanced self-containedamplifier

In the first part of the dissertation, we provide an extensive overview of sub-6 GHz wireless access technology known as massive multiple-input multiple-output (MIMO) systems, highlighting its benefits, deployment challenges, and the key enabling technologies envisaged for 5G networks. We investigate the fundamental issues that degrade the performance of massive MIMO systems such as pilot contamination, precoding, user scheduling, and signal detection. In the second part, we optimize the performance of the massive MIMO system by proposing several algorithms, system designs, and hardware architectures. To mitigate the effect of pilot contamination, we propose a pilot reuse factor scheme based on the user environment and the number of active users. The results through simulations show that the proposed scheme ensures the system always operates at maximal spectral efficiency and achieves higher throughput. To address the user scheduling problem, we propose two user scheduling algorithms bases upon the measured channel gain. The simulation results show that our proposed user scheduling algorithms achieve better error performance, improve sum capacity and throughput, and guarantee fairness among the users. To address the uplink signal detection challenge in the massive MIMO systems, we propose four algorithms and their system designs. We show through simulations that the proposed algorithms are computationally efficient and can achieve near-optimal bit error rate performance. Additionally, we propose hardware architectures for all the proposed algorithms to identify the required physical components and their interrelationships.

Multi-User Multi-Input Multi-Output (MU-MIMO) systems are considered to be the sustainable technologies of the current and future of the upcoming wireless and mobile networks generations. The perspectives of these technologies under several scenarios is the focus of the present thesis. The initial system model covers the MU-MIMO, especially in the massive form that is considered to be the promising ideas and pillars of the 5G network. It is observed that the optimal number of users should be served in the time-frequency resource even though the maximum limitation of the MU-MIMO is governed by the total receiving antennas (K) is less than or equal to the base station antennas (M). The system capacity of the massive MIMO (mMIMO) under perfect channel state information (CSI) of uncorrelated channel is investigated and studied. Two types of precoders were applied, one is directly based on channel inversion, and the other uses the Eigen decomposition that is derived subject to the signal to a leakage maximization problem. The two precoders show a degree of equivalency under certain assumptions for the number of antennas at the user end. The convex optimization of multi-antenna networks to achieve the design model of optimum beamformer (BF) based on the uniform linear array (ULA) is studied. The ULA is selected for its simplicity to analyse many scenarios and its importance to match the future network applied millimetre wave (mmWave) spectrum. The maximum beams generated by the ULA are explored in terms of several physical system parameters. The duality between the MU-MIMO and ULA and how they are related based on beamformer operation are detailed and discussed. Finally, two approaches for overloaded systems are presented when the availability of massive array that is not guaranteed due to physical restrictions since the existence of a large number of devices will result in breaking the dimension rule (i.e., K ≤ M). As a solution, a low complexity users selection algorithm is proposed. The channel considered is uncorrelated with full and perfect knowledge at the BS. In particular, these two channel conditions may not be available in all scenarios. The CSI may be imperfect, and even the instantaneous form does not exist. A hybrid precoder between the mixed CSI (includes imperfect and statistical) and rate splitting approach is proposed to deal with an overloaded system under a low number of BS antennas.
Ministry of Higher Education and Scientific Research of Iraq

La réduction de taille des technologies actives permet d'envisager des applications vers des fréquences toujours plus élevées. Cependant, l'exploitation de ces bandes de fréquences nécessite une redéfinition fondamentale des architectures en raison de pertes plus conséquentes qu'aux basses fréquences; c'est de cette assimilation de nouvelles architectures à base de réseaux d'antennes directives programmables, conjointement à l'utilisation de technologies performantes que les fréquences supérieures à 30 GHz peuvent être pleinement exploitées pour des applications télécoms, de défense et commerciales. Dans les architectures notamment adoptées pour la génération de systèmes de communications 5G, les besoins concernent tout aussi bien une forte intégration hardware qu'un besoin en puissance élevé dans les bandes Ku, K et Ka. De plus, le gain en maturité technologique des filières à grande bande interdite GaN les rend éligibles pour prétendre à la conception des modules de puissance à ces fréquences. En effet, les circuits Tx-Rx réalisés traditionnellement en technologie SiGe ou GaAs se voient de plus en plus associés à (voire sont remplacées par) des éléments en technologie GaN. Les tendances d'utilisation de cette technologie ne la limitent plus au segment de la puissance pour l'amplification haute fréquence. Des récepteurs robustes ont prouvé l'intérêt de cette technologie en étage de réception (LNA), et d'autres travaux font état de performances avantageuses pour la synthèse d'oscillateurs stables hautes fréquences. C'est dans cette logique que le fondeur OMMIC a souhaité compléter la gamme des produits déjà disponibles, en motivant une étude sur la conception de puces multi-fonctions (atténuateurs-déphaseurs programmables) MMIC en technologie GaN. Ce travail a pour but de démontrer à terme les avantages que l'on peut tirer de modules totalement intégrés GaN d'une part, et de réaliser les premiers travaux de core-chip en bande Ka sur cette technologie GaN d'autre part. En effet, il n'existe pas à notre connaissance de circuit de contrôle du signal (core-chip) réalisé dans cette technologie. Cette thèse a donc pour double objectif de démontrer la faisabilité de tels circuits, et de proposer une méthodologie de conception pour tendre vers les meilleures performances possibles. Pour atteindre le premier objectif, après une étude bibliographique approfondie, nous savons que la technologie à effet de champ GaN ne présente pas les propriétés intrinsèques les plus favorables pour réaliser de telles fonctions; une analyse spécifique de chaque circuit est réalisée sur deux types de réalisations (cellules single ended et différentielles). Cela représente donc un challenge de répondre à ce premier objectif. [...]
The reduction in size of the active technologies allows applications towards ever higher frequencies. However, the exploitation of these frequency bands requires a fundamental redefinition of the architectures due to more significant losses than at low frequencies; it is from this assimilation of new architectures based on networks of programmable directional antennas, together with the use of high-performance technologies that frequencies above 30 GHz can be fully exploited for telecommunications, defense and commercial applications. In the architectures adopted for the generation of 5G communications systems, the requirements relate to both a strong hardware integration as well as a high power requirement in the Ku, K and Ka bands. In addition, the gain in technological maturity of GaN technologies makes them eligible to claim the design of power modules at these frequencies. Indeed, the Tx-Rx circuits traditionally produced in SiGe or GaAs technology are increasingly associated with (or even replaced by) elements in GaN technology. Trends in the use of this technology no longer limit it to the power segment for high frequency amplification. Robust receivers have proven the advantage of this technology in reception stage (LNA), and other works report advantageous performances for the synthesis of stable high frequency oscillators. In this logic, the the founder OMMIC wanted to complete the range of products already available, by motivating a study on the design of multi-function chips (programmable attenuators-phase shifters) MMIC in GaN technology. The aim of this work is to demonstrate in the long term the advantages that we can derive from fully integrated GaN modules on the one hand, and to carry out the first Ka-core core-chip work on this GaN technology on the other hand. In fact, to our knowledge, there is no core-chip signal control circuit made in this technology. This thesis therefore has the double objective of demonstrating the feasibility of such circuits, and of proposing a design methodology to tend towards the best possible performances. To achieve the first objective, after an in-depth bibliographic study, we know that GaN field effect technology does not have the most favorable intrinsic properties for performing such functions; a specific analysis of each circuit is carried out on two types of outputs (single ended and differential cells). It therefore represents a challenge to meet this first objective. This is why, in a second step, we made a specific effort on the design methodology, which is divided into two parts: the design of individual cells of the core-chip and then the pooling of these. We realized that poor control of this cell assembly step could lead to degraded performance.[...]

L'elaborato affronta il tema dell'Inter-Cell Interference Coordination (ICIC) applicato ad un sistema 5G. Il sistema viene modellato mediante il software di simulazione ns-3. L'approccio utilizzato è quello di unire gli algoritmi di Frequency Reuse, che rappresentano un approccio statico di coordinamento dell'interferenza inter-cella, e il beamforming, caratteristica fondamentale introdotta dallo standard 5G, allo scopo di ottimizzare l'allocazione di risorse verso tutti gli utenti che il sistema cellulare copre. Lo studio effettuato affronta in maniera sistematica le specifiche dello standard 5G, con una particolare attenzione al modo in cui questo viene implementato all'interno del software di simulazione, con lo scopo di attuare modifiche in maniera consapevole delle caratteristiche che lo standard presenta. Infatti, proprio perché lo scenario di partenza non comprende l'applicazione di algoritmi di ICIC, è stato necessario modificare l'architettura iniziale della network già impostata all'interno di ns-3 e realizzare un interfacciamento con gli algoritmi di Frequency Reuse, andando a modificare il modo in cui la Base Station alloca le risorse. Inoltre, è stato necessario introdurre tutta la componente di segnali che utenti e Base Station si scambiano per fornirsi informazioni utili al coordinamento dell'interferenza inter-cella. In particolare, mediante il software viene modellato uno scenario di partenza, rappresentato da un generico stadio, e vengono valutate le performance del sistema in termini di pacchetti ricevuti sui totali pacchetti trasmessi. Con l'applicazione di un coordinamento dell'interferenza tra le celle si raggiungono risultati significativi, che portano ad un incremento delle performance del sistema. Il risultato finale mostra come l'utilizzo di algoritmi di ICIC migliori le performance del sistema grazie alla riduzione dell'interferenza, che permette un'allocazione di maggiori risorse con una perdita di pacchetti significativamente ridotta.

5G brings a few key technological improvements compared to previous generations in telecommunications. These include, but are not limited to, greater speeds, increased capacity and lower latency. These improvements are in part due to using high band frequencies, where increased capacity is found. By advancements in various technologies, mobile broadband traffic has become increasingly chatty, i.e. more small packets are being sent. From a capacity standpoint this characteristic poses a challenge for early 5G millimeter-wave advanced antenna systems. This thesis investigates if network performance of 5G millimetre-wave systems can be improved by increasing the utilisation of the bandwidth by using adaptive beamforming. Two adaptive codebook approaches are proposed; a single- beam and a multi-beam approach. The simulations are performed in an outdoor urban macro scenario. The results show that for a small packet scenario with good coverage the ability to frequency multiplex users is important for good network performance.

In order to support the new paradigm shift in fifth generation (5G) mobile communication, radically different network architectures, associated technologies and network operation algorithms, need to be developed compared to existing fourth generation (4G) cellular solutions. The evolution toward 5G mobile networks will be characterized by an increasing number of wireless devices, increasing device and service complexity, and the requirement to access mobile services ubiquitously. To realise the dramatic increase in data rates in particular, research is focused on improving the capacity of current, Long Term Evolution (LTE)-based, 4G network standards, before radical changes are exploited which could include acquiring additional spectrum. The LTE network has a reuse factor of one; hence neighbouring cells/sectors use the same spectrum, therefore making the cell-edge users vulnerable to heavy inter cell interference in addition to the other factors such as fading and path-loss. In this direction, this thesis focuses on improving the performance of cell-edge users in LTE and LTE-Advanced networks by initially implementing a new Coordinated Multi-Point (CoMP) technique to support future 5G networks using smart antennas to mitigate cell-edge user interference in uplink. Successively a novel cooperative uplink inter-cell interference mitigation algorithm based on joint reception at the base station using receiver adaptive beamforming is investigated. Subsequently interference mitigation in a heterogeneous environment for inter Device-to-Device (D2D) communication underlaying cellular network is investigated as the enabling technology for maximising resource block (RB) utilisation in emerging 5G networks. The proximity of users in a network, achieving higher data rates with maximum RB utilisation (as the technology reuses the cellular RB simultaneously), while taking some load off the evolved Node B (eNodeB) i.e. by direct communication between User Equipment (UE), has been explored. Simulation results show that the proximity and transmission power of D2D transmission yields high performance gains for D2D receivers, which was demonstrated to be better than that of cellular UEs with better channel conditions or in close proximity to the eNodeB in the network. It is finally demonstrated that the application, as an extension to the above, of a novel receiver beamforming technique to reduce interference from D2D users, can further enhance network performance. To be able to develop the aforementioned technologies and evaluate the performance of new algorithms in emerging network scenarios, a beyond the-state-of-the-art LTE system-level-simulator (SLS) was implemented. The new simulator includes Multiple-Input Multiple-Output (MIMO) antenna functionalities, comprehensive channel models (such as Wireless World initiative New Radio II i.e. WINNER II) and adaptive modulation and coding schemes to accurately emulate the LTE and LTE-A network standards.

The complexity of advanced antenna techniques used in the new generation of wireless networks (5G) makes communication between experts and non-technical staff more difficult than ever. As cooperation between network vendors and network operators affects the adoption of the new standard, a need for a new tool has emerged to make technical presentations more engaging and compelling. This thesis presents an exploratory study that aims to examine various design options for an interactive visualization of radiowave propagation to be used by advanced antenna systems experts. Through a Research-oriented Design, functional and non-functional requirements were identified with the help of domain expert. Later, an interactive prototype was designed and developed using a participatory design approach. Qualitative and quantitative data was gathered through usability testing, System Usability Scale (SUS) questionnaires and semi-structured interviews conducted with 12 researchers and engineers at Ericsson AB a multinational telecommunication company. User evaluation proved that such a tool could facilitate communication between technical experts and non-technical staff. The developed prototype was considered intuitive and useful by the majority of study participants as measured by interviews and the SUS survey. Future research is encouraged to include the target audience representatives in order to measure their engagement while using the tool.
Komplexiteten hos avancerade antenntekniker som anvnds i den nya generationen av mobilntverk (5G), gr kommunikationen mellan experter och icke-teknisk personal svrare n ngonsin. Eftersom samarbetet mellan telekommunikationsfretag och ntoperatrer pverkar anpassningen av den nya standarden, har behovet av ett nytt verktyg uppsttt fr att gra tekniska presentationer mer engagerande och vertygande. Avhandlingen presenterar en underskande studie som syftar till att underska olika designalternativ fr en interaktiv visualisering av radiovgsfrkning som anvnds av avancerade antennsystems experter. Genom en forskningsinriktad design identifierades funktionella och icke-funktionella krav med hjlp av en domnexpert. Senare konstruerades och utvecklades en interaktiv prototyp med hjlp av en co-operativ designmetod. Kvalitativa och kvantitativa data samlades in genom anvndbarhetstester, System Usability Scale (SUS) frgeformulr och halvstrukturerade intervjuer med 12 forskare och ingenjrer p Ericsson AB ett multinationellt telekommunikationsfretag. Anvndarutvrdering visade att ett sdant verktyg skulle underltta kommunikationen mellan tekniska experter och icke-teknisk personal. Den utvecklade prototypen ansgs intuitiv och anvndbar av majoriteten av studiedeltagarna, mtt genom intervjuer och SUS-underskningen. Framtida forskning uppmuntrar till att inkludera mlgruppsrepresentanterna fr att mta deras engagemang medan de anvnder verktyget.

Il progetto di tesi riguarda principalmente la progettazione di moderni sistemi wireless, come 5G o WiGig, operanti a onde millimetriche, attraverso lo studio di una tecnica avanzata detta Beamforming, che, grazie all'utilizzo di antenne direttive e compatte, permette di superare limiti di link budget dovuti alle alte frequenze e introdurre inoltre diversità spaziale alla comunicazione. L'obiettivo principale del lavoro è stato quello di valutare, tramite simulazioni numeriche, le prestazioni di alcuni diversi schemi di Beamforming integrando come tool di supporto un programma di Ray Tracing capace di fornire le principali informazioni riguardo al canale radio. Con esso infatti è possibile sia effettuare un assessment generale del Beamforming stesso, ma anche formulare i presupposti per innovative soluzioni, chiamate RayTracing-assisted- Beamforming, decisamente promettenti per futuri sviluppi così come confermato dai risultati.

[ES] La llegada de la próxima generación del estándar de comunicaciones móviles, la llamada quinta generación (5G), es prácticamente una realidad. Las primeras redes comerciales han comenzado a ser desplegadas, centrándose en ofrecer altas velocidades de transferencia de datos. Sin embargo, el estándar 5G va mucho más allá y prevé dar soporte a nuevos servicios que pretenden revolucionar la sociedad. Estos nuevos servicios imponen un nivel alto de requisitos en no solo en cuanto a velocidad del tráfico de datos, sino en cuanto a latencia o número de dispositivos conectados simultáneamente. La amplia variedad de requisitos no puede ser soportada por las redes de cuarta generación (4G), por lo que se hizo necesario plantear un nuevo paradigma para las redes inalámbricas. Con la promesa de grandes cantidades de ancho de banda sin utilizar, el estándar 5G contempla utilizar frecuencias en la comúnmente conocida como banda de milimétricas (mmWave). Esta banda presenta grandes pérdidas de propagación, que se acentúan si existen bloqueos de señal. Actividades regulatorias del uso de las bandas de milimétricas atrajo el interés tanto de la industria como de la academia en plantear soluciones para dar servicio en estas bandas. En los últimos años se han presentado infinidad de trabajos basados en sistemas con múltiples antenas o MIMO, para conformar las señales transmitidas o recibidas en haces apuntando en determinadas direcciones. La ganancia que aportan los sistemas MIMO pueden compensar las altas pérdidas de propagación, asegurando la viabilidad de las comunicaciones mmWave. Se ha detectado una evidente falta de estudios sobre la viabilidad de sistemas MIMO en entornos móviles y dinámicos con bloqueos que hagan necesario que el sistema se reconfigure. Esta Tesis pretende cubrir este espacio desde un enfoque práctico y propone mecanismos de gestión de los haces para hacerles un seguimiento utilizando los recursos y mecanismos del nuevo estándar 5G. Las soluciones aportadas se basan en el uso eficiente de los reportes de medidas de las señales de referencia estandarizadas en enlace descendente. En primer lugar, esta Tesis recoge un análisis minucioso del estado del arte, donde se corrobora la necesidad de aportar soluciones de seguimiento de haces en sistemas de comunicaciones en la banda de milimétricas. Además, se estudian los diferentes mecanismos definidos en el estándar 5G y que posibilitan el seguimiento. Cabe destacar que el estándar no define un mecanismo único a seguir, permitiendo presentar propuestas. Una vez conocidas las tecnologías, se centra el estudio en el impacto del seguimiento sobre las prestaciones a nivel de red y de enlace. Dicho estudio se realiza sobre un sistema punto a punto, donde el terminal móvil se desplaza por un entorno urbano. En base a simulaciones de red, se cuantifica el índice de seguimiento de haz y de cómo dicho seguimiento afecta a la relación señal a ruido más interferencia (SINR) y la tasa de transmisión del usuario. Las soluciones de seguimiento propuestas en esta Tesis se pueden clasificar en dos categorías. En una primera categoría, se realiza el seguimiento en base a reportes de medidas de las señales de referencia. Independientemente de la velocidad, se alcanza un seguimiento del 91% con poca penalización en la tasa de transmisión si se monitorizan los haces de interés con una periodicidad menor de 20 ms. En la segunda categoría caben mecanismos de seguimiento que hacen uso de fuentes externas de información. Dentro de esta categoría, se propone un fingerprinting que relacione haces con la localización reportada y un modelo de machine learning (ML) que prediga los haces a utilizar. El fingerprinting proporciona los mismos niveles de rendimiento. Sin embargo, esta solución es muy sensible a errores y requiere considerar todos los casos posibles, lo que la hace tecnológicamente inviable. En cambio, el modelo de ML, que hace p
[CAT] L'arribada de la següent generació de l'estàndard de comunicacions mòbils, l'anomenada cinquena generació (5G), es pràcticament una realitat. Les primeres xarxes comercials han començat a desplegar-se i s'han centrat en oferir altes velocitats de transferència de dades. No obstant, l'estàndard 5G va molt mes allà y preveu donar suport a nous serveis que pretenen revolucionar la societat. Estos nous serveis imposen un alt nivell de requisits no sols en quant a velocitat de tràfic de dades, si no també en quant a latència o número de connexions simultànies. L'ampla varietat de requisits no es suportada per les xarxes de quarta generació (4G) actuals, per el qual es va fer necessari un nou paradigma de xarxes sense fil. Amb la promesa de amplies quantitats d'ample de banda, l'estàndard 5G contempla utilitzar freqüències a la banda de mil·limètriques. Esta banda presenta l'inconvenient d'experimentar grans pèrdues de propagació, que s'accentuen en cas de bloqueigs. L'apertura de les bandes de mil·limètriques va atraure l'interès tant de l'industria com de l'acadèmia en plantejar solucions per a donar servei en estes bandes. En els últims anys s'han presentat infinitat de treballs basats en sistemes amb múltiples antenes o MIMO, per a conformar els senyals transmesos o rebuts en feixos apuntant en determinades direccions d'interès. El guany de feix es pot utilitzar per a compensar les pèrdues de propagació, assegurant la viabilitat de les comunicacions en la banda de mil·limètriques. No obstant això, s'ha detectat una preocupant manca d'estudis sobre la viabilitat d'estos sistemes en entorns mòbils i dinàmics, amb obstacles que bloquejen els feixos i facen necessari que el sistema es reconfigure. El present treball de Tesi pretén cobrir este espai buit i des d'un punt de vista pràctic, es proposen mecanismes de gestió dels feixos per a ser el seguiment utilitzant els recursos i mecanismes dels que disposa l'estàndard 5G. D'esta manera, les solucions aportades es basen en la utilització eficient dels reports de mesures dels senyals de referència del enllaç descendent. En primer lloc, esta Tesi recull una anàlisi minuciosa de l'estat de l'art on es corrobora la necessitat de aportar solucions de seguiment de feixos per a comunicacions en la banda de freqüències mil·limètriques. A més a més, s'estudien els diferents mecanismes definits a l'estàndard 5G i que possibiliten el seguiment. Cap destacar que l'estàndard no defineix un mecanisme únic, si no que deixa la porta oberta a presentar propostes. Una vegada conegudes les tecnologies, l'estudi es centra en l'impacte del seguiment sobre les prestacions a nivell de xarxa i d'enllaç. Este estudi es realitza sobre un sistema MIMO punt a punt, en una única estació base i un terminal mòbil desplaçant-se en un entorn urbà. En base a simulacions d'extrem a extrem, es quantifica l'índex de seguiment de feix i com l'anomenat seguiment afecta a la relació senyal a soroll més interferència (SINR) i a la taxa instantània de transmissió de l'usuari. Les solucions de seguiment de feixos propostes a la Tesi es poden classificar en dos categories. A la primera categoria, el seguiment de feixos es realitza en base als reports de mesures dels senyals de referència. Independentment de la velocitat, s'arriba a una taxa de seguiment del 91% amb poca penalització de taxa de transmissió si els feixos d'interès es mesuren amb una periodicitat menor a 20 ms. A la segona categoria pertanyen els algoritmes que utilitzen fonts d'informació externes. Dins d'aquesta categoria es proposa un fingerprinting que relaciona un parell de feixos amb la ubicació de l'usuari, i a banda un model d'intel·ligència artificial (IA) que preveu el feix a utilitzar. El fingerprinting ofereix el mateix rendiment. Però, esta solució es molt sensible a errors i requereix considerar tots els casos possibles, fent-la tecnològicament inviable. En canvi, el
[EN] The arrival of the next generation of mobile communication standards, the so-called Fifth Generation (5G), is already a reality. The first commercial networks have begun to be deployed, and they focus on providing higher data rates. However, the 5G standard goes much further from that and aims at providing support to new services which will revolutionise the society. These new services impose a high level of requirements not only in terms of the data traffic speed, but also in terms of very low latency or incredibly large number of simultaneous connections. This wide variety of requirements cannot be technologically supported by the current Fourth Generation (4G) networks, so it became necessary to move forward with a new paradigm for wireless networks. With the promise of large amounts of bandwidth, in the order of GHz, the 5G standard contemplates the use of frequencies in the commonly known Millimetre Wave (mmWave) band. The mmWave band experiences large propagation losses, which are accentuated in blockage events. Regulatory activities worldwide in the mmWave bands attracted the interest of both the industry and the academia. In the last few years, a tremendous number of contributions on mmWave propagation studies and networks have appeared, most of them based on Multiple-Input Multiple-Output (MIMO) solutions. MIMO architectures allow to beamform, which focuses the radiated energy on certain directions of interest called beams. The additional beam gain compensates the high propagation losses, ensuring the viability of the communications in the mmWave band. There is an evident lack of viability studies of mmWave MIMO systems in mobile and highly-dynamic environments, where obstacles may block beams and forcing frequent re-configurations. This Thesis work aims to fill this gap from a practical approach. This Thesis proposes beam management mechanisms utilising the mechanisms and resources offered by the Third Generation Partnership Project (3GPP) 5G radio access standard: 5G New Radio (NR). The practical solutions are based on the efficient use of measurement reports of standardised downlink Reference Signals (RS). In first place, this Thesis provides a thorough state-of-the-art analysis and corroborates the need of adopting beam tracking solutions for mmWave networks. Then, a complete overview of the 5G standard mechanisms that enable beam tracking is given. The NR standard does not define a standardised mechanism for beam tracking, leaving the door open to proposals to carry out such monitoring. Once the technologies have been identified, the Thesis continues with assessing the impact of the beam tracking strategies on the network and link-level performance. The study is focused on individual point-to-point mmWave links in a realistic urban environment. Based on end-to-end network simulations, the Thesis is interested in assessing the beam tracking success ratio and how beam misalignment affects the perceived Signal to Noise plus Interference Ratio (SINR) and user throughput at pedestrian and vehicular speeds. The beam tracking solutions proposed in this Thesis fall into two categories. The first category monitors beams based on measuring and reporting beamformed RS. Regardless of the speed, this beam tracking category provides up to 91 % tracking performance, with little throughput reduction if the beams of interest are measured with a periodicity below 20 ms. Beam tracking in the second category relies on external information sources. Within this category, this Thesis proposes a fingerprinting database relating beams to the user position and a machine learning (ML) model. Fingerprinting beam tracking is technologically viable and provides similar performance levels. However, this solution is very sensitive to errors and requires considering all possible situations. The ML beam tracking, which makes predictions with a 16 % of estimation error for the reference data set.
I want to thank the Spanish Ministry of Education and Professional Formation for funding this Thesis work with an official pre-doctoral contract grant.
Herranz Claveras, C. (2019). Beam Tracking Strategies for 5G New Radio Networks Operating in the Millimetre Wave Bands [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/130845
TESIS

Dans ce travail de thèse, on se proposait d’explorer les synergies inhérentes entre services de radiolocalisation et de communication au sein de systèmes sans fil en bandes millimétriques (mm-Wave). Ces derniers sont actuellement pressentis pour couvrir les besoins de la cinquième génération (5G) de réseaux en termes de débits et de charges utiles. Un objectif général consistait alors à montrer comment ces deux fonctions pouvaient s’avérer mutuellement bénéfiques. Tout d'abord, nous avons étudié comment la formation de faisceau (au sens du pré-codage) pouvait contribuer à améliorer les performances de localisation, pour des systèmes multi-porteuses mono- et multi-utilisateurs. En particulier, en s’appuyant sur les performances théoriques de localisation au sens de la limite inférieure de Cramér-Rao (CRLB), nous avons montré qu'il était possible, au moyen d’une formation de faisceau optimisée, d’améliorer l'estimation de variables radio intermédiaires, telles que le délai, l'angle de départ (AoD) et/ou l'angle d'arrivée (AoA) du signal transmis, et in fine, l’estimation de la position et/ou de l’orientation du mobile. Nous avons ensuite considéré le problème de la coexistence des deux services, en envisageant différentes stratégies de budgétisation et de partage de ressources, en temps et en fréquence. A cette occasion, nous avons illustré la présence de compromis non-triviaux entre les performances de localisation et de communication. Nous avons alors proposé des schémas d’allocation de ressources et d’optimisation des faisceaux (en termes de largeur et/ou d’alignement), permettant d’assurer conjointement le meilleur niveau de performances pour les deux services. Nous avons enfin étudié la possibilité d’exploiter explicitement l’information de localisation ainsi acquise, en particulier pour l'accès initial, l’estimation de canaux multi-trajets, ou encore la localisation et la cartographie simultanées (SLAM). En comparaison d’approches plus conventionnelles, nous avons montré comment les performances de telles applications pouvaient être améliorées en termes de précision, de latence et/ou de complexité calculatoire
In this thesis, we investigate different facets of localization and communication services motivated by the symbiosis between them in the millimeter wave (mm-Wave) context for the fifth generation (5G) of wireless communications. Our aim is twofold: first, show that this duality is mutually beneficial to both services, and second, aim towards a co-existence to capture these benefits in order to bring forth mm-Wave as a strong contender for 5G. First, we look into how beamforming, an integral part of mm-Wave communications, can aid in improving the localization performance. After characterizing the localization performance in terms of Cramer-Rao lower bound (CRLB), we show that with optimized beamforming, the estimation of localization variables (delay, angle of departure (AoD) and angle of arrival (AoA)) improves. Then we consider the problem of co-existence of the two services together in the same system while sharing time and frequency resources. We study the non-trivial trade-off between the performances of the two services during this resource budgeting. Then, relying on this trade-off, we design an optimal resource allocation scheme while also optimizing the beamwidth in order to ascertain high performance in terms of both localization and communication. In the same context, we also look into different applications of this improved location information namely initial access, channel estimation and simultaneous localization and communication (SLAM). We show that the related performances improve in terms of quality, latency and/or complexity in comparison to the conventional methods

Les communications basées sur le principe du beamforming imposent de concevoirdes systèmes complexes utilisant un grand nombre de frontaux radiofréquences (RF). Pour le bon fonctionnement du système, chaque élément doit pouvoir être dans sa zone optimale de travail, ce qui doit être aussi le cas pour l’amplificateur de puissance (PA) dont la linéarité et la puissance dépendent de l’adaptation de sortie. L’impédance de charge de l’amplificateur, qui correspond à un des éléments rayonnants du réseau d’antennes, peut subir des variations en fonction de son environnement (TOS) et détériorer les performances globales du système. Au final, le signal distribué sur chaque antenne pour former le faisceau global doit être contrôlé et maîtrisé en phase et en amplitude pour garantir une bonne communication.Les travaux de thèse se situent dans ce contexte et portent sur la recherche denouvelles topologies, ainsi que l’élaboration de blocs élémentaires, pour créer une nouvelle architecture d’amplificateur de puissance robuste à son environnement. L'un des principaux défis est le contrôle de la phase du PA et le maintien de ses performances RF en fonction des variations du processus de fabrication (PVT). Un autre défi consiste à réaliser un PA à haute efficacité, tout en maintenant une très bonne linéarité, ce qui constitue une rupture vis-à-vis du traditionnel compromis à trouver entre le haut rendement et la grande linéarité. Dans de telles conditions, le contrôle de phase du PA constitue un avantage majeur.Une première étape de ses travaux a consisté à proposer une approche globale de laconception du PA dans son environnement et ainsi quantifier l’impact des variations de l’impédance de charge du PA sur ses performances RF (gain, déphasage) en présence d’un réseau d’antennes. Une fois les points sensibles identifiés, plusieurs architectures de PA ont été envisagées pour adresser le ou les problèmes.Une première solution avec un PA autonome a permis d’améliorer la protection vis-àvis des variations de TOS d’antenne. Plusieurs topologies de PA dérivées de cette solution ont ensuite permis d’adresser les nouvelles problématiques de contrôle de la phase et de l’ajustement de la fréquence de fonctionnement. Ces architectures de PA intégrant les nouveaux concepts développés au cours de la thèse ont été implémentées dans les technologies 130nm SiGe et 65nm CMOS-SOI de STMicroelectronics. Les résultats de mesure ont permis de valider l’architecture du PA autonome avec l’ajustement de la fréquence de fonctionnement et la détection de phase et de tension.Cette approche de conception ne se limite pas aux communications 5G et peut êtrefacilement étendue à d'autres fréquences et pour d’autres applications telles que les télécommunications par satellites (SATCOM). Elle n’est pas dépendante du choix de la technologie silicium et peut être utilisée pour d’autres circuits RF tels que les amplificateurs faible bruit
Communications based on beamforming concept require the design of complexsystems using a large number of radio frequency (RF) front-end modules. For theefficient performance of the system, each element must be able to be in its optimalworking zone, which must also be the case for the power amplifier (PA) whose linearity and power depend on the output matching. The amplifier's load impedance, which corresponds to one of the radiating elements of the antenna array, can vary according to its environment (VSWR) and deteriorate the overall performance of the system. In the end, the signal distributed on each antenna to form the global beam must be controlled in phase and amplitude to guarantee the quality of the communication.In this context, the thesis works are related to the new topologies’ research, asthe development of elementary blocks, to create a new power amplifier architecturewhich will be robust to its environment variations. One of the main challenges iscontrolling the phase of the PA and maintaining its RF performances according to themanufacturing process (PVT) variations. Another challenge is to achieve high efficiency PA, while maintaining very good linearity, which is a break with the traditional high efficiency/good linearity trade. In such conditions, the phase control of the PA is a major advantage.A first step in his work consists in proposing a global approach to the PA designin its environment and thus quantifying the impact of the phased-array antennaimpedance variations on the power amplifier RF performances (gain, phase shift). Once the sensitive points have been identified, several PA architectures have been considered to address the problem (s).A first solution with a stand-alone PA improves the robustness against the VSWRantenna variations. Several PA topologies derived from this solution then do it possibleto address the new problems of phase control and fine-tuning of the operatingfrequency. These PA architectures integrating the new concepts developed during thisthesis were implemented in 130nm SiGe and 65nm CMOS-SOI technologies fromSTMicroelectronics. The measurement results validate the architecture of the selfcontained PA with the operating frequency fine-tuning and the phase/voltage detection.This design approach is not limited to 5G communications and can be easilyextended to other frequencies and for other applications such as satellitecommunications (SATCOM). It is not dependent on the silicon technology choice and can be used for other RF circuits such as low noise amplifiers

Providing mobile broadband (MBB) coverage to passengers in planes (and other yingobjects) has been one of the very important requirements by airline industry for sometime. With the emergence of high-capacity wireless network concepts, there is a renewedeort in dening systems based on 5G (also dened as NR, new radio) for air-to-ground(A2G) communication. When passenger planes have been taken into consideration, a fewhundreds of passengers may need to be supported, thus requiring a high-capacity backhaullink. When 5G is used for such A2G link, beamforming and other advanced physicallayer techniques can be used between the ground stations and ying objects to obtainhigh-data rate and reliable new radio link. This masters thesis work includes link andsystem level evaluations of such NR systems when beamforming, large bandwidth, higherantenna gains, coordination between ground stations, etc., are deployed. The evaluationswere carried out in Ericsson's internal state-of-the-art simulators. The study providesbaseline for system design principles for future A2G system based on NR. Also a properpropagation model for A2G communication has been identied and beamforming solutionwith other related techniques that could be used in A2G scenario have been investigated.
Att tillhandahålla mobil bredbandstäckning till passagerare i flygplan (samt andraluftburna föremål) har varit ett viktigt krav från flygsindustrin på senare tid. Medframväxten av trådlösa nätverkskoncept med hög kapacitet har en förnyad insats uppståttför att definiera system baserade på 5G (också kallat New Radio (NR)) för Airplane-to-Ground (A2G) kommunikation. För passagerarplan så kan hundratals passagerare behövatäckning, vilket kräver en backhaul-länk med hög kapacitet. När 5G används för en sådanA2G-länk så kan såkallad lobformning och andra avancerade tekniker användas mellanmarkstationerna och flygande objekt för att erhålla hög datahastighet och tillförlitlig radiolänk. I denna uppsats ingår länk- och systemnivåutvärderningar av sådana NR-systemnär lobformning, stor bandbredd, antenn-amplifikation, koordinering mellan markstationeretc utplaceras. Utvärderingarna genomfördes i Ericssons interna simulatorer. Studienger vägledning för principer inom systemdesign för framtida A2G-system baserat på NR.En lämplig utbredningsmodell för radiovågor för A2G-kommunikation har identifieratsoch en metod för lobformning och andra relaterade tekniker som kan användas i A2Gscenariothar också undersökts.

In-band full duplex is a new duplexing scheme that allows radio nodes to transmit and receive, utilizing the same frequency and time resources. The implementation of in-band full duplex was not feasible in practice, due to the effect of self-interference. But then, advances in signal processing made it possible to reduce this effect. However, the system level performance of in-band full duplex has not been investigated thoroughly.Through computer simulations, we investigate the performance of in-band full duplex, for indoor 5G small cell wireless networks. We examine the performance of in-band full duplex in comparison to dynamic and static time division duplexing. Additionally, we analyze the performance of the duplexing schemes with two interference mitigation techniques, namely beamforming and interference cancellation.Our results indicate that for highly utilized wireless networks, in-band full duplex should be combined with beamforming and interference cancellation, in order to achieve a performance gain over traditional duplexing schemes. Only then, in-band full duplex is considered advantageous, at any network utilization, and any downlink to uplink traffic demand proportion. Our results also suggest that in order to achieve a performance gain with in-band full duplex in both links, the transmit power of the access points should be comparable to the transmit power of the mobile stations.
Inomband hel duplex är en ny typ av duplexmetod som tillåter radionoder att sända och ta emot i samma frekvensoch tidsresurs. Att implementera inomband hel duplex har fram tills nu inte ansetts praktiskt genomförbart till följd av självstörningar. Framsteg inom signalbehandling har dock gjort det möjligt att begränsa denna självstörningseffekt. Emellertid har systemprestanda av inomband hel duplex inte undersökts tillräckligt noga i tidigare verk.Inomband hel duplex och dess prestanda för trådlösa 5G småcellsnätverk inomhus har studerats med hjälp av datasimuleringar och jämförts med dynamisk och statisk tidsdelning. Utöver detta har prestanda för de olika duplexmetoderna med avseende på två tekniker för störningsundertryckning, lobformning och störningseliminering, också undersökts.Våra resultat indikerar att för trådlösa nätverk med högt radioresursutnyttjande bör inomband hel duplex kombineras med lobformning och störningseliminering för att uppnå en prestandavinst jämfört med traditionella duplexmetoder. Bara då kan inomband hel duplex anses vara fördelaktig oberoende av radioresursutnyttjande och andelen upp- och nedlänkstrafik.Resultaten tyder också på att sändareffekten för radioaccesspunkterna bör vara jamförbar med den för mobilenheterna för att en prestandavinst med inomband hel duplex ska kunna uppnås.
Wireless networks, In-band full duplex, Static-time division duplexing, Dynamic-time division duplexing, Interference mitigation techniques, small cell, 5G, mmWave bands, Beamforming, Interference cancellation.

Millimeter wave technologies present an appealing solution for increasing data throughputs as they provide abundant contiguous channel bandwidths as compared to conventional microwave networks. However, millimeter wave technologies suffer from severe propagation limitations and channel impairments such as atmospheric attenuation and absorption, path and penetration losses, and blockage sensitivity. Therefore, phased arrays and beamforming technologies are necessary to compensate for the degraded signal levels due to the aforementioned factors. Namely, base stations and mobile stations utilize directional transmission in the control- and data- plane for an enhanced channel capacity, which results in initial access challenges due to the absence of omni-directional transmission. Here the base station and mobile station are compelled to exhaustively search the entire spatial domain, i.e., in order to determine the best beamforming and combining vectors that yield the highest received signal level.

Overall, a wide range of studies have looked at the initial beam access challenges in millimeter wave networks, with most efforts focusing on iterative and exhaustive search procedures, as well as subarrays schemes and out-of-band beam access. However, these studies suffer from significant signaling overhead attributed to the prolonged beam scanning cycle. In particular, access times here are excessively high that exceed control plane latencies and coherence times. Furthermore, existing work suffer from high computational complexity, power consumption, energy inefficiency, as well as low directivities and high outage probabilities.

In light of the above, the contributions in this dissertation propose fast initial beam access schemes based upon novel meta-heuristic search schemes and beamforming architectures. These contributions include modified search procedures inspired by Nelder Mead, Luss-Jaakola, divide-and-conquer with Tabu search, generalized pattern search, and Hooke Jeeves methods.

Furthermore, efficient and highly-directive access schemes are also developed in this dissertation levering sidelobe emissions, grating lobes and Hamming codes. The overall performance of the proposed solutions here is extensively evaluated versus traditional access schemes and incorporating different channel and path loss models.

Finally, this dissertation addresses the problem of link sensitivity and blockage effects in millimeter wave networks, a subsequent stage to beam access and link association. Nevertheless, a novel link recovery procedure is proposed here that features instantaneous link-recovery and high signal levels.

Actuellement, nous atteignons les limites de la quatrième génération de télécommunications mobiles (4G), notamment en termes de débit disponible et de nombre d’utilisateurs maximal. Une nouvelle génération (5G) est en cours de développement pour répondre à ces besoins. Elle adressera différent cas d’usages : l’internet des objets, les communications à ultra-haut débit ainsi que des applications plus critiques telles que les véhicules autonomes ou la chirurgie à distance. Les exigences étant bien supérieures aux capacités actuelles du réseau, des solutions de rupture ont été proposées.Dans ce travail, nous avons proposé une nouvelle méthode de dimensionnement des systèmes 5G adressant les communications à très haut débit en bande Ka. Différentes architectures permettant de répondre aux spécifications définies ont été étudiées. Nous avons ensuite mis au point une méthode pour comparer leurs performances par rapport à leur consommation énergétique afin de choisir le système le plus adapté. Enfin, nous avons choisi et caractérisé une technologie CMOS avancée afin de réaliser certaines parties de ces systèmes. Nous avons conçu des commutateurs RF et des amplificateurs faible bruit intégrés, adressant les fréquences millimétriques
The limitations of the current mobile telecommunication generation (4G) are actually reached. Indeed, the available data rate and the maximum number of users are no longer sufficient. A new generation (5G) is being developed to cope with these needs. It will target different use cases: internet of things, ultra-high data rate communications, and some critical applications such as autonomous vehicles or remote surgery. The needs are much higher than the existing network capabilities. So, innovative solutions have been proposed.In this thesis work, a new sizing methodology has been developed for 5G systems. It is applied to the Ka-band high data rate communication use case. Several architectures which meet the defined specifications have been studied. A methodology has been implemented to compare their performances depending to their power consumption. Thus, the best suitable architecture for the targeted use case is chosen. Finally, an advanced CMOS technology has been chosen and characterized in order to realize parts of the 5G system. RF switches and low noise amplifier operating in the Ka-band have been designed

L’objectif principal de ce travail est d’analyser analytiquement les performances de la formation de faisceaux hybrides (HBF) dans des systèmes MIMO massifs à ondes millimétriques (mmWave), de développer des algorithmes HBF de faible complexité et optimiser les systèmes hybrides comprenant des analogiques et numériques pour s’adapter à ces systèmes et enfin de vérifier la validité pratique de ces algorithmes. Le système MIMO massif fournit un gain de transmission élevé, permettent de compenser les pertes importantes en espace libre inhérentes aux transmissions mmWave. D'autre part, l’utilisation de système HBF dans des canaux clairs offre une performance proche de l'efficacité spectrale (SE) par rapport à la formation de faisceau entièrement numérique, avec un coût matériel et une consommation d'énergie inférieurs. Dans cette thèse, nous commençons par définir les conditions pour lesquelles le HBF et la formation de faisceau entièrement numérique peuvent atteindre des performances SE similaires. Ensuite, nous analysons l’écart de performance SE qui se produit entre eux dans des canaux MIMO mmWave. De plus, nous fournissons des modèles analytique SE pour les techniques de base analogiques et HBF dans des canaux MIMO mmWave typiques. Nous considérons ensuite une structure MIMO HBF massive multi-utilisateurs (MU) qui prend en compte plusieurs techniques de traitement de signaux spatiaux de faible complexité afin de fournir un système HBF de faible complexité de mise en oeuvre pour les futurs réseaux de communication sans fil
The main aim of this work is to analytically analyze the performance of Hybrid Beamforming (HBF) in Millimeter Wave (mmWave) massive Multiple Input Multiple Output (MIMO) systems, to develop low complexity HBF algorithms to adapt with such systems and finally to verify the practical validity of these algorithms. The massive MIMO antenna array provides high transmit gain overcoming the severe path-loss limitation of the mm Wave systems. On the other had applying HBF in sparse channels achieves close Spectral Efficiency (SE) perfonnance compared to the full digital beamforming, however with lower hardware cost and power consumption. In this thesis we start by defining the conditions for which bath the HBF and full digital beamfonning can achieve exactly similar SE performance. Then, we analyze the SE perfonnance gap that arise between them in sparse mmWave MIMO channels. Moreover, we provide closed form SE models for basic analog and HBF techniques in typical mmWave MIMO channels. Later we consider a Multi User (MU) massive MIMO HBF framework that considers multiple spatial signal processing techniques for the analog domain processing, digital domain processing, power allocation and users scheduling. We develop low complexity algorithms for such framework in order to provide a low complexity practical HBF framework for future wireless communication networks that can cope with the challenges of mm Wave channels

L’augmentation exponentielle des équipements d’utilisateurs sans fil (UEs) et des services des réseaux associés aux déploiements actuels de cinquième génération (5G) pose plusieurs défis de conception sans précédent qui doivent être résolus avec l’avènement des futurs réseaux au-delà de la 5G. Plus précisément, la demande croissante de débits de données élevés ainsi que la nécessité de desservir un grand nombre d’appareils hétérogènes, allant des téléphones mobiles classiques aux objets connectés formant l’internet des objets (IoT), motivent l’étude de nouveaux schémas de traitement et de transmission du signal. À cet égard, les sorties multiples massives à entrées multiples (massive MIMO) sont une technologie d’accès bien établie, qui permet de desservir plusieurs dizaines d’UEs en utilisant lesmêmes ressources temps-fréquence au moyen de techniques de formation de faisceau hautement directionnelles. Cependant, le massive MIMO présente des problèmes d’évolutivité dans les scénarios accès massif où la population UE est composée d’un grand nombre de périphériques hétérogènes. En effet, si la disponibilité d’un grand nombre d’antennes dans les émetteurs-récepteurs massive MIMO apporte des gains de performances substantiels, elle augmente également considérablement la surcharge et la complexité du système. Plus précisément, la dimensionnalité élevée des canaux nécessite l’allocation de ressources temps-fréquence considérables pour acquérir les informations d’état de canal (CSI) et se traduit par de grandes opérations matricielles pour construire des précodeurs/décodeurs. De plus, dans le contexte de communications de multidiffusion comme, par exemple, la mise en cache périphérique sans fil ou la diffusion de messages critiques pour la mission, les techniques d’antennes multiples conventionnelles présentent des taux de disparition lorsque le nombre d’UEs augmente même dans le régime d’antenne massif. Enfin, le grand nombre de chaînes de radiofréquences (RF) associées aux émetteurs-récepteurs massive MIMO, qui sont utilisés pour contrer les pertes de propagation dans des environnements difficiles tels que, par exemple, à des fréquences d’ondes millimétriques (mmWave), se heurte au budget de puissance limité des appareils IoT. Dans cette thèse, nous proposons de nouvelles méthodes à antennes multiples évolutives pour l’amélioration des performances dans les scénarios d’intérêt susmentionnés. Plus précisément, nous décrivons le rôle fondamental joué par le CSI statistique qui peut être mis à profit pour réduire à la fois la complexité et la surcharge pour l’acquisition de CSI et pour la suppression des interférences multi-utilisateurs. En effet, lorsque les UEs sont équipés au moins de duex antennes, leurs propriétés de sélectivité spatiale peuvent être exploitées pour imposer une orthogonalité statistique parmi les transmissions interférentes. De plus, nous exploitons les communications de périphérique à périphérique (D2D) pour surmonter le goulot d’étranglement fondamental de la multidiffusion conventionnelle. En particulier, nous exploitons les capacités de précodage d’un émetteur multi-antennes pour sélectionner soigneusement les UEs dans des conditions de canal favorables, qui à leur tour agissent comme des relais opportunistes et retransmettent le message via les liaisons D2D. Enfin, dans le cadre des communications mmWave, nous explorons les avantages des surfaces intelligentes reconfigurables (RISs) récemment proposées, qui sont un catalyseur clé de l’innovation grâce à leur structure intrinsèquement passive qui permet de contrôler l’environnement de propagation et de contrer efficacement les pertes de propagation. En particulier, nous utilisons la formation de faisceaux passive au niveau du RIS, c’est-à-dire sans aucune dépense d’énergie significative, ainsi que la formation de faisceaux active conventionnelle au niveau de l’émetteur pour augmenter considérablement les performances du réseau
The exponential increase of wireless user equipments (UEs) and network services associated with current 5G deployments poses several unprecedented design challenges that need to be addressed with the advent of future beyond-5G networks and novel signal processing and transmission schemes. In this regard, massive MIMO is a well-established access technology, which allows to serve many tens of UEs using the same time-frequency resources. However, massive MIMO exhibits scalability issues in massive access scenarios where the UE population is composed of a large number of heterogeneous devices. In this thesis, we propose novel scalable multiple antenna methods for performance enhancement in several scenarios of interest. Specifically, we describe the fundamental role played by statistical channel state information (CSI) that can be leveraged for reduction of both complexity and overhead for CSI acquisition, and for multiuser interference suppression. Moreover, we exploit device-to-device communications to overcome the fundamental bottleneck of conventional multicasting. Lastly, in the context of millimiter wave communications, we explore the benefits of the recently proposed reconfigurable intelligent surfaces (RISs). Thanks to their inherently passive structure, RISs allow to control the propagation environment and effectively counteract propagation losses and substantially increase the network performance

Providing a broadband access anytime and anywhere is one of the visions of the future 5G network. However, deploying a reliable network connection in remote/rural areas has been a challenging task because of its wide area that needed to be covered and a low density of user compared to urban area. Different geography and traffic condition may need different system solution. In this thesis, we analyze several solutions to providing a broadband access network in practical remote and rural area in Banten, Indonesia: Leuwidamar (remote) and Panimbang (rural). Two approaches are discussed, first one is fulfilling futuristic traffic demand by having LTE System, and the second one is by having 5G System. We included three key technology components in a 5G network: occupying wide bandwidth in high frequency, applying UE-Specific Beamforming, and implementing Carrier Aggregation (CA) scheme. We also account a rain attenuation when deploying a network in high operating frequency, since Indonesia has a high rain rate thus it is important to be considered. We compared five cases of solution: Case 1 is Single Carrier (SC) LTE 1.8 GHz system; Case 2 is Carrier Aggregation (CA) LTE 1.8 GHz + 2.6 GHz; Case 3 is SC 5G 15GHz; Case 4 is SC 5G 28 GHz; Case 5 is CA LTE 1.8 GHz + 5G 15 GHz. Basedon the evaluation, in Leuwidamar scenario, Case 5 gives us the least number of BS needed in order to meet the futuristic requirement with only 1.6 x densification from the current network. In Panimbang, the least number of BS neededis offered by two cases, Case 3 and Case 5 without any additional BS needed(1x densification). However, the solution with the lowest energy consumption for both area is Case 3. This is due to the fact that the carrier aggregation scenario needs additional power to generate the second system. Furthermore, if we introduce cell DTX ability in the 5G network, the Case 3 can give us impressive amount of energy saving, with 97% saving for Leuwidamar and 94% saving for Panimbang, compared to Case 1 solution without any DTX Capability.
Att tillhandahålla bredbandsanslutning när som helst och var som helst är en av visionerna för det framtida 5G-nätverket. Att använda en tillförlitlig nätverksanslutning i avlägsna- eller landsbygdsområden har dock varit en utmanande uppgift på grund av det breda området som måste täckas och den låga täthetenav användare jämfört med stadsområden. Olika geografiska förhållanden och trafikförhållanden kan behöva olika systemlösningar. I denna avhandling analyserarvi flera lösningar för att tillhandahåller ett bredbandsnätverk i verkligt avlägset eller landsbygdsområde i Banten, Indonesien: Leuwidamar (avlägset) och Panimbang (landsbygd). Två strategier diskuteras, den första uppfyller framtida trafikbehov genom att ha LTE-system och den andra är genom att ha5G System. Vi inkluderade tre viktiga teknikkomponenter i 5G-nätverk: bredbandbredd och hög frekvens, tillämpar UE-specifik strålformning och implementeringav carrier aggregation (CA). Vi redovisar också en dämpning av regn när nätverket används i hög bärvågsfrekvens, eftersom Indonesien har en hög regnhastighet och det är viktigt att överväga. Vi jämförde fem fall av lösning:Fall 1 är Single Carrier (SC) eller Enkelbärare LTE 1.8 GHz system; Fall 2 är bärareaggregation (CA) LTE 1,8 GHz + 2.6 GHz; Fall 3 är SC 5G 15 GHz;Fall 4 är SC 5G 28 GHz; Fall 5 är CA LTE 1.8 GHz + 5G 15 GHz. Baserat på utvärderingen, i Leuwidamar-scenariot,ger Fall 5 oss det minsta antalet BSsom behövs för att möta det futuristiska kravet med endast 1.6 gångers förtätning från nuvarande nätverk. I Panimbang erbjuds det minsta antalet BS somkrävs i två fall, fall 3 och fall 5 utan ytterligare BS behövs (1 gångers förtätning). Lösningen med den lägsta energiförbrukningen för båda områdena är fall 3. Detta beror på att bäraraggregations scenariot behöver ytterligare effekt för att generera det andra systemet. Om vi introducerar cell DTX-funktionen i 5G-nätverket kan Fall 3 ge oss en imponerande energibesparing, med 97% minskning för Leuwidamar och 94% för Panimbang jämfört med Fall 1-lösning utan DTX-funktion.

La formation de voies est une méthode de traitement du signal utilisée dans les réseaux d'antennes, permettant de favoriser certaines directions d'émission ou de réception des signaux par commande des différents éléments.Dans les réseaux de téléphonie mobile, elle peut permettre notamment de réduire l'interférence au niveau d'une station de base.Son implémentation entièrement numérique se heurte à des limitations de consommation énergétique et de coût quand on augmente le nombre d'antennes.En réponse à ces problèmes, l'implémentation hybride analogique-numérique peut être utilisée afin de réduire le nombre de chaînes radio-fréquences (RF) et de convertisseurs analogique-numérique.Dans cette implémentation, l'étage analogique peut être réalisé en utilisant différents types de dispositifs (déphaseurs, amplificateur/atténuateurs, impédances variables) et avec une connectivité variable avec le réseau d'antennes.Toutefois, si on souhaite garder une circuiterie RF simple en utilisant des déphaseurs uniquement (phase-only) afin de régler les poids du formateur de voies analogique, le problème d'optimisation de ces poids devient non-convexe.Les travaux actuels sur les réseaux de petites cellules montrent que l'interférence entre stations de base est un des facteurs limitant la couverture et le débit.De plus, dans une implémentation entièrement numérique, la présence de forts bloqueurs mène à la saturation ou à une désensibilisation des convertisseurs analogique-numérique.L'objet de ces travaux de thèse portent sur l'étude de la formation de voies avec une implémentation hybride phase-only, ainsi que de proposer un algorithme de calcul des matrices de formation de voies, afin de réduire les interférences en réception au niveau d'une petite cellule.Après une description du contexte et de l'état de l'art, on a en préliminaire proposé une caractérisation de l'interférence en utilisant un angle algébrique entre vecteurs des signaux utiles, et vecteurs des signaux interférants, ce qui nous a permis d'obtenir une borne inférieure sur les performances du formateur de voies optimal en RSIB.On a proposé ensuite une solution sous-optimale de formation de voies hybride phase-only, qui dans un modèle à résolution numérique infinie, a de faible pertes par rapport à une solution avec des poids variable en module et phase.Dans un second lieu, on a introduit un modèle de convertisseur analogique numérique dans la chaîne de réception, ce qui nous a permis de mettre en évidence les limitations de la première approche ainsi que de l'implémentation entièrement numérique en présence de forts bloqueurs.On a ensuite proposé un algorithme d'optimisation de l'étage analogique, qui repose sur une méthode de relaxation semi-définie.Cet algorithme montre des performances en RSIB et en somme-capacité proches de celles du benchmark à deux degrés de liberté module et phase.En comparaison, les solutions testées de l'état de l'art qui utilisent des fonction coût non-convexe restent dépendantes de l'initialisation et donnent des performances inférieures
Beamforming is a signal processing method used in antenna arrays, allowing to enhance directions of emission or reception of signals by controlling the different elements.In mobile networks especially, it allows interference reduction in base stations.Its full digital impementation is limited by energy consumption and cost when increasing the number of antennas.As a response, hybrid analog-digital implementation could be used to reduce the number of radiofrequency (RF) chains as well as the number of analog-to-digital converters.In this implementation, the analog stage could be realised using different types of devices (phase shifters, amlifiers/attenuators, variable impedances) and with a variable connectivity to the antenna array.Nevertheless, if we want to keep a simple RF circuitry by using phase shifters only to tune the analog beamformer, the problem of optimising these weights becomes non-convex.The current works on small cell networks show that the interference between base station is one of the limiting factors of the coverage and the datarate.Furthermore, in a full digital implementation, the presence of strong blockers leads to analog-to-digital converters saturation or desensitization.The purpose of this work is the study of hybrid beamforming with phase-only implementation, as well as to propose an algorithm to compute the beamforming matrices, to reduce the received interference in a small cell.After a description and a state-of-the-art, we preliminarily proposed an interference characterization using an algebraic angle between the signals of interest vectors and the interference vectors, which allowed us to obtain a lower bound on the SINR performance of the optimal beamformer.We have then proposed a sub-optimal solution of hybrid phase-only beamforming, which when using an infinite resolution digitization, has a low loss as compared to a solution using modulus and phase.Secondly, we introduced an analog-to-digital converter model, which allowed us to bring out the limitations of the first appproach as well as of the full digital implementation, in the presence of strong blockers.Afterwards, we proposed an optimisation algorithm of the analog stage, based on a semidefinite relaxation.The peroformance of this algorithm, in terms of SINR and sumrate are close to the benchmark with full degree of freedom, modulus and phase.In comparison, the performance state-of-the-art tested solutions using non-convex cost function are lower and depend on initialization point

Uno dei temi più recenti nel campo delle telecomunicazioni è l'IoT. Tale termine viene utilizzato per rappresentare uno scenario nel quale non solo le persone, con i propri dispositivi personali, ma anche gli oggetti che le circondano saranno connessi alla rete con lo scopo di scambiarsi informazioni di diversa natura. Il numero sempre più crescente di dispositivi connessi in rete, porterà ad una richiesta maggiore in termini di capacità di canale e velocità di trasmissione. La risposta tecnologica a tali esigenze sarà data dall’avvento del 5G, le cui tecnologie chiave saranno: massive MIMO, small cells e l'utilizzo di onde millimetriche. Nel corso del tempo la crescita delle vendite di smartphone e di dispositivi mobili in grado di sfruttare la localizzazione per ottenere servizi, ha fatto sì che la ricerca in questo campo aumentasse esponenzialmente. L'informazione sulla posizione viene utilizzata infatti in differenti ambiti, si passa dalla tradizionale navigazione verso la meta desiderata al geomarketing, dai servizi legati alle chiamate di emergenza a quelli di logistica indoor per industrie. Data quindi l'importanza del processo di positioning, l'obiettivo di questa tesi è quello di ottenere la stima sulla posizione e sulla traiettoria percorsa da un utente che si muove in un ambiente indoor, sfruttando l'infrastruttura dedicata alla comunicazione che verrà a crearsi con l'avvento del 5G, permettendo quindi un abbattimento dei costi. Per fare ciò è stato implementato un algoritmo basato sui filtri EKF, nel quale il sistema analizzato presenta in ricezione un array di antenne, mentre in trasmissione è stato effettuato un confronto tra due casi: singola antenna ed array. Lo studio di entrambe le situazioni permette di evidenziare, quindi, i vantaggi ottenuti dall’utilizzo di sistemi multi antenna. Inoltre sono stati analizzati altri elementi chiave che determinano la precisione, quali geometria del sistema, posizionamento del ricevitore e frequenza operativa.

Mestrado em Engenharia Eletrónica e Telecomunicações
Com o crescimento dos dispositivos de comunicações móveis e de serviços de banda larga, os requisitos do sistema tornam-se cada vez mais exigentes. O LTE-Advanced apresenta um melhoramento progressivo relativamente ao seu antecessor LTE, introduzindo redes heterogéneas, que têm vindo provar constituir uma solução sólida para melhorar tanto a capacidade, como a cobertura da rede. Quanto à implementação do 5G, será necessário um salto disruptivo na tecnologia, que permita novas possibilidades, tal como a de conectar pessoas e coisas. Para tornar isso possível, é necessário investigar e testar novas tecnologias. MIMO massivo e comunicações em ondas milimétricas são algumas das tecnologias que têm vindo a demonstrar resultados com potencial, tais como o aumento da capacidade e da eficiência espectral. No entanto, devido às características da propagação de ondas milimétricas, a existência de cenários com redes heterogéneas ultradensas é uma possibilidade. Ao se considerar cenários ultradensos com um número massivo de utilizadores, o sistema fica limitado devido à interferência, mesmo operando na banda das ondas milimétricas. Como tal, é de extrema importância o desenvolvimento de técnicas que mitiguem essa interferência. Nesta dissertação, propõe-se uma arquitetura de baixa complexidade para um transmissor e um recetor a operarem no sentido ascendente, numa rede heterogénea ultradensa. Nesta arquitetura são aplicadas tecnologias como MIMO massivo, ondas milimétricas e técnicas de beamforming, com o intuito de mitigar a interferência entre células. Usando a probabilidade de erro de bit como métrica de performance, os resultados mostram que a arquitetura proposta consegue remover a interferência eficientemente, alcançando resultados próximos de uma arquitetura completamente digital.
With the constant increase of mobile communication devices and broadband services, the system requirements are getting more demanding. Long Term Evolution (LTE) Advanced comes as a progressive enhancement to its predecessor LTE, introducing heterogeneous networks (HetNets), which have proven to be great solutions to improve both capacity and coverage. As for 5G, it takes more of a disruptive step, enabling new possibilities, such as connecting people and things. To enable such a step, new technologies and techniques need to be researched and tested. Massive Multiple-Input Multiple-Output (MIMO) and millimeter wave (mmWave) communications are two of such technologies, as they show promising results such as increased capacity and spectral efficiency. However, due to the mmWave propagation constraints, the existence of ultra-dense HetNet scenarios may be a possibility. When considering ultra-dense scenarios with a massive number of users, the system becomes interference-limited, even using mmWave band. As such, the design of interference mitigation techniques that deal with both inter and intra-tier interference are of the utmost importance. In this dissertation, a low complexity analog-digital hybrid architecture for both the transmitter and receiver in the uplink scenario is proposed. It is designed for an ultra-dense heterogeneous system and employing massive MIMO, mmWave and beamforming techniques in order to mitigate both intra- and inter-tier interference. Considering the Bit Error Rate (BER) as the performance metric, the results show that the proposed architecture efficiently removes both inter- and intra-tier interferences, achieving a result close to its fully digital counterpart.

碩士
逢甲大學
通訊工程學系
106
Along with the advancement of the 5G communication systems, the demand for data transmission keeps increasing. In recent years, many different methods have been put forward to achieve this goal. This thesis presents a large-scale multi input multiple output (Massive MIMO) antenna system using the hybrid beamforming technology in the heterogeneous wireless access network (Heterogeneous Cloud Radio Access Network). Such architecture can effectively increase the overall spectral efficiency to achieve the demand of the 5G system. In this thesis, a hybrid precoding (Hybrid Precoding) based on zero kernel space (Null-space) is used to eliminate the interfered users, to improve the spectral efficiency of the system. The proposed method can get better spectral efficiency when the user's antenna number is increased comparing to the traditional precoding. Furthermore, adopt the frequency quadrature amplitude modulation (FQAM) signaling in the considered system, and its transmission rate and error rate are also studied. As shown by the numerical results, the proposed system provides better transmission rate and lower error rate.

博士
國立中正大學
電機工程研究所
107
In this dissertation, the RF impairment effect on the beamforming performance and develop a massive integrated antennas-transceivers system design technique for 5G are presented. Four subjects have been investigated: 1) the RF-impairment beamforming model, 2) a 3.5GHz and a 50GHz integrated antenna-transceiver design, 3) built-in self-test (BIST) in phased array, and 4) CMOS Butler beamformer. On the RF-impairment beamforming model, an accurate microwave network model is derived for beamforming characteristic prediction, which can include the multi-channel RF transceiver impairment effect. The impairment, including the antenna mutual coupling, phase center uncertainty, element location, and inter-stage impedance mismatch, is precisely included. The model is based on scattering network, and each type of circuit, such as RF transceiver, radio distribution circuits, and antenna array, can be described. The predicted results show that the beam performances are affected by different influences with different level of impact. he phase center uncertainty and the mutual coupling are the two strongest impact for beamforming. On the integrated antenna-transceiver design, a 3.5-GHz 64-element 16 channel and a 50-GHz 4 element 4-channel transmit beamforming frontend modules are developed in this dissertation. A 3.5-GHz prototype has been developed for demonstration, and the complete design technique of a microwave beamforming transmitter is presented. The design procedures are derived and the integrated system measurement setup has been developed successfully. This prototype has distinct features of the operation-band scalability, array dimension extendibility, and beamforming flexibility, which composed of a 64-element bow-tie array antenna, 16 RF transmit channels, 16 injection-locked LOs, a DC power management unit, a status monitoring and control unit, and a developer operation panel. The measurement results demonstrate that EIRP is 40 dBm and the 3-dB beamwidth is 7˚, with spatial beam steering range of 120˚. Otherwise, a 50-GHz PCB-antenna-CMOS-transceiver module is designed for future 5G applications in millimeter-wave band. This circuit consists of four integrated transceiver chips and a four-element antenna array, flip-chip process is used for CMOS and PCB bonding. The angled dipole antenna is design as the element in array, which has 0.4 dBi gain, and the integrated antenna-transceiver module has 70˚ beam steering range. On the built-in self-test (BIST) design, an accurate phasor-sum method is proposed for the built-in detection of relative phase and amplitude between neighboring RF chains in phased array systems. The phasor sum of two RF signals provides a distinct amplitude-phase trigonometric relationship, from which the relative phase can be determined solely by the signal amplitudes. However, the amplitude distortion, attributed from the impedance mismatch or nonlinearity of detection circuits and devices, introduces considerable phase error. In our proposed method, the amplitude distortion error is first eliminated and then the phase error is significantly reduced. On the CMOS Butler beamformer, a 60-GHz CMOS beamformer for sixteen conical-beam generation in both azimuth and elevation dimensions from planar array antennas is presented. The conventional 4-way Butler matrix allows four beams generated only in one dimension. For two-dimensional generation, two stacks of 4-way Butler matrix are composed to generate 16 beams in azimuth and elevation dimensions. The 16-beam beamformer was implemented in 0.18-μm CMOS technology, where the chip size is 2×2 mm2. The progressive phase error between adjacent output ports is 17.6° at 60 GHz, which will result in 3° main-beam direction error. The insertion loss of one path is 4.7 dB. The overall array gain is 6.5 to 8.4dB. The overall performances demonstrate the important techniques for 5G beamforming in microwave and millimeter-wave bands. The prediction model provides an evaluation methodology for RF hardware impairment influences. The 3.5-GHz and 50-GHz integrated antenna-transceiver designs are developed for microwave and millimeter-wave massive antenna array. And the BIST circuit provides an enhanced detection methodology for phased array beamforming. Finally, the 16-beam Butler beamformer presents a two dimensional beamforming architecture in 60 GHz

Today's Long Term Evolution Advanced (LTE-A) networks cannot support the exponential growth in mobile traffic forecast for the next decade. By 2020, according to Ericsson, 6 billion mobile subscribers worldwide are projected to generate 46 exabytes of mobile data traffic monthly from 24 billion connected devices, smartphones and short-range Internet of Things (IoT) devices being the key prosumers. In response, 5G networks are foreseen to markedly outperform legacy 4G systems. Triggered by the International Telecommunication Union (ITU) under the IMT-2020 network initiative, 5G will support three broad categories of use cases: enhanced mobile broadband (eMBB) for multi-Gbps data rate applications; ultra-reliable and low latency communications (URLLC) for critical scenarios; and massive machine type communications (mMTC) for massive connectivity. Among the several technology enablers being explored for 5G, millimeter-wave (mmWave) communication, massive MIMO antenna arrays and ultra-dense small cell networks (UDNs) feature as the dominant technologies. These technologies in synergy are anticipated to provide the 1000_ capacity increase for 5G networks (relative to 4G) through the combined impact of large additional bandwidth, spectral efficiency (SE) enhancement and high frequency reuse, respectively. However, although these technologies can pave the way towards gigabit wireless, there are still several challenges to solve in terms of how we can fully harness the available bandwidth efficiently through appropriate beamforming and channel modeling approaches. In this thesis, we investigate the system performance enhancements realizable with mmWave massive MIMO in 5G UDN and cellular infrastructure-to-everything (C-I2X) application scenarios involving pedestrian and vehicular users. As a critical component of the system-level simulation approach adopted in this thesis, we implemented 3D channel models for the accurate characterization of the wireless channels in these scenarios and for realistic performance evaluation. To address the hardware cost, complexity and power consumption of the massive MIMO architectures, we propose a novel generalized framework for hybrid beamforming (HBF) array structures. The generalized model reveals the opportunities that can be harnessed with the overlapped subarray structures for a balanced trade-o_ between SE and energy efficiently (EE) of 5G networks. The key results in this investigation show that mmWave massive MIMO can deliver multi-Gbps rates for 5G whilst maintaining energy-efficient operation of the network.
As redes LTE-A atuais não são capazes de suportar o crescimento exponencial de tráfego que está previsto para a próxima década. De acordo com a previsão da Ericsson, espera-se que em 2020, a nível global, 6 mil milhões de subscritores venham a gerar mensalmente 46 exa bytes de tráfego de dados a partir de 24 mil milhões de dispositivos ligados à rede móvel, sendo os telefones inteligentes e dispositivos IoT de curto alcance os principais responsáveis por tal nível de tráfego. Em resposta a esta exigência, espera-se que as redes de 5a geração (5G) tenham um desempenho substancialmente superior às redes de 4a geração (4G) atuais. Desencadeado pelo UIT (União Internacional das Telecomunicações) no âmbito da iniciativa IMT-2020, o 5G irá suportar três grandes tipos de utilizações: banda larga móvel capaz de suportar aplicações com débitos na ordem de vários Gbps; comunicações de baixa latência e alta fiabilidade indispensáveis em cenários de emergência; comunicações massivas máquina-a-máquina para conectividade generalizada. Entre as várias tecnologias capacitadoras que estão a ser exploradas pelo 5G, as comunicações através de ondas milimétricas, os agregados MIMO massivo e as redes celulares ultradensas (RUD) apresentam-se como sendo as tecnologias fundamentais. Antecipa-se que o conjunto destas tecnologias venha a fornecer às redes 5G um aumento de capacidade de 1000x através da utilização de maiores larguras de banda, melhoria da eficiência espectral, e elevada reutilização de frequências respetivamente. Embora estas tecnologias possam abrir caminho para as redes sem fios com débitos na ordem dos gigabits, existem ainda vários desafios que têm que ser resolvidos para que seja possível aproveitar totalmente a largura de banda disponível de maneira eficiente utilizando abordagens de formatação de feixe e de modelação de canal adequadas. Nesta tese investigamos a melhoria de desempenho do sistema conseguida através da utilização de ondas milimétricas e agregados MIMO massivo em cenários de redes celulares ultradensas de 5a geração e em cenários 'infraestrutura celular-para-qualquer coisa' (do inglês: cellular infrastructure-to-everything) envolvendo utilizadores pedestres e veiculares. Como um componente fundamental das simulações de sistema utilizadas nesta tese é o canal de propagação, implementamos modelos de canal tridimensional (3D) para caracterizar de forma precisa o canal de propagação nestes cenários e assim conseguir uma avaliação de desempenho mais condizente com a realidade. Para resolver os problemas associados ao custo do equipamento, complexidade e consumo de energia das arquiteturas MIMO massivo, propomos um modelo inovador de agregados com formatação de feixe híbrida. Este modelo genérico revela as oportunidades que podem ser aproveitadas através da sobreposição de sub-agregados no sentido de obter um compromisso equilibrado entre eficiência espectral (ES) e eficiência energética (EE) nas redes 5G. Os principais resultados desta investigação mostram que a utilização conjunta de ondas milimétricas e de agregados MIMO massivo possibilita a obtenção, em simultâneo, de taxas de transmissão na ordem de vários Gbps e a operação de rede de forma energeticamente eficiente.
Programa Doutoral em Telecomunicações

Nos últimos anos o acentuado desenvolvimento das comunicações sem fios associado ao acréscimo exponencial de utilizadores tem levado a um aumento significativo de tráfego de dados consumidos. Atualmente encontra-se em desenvolvimento uma nova geração de comunicações sem fios, 5G, que pretende não só suportar esse aumento mas também aumentar a velocidade de transferência de dados e reduzir custos, entre outros. O espectro alocado para esta nova rede de comunicações está localizado em parte na banda de ondas milimétricas permitindo comunicações de alta velocidade e alto volume de tráfego de dados. No entanto, a utilização de sinais nesta gama de frequências apresenta fragilidades como a dificuldade em penetrar edifícios e a facilidade com que são absorvidos pela atmosfera. Para reduzir essas adversidades, as antenas adaptativas estão a ser adotadas nos sistemas de comunicação 5G. Nesse sentido, esta dissertação apresenta a conceção de um modulador vetorial para a frequência de 28 GHz com o objetivo de ser implementado numa rede de alimentação de uma antena adaptativa de modo a controlar o feixe de radiação. Este modulador é constituído por três blocos fundamentais: acoplador híbrido de 90 , atenuador do tipo-reflexão e divisor de Wilkinson. Ao longo deste documento é apresentado o dimensionamento de cada um desses blocos, bem como as suas respetivas simulações. Em seguida estes são agrupados num único bloco, obtendo-se assim o modulador vetorial, voltando a ser simulado como um bloco funcional. Após realizadas todas as simulações, o modulador é construído em circuito sendo caracterizado em laboratório. Os resultados obtidos permitem concluir a viabilidade do uso desta arquitetura de modulador vetorial para a banda em torno dos 28 GHz.
In recent years, the considerable development of wireless communications associated with the exponential growth of the number of users has led to a significant increase of consumed data traffic. A new generation of wireless communications, 5G, is now under development, which aims not only to support the growth of data traffic but also to improve data throughput and reduce costs, among others. The spectrum allocated for 5G wireless communication systems is mainly located in the millimeter-wave frequency bands, where a considerable amount of spectrum is available for allowing high speed communications and high data traffic volume. However, signals at these frequencies suffer large path-loss and high penetration loss. To get over these issues, adaptive antennas are taken into account, improving the performance of the overall communication system. In this dissertation a vector modulator is presented, designed to operate in the Ka band at 28 GHz, aiming to be implemented in the feeding of each element of an adaptive antenna array, in order to steer and shape its radiation pattern. This modulator consists in three fundamental blocks: a 90 hybrid coupler, a reflection-type attenuator and a Wilkinson divider. It is presented the simulation process of each one of these blocks, being then combined into a single block and simulated as a single circuit. After the whole simulation process, the vector modulator is built in printed circuit being characterized in laboratory. The obtained results allow us to conclude the feasibility of using this vector modulator architecture for the band around 28 GHz.
Mestrado em Engenharia Eletrónica e Telecomunicações

碩士
國立交通大學
光電系統研究所
107
With the rapid development of technology, the handle equipment become more common gradually, people start to use application of digital entertainment, or even virtual reality, the demand for high definition image, immediacy, and data access with cloud process techniques would increase sharply, data transmission also grows up exponentially, it would lead to demand exceed supply on the 4G wireless communication. To solve the insufficient problems, countries around the world are dedicated to the development of 5G of wireless communication research. In order to achieve the 5G target of high channel capacity, there are some advanced techniques, including massive MIMO, millimeter wave, beamforming, carrier aggregation and so on. Although there are large bandwidth in the high frequency bands, however, because of big gap between frequency bands, if every band equipped with one system like the traditional concept, it would lead to more component and energy cost, and it must be a serious problem on 5G. To resolve the problem, this article provides combination of carrier aggregation and massive MIMO. To verify this concept, we use MATLAB® software to simulate the real transmission and reception of process and show the data by capacity. By this concept, we could transmit more carriers’ signals at the same time to improve data rate and channel capacity in the same transmission system through rewriting and deriving new algorithm, name as “no delay compensation algorithm”. However, there are some problems which we need to overcome when we use the same transmission system to transmit different frequency signals, including spatial correlation and delay line problem in phase shifters. So we derives the other new algorithm, name as “delay compensation”. The results show that compared with independent systems, although there are some penalty on the integration system, there are some advantages of cost and power large reduction on the transmission architecture, it forms the tradeoff between cost and capacity. In the future work, we provide a conception that the antenna of hybrid beamforming subarray connect architecture are put separately, by this method, we can solve low SINR problem which caused by high path loss in the edge, and improve data rate transmission.

碩士
國立中正大學
電機工程研究所
104
In this thesis, an S-band 1×16 injection-locked oscillator array and a 1 16 beamforming transmit array based on the LO phase-shifting configuration were designed for the emerging 5G mobile communications. First, the S-band 1×16 oscillator array consists of 16 parallel voltage-controlled oscillators, where the frequency and phase of each oscillator was locked into the frequency and phase of the injecting phased-locked signal. The voltage-controlled oscillator was designed by using high-Q filter as the resonance tank. The resonance frequency was designed at the peak complex-Q factor of the filter. A fast and accurate phase measurement platform was developed, which includes a LabVIEW code, data acquisition card, and oscilloscope. The measurement phase errors, attributed from the oscilloscope and the analog-to-digital converter of the data acquisition card, were examined. On the developed 1×16 oscillator array, the measured resonance frequency tuning range is 2.88-3.19 GHz, equivalent to 10% tuning range. At 3.14 GHz, the measured output power is 5.4 dBm, the measured phase noise is -136.4 dBc/Hz at 1 MHz off carrier, and the phase locking range is 241 . Second, the bow-tie antenna was designed for the 1×16 antenna array, where the multi-finger stub was incorporated for isolation enhancement and the directive finger stub was added for front-to-back ratio improvement. The 1×16 injection-locked oscillators and 1×16 antennas were integrated into a beamforming transmit array. The maximal antenna gain is 14.2 dB, beam steering range is 106 , average direction error is 0.7 , and side-lobe-level error is 4.7 dB.

In multicell coordinated networks where multiple base stations cooperate to jointly combat interference from adjacent cells and fading to receivers, one of the outstanding questions is what is the role of receive antenna and receiver processing. Multiple receive antennas not only enable additional degrees of freedom at each receiver to combat the other-cell interference but also can change the transmitter design because transmitter and receiver beamforming design is often closely coordinated. In this dissertation, we investigate the role of the multiple receive antennas in multicell cooperative systems under different interference conditions. We then present novel non-iterative and iterative coordinated beamforming and precoding algorithms with different receiver processing. We present comprehensive performance comparison of various multicell cooperative systems and explore the feasibility of achieving much higher throughput via hyper-densification of heterogeneous and small cell networks with mandatory multicell cooperation.
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Fifth generation (5G), is being considered as a revolutionary technology in the telecommunication domain whose the challenges are mainly to achieve signal quality and great ability to work with free spectrum in the millimetre waves. Besides, other important innovations are the introduction of a more current architecture and the use of multiple antennas in transmission and reception. Digital communication using multiple input and multiple output (MIMO) wireless links has recently emerged as one of the most significant technical advances in modern communications. MIMO technology is able to offer a large increase in the capacity of these systems, without requiring a considerable increase in bandwidth or power required for transmission. This dissertation presents an overview of theoretical concepts of MIMO systems. With such a system a spatial diversity gain can be obtained by using space-time codes, which simultaneously exploit the spatial domain and the time domain. SISO, SIMO and MISO systems are differentiated by their channel capacity and their configuration in relation to the number of antennas in the transmitter/receiver. To verify the effectiveness of the MIMO systems a comparison between the capacity of SISO and MIMO systems has been performed using the Shannon’s principles. In the MIMO system some variations in the number of antennas arrays have been considered, and the superiority of transmission gains of the MIMO systems have been demonstrated. Combined with millimetre waves (mmWaves) technology, massive MIMO systems, where the number of antennas in the base station and the number of users are large, is a promising solution. SDR implementations have been performed considering a platform with Matlab code applied to MIMO 2x2 Radio and Universal Software Peripheral Radio (USRP). A detailed study was initially conducted to analyze the architecture of the USRP. Complex structures of MIMO systems can be simplified by using mathematical methods implemented in Matlab for the synchronization of the USRP in the receiver side. SISO transmission and reception techniques have been considered to refine the synchronization (with 16-QAM), thus facilitating the future implementation of the MIMO system. OpenAirInterface has been considered for 4G and 5G implementations of actual mobile radio communication systems. Together with the practical MIMO, this type of solution is the starting point for future hardware building blocks involving massive MIMO systems.
A quinta geração (5G) está sendo considerada uma tecnologia revolucionária no setor de telecomunicações, cujos desafios são principalmente a obtenção de qualidade de sinal e grande capacidade de trabalhar com espectro livre nas ondas milimétricas. Além disso, outras inovações importantes são a introdução de uma arquitetura mais atual e o uso de múltiplas antenas em transmissão e recepção. A comunicação digital usando ligaçõe sem fio de múltiplas entradas e múltiplas saídas (MIMO) emergiu recentemente como um dos avanços técnicos mais significativos nas comunicações modernas. A tecnologia MIMO é capaz de oferecer um elevado aumento na capacidade, sem exigir um aumento considerável na largura de banda ou potência transmitida. Esta dissertação apresenta uma visão geral dos conceitos teóricos dos sistemas MIMO. Com esses sistemas, um ganho de diversidade espacial pode ser obtido utilizando códigos espaço-tempo reais. Os sistemas SISO, SIMO e MISO são diferenciados pela capacidade de seus canais e a sua configuração em relação ao número de antenas no emissor/receptor. Para verificar a eficiência dos sistemas MIMO, realizou-se uma comparação entre a capacidade dos sistemas SISO e MIMO utilizado os princípios de Shannon. Nos sistemas MIMO condecideraram-se algumas variações no número de agregados de antenas, e a superioridade dos ganhos de transmissão dos sistemas MIMO foi demonstrada. Combinado com a tecnologia de ondas milimétricas (mmWaves), os sistemas massivos MIMO, onde o número de antenas na estação base e o número de usuários são grandes, são uma solução promissora. As implementações do SDR foram realizadas considerando uma plataforma com código Matlab aplicado aos rádios MIMO 2x2 e Universal Software Peripheral Radio (USRP). Um estudo detalhado foi inicialmente conduzido para analisar a arquitetura da USRP. Estruturas complexas de sistemas MIMO podem ser simplificadas usando métodos matemáticos implementados no Matlab para a sincronização do USRP no lado do receptor. Consideraram-se técnicas de transmissão e recepção SISO para refinar a sincronização (com 16-QAM), facilitando assim a implementação futura do sistema MIMO . Considerou-se o OpenAirInterface para implementações 4G e 5G de sistemas reais de comunicações móveis. Juntamente com o MIMO na pratica, este tipo de solução é o ponto de partida para futuros blocos de construção de hardware envolvendo sistemas MIMO massivos.

This thesis is motivated by the expected implementation of the next generation mobile networks (5G) from 2020, which is being designed with a radical paradigm shift towards millimeter-wave technology (mmWave). Operating in 30--300 GHz frequency band (1--10 mm wavelengths), massive antenna arrays that provide a high angular resolution, while being packed on a small area will be used. Moreover, since the abundant mmWave spectrum is barely occupied, large bandwidth allocation is possible and will enable low-error time estimation. With this high spatiotemporal resolution, mmWave technology readily lends itself to extremely accurate localization that can be harnessed in the network design and optimization, as well as utilized in many modern applications. Localization in 5G is still in early stages, and very little is known about its performance and feasibility. In this thesis, we contribute to the understanding of 5G mmWave localization by focusing on challenges pertaining to this emerging technology. Towards that, we start by considering a conventional cellular system and propose a positioning method under outdoor LOS/NLOS conditions that, although approaches the Cram\'er-Rao lower bound (CRLB), provides accuracy in the order of meters. This shows that conventional systems have limited range of location-aware applications. Next, we focus on mmWave localization in three stages. Firstly, we tackle the initial access (IA) problem, whereby user equipment (UE) attempts to establish a link with a base station (BS). The challenge in this problem stems from the high directivity of mmWave. We investigate two beamforming schemes: directional and random. Subsequently, we address 3D localization beyond IA phase. Devices nowadays have higher computational capabilities and may perform localization in the downlink. However, beamforming on the UE side is sensitive to the device orientation. Thus, we study localization in both the uplink and downlink under multipath propagation and derive the position (PEB) and orientation error bounds (OEB). We also investigate the impact of the number of antennas and the number of beams on these bounds. Finally, the above components assume that the system is synchronized. However, synchronization in communication systems is not usually tight enough for localization. Therefore, we study two-way localization as a means to alleviate the synchronization requirement and investigate two protocols: distributed (DLP) and centralized (CLP). Our results show that random-phase beamforming is more appropriate IA approach in the studied scenarios. We also observe that the uplink and downlink are not equivalent, in that the error bounds scale differently with the number of antennas, and that uplink localization is sensitive to the UE orientation, while downlink is not. Furthermore, we find that NLOS paths generally boost localization. The investigation of the two-way protocols shows that CLP outperforms DLP by a significant margin. We also observe that mmWave localization is mainly limited by angular rather than temporal estimation. In conclusion, we show that mmWave systems are capable of localizing a UE with sub-meter position error, and sub-degree orientation error, which asserts that mmWave will play a central role in communication network optimization and unlock opportunities that were not available in the previous generation.