Comparison of Optimization Methods for Aerial Base Station Placement with Users Mobility

Aerial base stations have been recently considered in the deployment of wireless networks. Finding the optimal position for one or multiple aerial base stations is a complex problem tackled by several works. However, just a few works consider the mobility of the users which makes necessary an online optimization to follow the changes in the scenario where the optimization is performed. This paper deals with the online optimization of an aerial base station placement considering different types of users mobility and three algorithms: a Q-learning technique, a Gradient-based solution and a Greedy-search solution. Our objective is to minimize in an urban environment the path loss of the user at street level with the highest path loss. Simulation results show that the performance of the three methods is similar when a high number of users move randomly and uniformly around the scenario under test. Nevertheless, in some situations when the number of users is reduced or when the users move together in a similar direction, both Gradient and Greedy algorithms present a significantly better performance than the Q-learning method.The work of Danaisy Prado was supported by the H2020 Marie Curie Program, with Project Grant No. 766231 WAVECOMBE - ITN - 2017Prado-Alvarez, D.; Inca-Sanchez, SA.; Martín-Sacristán, D.; Monserrat Del Río, JF. (2019). Comparison of Optimization Methods for Aerial Base Station Placement with Users Mobility. IEEE. 485-489. https://doi.org/10.1109/EuCNC.2019.8802053S48548

Millimeter-wave Human Blockage Model Enhancements for Directional Antennas and Multiple Blockers

[EN] The Third Generation Partnership Project (3GPP) has defined a blockage model as an add-on feature to the channel model used in its evaluations of the physical layer in the 0.5-100 GHz frequency range. This letter focuses on the human body blockage losses in the millimeter-wave band proposing: (i) a new criterion to place the diffraction points over the edges of the blockers that considers the precise position of the blocker with regard to the line-of-sight between the transmitter and the receiver, (ii) a specific criterion to determine which potential blockers, from a set of human bodies present in a certain scenario, should be considered effective blockers given the positions of a transmitter, a receiver, and those bodies, and (iii) a modification of the model to provide more accurate estimations in the case in which several blockers are closely located. The validity of our criteria and the accuracy improvement are confirmed by a set of measurements performed at 30 GHz with directional antennas and with multiple human blockers in different positions.The work of Danaisy Prado-Alvarez was supported by the H2020 Marie Curie Program, with Project Grant No. 766231 WAVECOMBE-ITN-2017. Part of this work has been performed in the framework of the H2020 project 5G-SMART co-funded by the EU. This was also supported by the Spanish Ministry of Science, Innovation and University under the project RTI2018-099880-B-C31. The associate editor coordinating the review of this letter and approving it for publication was J. Choi.Prado-Alvarez, D.; Inca-Sánchez, SA.; Martín-Sacristán, D.; Monserrat Del Río, JF. (2021). Millimeter-wave Human Blockage Model Enhancements for Directional Antennas and Multiple Blockers. IEEE Communications Letters. 25(9):2776-2780. https://doi.org/10.1109/LCOMM.2021.3095617S2776278025

Channel Modelling based on Game Engines Light Physics for mmW in Indoor Scenarios

[EN] The importance of Millimeter Waves (mmW) band for the Fifth Generation (5G) of mobile and wireless communications has motivated a lot of work in mmW channel modelling. In this paper, we assess the use of the light physics modelling of a game engine to calculate the propagation losses at mmW band in an indoor scenario. With that aim, we propose a model that we refer to as Light Intensity Model (LIM), in which a detailed 3D scenario is created in a game engine, radio transmitters and receivers are replaced by light sources and detectors, and the received light intensities are translated to received radio signal power through a translation function which is the key of the model. The results obtained corroborate the validity of the assessed approach to model propagation losses in indoor scenariosThis work has been partially funded by MSCA Project 766231 WaveComBE. This work has also been partially performed in the framework of the H2020 project 5G-SMART co-funded by the EU. The authors would like to acknowledge the contributions of their colleagues. The views expressed are those of the authors and do not necessarily represent the project. The consortium is not liable for any use that may be made of any of the information contained therein.Inca-Sánchez, SA.; Prado-Alvarez, D.; Martín-Sacristán, D.; Monserrat Del Río, JF. (2020). Channel Modelling based on Game Engines Light Physics for mmW in Indoor Scenarios. IEEE. 1-5. https://doi.org/10.23919/EuCAP48036.2020.9135755S1

5G Visualization: The METIS-II Project Approach

[EN] One of the main objectives of the METIS-II project was to enable 5G concepts to reach and convince a wide audience from technology experts to decision makers from non-ICT industries. To achieve this objective, it was necessary to provide easy-to-understand and insightful visualization of 5G. This paper presents the visualization platform developed in the METIS-II project as a joint work of researchers and artists, which is a 3D visualization tool that allows viewers to interact with 5G-enabled scenarios, while permitting simulation driven data to be intuitively evaluated. The platform is a game-based customizable tool that allows a rapid integration of new concepts, allows real-time interaction with remote 5G simulators, and provides a virtual reality-based immersive user experience. As a result, the METIS-II visualization platform has successfully contributed to the dissemination of 5G in different fora and its use will be continued after METIS-II.This work has been performed in the framework of the H2020/5G-PPP project METIS-II cofunded by the EU. The authors wish to thank the rest of METIS-II colleagues who contributed to the development of the METIS-II visualization platform.Martín-Sacristán, D.; Herranz Claveras, C.; Monserrat Del Río, JF.; Szczygiel, A.; Kuruvatti, NP.; Garcia-Roger, D.; Prado-Alvarez, D.... (2018). 5G Visualization: The METIS-II Project Approach. Mobile Information Systems. 1-8. https://doi.org/10.1155/2018/2084950S18Zyda, M. (2005). From visual simulation to virtual reality to games. Computer, 38(9), 25-32. doi:10.1109/mc.2005.297Johnson, C. (2004). Top scientific visualization research problems. IEEE Computer Graphics and Applications, 24(4), 13-17. doi:10.1109/mcg.2004.20Tullberg, H., Popovski, P., Li, Z., Uusitalo, M. A., Hoglund, A., Bulakci, O., … Monserrat, J. F. (2016). The METIS 5G System Concept: Meeting the 5G Requirements. IEEE Communications Magazine, 54(12), 132-139. doi:10.1109/mcom.2016.1500799cmLee, B., Riche, N. H., Isenberg, P., & Carpendale, S. (2015). More Than Telling a Story: Transforming Data into Visually Shared Stories. IEEE Computer Graphics and Applications, 35(5), 84-90. doi:10.1109/mcg.2015.99Yi, J. S., Kang, Y. ah, & Stasko, J. (2007). Toward a Deeper Understanding of the Role of Interaction in Information Visualization. IEEE Transactions on Visualization and Computer Graphics, 13(6), 1224-1231. doi:10.1109/tvcg.2007.70515Campbell, B. D. (2016). Immersive Visualization to Support Scientific Insight. IEEE Computer Graphics and Applications, 36(3), 17-21. doi:10.1109/mcg.2016.6

Study of Feasible Cell-Free Massive MIMO Systems in Realistic Indoor Scenarios

[ES] El uso masivo de las telecomunicaciones exige redes de mayor capacidad. Esta capacidad puede incrementarse de las siguientes maneras: aumentando el número de antenas, el ancho de banda, la eficiencia espectral o una combinación de ellas. En respuesta a esto, han surgido los sistemas masivos MIMO sin celdas. Estos sistemas pretenden ofrecer un servicio ubicuo y fiable, apoyándose en un número masivo de antenas y adaptando la red a las necesidades de los usuarios en cada momento. Se han estudiado sistemas MIMO masivos sin celdas tanto para frecuencias inferiores a 6 GHz como en la banda mmW, demostrando ser una buena alternativa a las celdas pequeñas. Sin embargo, hay muchas cuestiones que todavía requieren más estudio. Esta Tesis aborda las cuestiones relativas a los despliegues masivos MIMO sin celdas en términos de escalabilidad, consumo de energía, modelado realista de los escenarios de despliegue y diseño de precodificadores para dichos escenarios en la banda mmW. Los sistemas masivos sin celdas en su forma canónica consideran que todos los APs están conectados a una única CPU y que todos ellos sirven a todos los UEs al mismo tiempo. Sin embargo, en la práctica, tal sistema no es factible debido a temas de escalabilidad. Por ello, en esta Tesis se estudian y proponen diferentes soluciones de agrupación que alivian la carga tanto de cada AP individual como de la CPUs, ya que la carga total de procesamiento se divide entre ellas. Las soluciones propuestas muestran un mejor rendimiento que la solución del estado del arte estudiada para todos los tamaños de agrupación considerados e independientemente del número de UEs en el escenario. Tras las consideraciones sobre la topología lógica de la red, esta Tesis analiza el impacto en el rendimiento de la red de diferentes configuraciones de topologías físicas. En concreto, se estudia el modelado del consumo de energía considerando front-haul totalmente dedicado, híbrido y totalmente en serie. En este sentido, se sugieren algunas modificaciones al modelo tradicional de consumo de energía para obtener resultados más precisos cuando se analizan entornos en serie. A partir de los resultados obtenidos, se destaca la importancia de aplicar las modificaciones propuestas que consideran el ahorro de energía debido a las conexiones serie en un despliegue de MIMO masivo sin celdas donde cada AP transmite la misma información (excepto por los coeficientes de precodificación). Por otro lado, aunque en la banda milimétrica se dispone de mayores anchos de banda, el uso de estas frecuencias conlleva ciertos retos. Uno de estos retos es el modelado del canal radioeléctrico, ya que al trabajar con longitudes de onda del orden de decenas de milímetros cualquier objeto o rugosidad del mismo puede afectar a la propagación de la onda. En este sentido, esta Tesis, en primer lugar, propone algunas adaptaciones al modelo de bloqueo del cuerpo humano del 3GPP. Los resultados obtenidos tras las modificaciones se acercan más a los valores de las mediciones reales, lo que hace que el modelo adaptado sea más preciso para la consideración del bloqueo corporal en mmW. En segundo lugar, esta Tesis presenta una herramienta de simulación de radiocanales basada en el trazado de rayos. Se han obtenido resultados de pérdidas de trayecto para un escenario de interior que se aproximan notablemente a las medidas reales. Asimismo, los resultados obtenidos muestran que cuando no se modelan correctamente las características electromagnéticas de los materiales o no se tiene en cuenta el mobiliario en un escenario de interior, los resultados pueden diferir considerablemente de las medidas reales. Por último, esta Tesis aborda el diseño de precodificadores en sistemas MIMO masivos sin celdas en un escenario realista. Para ello, se considera un escenario industrial con requerimientos de potencia específicos. En particular, se resuelve un problema de optimización con diferentes restricciones de potencia por antena.[CA] L'ús massiu de les telecomunicacions exigeix xarxes de major capacitat. Aquesta capacitat pot incrementar-se de les següents maneres: augmentant el nombre d'antenes, l'amplada de banda, l'eficiència espectral o una combinació d'elles. En resposta a això, han sorgit els sistemes massius MIMO sense cel·les. Aquests sistemes pretenen oferir un servei ubic i fiable, secundant-se en un nombre massiu d'antenes i adaptant la xarxa a les necessitats dels usuaris a cada moment. S'han estudiat sistemes MIMO massius sense cel·les tant per a freqüències inferiors a 6 GHz com en la banda mmW, demostrant ser una bona alternativa a les cel·les xicotetes. No obstant això, hi ha moltes qüestions que encara requereixen més estudi. Aquesta Tesi aborda les qüestions relatives als desplegaments massius MIMO sense cel·les en termes d'escalabilitat, consum d'energia, modelatge realista dels escenaris de desplegament i disseny de precodificadors per a aquests escenaris en la banda mmW. Els sistemes massius sense cel·les en la seua forma canònica consideren que tots els APs estan connectats a una única CPU i que tots ells serveixen a tots els UEs al mateix temps. No obstant això, en la pràctica, tal sistema no és factible a causa de temes d'escalabilitat. Per això, en aquesta Tesi s'estudien i proposen diferents solucions d'agrupació que alleugen la càrrega tant de cada AP individual com de la CPUs, ja que la càrrega total de processament es divideix entre elles. Les solucions proposades mostren un millor rendiment que la solució de l'estat de l'art estudiada per a totes les grandàries d'agrupació considerats i independentment del número de UEs en l'escenari. Després de les consideracions sobre la topologia lògica de la xarxa, aquesta Tesi analitza l'impacte en el rendiment de la xarxa de diferents configuracions de topologies físiques. En concret, s'estudia el modelatge del consum d'energia considerant front-haul totalment dedicat, híbrid i totalment en sèrie. En aquest sentit, se suggereixen algunes modificacions al model tradicional de consum d'energia per a obtindre resultats més precisos quan s'analitzen entorns en sèrie. A partir dels resultats obtinguts, es destaca la importància d'aplicar les modificacions proposades que consideren l'estalvi d'energia a causa de les connexions serie en un desplegament de MIMO massiva sense cel·les on cada AP transmet la mateixa informació (excepte pels coeficients de precodificació). D'altra banda, encara que en la banda mil·limètrica es disposa de majors amplades de banda, l'ús d'aquestes freqüències comporta uns certs reptes. Un d'aquests reptes és el modelatge del canal radioelèctric, ja que en treballar amb longituds d'ona de l'ordre de desenes de mil·límetres qualsevol objecte o rugositat del mateix pot afectar la propagació de l'ona. En aquest sentit, aquesta Tesi, en primer lloc, proposa algunes adaptacions al model de bloqueig del cos humà del 3GPP. Els resultats obtinguts després de les modificacions s'acosten més als valors dels mesuraments reals, la qual cosa fa que el model adaptat siga més precís per a la consideració del bloqueig corporal en mmW. En segon lloc, aquesta Tesi presenta una eina de simulació de radiocanales basada en el traçat de raigs. S'han obtingut resultats de pèrdues de trajecte per a un escenari d'interior que s'aproximen notablement a les mesures reals. Així mateix, els resultats obtinguts mostren que quan no es modelen correctament les característiques electromagnètiques dels materials o no es té en compte el mobiliari en un escenari d'interior, els resultats poden diferir considerablement de les mesures reals. Finalment, aquesta Tesi aborda el disseny de precodificadors en sistemes MIMO massius sense cel·les en un escenari realista. Per a això, es considera un escenari industrial amb requeriments de potència específics. En particular, es resol un problema d'optimització amb diferents restriccions de potència per antena.[EN] The massive use of telecommunications demands higher capacity networks. This capacity can be increased by increasing the number of antennas, bandwidth, spectral efficiency, or a combination of these. In response to this, cell-free massive MIMO systems have emerged. These systems aim to offer a ubiquitous and reliable service, relying on a massive number of antennas and adapting the network to users' needs. Cell-free massive MIMO systems have been studied both for frequencies below 6 GHz and in the mmW band, proving to be a good alternative to small cells. However, many issues still require further study. This Thesis addresses the issues concerning cell-free massive MIMO deployments in terms of scalability, power consumption, realistic modeling of deployment scenarios, and design of precoders for such scenarios in the mmW band. Cell-free massive systems in their canonical form consider that all the APs are connected to a single CPU and serve all UEs simultaneously. However, in practice, such a system is not feasible, due to scalability reasons. Therefore, in this Thesis, different clustering solutions that alleviate the load of both each individual AP and the CPUs, as the total processing load is divided among them, are studied and proposed. The proposed solutions show a better performance than the state-of-the-art solution studied for all cluster sizes considered and independently of the number of UEs in the scenario. After the logical network topology considerations, the impact on the network performance of different physical topologies configurations is analyzed. Specifically, the power consumption modeling considering fully dedicated, hybrid, and fully serial front-haul is studied. In this sense, some modifications are suggested for the traditional power consumption model in order to get more accurate results when serial environments are analyzed. The obtained results highlight the importance of applying the proposed modifications that consider the power savings due to the serial connections in a cell-free massive MIMO deployment where each AP transmits the same information (except by the precoding coefficients). On the other hand, although wider bandwidths are available in the millimeter band, the use of these frequencies brings certain challenges. One of these challenges is modeling the radio channel since when working with wavelengths in the order of tens of millimeters, any object or roughness of the same order can affect the propagation of the wave. Another challenge is to consider the electromagnetic impact of the human body at mmW frequencies. In this sense, this Thesis, firstly, proposes some adaptations to the 3GPP body blockage model. The results obtained after the modifications are closer to real measurement values, what makes the adapted model more accurate for the consideration of body blockage at mmW. Secondly, this Thesis presents a radio channel simulation tool based on ray tracing. With this tool, path loss results have been obtained for an indoor scenario that are remarkably close to the actual measurements. Also, the results show that when the electromagnetic characteristics of the materials are not modeled correctly or the furniture is not taken into account in an indoor scenario, the adjustment of the simulation results can differ considerably from the actual measurements. Finally, the design of precoders in cell-free massive MIMO systems in a realistic scenario is addressed. For this purpose, an industrial scenario with specific power requirements is considered. In particular, an optimization problem with different per-antenna power constraints is solved. In this case, the scenario and the radio channel are modeled using the above-mentioned tool. This fact makes it possible to find with high precision the power coefficients to be used by each transmitting antenna to transmit to each user so that the achieved data rate is maximized.I would like to thank the H2020 Marie Curie Program that has funded this thesis within Project Grant No. 766231 WAVECOMBE - ITN - 2017Prado Alvarez, D. (2022). Study of Feasible Cell-Free Massive MIMO Systems in Realistic Indoor Scenarios [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19137

Creación de Interfaces de Realidad Virtual Móvil en Unity 3D y Validación Experimental de sus Requisitos de Red

[ES] El objetivo de esta tesina de máster es extender las funcionalidades de las soluciones de desarrollo de juegos para utilizarlas como herramientas de ingeniería. En concreto se utilizará la plataforma UNITY-3D y se integrará una plataforma de realidad virtual para permitir al ingeniero radio tener una inmersión total en la zona a diseñar. Mediante los propios mandos del mundo virtual el ingeniero deberá ser capaz de interactuar con la realidad y disponer los elementos de red de manera dinámica, observando en primera persona el impacto de cada modificación. Para ello esta tesina pretende integrar el conocimiento del iTEAM en simulación y diseño de sistemas, con las nuevas tendencias de desarrollo de juegos. Parte de la tesina será diseñar la interacción y evaluar distintas alternativas y niveles de profundidad de la experiencia virtual de manera que sean útiles para un trabajo eficiente de diseño. Además, se deberá investigar sobre las limitaciones del software utilizado en términos de carga y capacidad de envío remoto del vídeo generado a receptores móviles distantes. Esta solución en red en la nube, se pretende probar en laboratorio.[EN] The aim of this Master's thesis is to extend the functionalities of game development platforms to be used as serious engineering tools. In particular, the UNITY-3D platform will be used and a virtual reality platform will be integrated to allow the radio engineer to have a total immersion in the area to be designed. Through the virtual controls of the virtual world, the engineer must be able to interact with reality and arrange the network elements dynamically, observing in first person the impact of each modification. For this, this thesis intends to integrate the knowledge of iTEAM in simulation and systems design, with new trends in game development. Part of the thesis will be to design the interaction and evaluate different alternatives and levels of depth of the virtual experience so that they are useful for an efficient design work. In addition, the limitations of the software used in terms of load and remote forwarding capacity of the generated video to distant mobile receivers should be investigated. This network solution in the cloud is intended to be tested in the laboratory.Prado Alvarez, D. (2017). Creación de Interfaces de Realidad Virtual Móvil en Unity 3D y Validación Experimental de sus Requisitos de Red. Universitat Politècnica de València. http://hdl.handle.net/10251/165145TFG

Creación de Interfaces de Realidad Virtual Móvil en Unity 3D y Validación Experimental de sus Requisitos de Red

Prado Alvarez, D. (2017). Creación de Interfaces de Realidad Virtual Móvil en Unity 3D y Validación Experimental de sus Requisitos de Red. http://hdl.handle.net/10251/112997Archivo delegad

Evaluation Methodology for 6G Sensing-Assisted Communication System Performance

Nowadays, Integrated Sensing and Communication (ISAC) is receiving significant attention in the frame of the Sixth Generation (6G). To assess the performance of future candidate ISAC technologies and to be able to compare them with each other, the standardization of evaluation methodologies is necessary. This paper introduces a suitable methodology for evaluating sensing-assisted communication systems. For this purpose, features similar to those included in the International Telecommunications Union (ITU) recommendation have been adopted, mainly geometry-based stochastic channel modeling and Key Performance Indicator (KPI) selection. The key elements of this evaluation methodology are the existence of a correlation between the sensing and the communication channels and the need for a spatial consistency model to obtain spatially correlated stochastic channels using the geometry-based stochastic model (GBSM). Considering these elements allows a wide range of usage scenarios to be evaluated within the ISAC framework. Finally, to clarify the evaluation procedure, a sensing-assisted channel estimation use case has been presented as an example of the applicability of the proposed methodology. Promising results are presented, where the ISAC solution can outperform a conventional communication system in terms of Throughput

Received power modelling in ultra-dense networks

[EN] In received power modelling for system level simulations, the relative orientation of the transmitter and receiver antennas are not generally considered. By doing that, a constant gain of the receiver antenna, independently of the angle of arrival, is implicitly assumed. This is usually of minor relevance for small or low-dense scenarios. However, in ultra-dense deployments, especially those based on cell-free massive multiple-input¿multiple-output architectures where users interact with all access points, the consideration of the antennas relative orientation comes to the forefront. In this paper, the impact of whether to take the receiver antenna gain into account or not for ultra-dense indoor environments with ceiling-mounted antennas are studied. A simple approach to take this gain into account using the antenna effective area is provided. Finally, this approach is compared with that based on antenna radiation patterns.The work of Danaisy Prado was supported by the H2020 Marie Curie Program, with Project Grant No. 766231 WAVECOMBE - ITN - 2017. This was also supported by the Spanish Ministry of Science, Innovation and University under the project RTI2018-099880-B-C31.Prado-Alvarez, D.; Antón, A.; Calabuig Soler, D.; Monserrat Del Río, JF.; Bazzi, S.; Xu, W. (2022). Received power modelling in ultra-dense networks. Electronics Letters. 58(11):448-450. https://doi.org/10.1049/ell2.12470448450581

6G Technology Overview (third edition)

6G aims to address diverse, often competing needs, such as vastly increased data rates, a massive scale of communicating devices, energy efficiency, and the simultaneous demand for both high data rates and low communication latency. The White Paper covers several groundbreaking technologies pivotal for 6G evolution, such as terahertz frequencies, 6G radio access, integrated sensing and communication, non-terrestrial networks and more. For each technology, the White Paper offers background information, explains its relevance to 6G, presents key problems, and provides a thorough review of the current state of the art. The paper emphasises that while the listed technologies form the foundation for 6G, the landscape will continuously evolve. Subsequent versions of the white paper will spotlight new technologies and integrate them into a cohesive system. The “6G Technology Overview” concludes that 6G, with its vast potential, aims not only to meet the diverse requirements of novel use cases but also to ensure sustainability, user-friendliness, and ease of service deployment