Programa del congreso

Multiple-Input Multiple-Output (MIMO) systems play a crucial role in fifth-generation (5G) mobile communications, primarily achieved through the utilization of precoding matrix techniques. This paper presents precoding techniques employing codebooks in downlink MIMO-5G wireless communications, aiming to enhance network performance to meet the overarching 5G objectives of increased capacity and reduced latency. We conduct a comparative analysis of various precoding techniques outlined by the 5G standard through diverse simulations across different scenarios. These simulations enable us to assess the performance of the different precoding techniques, ultimately revealing the strengths and weaknesses inherent in Type I and Type II codebooks.

Sustainability is a critical factor in the development of future beyond-5G (b5G)/6G networks. This work highlights the importance of energy efficient practices to reduce environmental impact and resource consumption, in line with the objectives of the International Mobile Telecommunications (IMT) 2030. The increasing energy consumption in telecommunications networks highlights the need for corrective action without compromising network performance or security. The paper presents an Open Radio Access Network (O-RAN) architecture for 5G networks that enables the monitoring and optimization of energy consumption. The study integrates xApps and rApps into various emulated network elements to provide a real streaming service while monitoring the power consumption of the different network elements.

As Open Radio Access Network (O-RAN) architecture gains prominence, it also introduces new security challenges particularly concerning the open interfaces, virtualization and the intelligence embedded within the network. This paper makes an overview of the security of this architecture and presents a testbed for the extraction of different metrics for an E2E video service under two situations: with and without attack. This testbed can be used to generate datasets and evaluate the impact of poisoning and evasion on network intelligence.

The evolution of mobile networks is currently going through a stage of opening up the infraestructure, known as O-RAN, a paradigm that also proposes providing more intelligence to the Radio Access Network (RAN) of the users. The key element that allows this change is the RAN Intelligent Control (RIC). Possible service improvements to customers are affected by new security breaches that may occur on the network. This paper analyses the impact of poisoning and evasion attacks, where training and testing data, respectively, are altered on Machine Learning (ML) algorithms. To this end, an E2E scenario has been analysed, in which the direct effects of the users' perception is studied.

With the advances in 5G, and beyond,

mobile communications, more focus is directed toward implementing

massive MIMO. While numerous solutions exist for

high-frequency bands exceeding 1GHz, exploration of increasing

MIMO order in low-frequency bands has not been yet explored,

despite their unique characteristics as wide coverage area and

penetration through obstacles that are essential for covering a

massive number of connected devices. The challenges of designing

antenna base station arrays that can support massive MIMO

at 5G New Radio (5G NR) 700 MHz bands are summarized.

Here, the goal is to move from the current non-massive 4T4R

solution to a massive 16T16R MIMO without the increase in the

overall size of the base station (restricted to standard sizes) or

sacrificing array performance, especially in terms of bandwidth, gain,

beamwidth, and isolation. Results based on an array version of

differential metallic cap-loaded multi-layer Dielectric Resonator

Antenna (DRA) are presented.

In beyond 5G cellular systems, Network Slicing (NS) functionality allows splitting a physical network into several logical slices tailored for a specific application. In sliced networks, a slice-aware automatic optimization of Network Functions (NFs) is key to guarantee Service Level Agreement (SLA) compliance while minimizing operation costs. For this purpose, with the advances in artificial intelligence, massive data collected in the operations and support system can be leveraged to develop Deep Reinforcement Learning (DRL) solutions deriving optimization policies automatically. This work proposes the first algorithm for slice-aware traffic steering based on DRL. The algorithm trains a slice-specific double deep Q-learning agent that learns the optimal traffic steering policy to improve SLA compliance per slice. Simulation results have shown that the proposed algorithm outperforms other slice-aware traffic steering approaches, increasing SLA compliance on 11\% in a realistic scenario with 3 slices serving uRLLC, uLBC and eMBB traffic.

The “radio blackout” phenomenon is the communications loss between a spacecraft and the Earth during the re-entry in the atmosphere. The intense heating of the air around the spacecraft ionizes it creating a plasma layer that prevents the propagation of electromagnetic waves. Several techniques have been proposed to mitigate this phenomenon, such as the use of higher frequencies, the aerodynamic shape of the reentry capsule, the cooling of the thermal shield itself, or the creation of an intense magnetic field. However, none of them is completely effective. This paper describes the underlying Physics, presents the simulation results of the plasma properties around an ARD-like reentry capsule in terms of electron density, temperature, and pressure, and the attenuation in [dB/m] at three different heights. It is shown that the presence of an intense magnetic field significantly reduces the cut-off frequency and the attenuation above it favoring the propagation of radio waves.

This work presents preliminary results on a measurement campaign at mmW between 26 and 40 GHz in an indoor environment in line-of-sight conditions. 2D-virtual arrays and 3D-directional sounding were tested in the same identical positions to investigate the accuracy of both approaches by comparing the directional characteristics of the double directional radio channel. The radio channels and corresponding characteristics were also simulated with an in-house 3D ray tracer. The results show that both approaches are different by nature, due to the fact that different antennas are used in each approach. URA and 3D rotor share the same large-scale characteristics. The capacity of the 3D rotor to sound the channel in the elevation plane is better than that of the more complex planar URA due to its limited aperture and the use of an omnidirectional antenna. This comes at the expense of longer measurements as the number of positions is much larger

En los últimos años, los sistemas RFID se han utilizado para numerosas aplicaciones, incluyendo la apicultura. Por tanto, es necesario estudiar el entorno en el que se usan estos sistemas. En este trabajo, se modela el panal de una colmena y un sistema RFID UHF (lector y etiqueta) utilizando el software CST Studio, y se compara con medidas empíricas. El panal (44,5x23,5x2cm) está compuesto por un marco de madera con alambres y cera de abejas. La antena del lector se coloca en un lateral del panal y la etiqueta se posiciona en diferentes puntos sobre él, considerando entre y sobre los alambres. Los resultados muestran un comportamiento periódico en la potencia recibida de la etiqueta, tanto en las medidas como en la simulación. Además, cuando el tag se coloca sobre los alambres del panal, la potencia recibida es mayor que en el caso de colocarlo entre dos alambres.

Usually the analysis of intra-wagon environments is performed considering empty scenarios, without any person inside the wagon. Only some works have addressed the influence of passengers in the wireless channel in this kind of scenarios. Moreover, the analysis in these works is limited to the computation of the signal strength and the path loss values. In this work we have simulated the wireless channel in two sub-bands of the millimeter wave band using a ray tracing tool. The path loss and the root-mean-squared delay spread have been calculated from the simulations, allowing a deeper insight than previous works. The computed parameters have been compared with measured and simulated values.

El factor K es una medida de la calidad del canal radio, cuyo conocimiento es importante en el diseño de técnicas de transmisión y recepción orientadas a mitigar el efecto de selectividad en tiempo, espacio y frecuencia introducido por el canal. En esta comunicación se realiza un estudio experimental de la distribución del factor K en un escenario de laboratorio caracterizado por la existencia de un elevado número de contribuciones multicamino. Los valores del factor K han sido estimados a partir de medidas de banda ancha realizadas en el margen de frecuencias de 24 a 40 GHz. La estimación se ha realizado a partir de la función de transferencia compleja del canal, utilizando el método de los momentos como si de canales de banda estrecha se tratase. Los valores del factor K estimados se han utilizado para evaluar la capacidad de sistemas MIMO en este tipo de entornos, demostrando que es posible su implementación incluso en condiciones de visión directa sin una degradación importante con respecto al canal ideal tipo Rayleigh.

This paper presents a frequency modulation

continuous wave (FMCW) C-band radar system with high

sensitivity and 2D detection capacity to detect low-radar cross

section targets and to measure their range and velocity. A low

jitter high signal-to-noise and distortion ratio (SINAD) S band

signal is directly generated by an SDR system which greatly

increases the quality of the obtained and measured signals. Up

conversion to C-Band by x2 frequency multiplication is

performed. Proper amplification and filtering of emitted and

detected signals are implemented to achieve 70dB dynamic range

in the final system. The transmitter antenna is a single 60º

aperture whereas multi-long baseline interferometer (MLBI)

concept is implemented in the receiver antenna for a low cost, low

dimension, and high angle resolution in the 2D position of the

targets. Measurements in terms of the range and the velocity of a

small drone have been carried out to evaluate the proposed radar

system. Micro-Doppler signature is also measured and evaluated.

The results show that we can clearly detect, identify and track

the small drone within a 350 m range, which demonstrates the

high performance of the radar and its potential use for

unmanned aerial vehicles (UAV) tracking and identification.

The development of smart communications technologies brings new capabilities to the packaging industry, notably enhancing traceability within logistical operations. Radio Frequency IDentification (RFID) technologies hold significant promise in this regard but also pose challenges due to their expense and issues concerning recycling. Chipless RFID technology emerges as an alternative by eliminating the need for encoded chips and improving sustainability. This work introduces a chipless RFID system featuring an affordable reader designed for integration into packaging applications utilizing paper substrates. In this sense, 2-D geometrical patterns printed with conductive ink on paper-based substrates are analyzed, comparing them with printed circuit boards employing FR-4 substrate. The reader is developed utilizing conventional software-defined radio (SDR) platforms within the 0–6 GHz and 0–12 GHz frequency ranges, avoiding the use of a vector network analyzer (VNA) equipment.

In this contribution, the design of a novel logarithmic-spiral-shaped (LSS) anisotropic dielectric polarizer is presented for millimeter-wave applications within the Ka-band (28-30 GHz). The proposed antenna is composed of a conical horn fed by a waveguide dual-mode converter (DMC), where the TE01 and TM01 modes are independently excited to generate linearly azimuthal polarized and linearly radial polarized conical beam radiation patterns, respectively. The horn antenna is loaded with the novel LSS dielectric polarizer, which converts the linearly radial polarized wave generated by the excitation of the TE01 mode into a right-handed circularly polarized (RHCP) wave and the linearly azimuthal polarized wave generated by the excitation of the TM01 mode into a left-handed circularly polarized (LHCP) wave. In order to experimentally validate the proposed design, both the DMC along with the conical horn antenna and the novel LSS dielectric polarizer are manufactured by means of distinct 3D printing techniques. An excellent agreement between simulations and measurements is achieved.

This paper explores the potential of combining additive manufacturing (AM) with printed circuit board (PCB) technology for the fabrication of radio frequency (RF) components and circuits. This approach seeks to leverage the design freedom offered by AM while capitalizing on the established processes and design knowledge associated with PCB manufacturing. A helical microstrip line segment is chosen as the test vehicle for this study. The paper proposes a procedure for embedding this 3D structure into a printed circuit board (PCB) substrate. Electrical connectivity and mechanical stability are both considered during the definition of the embedding steps. To demonstrate the functionality of the proposed method for the design of more complex structures, two embedded helical microstrip line segments are combined to form a compact 2-way Wilkinson power divider/combiner suitable for operation at the low RF frequency band.

La fabricación aditiva (AM) se puede aplicar a nuevos escenarios donde las técnicas sustractivas tradicionales limitan la geometría y la libertad de ensamblaje. Uno de estos escenarios es el desarrollo de antenas, donde la AM ofrece la capacidad de implementar geometrías de alta complejidad, reduciendo el peso y coste de los dispositivos. Este trabajo presenta el proceso de fabricación aditiva de dos antenas MIMO de cuatro puertos con cavidad trasera utilizando tecnología de impresión 3D SLA. Los dispositivos impresos se metalizaron mediante un proceso autocatalítico de baños químicos. Finalmente, se midieron sus respuestas frecuenciales, ganancia, eficiencia, diagramas de radiación y peso, y se compararon con las fabricadas mediante métodos tradicionales de fresado sobre metal. La respuesta electromagnética de las antenas de AM es excelente y comparable con las fabricadas con técnicas sustractivas.

This communication aims to demonstrate the fea-

sibility of manufacturing complex structures through additive

manufacturing with conductive material. Enabling more intri-

cate designs and greater detail to meet the necessary specifi-

cations in today’s context. A comparison is conducted on the

performance of two conical horns, Ka-band and M-band, whose

manufacturing requirements are significantly different.

This paper presents a 3D-printed prototype of a novel top-metalized Dielectric Resonator Antenna (DRA). The inclusion of top metallization induces a modification in the boundary conditions, resulting in a frequency reduction in the fundamental mode of the DRA. Still, it does not degrade its radiation performance. The dielectric part is manufactured using fused deposition modeling (FDM) printing techniques and a commercially available Zirconia-loaded filament. The prototype presents a –10-dB bandwidth from 2.54 to 2.68 GHz with a minimum of –21 dB at 2.60 GHz. The radiation maxima occur in the top and bottom directions, with a simulated gain of 2.7 dBi. Thus, a low-cost and fast method to implement and manufacture a miniaturized DRA is presented.

This communication proposes an all-metal radial-line slot array antenna with a tilted beam, intended to mm-wave communications. An azimuthal variation of the propagation constant within the feeding waveguide is created by a non-uniform bed of nails, tailoring each pin height accordingly. When feeding a uniformly-spaced array with such inhomogeneous waveguide, the main beam tilts within a defined plane. Moreover, if such a waveguide illuminates a non-uniformly spaced slot array, beam-steering capability can be achieved by simply rotating the bottom plate with the bed of nails. This concept is intended to be experimentally validated through the fabrication of a prototype using additive manufacturing.

The multipactor effect is an RF breakdown discharge that creates an electron avalanche. Multipactor can result in serious consequences in satellites, such as transmission link degradation and even RF component damage. Thus, multipactor prevention is critical and early detection during development testing is necessary. The microwave nulling detection method is widely used to detect multipactor discharges in a test bed, using the forward and reflected power and adjusting their sum to zero. This work presents a variation of this detection method, using probes inserted directly into the device under test to implement the nulling system. This novel method allows to monitor the RF signal directly, using probes located near the critical gap. Results for several tests performed using the traditional nulling method, the new technique using just two probes, as well as mixing both strategies, are shown and discussed.

The integration between 5G networks and low Earth orbit satellites is recognized as a key enabler for achieving global coverage, becoming an inherent component of the forthcoming 6G network. This synergy not only facilitates direct connections between terminals and satellites, extending terrestrial network coverage, but also unveils a myriad of new service opportunities. Against this backdrop, the inherent mobility of satellite platforms poses significant challenges in the management and orchestration of network functions. Developing an accurate 5G-NTN emulation platform, which aids in the development and validation of these necessary functions for the network's proper operation, remains a considerable challenge. Previous attempts to simulate this environment have encountered obstacles, especially in replicating the latency characteristics typical of satellite communications in 5G Standalone (SA) configurations, which is critical for the final phase of 5G deployments, resulting in an imprecise representation of this environment. It is crucial that such a platform effectively reproduces the complexities arising from the interaction between 5G and NTN networks, including the peculiarities of non-terrestrial links and computational limitations on the satellite, in addition to enabling network function orchestration in this environment. Our research addresses this need with an innovative emulation platform designed to simulate the disaggregated network architecture of OpenRAN in an NTN setting. This solution not only precisely replicates the operational characteristics of 5G-NTN configurations but also optimizes the management of VNF lifecycle via Kubernetes, enhancing operational efficiency in mixed network environments. Through this platform, we propose an initial strategy for the optimal distribution of VNFs, laying the groundwork for future exploration aimed at maximizing resource utilization efficiency in these complex settings

Este documento desarrolla el proceso de diseño, implementación y validación de una metodología para la geolocalización de interferencias en satélites LEO (Low Earth Orbit). Este proyecto se ha desarrollado en colaboración entre la empresa Integrasys S.A. y el grupo de investigación GR (Grupo de Radiación) perteneciente a la ETSIT (Escuela Técnica Superior de Ingenieros de Telecomunicación). El objetivo principal es llevar a cabo esta geolocalización de la forma más eficiente posible y con un error máximo de 5 kilómetros. El proyecto se ha desarrollado en 3 fases principales. En primer lugar se ha propuesto la matemática que vamos a implementar, en este caso la técnica de doble TDOA. A continuación se ha diseñado e implementado un simulador en MatLab gracias a Satcom Toolbox para poder validar la matemática generando parámetros ideales. Finalmente, se ha llevado a cabo la visualización y análisis de los resultados obtenidos gracias a estas simulaciones.

Los sistemas de satélites federados surgen como solución para mejorar el rendimiento de los sistemas de observación de la Tierra y de telecomunicaciones en respuesta a la creciente demanda y proliferación de pequeños satélites en órbita. Sin embargo, los equipos de simulación de comunicaciones espaciales son limitados en lo que respecta a la simulación de redes de comunicaciones. Con la creciente demanda de servicios 5G, se necesitan herramientas de simulación de redes que tengan en cuenta tanto las mecánicas orbitales como las características de los satélites. Esta contribución propone la creación de un sistema de simulación utilizando el Simulador de Sistemas Satelitales Distribuidos desarrollado por NanosatLab de la Universidad Politécnica de Cataluña, actualmente mantenido y desarrollado por i2Cat. Este texto demuestra cómo se integran en el simulador la filosofía Hardware in the Loop y los protocolos necesarios para simular Sistemas de Satélites Federados.

The paper examines the utilization of onboard power resources of LEO satellites dedicated to broadband communication missions. It highlights the inefficiency of solely allocating transmit power for communication services, especially in regions with minimal service demand like vast oceanic areas. To address this issue, a realistic model of worldwide broadband demand is presented, considering factors such as population, purchasing capacity, technology, competition, and service availability. The analysis quantifies power usage based on the presented model, revealing opportunities to optimize resource allocation and enhance efficiency in hybrid mega-constellation operations beyond communication services.

Ionospheric scintillation is a major problem in satellite communications, notably in the low part of the radio-frequency spectrum, introducing random intensity and phase fluctuations in the received signal. LEO-PNT (Low Earth Orbit–Position Navigation and Timing) constellations are emerging to improve the performance of GNSS (Global Navigation Satellite Systems) constellations. Since the planned frequency bands span from VHF to C-band, some of these bands may be much affected by ionospheric scintillation. To optimize their operation, it is necessary to characterize the temporal behavior of the scintillation as realistically as possible, considering the geometry of the systems, the characteristics of the ionosphere, and the frequency of operation. In this study, Rino’s Physics-based ionospheric scintillation model is applied to obtain intensity and phase time series of perturbed signals transmitted from an arbitrary satellite (VLEO, LEO, MEO or GEO) to an arbitrary object under the ionosphere electron density peak (static ground receivers, planes…).

Este trabajo propone una técnica para el diseño de absorbedores de microondas y ondas milimétricas mediante la combinación de superficies selectivas en frecuencia (FSSs) y grafeno inducido por láser (LIG). Dos estructuras FSS han sido diseñadas y fabricadas experimentalmente, actuando como filtro frecuencial la primera de ellas y como absorbente de banda ancha la segunda.

This paper presents a metal-only reflectarray based on a 3D unit cell with dual-band capability. The 3D unit cell is a square waveguide whose vertical walls include resonator elements with independent frequency performance. Different resonator geometries are analyzed to obtain a reflected phase variation in the target frequency band and to be feasible for 3-D manufacturing. C-shaped, triangle-shaped, and circle-shaped resonators are selected to obtain the required phase shift in reflection. A reflectarray (RA) prototype is designed, including pairs of resonators where the C-shaped resonator controls the low-frequency band, and the triangle resonators do so for the high-frequency band. The main reflected beam directions for each frequency band are different to show the independent phase tuning of the resonators. The prototypes are manufactured using stereolithography (SLA) with a subsequent silver coating. Measured results show realized gains of 21 dBi in the 18 GHz band and 24 dBi in the 26.5 GHz band, with a high radiation efficiency and good agreement with the simulated results.

The potential of single-node mmWave radar systems can be expanded with more sophisticated configurations, such as multi-frequency, multistatic, or phased-array radars. This paper presents a 120 GHz radar node, designed with a focus on transitioning to multistatic or phased-array setups, emphasizing scalability for integration into phased-array configurations. This involves addressing critical factors often overlooked, such as synchronization and data handling. A 120 GHz phased-array radar has been developed based on the custom-made single-node radar sensor. The array comprises 15 synchronized radar nodes with a Multiple-Input Multiple-Output setup. After a calibration procedure with a point-like target, the array is used to generate a range-crossrange image.

Non-contact monitoring of vital signs has been increasing demand in healthcare applications. Monitoring biomarkers such as heart rate variability (HRV) or pulse wave velocity (PWV) in home scenarios is crucial for early detection of cardiovascular disease or the worsening of these diseases. This paper presents a mmWave radar network to measure pulse transit time (PTT) and PWV without contact. The experiment is carried out measuring simultaneously the carotid, the heart and the femoral of a healthy subject. Results reflect that the system is capable of measuring the carotid-femoral PWV (cfPWV), which is the gold standard for measuring arterial stiffness.

Este estudio introduce un novedoso modelo de circuito semianalítico destinado a caracterizar completamente las propiedades de una celda unitaria dieléctrica compuesta por bloques en forma de T, a diferencia de los estudios tradicionales donde se aplica la teoría de medios efectivos. Empleando diversos fittings, se alcanza una total comprensión de las propiedades de la celda unitaria. Posteriormente, aprovechando este enfoque, se desarrolla un modelo semianalítico que muestra una sólida concordancia con los parámetros de dispersión derivados de un simulador de onda. Mediante la manipulación de la proporción dieléctrico – aire, el modelo presentado recoge correctamente los diversos comportamientos exhibidos por celdas unitarias de distintas permitividades y tamaños eléctricos. A lo largo de todo el artículo se estudiarán las diversas limitaciones del modelo a la vez que su rango de aplicabilidad para diversas permitividades.

Además, como aplicación práctica, se diseñan transmitarrays cuyo objetivo sea generar ondas de momento angular orbital (OAM) basadas en las celdas unitarias dieléctricas analizadas y posteriormente se fabrican mediante impresión 3D. El objetivo de estos sistemas será la comunicación a altas frecuencias. Los resultados simulados muestran un correcto resultado de modos OAM a 85 GHz, a la espera de ser medidos experimentalmente

Los polarizadores integrados en chip se han utilizado ampliamente para controlar la polarización de los sistemas fotónicos basados en la plataforma de silicio sobre aislante, que presenta una fuerte birrefringencia. El diseño de polarizadores que atenúan la luz polarizada TE mientras permiten el paso de la luz polarizada TM con pocas pérdidas supone un reto importante en la plataforma estándar de silicio sobre aislante de 220 nm debido al mayor confinamiento que experimenta la polarización TE en comparación con la polarización TM. En este trabajo, proponemos y demostramos experimentalmente un polarizador paso-TM de banda ancha, bajas pérdidas y alta relación de extinción que utiliza una estructura de Bragg. Aprovechando un metamaterial de sub-longitud de onda, manipulamos la estructura de Bragg para reflejar el modo TE fundamental en el modo TE de primer orden, permitiendo al mismo tiempo la transmisión del modo TM. Los resultados experimentales muestran una relación de extinción superior a 20 dB y pérdidas de inserción inferiores a 1 dB dentro de un ancho de banda de al menos 120 nm.

With the advent of commercial products, such as Google Glass, Samsung Galaxy Gear and the expected iWatch, body-centric communication has increasingly garnered the public attention and smoothly translated state-of-the-art research work into reality. With the development of nanotechnology, the idea of connecting nano-devices to conduct complicated tasks and communicate the information collected by these sesnors was a natural progression in order to complete the overall picture of a new generation of body-centric wireless networks. Connecting these nano-machines (or nano-devices) together in order for them to execute a useful function and deliver information between nano-nodes and ultimately interfacing to users or the outside world, the birth of nano-communication and networking was a necessity. Nano-scale communication is referred to the exchange of information at the nanoscale and it is the basis of any wired/wireless interconnection of nano-devices in a nano-network. The way the nano-devices communicate with each other has strong dependence on the way in which they are realised. In addition, the specific application of the nano-network determines the deployment of the nano-networks, thus constraining the choice on the particular type of nano-communication.

The talk will present development of reliable and comprehensive channel modelling, human tissue electric properties in the THz band and networking technologies to address the major challenges of the nano-scale electromagnetic channels needed for body-centric wireless nano-networks deployed in future healthcare applications. With the advancement of nano-scale machine fabrication and the deep understanding of molecular behaviour within the human body, future healthcare monitoring and feedback systems are expected to be comprehensive, efficient and ubiquitous hence coupling existing wireless wearable sensors and implantable units with nano-machines and networks.

This paper examines the non-idealities inherent in commercially available beamformers and explores their implications in the calibration procedures for phased array antennas. The non-ideal nature of the beamformer is meticulously modeled and assessed through extensive S-Parameter measurements to discern its impact on analyzed excitation retrieval methods. The Rotating-element Electric-field Vector (REV) and Control Circuit Encoding (CCE) methods are simulated using a synthetic array with spherical wave expansion driven by output coefficients measured from the beamformer. Simulations are executed to compare the REV method with a Selective-REV variant, designed to enhance coefficient prediction accuracy by leveraging a priori knowledge of phase-shifter amplitude deviations. Additionally, amplitude, phase, and complex CCE encodings are employed to determine the encoding technique that best accommodates beamformer non-idealities. Finally, anechoic chamber measurements assess the pattern prediction capabilities of the calibration methods explored in the simulation.

En los sistemas 5G y posteriores, Network Slicing (NS) permite el despliegue de múltiples redes lógicas personalizadas para sectores verticales específicos sobre una infraestructura física común. En la red de acceso radio, los operadores móviles necesitan modelos para predecir el rendimiento de los segmentos de manera proactiva, anticipándose a posibles degradaciones en la red.

Este trabajo aborda la previsión del rendimiento de los segmentos a corto plazo mediante el aprendizaje supervisado haciendo uso del algoritmo de predicción Time Series Mixer-Only.

En concreto. se evalúan cuatro estrategias de entrenamiento basándose en series temporales realistas de rendimiento por segmento, series temporales sintéticas o

una combinación de ambas.

La evaluación del rendimiento se lleva a cabo con un conjunto de datos realista generado mediante simulación en una red con 4 segmentos que ofrecen servicios con diferentes modelos de tráfico y requisitos de rendimiento a usuarios terrestres y aéreos.

Los resultados muestran que el uso del aprendizaje por transferencia para combinar

datos sintéticos y de rendimiento del segmento correspondiente

es un enfoque prometedor, con un mejor rendimiento que el método Random

Walk para un horizonte temporal de 30 días en todos los segmentos.

In 5G networks, densification of network elements is a key point for a fast and efficient deployment of this technology. This technique consists of adding small cells in areas where traditional cells have coverage problems or where there is a high flow of users, affecting their capacity. Therefore, the coordination and relationship between these cells during deployments must be managed efficiently. With the current advances in artificial intelligence for network management and automation tasks, this task can be automated through supervised learning. This paper proposes an automatic method to estimate neighborhood relationships between cells during deployments using deep neural networks. The evaluation of the model has been performed using a dataset extracted from a real LTE network. The results show that the proposed method promises to improve upon current neighborhood relationship algorithms.

Se prevé que las redes de sexta generación (6G) soporte una amplia gama de tecnologías por lo cual es necesario que estas redes ofrezcan servicios de alta calidad, con lo cual el

concepto de confianza desempeña un rol fundamental para cumplir con los retos de las redes 6G. En este artículo se realiza una revisión de los conceptos de confianza y las metodologías y técnicas usadas para garantizar un ecosistema 6G seguro y confiable, para esto se hace una categorización de las técnicas de evaluación de la confianza basada en el campo de estudio que aborda cada técnica. Por último, se presenta un análisis de las

diferentes técnicas en base a los enfoques definidos en cada categoría, en donde se presentan los retos técnicos, ventajas y desventajas que supone el uso de cada una de las técnicas revisada.

Este estudio profundiza en el ámbito de la gestión de la confianza en el contexto de las redes 6G, centrándose en la utilización de algoritmos de lógica difusa. Aprovechando metodologías avanzadas y dando prioridad a la confianza como elemento fundamental, El objetivo de este estudio es investigar formas de avanzar hacia un ecosistema 6G seguro y eficiente que proporcione servicios de alta calidad en diversas aplicaciones y entornos. A través de un análisis exhaustivo de los conceptos de confianza y de técnicas de evaluación que utilizan la lógica difusa en conjunto con otras tecnologías innovadoras como la inteligencia artificial y el blockchain, este estudio arroja luz sobre los beneficios potenciales y las implicaciones de integrar estas soluciones en escenarios del mundo real. Palabra clave: gestión de la confianza, difusa, 6G

This study explores the characteristics of the substrate-integrated hole (SIH) unit cells within parallel-plate waveguides (PPW). The fundamental SIH unit cell has been enhanced by integrating a metallic patch. A comparative analysis has been conducted between the unit cell featuring a perfect dielectric hollow with a patch and the one incorporating SIH with a patch. The dimensions of the unit cells are investigated to examine the various effective refractive indices. Furthermore, an application scenario is presented, demonstrating the design of a lens leveraging the SIH unit cells within a horn-type aperture antenna in Contact Less Air Filled SIW (CLAF-SIW) technology.

En este artículo se describe el desarrollo, fabricación y medida de una celda unitaria ajustable mecánicamente para el diseño de una superficie inteligente reconfigurable (RIS). Se ha implementado un diseño innovador basado en un cilindro metálico y un elemento cónico metalizado para lograr una reconfiguración de 1-bit (desfase de 180º) a 28 GHz. Además se ha realizado su fabricación y la validación experimental del prototipo así como un estudio de propagación en un entorno indoor real.

This paper extends and consolidates previous work related to an all-metallic, low-loss mechanical phase shifter implemented in gap-waveguide technology. The phase shifter is developed for Ka-band, to be used as part of a ground terminal for satellite-on-the-move communications. The device is formed by three levels. Levels 0 and 2 remain fixed whereas level 1 is rotatory. The rotation of level 1 does not increase the volume of the device in any case, and allows for the device to introduce a progressive phase shift between consecutive channels. This progressive phase shift provides beam steering capabilities to any array. Thanks to the arc-shaped and inverted-arc-shaped phase shifting waveguides, the device is able to provide continuous beam steering across the broadside point.

In this paper we have compared the time domain

delay spread parameters for the FR3 band using 1-40 GHz

measured data with those obtained from simulations in the

Wireless Insite software. Path loss models have been proposed

and a difference of about 2.7 dB in measured and simulated

received power has been obtained, the percentage error in the

mean square value of the measured and simulated delay spread

varies and is at best equal to 2.63 %. A convergence study shows

that it is not necessary to simulate more than 4 reflections, since

the percentage error in the relative received power and the root

mean square delay spread between the measured and simulated

results remain almost constant as the number of reflections

increases.

The combination of two leaky wave antennas implemented in Groove Gap Waveguide (GGWG) technology is proposed in this work as a simple way to obtain a flat-top radiation pattern. The design consists of two stacked GGWG leaky wave antennas with different radiation angles and full control on the amplitude distribution of the field to achieve low side-lobes and high radiation efficiency.

Advanced Driver Assistance Systems (ADAS) heavily rely on radar technology, particularly within the 76-81 GHz band, for precise obstacle detection and enhanced road safety. This paper introduces a novel metal-only antenna designed using gap waveguide technology. The antenna, featuring a scalable 1×8 slotted array fed through groove gap waveguide technology, offers multi-channel and multibeam operation, making it adaptable to various traffic scenarios.

Key features of the antenna include low transmission losses and robust obstacle detection capabilities within the 76-81 GHz band, crucial for ADAS applications. Its metal-only construction allows for integration into vehicle chassis, optimizing performance within automotive frequency bands.

Validation through simulations using CST Microwave Studio confirms the behavior and performance of the antenna. Results suggest potential as a candidate for antennas capable of multibeam performance in the E-band, underscoring its suitability for radar-based ADAS applications.

This work introduces a metal-only slot array built upon groove gap waveguide technology. This metal-only design facilitates seamless integration into vehicle chassis and ensures minimal losses within the automotive frequency bands. The fully integrated feeding network, featuring a -3dB power splitter, offers the flexibility of multi-port feeding. This adaptability has proven particularly valuable in achieving beam scanning, as changing the feeding port enables this capability. Furthermore, the multiport configuration has the potential to support multiple input/output channels, enhancing the extraction of additional angular information for a wide range of applications.

This paper presents a fully metallic radiating element that produces dual circular polarization over a wide bandwidth. A quasi-square waveguide section with a pair of corrugated walls is used, which converts ±45º linear polarization into dual circular polarization. The inclusion of periodic corrugations slows the propagation of one of the fundamental modes, leading to a phase difference exhibiting parabolic behavior. This significantly broadens the range in which a pure circular polarization of less than 1 dB of axial ratio can be attained. The behavior of the semi-corrugated waveguide is studied, and its dimensions are analyzed as a function of the bandwidth and required length. Two versions of the element with different heights and bandwidths are designed. The proposed fully metallic radiating element has small dimensions, which allow for integration into an array with low profile, while its versatile design enables the attainment of large bandwidths with pure dual circular polarization.

En este trabajo se propone un análisis de distintos métodos para la obtención de las propiedades dieléctricas de materiales de impresión 3D. En el diseño de dispositivos de microondas fabricados mediante impresión 3D, es esencial conocer con precisión las propiedades dieléctricas de los materiales empleados. Este trabajo compara tres métodos aplicados en materiales dispersivos (TW-CON175BK) y no dispersivos (PLA, ABS, Preperm-dk3, Preperm-dk10), para identificar las técnicas que obtienen las características de cada material de forma precisa. Las muestras se fabrican con la anchura y altura de las guías de onda estandarizadas WR-90 y WR-137. La longitud de las muestras depende de las propiedades de absorción del material, siendo TW-CON175BK el único cuya longitud es más corta respecto a las secciones de 51 mm empleadas en el resto de materiales. Se mide la respuesta de los parámetros [S] para cada material, y se aplican los métodos, proporcionando resultados favorables para materiales no dispersivos, y ajustando correctamente las características del material dispersivo únicamente con dos de estos métodos.

In this contribution a water drop Luneburg lens is presented. These types of antennas are very interesting in contexts such as mobile communications. With the rise of 5G, especially in the millimeter band, new radiant systems are necessary to solve the problems involved. With the increase in frequency and, therefore, propagation losses, high gain and efficiency antennas are needed. This is why devices such as geodesic lenses are a very attractive solution since they eliminate dielectric losses and can present a high gain. Additionally, their multiport and angular scanning capabilities make them highly desirable for MIMO system implementation. Additionally, thanks to advances in the development of additive manufacturing technologies, this type of geodesic lenses can have their manufacturing process greatly simplified. Light devices can be obtained at very low cost and granting great performance.

Additive Manufacturing Laser Powder-Bed Fusion (AM LPBF) technique is evaluated to manufacture monolithic antennas in metal, simplifying the conventional procedure based on, first, manufacturing a dielectric skeleton, and then, applying a coating process to obtain the desire microwave component. To validate the technique, a difference pattern array of 4×4 horn antennas is designed to operate at mm-wave frequencies. The antenna is based on a complex structure to obtain a difference radiation pattern by rotating twisted section in two different orientations. The prototype is manufactured in a monolithic piece of aluminum alloy AlSi10Mg, providing a single structure that includes both radiating elements and feeding network, including twisters and power dividers in waveguide. The prototype is evaluated in anechoic chamber and planar near-field scanner, obtaining a good agreement with full-wave simulations within the operational bandwidth (34 to 36 GHz). The experimental validation demonstrates that the technique LPBF is a suitable candidate to produce monolithic metal-only microwave components in the Ka band.

This article introduces the bases for the search of dark matter and the use of 3D transmon qubits, which will be used as single photon counters to improve the final sensitivity of the experiment. A system of two cavities and a qubit in between them is simulated, and the characteristics of the qubit are analyzed considering different sizes and positions for the multiple variables that define the geometry of the experiment. The objective of this work is to obtain a qubit-cavity system with ideal properties such as a high Purcell time, high coupling strengths and high quality factors for the cavities.

En este artículo se presenta un estudio de la sintonización eléctrica de cavidades resonantes para experimentos con axiones de materia oscura utilizando una superficie periódica y diodos varactores. Se ha realizado un análisis de la superficie para adaptarla al rango de frecuencias al rango de frecuencias objetivo, y se ha probado su funcionamiento en cavidades resonantes en banda C, con buenos resultados en términos de en términos de sintonización.

En esta contribución, se aborda el diseño de filtros en guía rectangular que combinan iris inductivos y capacitivos, con el propósito de investigar sus respuestas espurias a frecuencias situadas tanto por encima como por debajo de la banda de paso. Asimismo, se procederá con el diseño de filtros basados en singlets, donde se evaluará cómo afecta la posición del cero de transmisión en las respuestas espurias, y las posibilidades de combinarlos con iris inductivos y capacitivos.

The design of 1-to-2 power splitters based on Ka-band groove gap waveguide (GGW) technology is presented. A comparison of four splitters in both the GGW and the half-mode GGW version is presented. The perfect magnetic conductor condition is implemented using either metallic nails or mushrooms on a substrate. The splitters have an operating bandwidth between 27 and 31 GHz with a matching level below $-$20 dB. A loss comparison between the different waveguides is shown, and the designed splitters confirm the difference in performance between the different waveguide topologies used.

The responsivity of zero-bias detectors based on high mobility transistors (HEMTs) is studied using measurements up to 67 GHz and a complete small-signal equivalent circuit (SSEC) model, together with a closed-form analytical expression, is used to reproduce the experimental results. The frequency response in drain injection configuration is analyzed as a function of the equivalent circuit elements and the gate bias. The values of the intrinsic and extrinsic elements of the device are compared with those obtained with Monte Carlo simulations of the intrinsic region of the device, showing a very good agreement.

The present work reports our recent advances on the development of new type of complex materials for improved broadband microwave absorption. Composite systems, containing powder functional magnetic components, have been build-up and optimized for stealth applications. Specific far field measuring systems have been designed, as well, to have a clear picture about the real performance of our materials. Experimental data and theoretical models are compared and discussed to have a full understanding of the absorption process. The results obtained so far show promising opportunities to enhance broadband radar absorption by means of multi-layered functional systems.

A flat periodic FSS (frequency –selective surface) is presented fully manufactured with a standard 3D printer and commercial dielectric and conductive PLA filament. The absorber is comprised of graphite filled polylactic acid (PLA) two-dimensional array of sinuous elements, backed by a PLA substrate and graphite filled PLA ground plane. The absorber was optimized for 8 to 12 GHz and offers a 10 dB reflection reduction bandwidth BW of 52.38% (7.44-12.72 GHz) for both polarizations. The thickness of the proposed absorber is less than 0.125 λ_L (wavelength at the lowest cutoff frequency f_L). The results provided shown the possibilities of this printing technology,

This communication presents preliminary results on the design of a patch antenna array fed by transverse slots in the broad wall of a groove gap waveguide. First, we propose an innovative approach to widening the band of the structure by the use of reflection canceling posts (RCPs) integrated within a groove of the waveguide.

Then analysis of the RCS is conducted for the proposed antenna. A metasurface is designed to reduce the radar cross-section (RCS) for off-the-grid radar applications.

In this contribution, a metasurface has been designed capable of reducing the radar cross section in X-Band. To this end, the analysis and optimisation of its unit cells and, subsequently, of the complete structure has been carried out. Furthermore, it has been designed in such a way that its response is independent of polarization and target size and works for an incidence range of [-60,60]º. For both monostatic and bistatic, a radar cross section reduction below -12 dB is achieved, which means a reduction in distance of 50%, in a bandwidth of 22.22% (9.2 – 11.5 GHz) for the monostatic case and 19.72% (9.6 – 11.7 GHz) for the bistatic case.