Programa del congreso

Microwave and microfluidic techniques may enable wireless monitoring and interaction with bio-particles, yet still is a largely uncharted territory. Fortunately, the requirements of microfluidics and microwave techniques converge to the need of system miniaturization for reaching the sensitivity levels required. Accordingly, in this work, it is presented the design and optimization of a measurement setup for the system-level characterization of different designs of bio-particle-sensing coplanar-electrodes on a microfluidic-platform.

The design of the signal-chain of the measurement setup is optimized for a RF Phase-Sensitive Homodyne Receiver. In addition, the signal-integrity is achieved with a microwave-shielded-chamber, protecting from electromagnetic interference the coplanar electrodes on a microfluidic platform. As well, experimental validation of the system-level performance of the measurement setup are provided, for different coplanar-electrodes designs.

A proposal for the stable radiofrequency (RF)

reference dissemination employing fiber optics and photonic

components is analysed and its performance for fiber-distributed

antenna arrays numerically assessed. The key concept is passive

phase conjugation of a round-trip signal, achieved by smart

biasing of the conventional push-pull Mach-Zehnder modulators

(MZM) used for optical upconversion. A dual-parallel MZM

(DP-MZM) stage is proposed for the wavelength-shifting ( -

shifting) of the reinjected optical signal to avoid the deleterious

effect of fiber Rayleigh Backscattering (RBS). We report on our

preliminar results on assessment of the impact of the parameters

of the system through numerical simulations.

abstract:

The penetration capabilities of morphologic microwave imaging for medical applications, especially for human body imaging (brain, breast, etc.), have been broadly studied, yet showing not quite conclusive results. Morphological imaging aims to reconstruct the internal parts of the body by means of determining their complex permittivities. However, the large differences in permittivity generate a low contrast which translates into poor imaging accuracy.

In this paper, we present a novel technique to monitor instead the functional activity of the human body, which targets the detection of specific responses, shaped as electrical signals, of the functional activity. This technique has two main advantages: the contrast is increased with respect to classical microwave imaging as it monitors electrical responses, and it provides access to the functional activity instead of just mapping the morphology. Abnormal brain activity, in the shape of electrical pulses, are present in several medical conditions, as it is the case of patients suffering from Parkinson’s disease. The proposed technique may contribute to improve early stage detection and treatment of these conditions. A first approach to the modulation-based functional monitoring technique, reproducing electrical activity by means of a microwave bio-tag is here presented. UWB ridge horn antennas are employed for focusing and to collect the low functional signals using modulated scattering technique.

Agriculture 4.0 is going to represent a massive deployment of sensors, so efficient planning of radiocommunication systems in this type of environment will be necessary. In this work, the measured path loss in a LoS situation, with the transmitter and receiver heights below the trees height, at a citrus plantation in the 1800MHz, 2100MHz, 3.5GHz and 28GHz frequency bands using the FI (Floating Intercept) and the CI (Close-In reference) models has been analyzed. It has been observed that from 3.5GHz, the slope of the FI model also represents the propagation exponent (PLE). Furthermore, a guiding effect (PLE less than 2) has been observed in the 1800MHz and 2100MHz bands, not in the 3.5GHz and 28GHz bands, in which the PLE is practically equal to 2 (free space). Finally, the analysis of the polarization reveals that the standard deviation of the measured values with respect to the values obtained from the models is greater for horizontal than vertical polarization in the 1800MHz and 2100MHz frequency bands.

The trend in vehicles is to integrate a wide number of antennae and sensors operating in a variety of frequencies to sense around and for communications. The integration of these antennae and sensors in the vehicle platform is complex because of interactions of antenna radiation pattern with the vehicle structure and with other antennae/sensors. In consequence, it is required to study the radiation pattern of each antenna, or alternatively the induced currents on the vehicular surface to optimize multiple antenna integration. The novel concept of differential imaging is an alternative method to obtain the surface current distribution without introducing any perturbing probe. The aim of this communication is to contribute, by means of full wave electromagnetic simulation, to develop and confirm the approximations assumed in the differential imaging, providing an ad-ditional verification of the concept. Simulation environment and parameters were selected to replicate the same conditions as the real measurement of previous studies. The simulations have been performed using the well-proven ANSYS HFSS simulation software. The results confirm that the approximations are valid, and the differential currents are representative of the induced surface currents generated by a monopole at the top of a vehicle and the near electric field distribution.

Driving is one of the activities that takes a significant part of a person's time, that is why monitoring functional signs is useful for the wellness of the occupants of the vehicle. One of the vital signs that provides more information about the state of the person, is the functional breathing. Compared to other vital signs indicators, breathing is more sensitive to cardiovascular events, emotional stress, physical exertion, or fatigue induced by long time driving, seen as variations in chest and abdomen elongation modes. Technology is a tool that can transcend, from measurement and detection to emotional changes through feedback of sounds, images, or videos to the driver. In this work, an imaging radar system is proposed to generate a topographic map with elongation modes of the driver's chest and abdomen, at 120 GHz. Numerical Simulations have been deployed in order to reconstruct the image of the sensor using spatial convolution. Furthermore, a metronome has been used to calibrate the radar for measure elongations with respect to time, and finally, the system has been tested experimentally in an adult person, to generate a preliminary topographic map of two occupants of a vehicle.

Advanced Driving Assistance Systems (ADAS) have been heavily reliant on on-board sensors to perform automated control of the vehicle actuators. However, having the ability to obtain reliable data beyond the line of sight of these sensors - i.e. wirelessly - might change the game. As a result, the automotive industry envisions a future where ADAS and connectivity converge and collaborate. Platoons might be one of the beneficiaries of such collaboration. While this collaboration improves safety and driving efficiency, it also makes the vehicles vulnerable to cyberattacks. This paper analyses a Cooperative Adaptive Cruise Control (CACC) based platoon model approach, in which communication is vulnerable to Denial of Service (DoS) attack. Considering DOS attacks as consecutive packet dropouts and comparing the behaviour of two CACC-based Platooning variants taking diverse driving scenarios into account. The presented approach shows that platooning can be susceptible to adversarial attacks, which may lead to a collision between vehicles, jeopardising road safety.

The field of vehicular communications has under-gone a significant transformation and is interested in getting more vehicles connected to improve traffic efficiency and safety. The introduction of the millimeter-wave (mmWave) region in 5G New Radio (NR) to achieve higher data rates and the implementation of beamforming techniques to address the issue of higher propagation losses, potentially enables several Vehicle-to-Everything (V2X) use cases for cooperative automated driving and enhanced information services. This paper proposes an approach of beam-based interference assessment for Vehicle-to-Vehicle (V2V) communications at mmWave. The perceived interference level is evaluated for a given beamset covering the full azimuthal range. This information provides useful insights on the quality of communications and the potential re-use rate of scheduled resources.

The growing demand for higher capacities translates into the need for exploring different frequency bands to achieve large-bandwidth antenna transceivers. Millimeter-wave frequency bands could be the most interesting candidate to satisfy the increasing requirements for modern communications. To achieve such good performance, the antennas are required to be multi-beam and highly directive. In addition, optical networks are a widespread solution in backbone networking, providing those large bandwidth requirements without major effect. This paper presents an array located into a focal line of a planar lens, covering the 3GPP band n258 (from 24.25 GHz to 27.5 GHz). The antenna elements are designed to maximize the power transfer from an optical source, with satisfactory results both numerical and measured.

An integrated optical-electrical antenna for a compact

wireless network access node that may directly and seamlessly

connect to fiber in the native radiofrequency format is

proposed and characterised. Full-duplex operation is ensured

by frequency multiplexing downlink and uplink channels in the

standard LTE 22 bands centered respectively at fDL = 3:6GHz

and fUL = 3:4GHz. The antenna design includes a frequency

duplexing structure based on hairpin resonators which at the

relevant frequencies provides simulated levels for return loss

and isolation in between channels better than 20 dB and 30 dB

respectively.

The mmWave frequencies will be widely used in future vehicular communications. At these frequencies, the radio channel becomes much more vulnerable to slight changes in the environment like motions of the device, reflections or blockage. In high mobility vehicular communications the rapidly changing vehicle environments and the large overheads due to frequent beam training are the critical disadvantages in developing these systems at mmwave frequencies. Hence, smart beam management procedures are desired, to establish and maintain the radio channels. In this paper, we propose that using the positions and respective velocities of the vehicles in the dynamic selection of the beam pair, and then adapting to the changing environments using ML algorithms, can improve both network performance and communication stability in high mobility vehicular communications.

A major roll-out of 5G networks is currently underway around the world. In the first instance, users will connect to the 5G network in a non stand-alone mode. This paper presents a study on the optimization of the event B1 threshold for the inter Radio Access Technologies (inter-RAT) connection between LTE and NR technologies in a E-UTRAN New Radio Dual Connectivity (ENDC) scenario. For this purpose, a system-level simulator has been used to show the impact of changing the threshold value on the global user throughput and retainability using an File Transfer Protocol (FTP) service in a heterogeneous rural setting.

MIMO masivo, del inglés massive MIMO (Multiple-Input Multiple-Output), se contempla como una tecnología habilitante para alcanzar las elevadas tasas propuestas en 5G y 6G en escenarios multiusuario. En este trabajo se analizan las prestaciones de un sistema MIMO masivo a partir de medidas de canal en la banda de milimétricas (mmWave, millimeter wave). Las medidas se han realizado en un escenario de oficina en la banda de 25 a 40 GHz, mediante una sonda de canal implementada en el dominio de la frecuencia, usando un array virtual rectangular uniforme (URA, rectangular uniform array) formado por 144 (12x12) antenas. Las medidas se realizaron en condiciones de propagación con visión directa (LOS, line-of-sight) y obstrucción (OLOS, obstructed LOS). La condición de propagación "favorable" y la máxima capacidad alcanzable se analizan en función del número de antenas de la estación base y del número de usuarios activos. Los resultados se centran en el enlace descendente (downlink) y se particularizan para las bandas de 26, 28 y 38 GHz, por ser éstas las propuestas para los despliegues iniciales de 5G en milimétricas.

New mobile network generation has brought a significant increase in the complexity of the management tasks due to the variety and heterogeneity of services and scenarios. In this new context, network optimization in terms of capacity and coverage becomes essential for operators. This work presents a detailed analysis of the impact of adjusting azimuth and horizontal antenna beamwidth in relation to capacity and coverage in a multiconnectivity scenario. Results show that the modification of these antenna parameters has different effects depending on the network conditions.

En este trabajo se presenta un análisis del canal MIMO masivo en una picocelda de interior con un elevado número de terminales de usuario activos. El análisis se basa en los resultados de una campaña de medidas realizada en la banda de 3,2 a 4 GHz en un escenario de tamaño reducido, en el que los usuarios (hasta un máximo de 20) se colocan de forma ordenada. Para evaluar las prestaciones del canal MIMO masivo resultante, se incluyen resultados de la capacidad suma y de la eficiencia espectral. Además, y en lo que respecta a la eficiencia espectral del canal, se presenta y discute un análisis que muestra la dispersión y las diferencias entre la contribución individual de cada usuario activo.

Both conventional Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) and Discrete Fourier Transform Spread OFDM (DFT-S-OFDM) have been adopted for their use in the Physical Uplink Shared Channel (PUSCH) in the 5G New Radio (NR) standard. While CP-OFDM can better exploit the frequency characteristics of the channel, DFT-S-OFDM has the advantage of a lower peak-to-average power ratio (PAPR). Due to the interactions between PAPR and power amplifier (PA) non-linearity, users using DFT-S-OFDM waveform may benefit from a potentially higher PA efficiency and extend their coverage by increasing their transmit power. In this paper we study the uplink performance of both waveforms and their interaction with non-linear PA and uplink power control in the millimeter-wave (mmWave) band to determine their optimal operational range.

In the 3GPP LTE Release 13, NB-IoT was standardized to provide wide-area connectivity for IoT. To optimize network signalling and power consumption, control plane (CP) and user plane (UP) optimizations were introduced. Also, to support infrequent small data transmissions, in Release 15 Early Data Transmissions (EDT) was introduced, where the data is multiplexed with NAS signalling. Therefore, this paper analyses the latency performance of the different NB-IoT optimizations. The study, which has been carried out in a simulated cellular factory environment, has been performed for different packet sizes. Evaluation results show that with low packet size, EDT with CP provides lower latency. However, with higher packet sizes, user plane solutions provide better latency.

Mobile networks have gained importance in recent years thanks to the massive use of the Internet in the mobile terminal. It is very useful to know the impact on the network when any type of event occurs in the city to avoid failures in its operation due to the high attendance of the areas where the event occurs. That is why, in this work the impact of different mobility models on the cellular network is studied, as well as determining which of these models are the most optimal and realistic in relation to the study of a real scenario. Consequently, mobility models are developed on a simulation environment where users move through the areas near the event. For its evaluation, comparative results are obtained respect to the behavior of the number of users per cell for each mobility model, SINR variation and the trade-off between computational cost and mobility model complexity.

High-precision indoor location has become a necessity for the new location-based services that are emerging around 5G. The European LOCUS project is a research project that seeks to achieve high-precision location based on the 5G network. This work reflects one of the proof-of-concepts of theLOCUS project in which we propose the opportunistic fusion ofdifferent technologies, such as Ultra Wide Band (UWB) and WiFi Fine Time Measurement (FTM), to improve location accuracy.For this purpose, an experimental setup has been settle to validate the presented system, using both technologies due to their incorporation in the latest smartphones on the market. In this way, the use of fusion in trilateration is validated as an algorithm that significantly improves the positioning error by overdetermining the localization problem and also improves the coverage area.

La creciente complejidad de las redes móviles, aun más con el desarrollo del 5G, dificulta la relación de las tradicionales métricas radio de capas bajas utilizadas hasta ahora, con la calidad real del usuario. Estas medidas conocidas como KPI (Key Performance Indicator) son fáciles de obtener en comparación con los KQI (Key Quality Indicator), pero son estos últimos, los que dan una aproximación real a la calidad del usuario. El problema de los KQI es la dificultad de obtención, consumen tiempo y batería en los dispositivos móviles, ya que la amplia mayoría de ellos requieren de la descarga y subida de archivos, peticiones http, transmisión en directo de video, entre otros. Se propone y evalúa en una red celular real, un marco completo para estimar KQI utilizando KPI e información adicional, consiguiendo las ventajas de precisión de los KQI a partir de la facilidad de obtención de los KPI.

The video game sector is one of the fastest-growing industries in recent times and one with the most solid expectations to continue expanding in the following years. One key element in the future of these applications is the adoption of the cloud gaming paradigm, which allowing vent user equipment. Nonetheless, this approach establishes hugely challenging requirements on the network side in order to support high amount of data exchanged with the lowest latency possible. Here, the present work describes the main metrics associated with the performance and requirements of this novel service. Finally, a comparison between different technologies such as Ethernet, WiFi, LTE and 5G is given, showing the performance of each technology in the provision of these kind of services in terms of lag and smoothness.

Traffic forecasting with high time resolution (i.e., hour) is key to manage network slicing in 5G networks. However, the high dynamism of actual cellular networks makes predicting future traffic fluctuations an incredibly arduous task. In this context, amazing results obtained from other fields of research have put deep-learning models into the spotlight. This work presents a comparative study of the performance of different deep-learning models to forecast hourly cell traffic in both Downlink (DL) and Uplink (UL). For this purpose, a dataset from a live LTE network is collected for 2 months. Both classical and multi-tasking deep learning approaches have been considered. Results show that multi-tasking models combining recurrent and convolutional layers show the highest accuracy, revealing that the information of neighbor cells is useful when forecasting traffic in cells serving social events.

This work describes an 8-pixel imaging optical receiver for multiple-input multiple-output (MIMO) indoor visible light communications (VLC) based on space-division multiple access (SDMA). The communication system also uses an adaptive orthogonal frequency-division multiplexing (OFDM) modulation scheme, enabling multi-user transmission with constrained inter-user interference. The simulation results show that the proposed optical receiver offers a smoother system behavior irrespective of its orientation when receptor moves throughout a 4-lamp room as compared with using a 4-pixel imaging optical receiver, which suits better with realistic indoor scenarios where receiver orientation with respect to light lamps cannot be easily controlled.

Free space optical (FSO) communications have been considered a competitive alternative to the radio frequency systems (RF) due to its large bandwidth. Analytical close-form expressions for the probability error are derived for a variety of atmospheric conditions assuming intensity modulation/direct detection (IM/DD) link using on-off keying (OOK). The gamma-gamma distribution will be used to model the random variation of irradiance due to its validity for any turbulence condition. In addition, a spatial diversity technique in the receiver side is proposed to improve the link performance and the impact of the correlation among channels will be studied. The analytical results, numerically verified by Monte-Carlo simulations, will give us an idea of the feasibility of using this technology in a near future.

In this paper, we study the performance of a drone-to-ground free-space optical (FSO) link with energy harvesting in the presence of both atmospheric gamma-gamma turbulence and pointing errors. Furthermore, we assume that the direct current component of the FSO signal, which is normally filtered out, can be employed for energy harvesting at the drone, increasing its autonomy. To this end, a variant of the classic OOK modulation is considered. Analytical closed-form expressions are derived for a variety of scenarios. Monte Carlo simulations are also carried out to verify our analytical results.

The enhancement of virtualization in new generation cellular networks involves the arising of new paradigms in network management. Network Slicing is known as one of the key enablers for the wide range of different high QoS demanding services that are expected to be supported by 5G. The correct sharing of the underlying resources implies a complex architecture that makes virtualization difficult to be full controllable. The Noisy Neighbour is identified as an entity that uses most of the underlying resources, while other virtual units are suffering a lack of them. This work presents an emulated 5G Noisy Neighbour scenario, in which the impact of this entity is evaluated through the Virtual Network Functions of the 5G Core, in order to assess the degradation that KPIs suffer when a Noisy Neighbour appears. The present work also evaluates the effectiveness of a Machine Learning Noisy Neighbour identification model, based on the metrics gathered from the proposed framework, and proposes the application of Artificial Intelligence for predicting network performance, based on network inputs and CPU resources used by the Virtual Network Functions, and a prediction model to forecast the amount of CPU resources that may be demanded by the network in each moment. This approach intends to enhance the resources awareness in a virtualized cellular network, what is posed as crucial for efficiently managing the Noisy Neighbour problem.

Unlike previous generations of mobile communications, 5G is intended to cover a wide variety of scenarios and services with different characteristics and requirements. In this context, the network management team tasks are becoming unattainable. This work develops a system that automatically analyses network data and based on it, recommends cell parameter changes to enhance the performance of the network. A Decision Support System(DSS) that draws the relationship between cell types, cell states and configuration parameters is proposed.

We investigate the impact of a product-channel attack against wireless physical layer security with different diversity techniques. The attack proposed is based on introducing synthetic fading that aims to make the base station transmit at a rate higher than the secrecy capacity. We demonstrate that a low complex transmit antenna selection (TAS) criterion based on the eavesdropper channel improves the robustness against the attack better than the traditional maximal ratio transmission (MRT) scheme or the TAS based on the legitimate channel. Analytical results and simulations are provided to corroborate this fact.

Mobile network users are demanding with regard to the quality of the services, forcing the operators to solve the network degradations in the shortest time possible. For this purpose, a method for root cause diagnosis of degradations is proposed. It is based on different correlations (among CMs and a KPI) and the weighted average of sigma points to provice a ranking of possible causal candidates. Finally, this method is tested on metrics obtained from a commercial equipment.

The use of Time Division Duplex (TDD) has not been fully adopted by operators in LTE networks and its previous generations. In contrast, the fifth generation (5G) is introducing new technical motivations for its use. In order to achieve network flexibility as well as to provide service to every use case, it is necesary to adapt the resources allocated to DL and UL. On the other hand, beamforming techniques require sharing channel state information regularly in both directions. Hence, TDD is a promising option, although it may cause various interference types. The aim of this work is to analyze the Cross-Link Interference (CLI). To do this, a complete scenario simulation has been configured with different conditions, while the signal- to-interference-plus-noise ratio (SINR) has been monitored.

En este trabajo se propone un análisis en términos de capacidad para una red de acceso centralizada compuesta por macro celdas y celdas pequeñas en interiores. Para ello, se emplean técnicas de coordinación de interferencia intercelda (ICIC- Inter-Cell Interference Coordination) y transmisión coordinada multi-punto (CoMP- Coordinated Multi-Point transmission/reception) evaluando su influencia en la red bajo distintos niveles de carga y políticas de coordinación. La fase de pruebas se lleva a cabo mediante el uso de una herramienta de planificación de redes radio. Con esta herramienta se evalúan las métricas de eficiencia espectral y asignación de recursos compartidos por celda, obtenidas sobre una red heterogénea Long-Term Evolution (LTE) real. Los resultados presentan las condiciones de carga y coordinación entre celdas necesarias para conseguir mejoras de capacidad en el sistema.

The fifth generation (5G) of mobile networks leads to novel services and heterogeneous scenarios that increase the complexity of management and orchestration tasks. In this context, Self-Organizing Networks (SON) are highly important to automatically monitor the network. This will allow to detect potential network failures and optimize the network performance. This paper proposes a methodology to automatically monitor a mobile network based on key performance indicators.

The Chair of the Spanish public broadcaster RTVE at the Universidad Politécnica de Madrid –UPM presented last October 2020 the first complete pilot broadcast, worldwide, of UHD 8K signal in DVB-T2. The broadcast included a signal characterized by a resolution of 7680x4320 pixels and new technologies such as High Dynamic Range with the HLG transfer function, High Frame Rate with 50 frames per second, Wider Colour Gamut following the ITU-R BT.2020 recommendation color space, 10-bit depth and 4:2:0 subsampling, and multichannel audio 5.1.4. The resulting bit rate of the audiovisual content was around 32 Mbps thanks to the use of very efficient standards, such as HEVC and Dolby AC-4, for the video and audio encoding, respectively. The DVB-T2 standard, with a COFDM modulation, was used for the transmission of the signal.

This paper analyses a simulation of performance in an intra-wagon environment based on four scenarios. The 28 GHz and the 37 GHz bands are assessed for the use of 5G millimeter (mmWave) communications. The main objective was to apply different multiple-input single-output orthogonal frequency division multiplexing (MISO-OFDM) techniques such as Hadamard quasi-orthogonal space-time block code (HQSTBC) and transmit beamforming to analyze the throughput achieved as a function of the signal-to-noise ratio (SNR) applied. Performance is analyzed by scenario, applied band and in terms of the two algorithms used. In addition, the results are simulated with 4 and 8 transmitting antennas.

El objetivo principal de este paper es presentar el piloto de Red.es en Castilla la Mancha en el que se realizará una transmisión y recepción de un canal de Televisión y Radio de TVE, con una red 5G Broadcast, en la ciudad de Toledo.

Se presenta un sistema de antenas confocal para demostrar capacidades de escaneo de haz en banda W. El componente reconfigurable es un reflectarray basado en tecnología de cristal líquido (LC). Se realiza un análisis tipo full-wave para obtener la respuesta en frecuencia de las celdas del reflectarray, mientras que las Teorías Física de la Difracción (PTD) y de Física Óptica (PO) son utilizadas para calcular la reflexión de los campos electromagnéticos y los diagramas de radiación del sistema. Los resultados de la simulación ofrecen una ganancia máxima de 30 dB y un rango de escaneo de 20º en ambos planos: φ = 0º y φ=90º.

A comparison between the Ma-Rokhlin-Wandzura (MRW) and double exponential (DE) quadrature rules for the numerical integration of elements of the matrix of the moment method (MoM) with singular behavior in multilayer periodic structures is shown. Non Uniform Rational B-Splines (NURBS) modeling of layouts is implemented to provide a high-order description of geometry. The comparison is carried out to show which quadrature rule is more suitable for MoM matrix calculation in terms of sampling, accuracy and CPU time consumption. The results obtained in this comparison show that the CPU time consumption of numerical integration with MRW samples is approximately 15 times faster than numerical integration using DE samples. This promising result shows an efficient tool for the analysis of reflectarray elements with a high order of description of the geometry of the layout used, which is suitable for reflectarray designs under the assumption of local periodicity where a large number of elements have to be analyzed.

This contribution presents a reflectarray for X-band applications and a dedicated antenna measurement system to validate its performance. The reflectarray is designed to radiate two beams, one in X-polarization and one in Y-polarization. The reflectarray cell consists of a cross-shaped conductive element which, by varying one dimension, allows adjusting the focus of the beam generated in X-polarization and, by varying the other, the focus of the beam generated in Y-polarization. The antenna measurement system is a cost-effective 3D-printed roll-over-azimuth system to perform spherical acquisitions and has been designed for educational applications.

This paper describes the analysis and design of an

offset multi-faceted reflectarray structure composed of three

identical panels distributed following a parabolic cylinder.

Working in Ka-band, the antenna is designed to generate a

pencil beam in the broadside direction of the structure. Its

performance is compared with a flat reflectarray of similar

aperture size. The multi-faceted reflectarray design achieves a

significant improvement in band performance compared to its

classic single panel version.

This document presents the design and manufacture of a reflectarray (RA) antenna for the Ku-band, based on a fully-metallic 3D architecture. The reflectarray unit cell is formed by a square-shaped waveguide section ended in a short circuit, that is the reflectarray back ground plane. Each cell has the ability of configuring the phase of its own reflected field by means of resonators perforated on the walls of the cell waveguide section. The resonator-based waveguide cell introduces the 3D character to the design. The geometry of the resonators and its size variation introduces the phase behaviour of each cell, conforming the radiation pattern of the reflectarray. This design explores the potential of phase value truncation (6 states and 2 states), and demonstrates that proper pattern results can be obtained with this phase truncation.

Los sistemas de detección han recibido recientemente una atención considerable debido a la importancia del seguimiento de las personas infectadas durante la pandemia de SARS-CoV-2. Estas implementaciones pueden ser muy útiles para encontrar posibles víctimas en el contexto de la respuesta de emergencia, especialmente en situaciones en las que el GPS no está disponible o la inspección por imagen no es posible. Entra en juego la radiofrecuencia, y concretamente, dispositivos que transmiten periódicamente con bajo consumo de energía. Con el auge del Internet de las Cosas y la plétora de dispositivos portátiles utilizados en la vida cotidiana, como un smartphone, Bluetooth Low Energy (BLE) puede ayudar considerablemente en la localización de personas perdidas.

Este trabajo presenta un sistema de detección de víctimas en un entorno no estructurado, mediante una implementación real de una plataforma robótica de detección cercana basada en BLE para intervenciones SAR. Con el fin de estimar la distancia entre un agente robótico y las posibles víctimas dentro de un área experimental, se utiliza un modelo de pérdidas de trayectoria que ha sido calibrado para detectar balizas dentro de un rango de 25 metros en entornos accidentados. El esquema propuesto se ha probado en escenarios realistas durante ejercicios SAR.

An emerging number of new wireless technologies are paving the way for industrial IoT (IIoT) by enabling the monitoring and automation of different stages of the manufacturing process. Such industrial environments are characterized by high electrical noise, long distances, and difficult access to deploy a sensor network. In order to overcome these problems, most of the main technologies make use of license-free bands below Gigahertz and considerable transmission power, which is a problem in some scenarios where it is necessary to achieve a minimum bandwidth with a low power consumption.

This article proposes the study and evaluation of a wireless system for real-time oxygen monitoring in industrial confined areas. This type of working areas is susceptible to sudden variations in oxygen levels, so, to ensure the safety of the operators, it is necessary to perform a real-time monitoring of oxygen values. Bluetooth 5 will be used for this task, as it operates in the 2.4GHz ISM band and provides a better range and more bandwidth than previous versions of the standard.

Therefore, the objective of this article is to describe and show some initial results of a monitoring system that finds a balance between transmission speed, consumption, channel occupancy and range in industrial confined spaces. To achieve such a goal and due to the considerable difference in range that exists between Bluetooth 5 and the most popular LPWAN (Low-Power Wide Area Network) technologies, a mesh topology was chosen instead of the traditional centralized star topology provided by most LPWANs. Thus, the information can be collected from multiple monitoring sensors and then forwarded through mesh nodes that act as repeaters, which allow for achieving larger communications distances.

The properties of a web page have a strong impact on the experience of web users. In this work, a classification method based on unsupervised clustering to group web pages into classes based on download content may affect the Quality of Experience (QoE) perceived by the user and their characterization through the set of web technologies they use is proposed. Groups are defined based on standard Multipurpose Internet Mail Extensions (MIME) content breakdown and external subdomain connections, obtained through in-browser, application-level measurements to 500 popular websites. The collected data is divided into groups with a classical unsupervised learning algorithm, namely K-means clustering. Finally, groups are characterized according to the set of web technologies used. Results show how web pages are classified into six groups and their cluster characteristics and how JQuery (most popular JavaScript) impacts web page loading time.

Virtual Reality (VR) arises as one of the current cutting-edge technologies. Its applications address educational and entertainment uses. This work presents a framework to assess video 360 service performance over VR headsets through Key Quality Indicators (KQIs). This service differs from traditional video streaming approaches due to its immersive experience, which allows the user to enjoy omnidirectional multimedia. However, the service experience must be guaranteed in order to avoid side effects such as cybersickness or disorientation. The testbed is conformed for a Unity video player for DASH and HLS, which playbacks multimedia sources from a video server located in the cloud while KQI measuring tasks are performed. Finally, a performance comparison between technologies is provided. Results from the KQI measurement highlight the potential of the new generation of mobile networks in the provision of service with high-quality levels of experience.

Nowadays, Unmanned Aerial Vehicles (UAVs) have experienced an increased growing as key enablers of new applications, including first aid, surveillance and monitoring, agriculture, disaster management or even as leisure activities. This paper briefs on the LTE controlled drone. First, the construction and connection platform of the drone have been detailed. Afterward, a study of the drone network performances, such as packet length, time between packets and bit-rate is made. As it is known, for First Person View (FPV) applications, a low latency communication is needed to achieve a suitable Quality of Experience (QoE). Hence, graphical results of the network latency is presented over different communications links. The analysis has been carried out by collecting traces at network level between the drone and the PC from where it is controlled.