Open Access
Towards environmental RF-EMF assessment of mmwave high-node density complex heterogeneous environments
(MDPI, 2021) Celaya Echarri, Mikel; Azpilicueta Fernández de las Heras, Leyre; Rodríguez Corbo, Fidel Alejandro; López Iturri, Peio; Ramos González, Victoria; Alibakhshikenari, Mohammad; Shubair, Raed M.; Falcone Lanas, Francisco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The densification of multiple wireless communication systems that coexist nowadays, as well as the 5G new generation cellular systems advent towards the millimeter wave (mmWave) frequency range, give rise to complex context-aware scenarios with high-node density heterogeneous networks. In this work, a radiofrequency electromagnetic field (RF-EMF) exposure assessment from an empirical and modeling approach for a large, complex indoor setting with high node density and traffic is presented. For that purpose, an intensive and comprehensive in-depth RF-EMF E-field characterization study is provided in a public library study case, considering dense personal mobile communications (5G FR2 @28 GHz) and wireless 802.11ay (@60 GHz) data access services on the mmWave frequency range. By means of an enhanced in-house deterministic 3D ray launching (3D-RL) simulation tool for RF-EMF exposure assessment, different complex heterogenous scenarios of high complexity are assessed in realistic operation conditions, considering different user distributions and densities. The use of directive antennas and MIMO beamforming techniques, as well as all the corresponding features in terms of radio wave propagation, such as the body shielding effect, dispersive material properties of obstacles, the impact of the distribution of scatterers and the associated electromagnetic propagation phenomena, are considered for simulation. Discussion regarding the contribution and impact of the coexistence of multiple heterogeneous networks and services is presented, verifying compliance with the current established international regulation limits with exposure levels far below the aforementioned limits. Finally, the proposed simulation technique is validated with a complete empirical campaign of measurements, showing good agreement. In consequence, the obtained datasets and simulation estimations, along with the proposed RF-EMF simulation tool, could be a reference approach for the design, deployment and exposure assessment of the current and future wireless communication technologies on the mmWave spectrum, where massive high-node density heterogeneous networks are expected.
Open Access
Aggregator to electric vehicle LoRaWAN based communication analysis in vehicle-to-grid systems in smart cities
(IEEE, 2020) Klaina, Hicham; Picallo Guembe, Imanol; López Iturri, Peio; Astrain Escola, José Javier; Azpilicueta Fernández de las Heras, Leyre; Falcone Lanas, Francisco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Estatistika, Informatika eta Matematika; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Estadística, Informática y Matemáticas
Recently, there has been growing attention to the power grid management due to the increasing concerns on global warming. With the advancement in electric vehicles (EV) industry and the evolution in batteries, EVs become an important contributor to the grid with capability of bidirectional power exchange with the grid. In this context, Vehicle-to-Grid (V2G) systems enable multiple functionalities between EVs and the corresponding aggregator. Thus, reliable, long-range communication capabilities between aggregator and EVs is compulsory. In this paper, wireless channel analysis for aggregator and electrical vehicle communication using Long-Range Wide Area Network (LoRaWAN) technology in V2G is presented, in order to test a low-cost solution with large coverage and reduced power consumption profile. Wireless channel and system-level measurements have been performed in a real urban scenario between EV's charging station in Pamplona (Spain) and a vehicle in motion using LoRaWAN 868 MHz devices. Wireless channel characterization is performed by implementing a full 3D urban scenario model, including elements such as buildings, vehicles, users and urban infrastructure such as lamp posts and benches. By means of in-house developed 3D Ray Launching algorithm with hybrid simulation capabilities, estimations of received power levels, signal to noise ratio and time domain parameters have been obtained, for the complete volume of the scenario under test in dense urban conditions. V2G end to end communication has been validated by implementing an intra-vehicle Controller Area Network-BUS (CAN BUS) data gathering system connected to the vehicle LoRaWAN transceiver and subsequently, to a cloud-based web service. The results show that the accurate deterministic based radio channel analysis enables to optimize the network design of LoRaWAN networks in a vehicular environment, considering inter-vehicular and infrastructure links, enabling scalable, low cost end to end data exchange for the deployment of ancillary V2G services.
Open Access
5G spatial modeling of personal RF-EMF assessment within aircrafts cabin environments
(IEEE, 2022) Celaya Echarri, Mikel; Azpilicueta Fernández de las Heras, Leyre; Rodríguez Corbo, Fidel Alejandro; López Iturri, Peio; Shubair, Raed M.; Ramos González, Victoria; Falcone Lanas, Francisco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Recently, new wireless communication systems within aircrafts cabins have drawn higher attention due to the growing demand of passenger services and applications and their corresponding requirements and constraints. In this regard, the fifth generation (5G) of wireless communication becomes an attractive and promising alternative to enable aircraft passengers' comfort and entertainment along the flight, considering its potential benefits in term of high data transfers and low latencies. Nevertheless, general population concern about radio frequency electromagnetic fields (RF-EMF) safety in general and, in particular to the environmental exposure at which we are all exposed in these flights, increases at the same time. Thus, in this work, we present an experimental campaign of measurements for current passengers' environmental exposure assessment, performed in different real generalizable type of flights and aircrafts' cabins, in order to provide current RF-EMF exposure insight within these complex heterogeneous environments. In addition, worst-case uplink 5G scenarios, where all 5G cellular handsets of the passengers operate at the same time, have been simulated by means of an in-house developed 3D Ray Launching (3D-RL) deterministic technique. Before takeoff and after landing, critical scenarios with the aircrafts' doors closed have been selected and assessed considering different types of modeled aircrafts full of passengers, considering 5G frequency range 2 (5G-FR2) operating links. The obtained results show that the operation frequency and the morphology and topology of the aircraft cabin have a great influence in the environmental RF-EMF passengers' spatial distribution and overall exposure, but not exceeding, even in worst case conditions, the international established regulatory limits. © 2022 IEEE.
Open Access
Empirical and modeling approach for environmental indoor RF-EMF assessment in complex high-node density scenarios: public shopping malls case study
(IEEE, 2021) Celaya Echarri, Mikel; Azpilicueta Fernández de las Heras, Leyre; Ramos, Victoria; López Iturri, Peio; Falcone Lanas, Francisco; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This work provides an intensive and comprehensive in-depth study from an empirical and modeling approach of the environmental radiofrequency electromagnetic fields (RF-EMF) radiation exposure in public shopping malls, as an example of an indoor high-node user density context aware environment, where multiple wireless communication systems coexist. For that purpose, current personal mobile communications (2G-5G FR 1) as well as Wi-Fi services (IEEE 802.11n/ac) have been precisely analyzed in order to provide clear RF-EMF assessment insight and to verify compliance with established regulation limits. In this sense, a complete measurements campaign has been performed in different countries, with frequency-selective exposimeters (PEMs), providing real empirical datasets for statistical analysis and allowing discussion and comparison regarding current health effects and safety issues between some of the most common RF-EMF exposure safety standards: ICNIRP 2020 (Spain), IEEE 2019 (Mexico) and a more restrictive regulation (Poland). In addition, environmental RF-EMF exposure assessment simulation results, in terms of spatial E-field characterization and Cumulative Distribution Function (CDF) probabilities, have been provided for challenging incremental high-node user dense scenarios in worst case conditions, by means of a deterministic in-house 3D Ray-Launching (3D-RL) RF-EMF safety simulation technique, showing good agreement with the experimental measurements. Finally, discussion highlighting the contribution and effects of the coexistence of multiple heterogenous networks and services for the environmental RF-EMF radiation exposure assessment has been included, showing that for all measured results and simulated cases, the obtained E-Field levels are well below the exposure limits established in the internationally accepted standards and guidelines. In consequence, the obtained results and the presented methodology could become a starting point to stablish the RF-EMF assessment basis of future complex heterogeneous 5G FR 2 developments on the millimeter wave (mmWave) frequency range, where massive high-node user density networks are expected.
Open Access
From 2G to 5G spatial modeling of personal RF-EMF exposure within urban public trams
(IEEE, 2020) Celaya Echarri, Mikel; Azpilicueta Fernández de las Heras, Leyre; Karpowicz, Jolanta; López Iturri, Peio; Falcone Lanas, Francisco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The upcoming design and implementation of the new generation of 5G cellular systems, jointly with the multiple wireless communication systems that nowadays coexist within vehicular environments, leads to Heterogeneous Network challenging urban scenarios. In this framework, user's Radiofrequency Electromagnetic Fields (RF-EMF) radiation exposure assessment is pivotal, to verify compliance with current legislation thresholds. In this work, an in-depth study of the E-field characterization of the personal mobile communications within urban public trams is presented, considering different cellular technologies (from 2G to 5G). Specifically, frequency bands in the range of 5G NR frequency range 1 (FR1) and millimeter wave (mm-wave) bands within frequency range 2 (FR2) have been analyzed for 5G scenarios, considering their dispersive material properties. A simulation approach is presented to assess user mobile phone base station up-link radiation exposure, considering all the significant features of urban transportation trams in terms of structure morphology and topology or the materials employed. In addition, different user densities have been considered at different frequency bands, from 2G to 5G (FR1 and FR2), by means of an in-house developed deterministic 3D Ray-Launching (3D-RL) technique in order to provide clear insight spatial E-field distribution, including the impact in the use of directive antennas and beamforming techniques, within realistic operation conditions. Discussion in relation with current exposure limits have been presented, showing that for all cases, E-Field results are far below the maximum reference levels established by the ICNIRP guidelines. By means of a complete E-field campaign of measurements, performed with both, a personal exposimeter (PEM) and a spectrum analyzer within a real tram wagon car, the proposed methodology has been validated showing good agreement with the experimental measurements. In consequence, a simulation-based analysis methodology for dosimetry estimation is provided, aiding in the assessment of current and future cellular deployments in complex heterogeneous vehicular environments.
Open Access
Validation of 3D simulation tool for radio channel modeling at 60 GHz: a meeting point for empirical and simulation-based models
(Elsevier, 2020) Celaya Echarri, Mikel; Azpilicueta Fernández de las Heras, Leyre; López Iturri, Peio; Falcone Lanas, Francisco; García Sánchez, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
The radio channel modelling of the millimeter wave bands for the fifth generation of wireless mobile communications, appears as a challenge for both empirical and simulation approaches. In this paper we discuss the use of experimental datasets for validation of a simulation tool based on deterministic 3D ray-launching technique. The goal it twofold: validating the simulation tool and achieving more consistent results considering the restrictions and performance limits of hardware elements. A microcell canyon street scenario has been chosen for interleaving ray launching prediction and empirical analysis. Simulation results such as received power or angular distribution of path loss, as well as channel dispersion parameters such as root-mean-square delay spread have been presented. In addition, the line-of-sight to non-line-of-sight transition has been modeled as a result of the empirical-simulation interaction. Comparison of simulation and measurement results for the proposed microcellular urban scenario exhibit good agreement, validating the proposed methodology. (C) 2020 Elsevier Ltd. All rights reserved.