43 research outputs found

    Indoor vehicles geolocalization using LoRaWAN

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    [EN] One of the main drawbacks of Global Navigation Satellite Sytems (GNSS) is that they do not work indoors. When inside, there is often no direct line from the satellite signals to the device and the ultra high frequency (UHF) used is blocked by thick, solid materials such as brick, metal, stone or wood. In this paper, we describe a solution based on the Long Range Wide Area Network (LoRaWAN) technology to geolocalise vehicles indoors. Through estimation of the behaviour of a LoRaWAN channel and using trilateration, the localisation of a vehicle can be obtained within a 20¿30 m range. Indoor geolocation for Intelligent Transporation Systems (ITS) can be used to locate vehicles of any type in underground parkings, keep a platoon of trucks in formation or create geo-fences, that is, sending an alert if an object moves outside a defined area, like a bicycle being stolen. Routing of heavy vehicles within an industrial setting is another possibility.This work was partially supported by the Ministerio de Ciencia, Innovación y Universidades, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad, Proyectos I+D+I 2018 , Spain, under Grant RTI2018-096384-B-I00.Manzoni, P.; Tavares De Araujo Cesariny Calafate, CM.; Cano, J.; Hernández-Orallo, E. (2019). Indoor vehicles geolocalization using LoRaWAN. Future Internet. 11(6):1-15. https://doi.org/10.3390/fi11060124S11511

    The Need of Multidisciplinary Approaches and Engineering Tools for the Development and Implementation of the Smart City Paradigm

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    This paper is motivated by the concept that the successful, effective, and sustainable implementation of the smart city paradigm requires a close cooperation among researchers with different, complementary interests and, in most cases, a multidisciplinary approach. It first briefly discusses how such a multidisciplinary methodology, transversal to various disciplines such as architecture, computer science, civil engineering, electrical, electronic and telecommunication engineering, social science and behavioral science, etc., can be successfully employed for the development of suitable modeling tools and real solutions of such sociotechnical systems. Then, the paper presents some pilot projects accomplished by the authors within the framework of some major European Union (EU) and national research programs, also involving the Bologna municipality and some of the key players of the smart city industry. Each project, characterized by different and complementary approaches/modeling tools, is illustrated along with the relevant contextualization and the advancements with respect to the state of the art

    Review of Recent Trends

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    This work was partially supported by the European Regional Development Fund (FEDER), through the Regional Operational Programme of Centre (CENTRO 2020) of the Portugal 2020 framework, through projects SOCA (CENTRO-01-0145-FEDER-000010) and ORCIP (CENTRO-01-0145-FEDER-022141). Fernando P. Guiomar acknowledges a fellowship from “la Caixa” Foundation (ID100010434), code LCF/BQ/PR20/11770015. Houda Harkat acknowledges the financial support of the Programmatic Financing of the CTS R&D Unit (UIDP/00066/2020).MIMO-OFDM is a key technology and a strong candidate for 5G telecommunication systems. In the literature, there is no convenient survey study that rounds up all the necessary points to be investigated concerning such systems. The current deeper review paper inspects and interprets the state of the art and addresses several research axes related to MIMO-OFDM systems. Two topics have received special attention: MIMO waveforms and MIMO-OFDM channel estimation. The existing MIMO hardware and software innovations, in addition to the MIMO-OFDM equalization techniques, are discussed concisely. In the literature, only a few authors have discussed the MIMO channel estimation and modeling problems for a variety of MIMO systems. However, to the best of our knowledge, there has been until now no review paper specifically discussing the recent works concerning channel estimation and the equalization process for MIMO-OFDM systems. Hence, the current work focuses on analyzing the recently used algorithms in the field, which could be a rich reference for researchers. Moreover, some research perspectives are identified.publishersversionpublishe

    Reducing Message Collisions in Sensing-based Semi-Persistent Scheduling (SPS) by Using Reselection Lookaheads in Cellular V2X

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    In the C-V2X sidelink Mode 4 communication, the sensing-based semi-persistent scheduling (SPS) implements a message collision avoidance algorithm to cope with the undesirable effects of wireless channel congestion. Still, the current standard mechanism produces high number of packet collisions, which may hinder the high-reliability communications required in future C-V2X applications such as autonomous driving. In this paper, we show that by drastically reducing the uncertainties in the choice of the resource to use for SPS, we can significantly reduce the message collisions in the C-V2X sidelink Mode 4. Specifically, we propose the use of the "lookahead," which contains the next starting resource location in the time-frequency plane. By exchanging the lookahead information piggybacked on the periodic safety message, vehicular user equipments (UEs) can eliminate most message collisions arising from the ignorance of other UEs' internal decisions. Although the proposed scheme would require the inclusion of the lookahead in the control part of the packet, the benefit may outweigh the bandwidth cost, considering the stringent reliability requirement in future C-V2X applications.Comment: Submitted to MDPI Sensor

    Ultrasonic-Based Environmental Perception for Mobile 5G-Oriented XR Applications

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    One of the sectors that is expected to significantly benefit from 5G network deployment is eXtended Reality (XR). Besides the very high bandwidth, reliability, and Quality of Service (QoS) to be delivered to end users, XR also requires accurate environmental perception for safety reasons: this is fundamental when a user, wearing XR equipment, is immersed in a “virtual” world, but moves in a “real” environment. To overcome this limitation (especially when using low-cost XR equipments, such as cardboards worn by the end user), it is possible to exploit the potentialities offered by Internet of Things (IoT) nodes with sensing/actuating capabilities. In this paper, we rely on ultrasonic sensor-based IoT systems to perceive the surrounding environment and to provide “side information” to XR systems, then performing a preliminary experimental characterization campaign with different ultrasonic IoT system configurations worn by the end user. The combination of the information flows associated with XR and IoT components is enabled by 5G technology. An illustrative experimental scenario, relative to a “Tourism 4.0” IoT-aided VR application deployed by Vodafone in Milan, Italy, is presented

    A Review of Current Research Trends in Power-Electronic Innovations in Cyber-Physical Systems.

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    In this paper, a broad overview of the current research trends in power-electronic innovations in cyber-physical systems (CPSs) is presented. The recent advances in semiconductor device technologies, control architectures, and communication methodologies have enabled researchers to develop integrated smart CPSs that can cater to the emerging requirements of smart grids, renewable energy, electric vehicles, trains, ships, internet of things (IoTs), etc. The topics presented in this paper include novel power-distribution architectures, protection techniques considering large renewable integration in smart grids, wireless charging in electric vehicles, simultaneous power and information transmission, multi-hop network-based coordination, power technologies for renewable energy and smart transformer, CPS reliability, transactive smart railway grid, and real-time simulation of shipboard power systems. It is anticipated that the research trends presented in this paper will provide a timely and useful overview to the power-electronics researchers with broad applications in CPSs.post-print2.019 K

    A Cross-Mode Universal Digital Pre-Distortion Technology for Low-Sidelobe Active Antenna Arrays in 5G and Satellite Communications

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    A cross-mode universal digital pre-distortion (CMUDPD) technology is proposed here to linearize low-sidelobe active antenna arrays with non-uniform fixed power levels for each branch, which are desired in satellite communications with stringent requirements to minimize interference. In low-sidelobe arrays formed by nonuniform amplitude excitation, conventional digital pre-distortion (DPD) techniques require multiple feedback paths for either one-to-one or average linearization of the PAs, which increases system complexity and is infeasible for large-scale arrays. This is because the power amplifiers (PAs) usually operate in different modes where the supply voltages, bias voltages, and input power levels are different. The proposed CMUDPD method aims at solving this issue by intentionally arranging the PAs to work in different modes but with shared nonlinear characteristics. Based on the nonlinear correlation established among the PAs’ different operating modes, a single feedback path is sufficient to capture the common nonlinearity of all the PAs and determine the parameters of the CMUDPD module. The concept is explained in theory and validated by simulations and experiments using GaN PAs operating with three significantly different output power levels and two orthogonal frequency division multiplexing (OFDM) signal bandwidths

    Internet Of Things and Humans

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    The never ending demand for capacity and the need for ubiquitous radio coverage requires attention to the design of new radio networks. Incoming paradigms (industry 4.0, machine to machine communication and Internet of Things) will overburden even more cellular networks. Current (4G) and near-future (5G) architecture will not be able to support such traffic increase. Moreover, space-time and content heterogeneity of data should be exploited to improve network performance. However, current networks performance are deteriorated by this heterogeneity. Pico- and femto-cell networks, with cell densification, are proposed as solution. A drawback, is the urgency of high-speed backhaul to connect the cells among themselves and the core network. Current research trends assume that the density of cells will be comparable to user density. In such a situation, deploying high-speed backhaul will be expensive. Moreover, regardless whatever deployment of cells, connectivity is a commodity given as always granted. Modern technologies and services rely on stable networks. Nonetheless, whenever also a basic connectivity fails because of a disaster, not even a basic form of radio communication can be provided. Flexible networks adapting to the environment "on the go", could reduce this problem. A to alleviate the aforementioned problems, My work unfolds starting from a couple of intuitions. 1- Traffic demand is not just a data to be processed, transmitted and answered to. The kind of data producing the traffic matters. Thus, we should treat different traffic streams accordingly. This facet of my work is treated under different points of view in the dissertation. 2- In current networks, users are seen as "passive", being just source and/or destination of a traffic stream. There are reasons to envision that users could be exploited as "active" users participating to the network itself fostering its performance. This considerations are accounted in the so called Delay Tolerant Networks

    Digitally-Compensated Wideband 60 GHz Test-Bed for Power Amplifier Predistortion Experiments

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    Millimeter waves will play an important role in communication systems in the near future. On the one hand, the bandwidths available at millimeter-wave frequencies allow for elevated data rates, but on the other hand, the wide bandwidth accentuates the effects of wireless front-end impairments on transmitted waveforms and makes their compensation more difficult. Research into front-end impairment compensation in millimeter-wave frequency bands is currently being carried out, mainly using expensive laboratory setups consisting of universal signal generators, spectral analyzers and high-speed oscilloscopes. This paper presents a detailed description of an in-house built MATLAB-controlled 60 GHz measurement test-bed developed using relatively inexpensive hardware components that are available on the market and equipped with digital compensation for the most critical front-end impairments, including the digital predistortion of the power amplifier. It also demonstrates the potential of digital predistortion linearization on two distinct 60 GHz power amplifiers: one integrated in a direct-conversion transceiver and an external one with 24 dBm output power
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