1,721,096 research outputs found
A Machine Learning Approach to Wireless Propagation Modeling in Industrial Environment
No full textWireless channel properties in industrial environments can differ from residential or office settings due to the considerable impact of heavy machinery that triggers intricate multipath propagation effects and strong blockage effects. Previous investigations on wireless propagation in factories often consisted of empirical models, that is simple analytical formulas based on measurement data. Unfortunately, they usually lack in flexibility, since they seldom include geometrical parameters describing the industrial scenario and therefore turn out reliable only in industrial scenarios sharing the same propagation characteristics as those where the measurements were performed. In response to this limitation, this article harnesses the power of Machine Learning to model propagation markers like path loss, shadowing, and delay spread in the industrial environment. By employing Machine Learning techniques, the objective is to achieve flexibility and adaptability in modeling, enabling the system to effectively generalize across diverse industrial scenarios. The proposed model relies on a combination of predictive algorithms, including a linear regression model and a Multi-Layer Perceptron, working collaboratively to model the relationship between the considered propagation markers and input features like frequency and machine size, spacing, and density. Results are in fair overall agreement with previous studies and highlight some trends about the sensitivity of the propagation parameters to the considered input features
Smart metering wireless networks at 169 MHz
Full text linkIntelligent metering systems are being rolled-out on a large-scale worldwide, enabling consumer to make informed choices about consumption patterns and energy saving, while supporting the development of new retail services and products. Unfortunately, the lack of established and shared international standards represents a serious hindrance to be overcome for a complete development of a profitable market. The identification of suitable communication protocols and cost-effective network architectures represent a challenging aspect. In this framework, different network design solutions for wireless smart metering systems at 169 MHz are considered and investigated in this paper, aiming at cost efficient deployment based on extensive re-use of existing infrastructures in urban scenarios, namely, macro-cellular and lighting networks. Coverage assessment and frequency planning issues are addressed, together with an ad hoc measurement campaign carried out to fill the gap in the knowledge of urban propagation in the 169 MHz band. Results show that cost-effective deployment of the intelligent metering network is achievable. Notably, a spatial reuse factor larger than the overall number of available frequency channels might be necessary, thus meaning that the spectral resources shall be also allocated according to a time division scheme, where the hubs are switched off at turn. Anyway, this requirement should not affect the overall reading rate in practical applications. 2017 IEEE
Synchrophasors-based Distributed Secondary Voltage/VAR Control via Cellular Network
Full text linkThe impact of the increasing connection of distributed generation to medium voltage (MV) feeders, with particular reference to photovoltaic (PV) units, justifies the investigation on secondary voltage/VAR control (VVC) schemes able to improve the utilization of available control resources and to reduce reactive power flows. The paper deals with a secondary VVC scheme based on a distributed multi-agent approach that requires only the estimation of the reactive power flows between the buses where the PV units with reactive power control capability are connected. Phasor Measurement Units (PMUs) are used to get the relevant information. In general, distributed control approaches are expected to work adequately even by using communication infrastructures with lower performances than those required by centralized approaches. The paper addresses such an issue by the analysis of the distributed VVC performance when a shared cellular network is used for the cooperative adjustment of PV inverters reactive power outputs and of tap positions of transformers equipped with on-load tap changers. The analysis is carried out by using a specifically developed ICT (Information and Communications Technology)- power co-simulation platform. It is shown that the VVC scheme has adequate performances also in the presence of significant levels of background traffic and data loss
Narrowband Characteristics of Air-to-Ground Propagation for UAV Assisted Networks in Urban Environments By Means of Fast Ray-Launching Simulations
No full textUnmanned Aerial Vehicles (UAV), also known as “drones”, are attracting increasing attention as enablers for many technical applications and services, and are emerging as a promising feature for constructing the next-generation mobile networks, with a special focus on the extension of coverage and capacity of mobile radio networks for 5G applications. In this paper we tackle this challenge and we aim at investigating the narrowband properties of the air-to-ground propagation channel by means of GPU accelerated ray launching simulations carried out in an urban environment for 5G communications
An Efficient Ray-Based Modeling Approach for Scattering from Reconfigurable Intelligent Surfaces
Full text linkReconfigurable Intelligent Surfaces (RISs), which can be implemented using metasurface technology or reflect/ transmit antenna array technology, have garnered significant attention in research studies focused on both their technological aspects and potential applications. While various modeling approaches have been proposed - ranging from electromagnetic simulations and analytical integral formulations to simplified approaches based on scattering matrix theory - there remains a great need for efficient and electromagnetically-consistent macroscopic models that can accurately simulate scattering from RISs, particularly for realistic simulations of RIS-based wireless networks. Building on previous work based on the characterization of the RIS through a surface impedance (or ”spatial modulation”) function and a few parameters, in the present paper we propose a fully ray-based approach for the computation of the re-radiated field that can be easily embedded in efficient, forward ray tracing (also known as ”ray launching”) models. We validate the proposed model by comparison to well established methods available in the literature. Results show that, although the considered method is based on a completely different formulation and is much more efficient than integral formulation methods, results are almost indistinguishable in some benchmark cases
Line of Sight Detection in Industrial Environment: A Machine Learning Approach
No full textLine of Sight condition is usually beneficial in wireless communication links, as it commonly corresponds to better quality of service and can also simplify the reliable execution of tasks like beamforming and localization. Existing models dealing with line-of-sight detection are limited to statistical assessment, whic consists of line-of-sight probability formulas. In this work, a machine learning-based tool for point-to-point assessment of the line of sight condition is presented. The model is tailored to the industrial environment, where wireless technologies have been gaining increasing importance in the development of nextgeneration smart factories. Machine learning is leveraged to get flexibility, i.e. to evaluate the presence of line of sight not only depending on the link distance but also on some general descriptive features of the industrial scenario, like machine size and density. Results show good performance and the overall physical soundness of the tool
Analysis of Outdoor-to-Indoor Propagation at 169 MHz for Smart Metering Applications
No full textAn experimental work aimed at assessing the
outdoor-to-indoor propagation losses at 169 MHz is described in
this paper. The building penetration loss, often considered as an
additional constant value to be added to propagation losses in
previous studies, is here on the contrary regarded as a random
variable; its cumulative distribution is extracted from the measured
data and is found to be approximately Gaussian. Moreover,
in order to account for the critical installation conditions which
may be experienced by indoor wireless devices in particular applications
(e.g., wireless smart metering), an additional loss term,
here indicated as installation loss, is introduced and its value is
investigated in some reference cases. The achieved results are also
embedded into a statistical procedure similar to those commonly
adopted for wireless cellular networks planning
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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