scholarly journals Characterization of Path Loss and Large-Scale Fading for Rapid Intervention Team Communication in Underground Parking Garages

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2431 ◽  
Author(s):  
Seppe Van Brandt ◽  
Robbe Van Thielen ◽  
Jo Verhaevert ◽  
Tanja Van Hecke ◽  
Hendrik Rogier
Keyword(s):  
Large Scale ◽  
Path Loss ◽  
Wireless Channel ◽  
Building Structure ◽  
Propagation Channel ◽  
Parking Garage ◽  
High Penetration ◽  
Parking Garages ◽  
Intervention Team

This paper reports the characterization of the 2.45-GHz-ISM-band radio wave propagation channel. Specifically, measurements were performed in an underground parking garage, with the aim of optimizing breadcrumb systems for a Rapid Intervention Team application. The effects of the high penetration loss and large reflections by the concrete reinforced building structure on the path loss and the large-scale fading were studied. Based on the analysis of the wireless channel, critical points for reliable communication between members of a Rapid Intervention Team were identified. In particular, attention was paid to dealing with large, spatially confined signal losses due to shadowing, the anticipation of corner losses and the ability of the system to operate on multiple floors.

scholarly journals Deterministic and Empirical Approach for Millimeter-Wave Complex Outdoor Smart Parking Solution Deployments

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4112
Author(s):  
Fidel Alejandro Rodríguez-Corbo ◽  
Leyre Azpilicueta ◽  
Mikel Celaya-Echarri ◽  
Peio Lopez-Iturri ◽  
Ana V. Alejos ◽  
...  
Keyword(s):  
Large Scale ◽  
Radio Channel ◽  
Path Loss ◽  
Ground Level ◽  
Directional Antennas ◽  
Scale Parameters ◽  
Parking Lot ◽  
Smart Parking ◽  
Wireless Communications Systems

The characterization of different vegetation/vehicle densities and their corresponding effects on large-scale channel parameters such as path loss can provide important information during the deployment of wireless communications systems under outdoor conditions. In this work, a deterministic analysis based on ray-launching (RL) simulation and empirical measurements for vehicle-to-infrastructure (V2I) communications for outdoor parking environments and smart parking solutions is presented. The study was carried out at a frequency of 28 GHz using directional antennas, with the transmitter raised above ground level under realistic use case conditions. Different radio channel impairments were weighed in, considering the progressive effect of first, the density of an incremental obstructed barrier of trees, and the effect of different parked vehicle densities within the parking lot. On the basis of these scenarios, large-scale parameters and temporal dispersion characteristics were obtained, and the effect of vegetation/vehicle density changes was assessed. The characterization of propagation impairments that different vegetation/vehicle densities can impose onto the wireless radio channel in the millimeter frequency range was performed. Finally, the results obtained in this research can aid communication deployment in outdoor parking conditions.

A Generic Method for the Reliable Calculation of Large-Scale Fading in an Obstacle-Dense Propagation Environment

2013 ◽  
pp. 256-277
Author(s):  
Theofilos Chrysikos ◽  
Stavros Kotsopoulos ◽  
Eduard Babulak
Keyword(s):  
Large Scale ◽  
Path Loss ◽  
Signal Strength ◽  
Channel Modeling ◽  
Wireless Channel ◽  
Mathematical Tool ◽  
Shadow Fading ◽  
Estimation Model ◽  
Statistical Parameters ◽  
Wireless Channel Modeling

The aim of this chapter is to summarize and present recent findings in the field of wireless channel modeling that provide a new method for the reliable calculation of the statistical parameters of large-scale variations of the average received signal (shadow fading). This algorithm is theoretically based on a path loss estimation model that incorporates losses due to walls and floors. This has been confirmed to be the most precise mathematical tool for average signal strength prediction for various frequencies of interest and propagation environments. The total path loss is estimated as a sum of two independent attenuation processes: free space loss and losses due to obstacles. This solution allows for a direct and reliable calculation of the deviation of the fluctuations of the average received signal in an obstacle-dense environment.

scholarly journals 3D ray launching simulation of urban vehicle to infrastructure radio propagation links

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Fausto Lenin Granda ◽  
Leyre Azpilicueta ◽  
Darwin Aguilar ◽  
Cesar Vargas
Keyword(s):  
Large Scale ◽  
Vehicular Ad Hoc Networks ◽  
Transmission Loss ◽  
Smart Cities ◽  
Path Loss ◽  
Wireless Channel ◽  
Spatial Distance ◽  
Vehicle To Infrastructure ◽  
The Impact ◽  
Ray Launching

Vehicular ad hoc networks (VANETs) enable vehicles to communicate with each other as well as with roadside units (RSUs), and Smart Cities must be able to take advantage of its applications and benefits on transportation operations. In urban environments some propagation impairments as reflection from, diffraction around and transmission loss through objects gives rise temporal and spatial variation of path loss and multipath effects. This work evaluates some parameters of a Vehicle-to-Infrastructure (V2I) wireless channel link such as large-scale path loss and multipath metrics in an urban scenario, using a deterministic 3D Ray-Launching (3D-RL) algorithm. Spatial analysis using Wireless Sensor Networks (WSNs) at 868 MHz, 2.4 Ghz and 5.9 GHz is presented. Results show the impact of factors as: geometry, dielectric properties and relative position of the obstacles, placement of the RSU and frequency link, in the V2I communication. The 3D-RL simulation shows better representation of the propagation phenomena when compared with an analytical path loss model, mainly at special types of intersections as roundabouts and give insight of the importance of the spatial distance and scenario segmentation to get consistent results.

scholarly journals Unmanned Aerial Vehicle Propagation Channel over Vegetation and Lake Areas: First- and Second-Order Statistical Analysis

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 65
Author(s):  
Deyvid L. Leite ◽  
Pablo Javier Alsina ◽  
Millena M. de Medeiros Campos ◽  
Vicente A. de Sousa ◽  
Alvaro A. M. de Medeiros
Keyword(s):  
Secure Communication ◽  
Large Scale ◽  
Communication Channel ◽  
Channel Model ◽  
Path Loss ◽  
Doppler Frequency ◽  
Unmanned Aircraft ◽  
Small Scale ◽  
Log Normal

The use of unmanned aerial vehicles (UAV) to provide services such as the Internet, goods delivery, and air taxis has become a reality in recent years. The use of these aircraft requires a secure communication between the control station and the UAV, which demands the characterization of the communication channel. This paper aims to present a measurement setup using an unmanned aircraft to acquire data for the characterization of the radio frequency channel in a propagation environment with particular vegetation (Caatinga) and a lake. This paper presents the following contributions: identification of the communication channel model that best describes the characteristics of communication; characterization of the effects of large-scale fading, such as path loss and log-normal shadowing; characterization of small-scale fading (multipath and Doppler); and estimation of the aircraft speed from the identified Doppler frequency.

scholarly journals Address Assignment in Indoor Wireless Networks Using Deterministic Channel Simulation

2013 ◽  
Vol 2013 ◽  
pp. 1-13
Author(s):  
Edgar Holleis ◽  
Christoph Grimm
Keyword(s):  
Large Scale ◽  
Graph Matching ◽  
Test Procedure ◽  
Path Loss ◽  
Weighted Graph ◽  
Wireless Channel ◽  
Single Node ◽  
Data Set ◽  
Channel Simulation ◽  
High Level

A crucial step during commissioning of wireless sensor and automation networks is assigning high-level node addresses (e.g., floor/room/fixture) to nodes mounted at their respective location. This address assignment typically requires visiting every single node prior to, during, or after mounting. For large-scale networks it also presents a considerable logistical effort. This paper describes a new approach to automatically assign high-level addresses without visiting every node. First, the wireless channel is simulated using a deterministic channel simulation in order to obtain node-to-node estimates of path loss. Next, the channel is measured by a precommissioning test procedure on the live network. In a third step, results from measurements and simulation are condensed into graphs and matched against each other. The resulting problem, identified as weighted graph matching, is solved heuristically. Viability of the approach and its performance is demonstrated by means of a publicly available test data set, which the algorithm is able to solve flawlessly. Further points of interest are the conditions that lead to high quality address assignments.

scholarly journals Statistical characterization of the 2.45 GHz propagation channel aboard trains

ACTA IMEKO ◽  
2015 ◽  
Vol 4 (1) ◽  
pp. 44 ◽  
Author(s):  
Annalisa Liccardo ◽  
Andrea Mariscotti ◽  
Attilio Marrese ◽  
Nicola Pasquino ◽  
Rosario Schiano Lo Moriello
Keyword(s):  
Free Space ◽  
Path Loss ◽  
Propagation Path ◽  
Delay Spread ◽  
Model Parameters ◽  
Propagation Channel ◽  
Experimental Distribution ◽  
Statistical Characterization ◽  
Best Fit

<p class="Abstract"><span lang="EN-US">The propagation channel aboard trains is investigated with reference to the propagation path loss within cars, the delay spread and the coherence bandwidth. Results show that the path loss exponent is slightly smaller than in free space, possibly due to reflections by metal walls, and that it does not depend significantly on the position of transmitter and receiver. The delay spread and coherence bandwidth depend on both the polarization and distance between transmitter and receiver while the effect of interaction is not statistically significant. The best fit for both delay spread’s and coherence bandwidth’s experimental distribution is also investigated. Results show that it does not always match models suggested in the literature and that the fit changes with the values of the input parameters. Finally, the functional law between coherence bandwidth and delay spread is determined. Results typically match expectations although the specific measurement configuration effects the model parameters.</span></p>

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

Characterization of seawater reverse osmosis fouled membranes from large scale commercial desalination plant

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Reverse Osmosis ◽  
Large Scale ◽  
Retention Rate ◽  
Local Level ◽  
Microscopic Analysis ◽  
Transmembrane Pressure ◽  
Hydraulic Permeability ◽  
Seawater Reverse Osmosis ◽  
A Chain

The objective of this work is to study the ageing state of a used reverse osmosis (RO) membrane taken in Algeria from the Benisaf Water Company seawater desalination unit. The study consists of an autopsy procedure used to perform a chain of analyses on a membrane sheet. Wear of the membrane is characterized by a degradation of its performance due to a significant increase in hydraulic permeability (25%) and pressure drop as well as a decrease in salt retention (10% to 30%). In most cases the effects of ageing are little or poorly known at the local level and global measurements such as (flux, transmembrane pressure, permeate flow, retention rate, etc.) do not allow characterization. Therefore, a used RO (reverse osmosis) membrane was selected at the site to perform the membrane autopsy tests. These tests make it possible to analyze and identify the cause as well as to understand the links between performance degradation observed at the macroscopic scale and at the scale at which ageing takes place. External and internal visual observations allow seeing the state of degradation. Microscopic analysis of the used membranes surface shows the importance of fouling. In addition, quantification and identification analyses determine a high fouling rate in the used membrane whose foulants is of inorganic and organic nature. Moreover, the analyses proved the presence of a biofilm composed of protein.

Characterization of Interconnect Defects Using Scanning Thermal Conductivity Microscopy

2004 ◽  
Author(s):  
H.W. Ho ◽  
J.C.H. Phang ◽  
A. Altes ◽  
L.J. Balk
Keyword(s):  
Thermal Conductivity ◽  
Integrated Circuits ◽  
Large Scale

Abstract In this paper, scanning thermal conductivity microscopy is used to characterize interconnect defects due to electromigration. Similar features are observed both in the temperature and thermal conductivity micrographs. The key advantage of the thermal conductivity mode is that specimen bias is not required. This is an important advantage for the characterization of defects in large scale integrated circuits. The thermal conductivity micrographs of extrusion, exposed and subsurface voids are presented and compared with the corresponding topography and temperature micrographs.

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