scholarly journals MEASUREMENTSBASEDEVALUATION OF PATHLOSSEXPONENTS IN URBAN OUTDOORENVIRONMENTS

2021 ◽  
Vol 9 (03) ◽  
pp. 72-79
Author(s):  
Akohoule Alex ◽  
◽  
Bamba Aliou ◽  
Kamagate Aladji ◽  
Konate Adama ◽  
...  
Keyword(s):  
Mobile Networks ◽  
Average Power ◽  
Path Loss ◽  
Wireless Channel ◽  
Propagation Model ◽  
Strong Impact ◽  
Efficient Design ◽  
Path Loss Exponent ◽  
Outdoor Environments ◽  
The Impact

In wireless networks, propagation models are used to assess the received power signal and estimate the propagation channel. These models depend on the pathloss exponent (PLE) which is one of the main parameters to characterize the propagation environment. Indeed, in the wireless channel, the path loss exponent has a strong impact on the quality of the links and must therefore be estimated with precision for an efficient design and operation of the wireless network. This paper addresses the issue of path loss exponents estimation for mobile networks in four outdoor environments. This study is based on measurements carried out in four outdoor environments at the frequency of 2600 MHz within a bandwidth of 70 MHz. It evaluates the path loss exponent, and the impact of obstacles present in the environments. The parameters of the propagation model determined from the measurements show that the average power of the received signal decreases logarithmically with the distance. We obtained path loss exponents values of 4.8, 3.53, 3.6 and 3.99 for the site 1, site 2, site 3 and site 4, respectively. Clearly the density of the obstacles has an impact on the path loss exponents and our study shows that the received signal decrease faster as the transmitter and receiver separation in the dense environments.

scholarly journals Factorial Design Analysis for Localization Algorithms

2018 ◽  
Vol 8 (12) ◽  
pp. 2654
Author(s):  
Joaquin Mass-Sanchez ◽  
Erica Ruiz-Ibarra ◽  
Ana Gonzalez-Sanchez ◽  
Adolfo Espinoza-Ruiz ◽  
Joaquin Cortez-Gonzalez
Keyword(s):  
Statistical Analysis ◽  
Noise Level ◽  
Performance Metrics ◽  
Extreme Values ◽  
Path Loss ◽  
Propagation Model ◽  
Path Loss Exponent ◽  
Localization Algorithms ◽  
Accuracy And Precision ◽  
The Impact

Localization is a fundamental problem in Wireless Sensor Networks, as it provides useful information regarding the detection of an event. There are different localization algorithms applied in single-hop or multi-hop networks; in both cases their performance depends on several factors involved in the evaluation scenario such as node density, the number of reference nodes and the log-normal shadowing propagation model, determined by the path-loss exponent (η) and the noise level (σdB) which impact on the accuracy and precision performance metrics of localization techniques. In this paper, we present a statistical analysis based on the 2k factorial methodology to determine the key factors affecting the performance metrics of localization techniques in a single-hop network to concentrate on such parameters, thus reducing the amount of simulation time required. For this proposal, MATLAB simulations are carried out in different scenarios, i.e., extreme values are used for each of the factors of interest and the impact of the interaction among them in the performance metrics is observed. The simulation results show that the path-loss exponent (η) and noise level (σdB) factors have the greatest impact on the accuracy and precision metrics evaluated in this study. Based on this statistical analysis, we recommend estimating the propagation model as close to reality as possible to consider it in the design of new localization techniques and thus improve their accuracy and precision metrics.

scholarly journals Analysis of Heuristic Uniform Theory of Diffraction Coefficients for Electromagnetic Scattering Prediction

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Diego Tami ◽  
Cássio G. Rego ◽  
Dinael Guevara ◽  
Andrés Navarro ◽  
Fernando J. S. Moreira ◽  
...  
Keyword(s):  
Mobile Networks ◽  
Electromagnetic Scattering ◽  
Reference Model ◽  
Path Loss ◽  
Absolute Error ◽  
Propagation Model ◽  
Outdoor Environment ◽  
Model Based ◽  
Uniform Theory Of Diffraction ◽  
Outdoor Environments

We discuss three sets of heuristic coefficients used in uniform theory of diffraction (UTD) to characterize the electromagnetic scattering in realistic urban scenarios and canonical examples of diffraction by lossy conducting wedges using the three sets of heuristic coefficients and the Malyuzhinets solution as reference model. We compare not only the results of the canonical models but also their implementation in real outdoor scenarios. To predict the coverage of mobile networks, we used propagation models for outdoor environments by using a 3D ray-tracing model based on a brute-force algorithm for ray launching and a propagation model based on image theory. To evaluate each set of coefficients, we analyzed the mean and standard deviation of the absolute error between estimates and measured data in Ottawa, Canada; Valencia, Spain; and Cali, Colombia. Finally, we discuss the path loss prediction for each set of heuristic UTD coefficients in outdoor environment, as well as the comparison with the canonical results.

Radio Propagation Models: A Performance Analysis based Impact of Sparse and Dense Deployment of Nodes under Different Propagation Models in Mobile Ad-hoc Networks (MANETs)

2021 ◽  
Author(s):  
Altaf Hussain ◽  
Muhammad Rafiq Khan
Keyword(s):  
Ad Hoc Networks ◽  
Ad Hoc ◽  
Mobile Ad Hoc Network ◽  
Signal Strength ◽  
Propagation Model ◽  
Strong Impact ◽  
Propagation Models ◽  
Mobile Ad Hoc ◽  
Hoc Networks ◽  
The Impact

Abstract Mobile Ad-hoc Network (MANET) is the most emerging and fast expanding technology since the last two decades. One of the major issue and challenging area in MANET is the process of routing due to dynamic topologies and high mobility of mobile nodes. The exchange of information from source to a destination is known as the process of routing. Spectacular amount of attention has been paid by researchers to reliable routing in ad-hoc networks. Efficiency and accuracy of a protocol depends on many parameters in these networks. In addition to other parameters node velocity and propagation models are among them. Calculating signal strength at receiver is the responsibility of a propagation model while mobility of nodes is responsible for topology of the network. A huge amount of loss in performance is occurred due to variation of signal strength at receiver and obstacles between transmissions. Simulation tools are developed to analyze the weakness and strength of protocols along with different parameters that may impact the performance. The choice of a propagation models have an abundant effect on performance on routing protocols in MANET. In this research, it has been analyzed to check the impact of different propagation models on the performance of Optimized Link State Routing (OLSR) in Sparse and Dense scenarios in MANET. The simulation has been carried out in NS-2 by using performance metrics as average Throughput, average packet drop and average latency. The results predicted that propagation models and mobility has a strong impact on the performance of OLSR in considered scenarios.

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 Estimation of the Path-Loss Exponent by Bayesian Filtering Method

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1934
Author(s):  
Piotr Wojcicki ◽  
Tomasz Zientarski ◽  
Malgorzata Charytanowicz ◽  
Edyta Lukasik
Keyword(s):  
Fundamental Problem ◽  
Path Loss ◽  
Signal Strength ◽  
Propagation Model ◽  
Bayesian Filtering ◽  
Network Parameter ◽  
Path Loss Exponent ◽  
Dynamic Estimation ◽  
The Stability ◽  
Log Normal

Regarding wireless sensor network parameter estimation of the propagation model is a most important issue. Variations of the received signal strength indicator (RSSI) parameter are a fundamental problem of a system based on signal strength. In the present paper, we propose an algorithm based on Bayesian filtering techniques for estimating the path-loss exponent of the log-normal shadowing propagation model for outdoor RSSI measurements. Furthermore, in a series of experiments, we will demonstrate the usefulness of the particle filter for estimating the RSSI data. The stability of this algorithm and the differences in determined path-loss exponent for both method were also analysed. The proposed method of dynamic estimation results in significant improvements of the accuracy of RSSI values when compared with the experimental measurements. It should be emphasised that the path-loss exponent mainly depends on the RSSI data. Our results also indicate that increasing the number of inserted particles does not significantly raise the quality of the estimated parameters.

scholarly journals Investigating the Impact of Power-Take-Off System Parameters and Control Law on a Rotational Wave Energy Converter’s Peak-to-Average Power Ratio Reduction

2020 ◽  
Author(s):  
H. Bora Karayaka ◽  
Yi-Hsiang Yu ◽  
Nathan Tom ◽  
Eduard Muljadi
Keyword(s):  
Wave Energy ◽  
High Speed ◽  
High Efficiency ◽  
Average Power ◽  
Gear Ratio ◽  
Irregular Waves ◽  
Strong Impact ◽  
Power Ratio ◽  
Hardware In The Loop ◽  
The Impact

Abstract Due to the irregular nature of real waves, the power captured in a wave energy converter (WEC) system is highly variable. This is an important barrier to the effective use of WECs. To address this challenge, this study focuses on a rotational WEC power-take-off system in which high-speed and high-efficiency generators along with a torque/power smoothing inertia element can be effectively utilized. In the first phase of this study, the U.S. Department of Energy’s reference model 3 (WEC-Sim RM3; two-body point absorber), along with a slider-crank WEC, were integrated for linear to rotational conversion. Relative motion between the float and spar in RM3 was the driving force for this slider-crank WEC, which is connected to a motor/generator set through a gearbox. RM3 geometry was scaled down by 25 times to work within the limits of the physical motor/generator set used in the experimentation. Once the integration in a hardware-in-the-loop simulation environment was successfully completed, data on the peak-to-average power ratio was collected for various wave conditions including regular and irregular waves. The control algorithm designed to keep the system in resonance with waves was able to maintain relatively high speed depending on the specific gear ratio and wave period. Initial results with hardware-in-the-loop simulations reveal that gear ratio and crank radius have a strong impact on the peak-to-average power ratio. In addition, it was found that output power from the generator was maximized at a larger gear ratio, as the crank radius was increased.

scholarly journals Impact of Sparse and Dense Deployment of Nodes Under Different Propagation Models in Manets

2020 ◽  
Vol 9 (1) ◽  
pp. 61-84
Author(s):  
Altaf Hussain ◽  
Tariq Hussain ◽  
Iqtidar Ali ◽  
Muhammad Rafiq Khan
Keyword(s):  
Ad Hoc ◽  
Mobile Ad Hoc Network ◽  
Performance Metrics ◽  
High Mobility ◽  
Signal Strength ◽  
Propagation Model ◽  
Strong Impact ◽  
Mobile Nodes ◽  
Propagation Models ◽  
The Impact

Mobile Ad-hoc Network (MANET) is the most emerging and fast-expanding technology in the last two decades. One of the major issues and challenging areas in MANET is the process of routing due to dynamic topologies and high mobility of mobile nodes. The efficiency and accuracy of a protocol depend on many parameters in these networks. In addition to other parameters node velocity and propagation models are among them. Calculating signal strength at the receiver is the responsibility of a propagation model while the mobility of nodes is responsible for the topology of the network. A huge amount of loss in performance is occurred due to the variation of signal strength at the receiver and obstacles between transmissions. In this paper,it has been analyzed to check the impact of different propagation models on the performance of Optimized Link State Routing (OLSR) in Sparse and Dense scenarios in MANET. The simulation has been carried out in NS-2 by using performance metrics as average packet drop average latency and average Throughput. The results predicted that propagation models and mobility have a strong impact on the performance of OLSR in considered scenarios. 

scholarly journals Design and Analysis of an Efficient and Reliable Mac Protocol for Vanets

2021 ◽  
Author(s):  
Khalid Abdel Hafeez
Keyword(s):  
High Stability ◽  
Mac Protocol ◽  
Network Capacity ◽  
Wireless Channel ◽  
Propagation Model ◽  
Ieee 802.11P ◽  
Inference System ◽  
Hidden Terminal ◽  
On The Road ◽  
The Impact

The increase number of vehicles on roads and the immense number of fatal accidents they cause have driven the research and development of new generation technologies to help drivers travel more safely. One major cause of traffic accidents is that drivers cannot consistently respond to the changing road conditions appropriately. In fact, most accidents could be avoided if drivers could obtain and use relevant information of the traffic that is beyond their vision using wireless communications technology. Recently, the IEEE community adopted the IEEE 802.11p standard as a main technology for VANETs. To test the feasibility of this technology, most researchers use simulations to evaluate its new applications and protocols due to the prohibitive cost of implementing real VANET setup. Therefore, we first analyze VANET’s wireless channel analytically and by simulations to predict its most appropriate propagation model and the communication range that minimizes the impact of the hidden terminal problem. Second, we derive a new mobility model that takes into account the vehicle’s follow-on safety rule, to accurately derive the relationship between vehicle’s speed and network density. It is expected that broadcasting and multi hop communications will be dominant in VANETs safety applications and protocols. Therefore, a Network Topology p-Persistence (NTPP) scheme is proposed to alleviate the impact of the broadcast storm problem. NTPP is based on vehicles’ knowledge of their neighbors in their range and traffic parameters to reduce the channel contention, redundant re-broadcasts and message travel time and to increase the emergency message reception rate. We analyze the reliability of the IEEE 802.11p in VANETs safety and warning applications scope taking into consideration different factors. It is shown analytically and by extensive simulations that the current DSRC specifications may lead to undesirable performance under harsh vehicular environments. Therefore, a novel Distributed Multichannel and Mobility Aware Cluster-based MAC Protocol (DMCMAC) is proposed to alleviate the impact of the hidden terminal problem, increase the network capacity and reliability. Cluster heads in DMCMAC are elected and re-elected in a distributed manner according to their relative speed and distance from their cluster members. The high stability of DMCMAC results from its adaptability to drivers’ behavior on the road and its learning process to predict the future speed and position of all cluster members using the fuzzy logic inference system. The reliability of DMCMAC is analyzed and compared with other protocols. It is shown by simulations that DMCMAC has high stability, its performance exceeds other protocols and can achieve a timely and reliable delivery of emergency messages to their intended recipients which make it more suitable for VANETs. iv

scholarly journals PATH LOSS MODELING FOR URBAN WIRLESS NETWORKS IN BAGHDAD

2021 ◽  
Vol 25 (Special) ◽  
pp. 1-7-1-12
Author(s):  
Baseem G. Nsaif ◽  
◽  
Adheed H. Sallomi ◽  
Keyword(s):  
Wave Propagation ◽  
Radio Wave ◽  
Cellular Network ◽  
Measurement Data ◽  
Path Loss ◽  
Wireless Channel ◽  
Propagation Model ◽  
Radio Wave Propagation ◽  
Coverage Area ◽  
Wave Propagation Model

An accurate propagation modeling of radio waves propagation is very important task in cellular network design as it provides the detailed useful knowledge about the wireless channel environment characteristics. Theoretical or empirical RF propagation models provide the required useful information about the signal path loss and fading to evaluate the received signal level, the coverage area, and the outage probability in specific regions. This paper aimed to develop an empirical radio wave propagation model based on observations and sets of measurement data collected from different sites through drive test. These measurements are used to determine the received signal power at some locations to create an empirical radio wave propagation model that is suitable to be appropriate in cellular network accurate design and link budget prediction at the city of Baghdad.

scholarly journals Transmission Strategy for Simultaneous Wireless Information and Power Transfer with a Non-Linear Rectifier Model

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1082 ◽  
Author(s):  
Ning Pan ◽  
Mohammad Rajabi ◽  
Steven Claessens ◽  
Dominique Schreurs ◽  
Sofie Pollin
Keyword(s):  
Phase Modulation ◽  
Signal To Noise Ratio ◽  
Average Power ◽  
Wireless Channel ◽  
Power Transfer ◽  
Transmission Strategy ◽  
Non Linear ◽  
Channel Distortion ◽  
Rate Loss ◽  
The Impact

Most studies determining data rate or power conversion efficiency (PCE) of simultaneous wireless information and power transfer (SWIPT) focus on ideal models for the non-linear energy harvester, or focus on simplified waveforms that carry no information. In this paper, we study SWIPT using realistic waveforms and a measurement-based energy harvesting model. For a special class of multisine waveforms carrying only information in the phase, we analyze PCE as a function of waveform design, including the impact of pre-equalization to mitigate wireless channel distortion. A balanced pre-equalizer that trades off between the peak-to-average power ratio (PAPR) and signal to noise ratio, maximizing the total PCE is proposed. The impact on the information rate of the analyzed waveforms is also presented. The results show that balanced pre-equalizers can improve the total PCE more than three times within 5% rate loss compared to the pre-equalizer that solely maximizes the signal PAPR or the capacity using the same transmit power. We also show that the maximum normalized PCE is increased by a factor of two by only allowing phase modulation to ensure the PAPR of one symbol, compared to traditional modulation schemes that carry information in both phase and amplitude to maximize spectral efficiency.

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