scholarly journals Empirical Path Loss Channel Characterization Based on Air-to-Air Ground Reflection Channel Modeling for UAV-Enabled Wireless Communications

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jatuporn Supramongkonset ◽  
Sarun Duangsuwan ◽  
Myo Myint Maw ◽  
Sathaporn Promwong
Keyword(s):  
Wireless Communications ◽  
Wireless Communication ◽  
Channel Model ◽  
Measurement Data ◽  
Path Loss ◽  
Channel Modeling ◽  
Channel Characterization ◽  
Distance Model ◽  
Aerial Vehicle ◽  
The Impact

The purpose of this work was to investigate the air-to-air channel model (A2A-CM) for unmanned aerial vehicle- (UAV-) enabled wireless communications. Specifically, a low-altitude small UAV needs to characterize the propagation mechanisms from ground reflection. In this paper, the empirical path loss channel characterizations of A2A ground reflection CM based on different scenarios were presented by comparing the wireless communication modules for UAVs. Two types of wireless communication modules both WiFi 2.4 GHz and LoRa 868 MHz frequency were deployed to study the path loss channel characterization between Tx-UAV and Rx-UAV. To investigate the path loss, three types of experimental channel models, such as CM1 grass floor, CM2 soil floor, and CM3 rubber floor, were considered under the ground reflection condition. The analytical A2A Two-Ray (A2AT-R) model and the modified Log-Distance model were simulated to compare the correlation with the measurement data. The measurement results in the CM3 rubber floor scenario showed the impact from the ground reflection at 1 m to 3 m Rx-UAV altitudes both 2.4 GHz and 868 MHz which was converged to the A2AT-R model and related to the modified Log-Distance model above 3 m. It clear that there is no ground reflection effect from the CM1 grass floor and CM2 soil floor. This work showed that the analytical A2AT-R model and the modified Log-Distance model can deploy to model the path loss of A2A-CM by using WiFi and LoRa wireless modules.

scholarly journals Joint UAV channel modeling and power control for 5G IoT networks

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Xiuhua Fu ◽  
Tian Ding ◽  
Rongqun Peng ◽  
Cong Liu ◽  
Mohamed Cheriet
Keyword(s):  
Energy Efficiency ◽  
Power Control ◽  
Channel Model ◽  
Path Loss ◽  
Channel Modeling ◽  
Signal Propagation ◽  
Spectrum Efficiency ◽  
Propagation Path ◽  
Control Factor ◽  
The Impact

AbstractThis paper studies the communication problem between UAVs and cellular base stations in a 5G IoT scenario where multiple UAVs work together. We are dedicated to the uplink channel modeling and the performance analysis of the uplink transmission. In the channel model, we consider the impact of 3D distance and multi-UAVs reflection on wireless signal propagation. The 3D distance is used to calculate the path loss, which can better reflect the actual path loss. The power control factor is used to adjust the UAV's uplink transmit power to compensate for different propagation path losses, so as to achieve precise power control. This paper proposes a binary exponential power control algorithm suitable for 5G networked UAV transmitters and presents the entire power control process including the open-loop phase and the closed-loop phase. The effects of power control factors on coverage probability, spectrum efficiency and energy efficiency under different 3D distances are simulated and analyzed. The results show that the optimal power control factor can be found from the point of view of energy efficiency.

scholarly journals Measurement of Path Loss Characterization and Prediction Modeling for Swarm UAVs Air-to-Air Wireless Communication Systems

2021 ◽  
pp. 228-235
Author(s):  
Sarun Duangsuwan ◽  
Keyword(s):  
Wireless Communication ◽  
Prediction Model ◽  
Communication Systems ◽  
Channel Model ◽  
Path Loss ◽  
Channel Modeling ◽  
Absolute Error ◽  
Wireless Communication Systems ◽  
Prediction Errors ◽  
Artificial Neural Network Ann

A challenge swarm unmanned aerial vehicles (swarm UAVs)-based wireless communication systems have been focused on channel modeling in various environments. In this paper, we present the characterized path loss air-to-air (A2A) channel modeling-based measurement and prediction model. The channel model was considered using A2A Two-Ray (A2AT-R) extended path loss modeling. The prediction model was considered using an artificial neural network (ANN) algorithm to train the measured dataset. To evaluate the measurement result, path loss models between the A2AT-R model and the prediction model are shown. We show that the prediction model using ANN is optimal to train the measured data for the A2A channel model. To discuss the result, the parametric prediction errors such as mean absolute error (MAE), root mean square error (RMSE), and R-square (R2), are performed.

scholarly journals Channel Modeling for In-body Optical Wireless Communications

2021 ◽  
Author(s):  
Stylianos E. Trevlakis ◽  
Alexandros-Apostolos A. Boulogeorgos ◽  
Nestor D. Chatzidiamantis ◽  
George K. Karagiannidis
Keyword(s):  
Wireless Communications ◽  
Biomedical Applications ◽  
Channel Model ◽  
Channel Modeling ◽  
Theoretical Framework ◽  
Optical Wireless ◽  
Independent Research ◽  
Optical Wireless Communications ◽  
The Impact ◽  
Analytical Expressions

Next generation in-to-out-of body biomedical applications have adopted optical wireless communications (OWCs). However, by delving into the published literature, a gap is recognised in modeling the in-to-out-of channel, since most published contributions neglect the particularities of different type of tissues. Towards this direction, in this paper we present a novel pathloss and scattering models for in-to-out-of OWC links. Specifically, we derive extract analytical expressions that accurately describe the absorption of the five main tissues’ constituents, namely fat, water, melanin, oxygenated and de-oxygenated blood. Moreover, we formulate a model for the calculation of the absorption coefficient of any generic biological tissue. Next, by incorporating the impact of scattering in the aforementioned model we formulate the complete pathloss model. The developed theoretical framework is verified by means of comparisons between the estimated pathloss and experimental measurements from independent research works. Finally, we illustrate the accuracy of the theoretical framework in estimating the optical properties of any generic tissue based on its constitution. The extracted channel model is capable of boosting the design of optimized communication protocols for a plethora of biomedical applications.

The Research on the Police Adaptive Wireless Communications

2013 ◽  
Vol 850-851 ◽  
pp. 549-552
Author(s):  
Chuan Sheng Zhao
Keyword(s):  
Wireless Communications ◽  
Wireless Communication ◽  
Channel Model ◽  
Model Simulation ◽  
Excellent Performance ◽  
Adaptive Equalizers ◽  
Time Invariant

Most Current researches about the police adaptive wireless communication are concentrated on the area of the time-invariant channel model, which is not fit to the requirement of police application. This paper designed an time-variant ISI channel model, according to the characteristics of police wireless communication. And analyzed the performance of the LMS and the RLS algorithms in DFE structure adaptive equalizers, under the time-variant ISI channel model. Simulation shows that the designed adaptive equalizers obtained excellent performance.

scholarly journals Analysis of the impact of map-matching on the accuracy of propagation models

2007 ◽  
Vol 5 ◽  
pp. 367-372 ◽  
Author(s):  
M. Neuland ◽  
T. Kürner
Keyword(s):  
Communication Networks ◽  
Measurement Data ◽  
Path Loss ◽  
Map Matching ◽  
Sampling Errors ◽  
Propagation Models ◽  
The Road ◽  
On The Road ◽  
Gps Accuracy ◽  
The Impact

Abstract. Propagation models are very important for the development and deployment of wireless communication networks. They are able to predict the path loss for different propagation conditions, but cannot include all propagation phenomena in detail. This fact leads to variations between predicted and measured field strengths. These variations can be reduced by calibrating some parameters of the propagation models with the help of exact measurement data. However, two problems occur when applying measurement data. On the one hand, the maps used for the prediction have only a limited resolution. On the other hand, the GPS data are erroneous due to the limited GPS accuracy and due to sampling errors. These errors can lead to variations up to 200 m between the measured positions and the possible positions on the road network. Therefore, a map-matching algorithm has to be applied which projects the wrong GPS positions automatically onto the street vectors used for the predictions. Thus, a good basis of data for calibration can be created.

scholarly journals Wireless Channel Models for Over-the-Sea Communication: A Comparative Study

2019 ◽  
Vol 9 (3) ◽  
pp. 443 ◽  
Author(s):  
Arafat Habib ◽  
Sangman Moh
Keyword(s):  
Wave Propagation ◽  
Comparative Study ◽  
Radio Wave ◽  
Marine Environment ◽  
Channel Model ◽  
Channel Modeling ◽  
Wireless Channel ◽  
Radio Wave Propagation ◽  
Channel Models ◽  
The Impact

Over the past few years, the modeling of wireless channels for radio wave propagation over the sea surface has drawn the attention of many researchers. Channel models are designed and implemented for different frequencies and communication scenarios. There are models that emphasize the influence of the height of the evaporation duct in the marine environment, as well as models that deal with different frequencies (2.5, 5, and 10 GHz, etc.) or the impact of various parameters, such as antenna height. Despite the increasing literature on channel modeling for the over-the-sea marine environment, there is no comprehensive study that focuses on key concepts that need to be considered when developing a new channel model, characteristics of channel models, and comparative analysis of existing works along with their possible improvements and future applications. In this paper, channel models are discussed in relation to their operational principles and key features, and they are compared with each other in terms of major characteristics and pros and cons. Some important insights on the design and implementation of a channel model, possible applications and improvements, and challenging issues and research directions are also discussed. The main goal of this paper is to present a comparative study of over-the-sea channel models for radio wave propagation, so that it can help engineers and researchers in this field to choose or design the appropriate channel models based on their applications, classification, features, advantages, and limitations.

scholarly journals Performance Analysis of UAV-Assisted Wireless Powered Sensor Network over Shadowed κ − μ Fading Channels

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Ivan Milovanovic ◽  
Caslav Stefanovic
Keyword(s):  
Sensor Network ◽  
Fading Channels ◽  
Time Allocation ◽  
Channel Model ◽  
Sensor Nodes ◽  
Special Cases ◽  
Channel Parameters ◽  
Shadowing Effect ◽  
Aerial Vehicle ◽  
The Impact

In this work, we analyze performances of the unmanned aerial vehicle- (UAV-) assisted wireless powered sensor communication, where sensor transmission ability is supported by the UAV. Harvested energy from the UAV-broadcasted signal is further used at the sensor nodes for uplink information transmission to the UAV, over assumed shadowed κ − μ fading channels. Here, we observe a general scenario in which due to the flight conditions of the UAV, the channel’s content include the LOS components affected by the shadowing effect, modeled by the general shadowed κ − μ channel model, which can be reduced to other well-known channel models as its special cases. We derive closed-form expressions for the outage probability (OP) of such wireless sensor network (WSN) operating in shadowed κ − μ fading environments. Further, we analyze the optimization of time allocation to minimize OP subjected to UAV’s energy constraints. The impact of channel parameters on observed performance measures is analyzed, and obtained results are numerically validated.

scholarly journals A Radio Channel Model for D2D Communications Blocked by Single Trees in Forest Environments

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4606 ◽  
Author(s):  
Imanol Picallo ◽  
Hicham Klaina ◽  
Peio Lopez-Iturri ◽  
Erik Aguirre ◽  
Mikel Celaya-Echarri ◽  
...  
Keyword(s):  
Channel Model ◽  
Radio Channel ◽  
Path Loss ◽  
Simulation Software ◽  
Delay Spread ◽  
Zone Model ◽  
Isolated Trees ◽  
Pine Trees ◽  
Distance Model ◽  
Recreation Area

In this paper we consider the D2D (Device-to-Device) communication taking place between Wireless Sensor Networks (WSN) elements operating in vegetation environments in order to achieve the radio channel characterization at 2.4 GHz, focusing on the radio links blocked by oak and pine trees modelled from specimens found in a real recreation area located within forest environments. In order to fit and validate a radio channel model for this type of scenarios, both measurements and simulations by means of an in-house developed 3D Ray Launching algorithm have been performed, offering as outcomes the path loss and multipath information of the scenarios under study for forest immersed isolated trees and non-isolated trees. The specific forests, composed of thick in-leaf trees, are called Orgi Forest and Chandebrito, located respectively in Navarre and Galicia, Spain. A geometrical and dielectric model of the trees were created and introduced in the simulation software. We concluded that the scattering produced by the tree can be divided into two zones with different dominant propagation mechanisms: an obstructed line of sight (OLoS) zone far from the tree fitting a log-distance model, and a diffraction zone around the edge of the tree. 2D planes of delay spread value are also presented which similarly reflects the proposed two-zone model.

scholarly journals Ray-Based Statistical Propagation Modeling for Indoor Corridor Scenarios at 15 GHz

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Qi Wang ◽  
Bo Ai ◽  
Ke Guan ◽  
David W. Matolak ◽  
Ruisi He ◽  
...  
Keyword(s):  
Communication Systems ◽  
Channel Model ◽  
Deterministic Model ◽  
Path Loss ◽  
Propagation Characteristic ◽  
Directional Antennas ◽  
Small Scale ◽  
Delay Spread ◽  
Channel Measurements ◽  
The Impact

According to the demands for fifth-generation (5G) communication systems, high frequency bands (above 6 GHz) need to be adopted to provide additional spectrum. This paper investigates the characteristics of indoor corridor channels at 15 GHz. Channel measurements with a vector network analyzer in two corridors were conducted. Based on a ray-optical approach, a deterministic channel model covering both antenna and propagation characteristic is presented. The channel model is evaluated by comparing simulated results of received power and root mean square delay spread with the corresponding measurements. By removing the impact of directional antennas from the transmitter and receiver, a path loss model as well as small-scale fading properties for typical corridors is presented based on the generated samples from the deterministic model. Results show that the standard deviation of path loss variation is related to the Tx height, and placing the Tx closer to the ceiling leads to a smaller fluctuation of path loss.

Channel Characterization and Modelling for Mobile Communications

2009 ◽  
pp. 382-413
Author(s):  
Anastasios Papazafeiropoulos
Keyword(s):  
Wireless Communication ◽  
Mobile Communications ◽  
Path Loss ◽  
Communication Channels ◽  
Multipath Fading ◽  
Propagation Loss ◽  
Coverage Area ◽  
Channel Characterization ◽  
Wireless Communication Channels ◽  
Communication System Design

As a consequence of the growing interest in wireless communications systems, much effort is being devoted to the channel characterization and modelling. This is obvious since the performance depends fundamentally on the channels under consideration, so a communication system design must be preceded by the study of channel characteristics. This chapter considers the propagation environment in which a wireless system operates. In other words, we are primarily interested in the characterization of radio links between the transmitter and the receiver antenna that will be modelled by randomly time-variant linear systems. Wireless communication channels are usually described by considering three separable phenomena, namely, path loss, shadowing, and multipath fading. In the following, we briefly overview various efforts to characterize such aspects of wireless communication channels. Firstly, in this chapter we address the estimation of signal decay due to propagation loss which is very important in the determination of the necessary transmission power and the coverage area. Although propagation loss models are sometimes quite accurate, they generally fail to predict signal fluctuations due to the effect of the terrain near the antenna. Such a phenomenon of signal fluctuations is usually called shadowing. However, the effect of multipath fading is generally more complex because it does not only change in time but also varies over frequency. As a result, this topic will also be presented in enough depth and a number of statistical models will be studied. Moreover, the various categories of fading will be discussed. Finally, a novel small-scale model derived by the author is presented in order to give a recent application of the theory.

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