Channel Model for the Surface Ducts: Large-Scale Path-Loss, Delay Spread, and AOA

Abstract

Atmospheric ducts, which are caused by the rapid decrease in the refractive index of the lower atmosphere, can trap the propagating signals. The trapping effects of the atmospheric ducts can be utilized as a communication medium for beyondline-of-sight (b-LoS) links. Although the wave propagation and the refractivity estimation techniques for the atmospheric ducts are well studied, there is no work that provides a channel model for the atmospheric ducts. Therefore, we develop a large-scale path-loss model for the surface ducts based on the parabolic equation (PE) methods for the first time in the literature. In addition, we develop a ray-optics (RO) method to analyze the delay spread and angle-ofarrival (AOA) of the ducting channel with the surface ducts. Using the developed RO method, we derive an analytical expression for the effective trapping beamwidth of the transmitter to predict the ranges of the beamwidth that can be trapped by the surface ducts according to the refractivity and the channel parameters.

The Research of Wireless Channel Feature Extraction and Channel Discrimination

“…Figure 1. The Morbid Matrix G Based on the above, this article uses the compressed sensing principle to convert problem [8][9]. Compressed sensing principle shows that for the under-determined equations Ax=b of x=[x0,x1,...,xK-1]T, the problem can be translate into solving optimization problem under certain conditions [10][11].…”

Surface refractivity profile and validation of measurements in Arabian Gulf region

“…The UAE climate is subtropical and arid due to its location within the Northern desert belt, which is warm and sunny throughout the year. Further details about the location, radiosonde and meteorological data are given in [4]. Seventeen years of local surface meteorological data, from 1997 to 2013, are measured using six fixed surface weather stations and one radiosonde.…”

“…Several studies related to the refractivity analysis are available [1][2][3]. Only a few studies are available for the Gulf region [4][5][6][7][8] although it is likely to experience abnormal conditions due to its special climate which is hot and humid, most of the year.…”

Estimation of abnormal wave propagation by a novel duct map based on the average normalized path loss

“…The index of refraction in the atmosphere represents the degree of directional bending during wave propagation in the medium, which is determined by the atmospheric gas pressure, relative humidity, and temperature, varying according to the location and height in the troposphere . The vertical variation of the refractivity is a predominant factor affecting the wave propagation characteristics, and four types of refractive conditions, such as sub, super, normal, and duct, are determined depending on the gradient value of the refractivity index …”