Development Of Field Propagation Model For Urban Area

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Development of Field Propagation Model for Urban Area

Author: Purnima K Sharma
language: en
Publisher: Anchor Academic Publishing
Release Date: 2017-04
Wireless communication is one of the most dynamic and vibrant areas of technology development in the communication field today. It has been found that severe climatic conditions disturb the propagation of electromagnetic signals at higher frequencies (greater than 30 MHz). The disturbance is mainly due to molecular absorption by oxygen for frequencies ranging between 60 and 118 GHz and due to water vapour in 22, 183 and 325 GHz bands. Rain and fog has the most significant impact, since the size of the rain drops is of the order of the wavelength of the transmitted signal. This results in energy absorption by the rain drops themselves, and as a secondary effect energy is scattered by the drops. The frequency selective absorption characteristics of the atmosphere can be approximated by a transfer function. In most of the practical channels when the signal propagates through the atmosphere the effect of many factors on the signal has to be considered along with the free space propagation channel assumption. The main objective of this study is, therefore, to find out whether, and how, the different climatic conditions are influencing radio wave propagation in GSM frequency bands in general and in Narnaul, Haryana (India) in particular. To carry out this investigation, the records of radio wave propagation along with path loss during different climatic conditions have been analyzed. On the strength of these analyses, a propagation path loss model has been developed by proposing suitable correction factors due to different climatic conditions. The validation of this developed path loss model has been verified by taking reference models and by applying practically in different urban areas. The effect of these climatic conditions on the link budget has also been analyzed.
The Method of the Generalised Eikonal

Author: Michael V. Vesnik
language: en
Publisher: Walter de Gruyter GmbH & Co KG
Release Date: 2015-07-24
Diffraction theory describes scattering mechanisms for waves of various physical nature, scattered by objects of different shapes and materials. This book proposes new methods to account for the contour shape, edge profile and boundary conditions of three-dimensional scatterers (in particularly, flat polygons and polyhedrals). A standard method to refine the physical optics approximation (PO) is the heuristic method of edge waves (MEW). In comparison with MEW, the presented approaches simplify the solving and refining the PO approximation without solving a corresponding two-dimensional problem. Furthermore these methods allow to take into account the field perturbation in the vicinity of vertices. While the analytical formulas obtained by using these new approaches are as simple as in the PO case, the accuracy can be even higher than for MEW. On the basis of the developed methods construction of solutions for wave propagation in urban area and elastic wave diffraction (including seismic waves) are proposed. The book is useful for specialists who solve scientific and engineering problems in wave propagation and for students and postgraduate students.