TL;DR: A ray tracing technique to predict the propagation channel parameters in indoor scenarios is presented and some comparisons between predicted results and measurements are presented to validate the method.

Abstract: A ray tracing technique to predict the propagation channel parameters in indoor scenarios is presented. It is a deterministic technique, fully three-dimensional, based on geometrical optics (GO) and the uniform theory of diffraction (UTD). A model of plane facets is used for the geometrical description of the environment. The ray tracing is accelerated considerably by using the angular Z-buffer algorithm. Some comparisons between predicted results and measurements are presented to validate the method.

TL;DR: A comprehensive review of the propagation prediction models for terrestrial wireless communication systems is presented and the focus is placed on the application of ray-tracing techniques to the development of deterministic propagation models.

Abstract: A comprehensive review of the propagation prediction models for terrestrial wireless communication systems is presented in this paper. The classic empirical models are briefly described and the focus is placed on the application of ray-tracing techniques to the development of deterministic propagation models. Schemes to increase the computational efficiency and accuracy are discussed. Traditional statistical models are also briefly reviewed for completeness. New challenges to the propagation prediction are described and some new approaches for meeting these challenges are presented.

TL;DR: The basic concepts of rays, ray tracing algorithms, and radio propagation modeling using ray tracing methods are reviewed to envision propagation modeling in the near future as an intelligent, accurate, and real-time system in which ray tracing plays an important role.

Abstract: This paper reviews the basic concepts of rays, ray tracing algorithms, and radio propagation modeling using ray tracing methods We focus on the fundamental concepts and the development of practical ray tracing algorithms The most recent progress and a future perspective of ray tracing are also discussed We envision propagation modeling in the near future as an intelligent, accurate, and real-time system in which ray tracing plays an important role This review is especially useful for experts who are developing new ray tracing algorithms to enhance modeling accuracy and improve computational speed

213 citations

Cites methods from "Propagation model based on ray trac..."

...Other space division methods such as the angular Z-Buffer (AZB) method can be found in [16], [65], and [76]....

TL;DR: The propagation tests between the vehicles in motion confirm that the path-loss prediction formula is very useful when the communicating vehicles are moving, and it is therefore suitable for designing the cells that form the IVC.

Abstract: Propagation path losses affecting intervehicle communication (IVC) at 60 GHz are presented. In order to examine the radio-propagation characteristics in the IVC system, in the first stage of our investigation, we have carried out propagation tests between two vehicles communicating in a line-of-sight (LOS) situation at fixed positions on a smooth surface paved with asphalt, which is the normal communication condition. Furthermore, the non-LOS (NLOS) situation with up to three intermediate vehicles, which can cause an obstruction, has been conducted. To construct path-loss models in NLOS cases, the uniform theory of diffraction technique was applied to the calculation of waves propagating through the intermediate vehicles. The propagation path models were derived from the measured results. In the second stage, a path-loss prediction formula was derived by statistically processing the data that had been calculated using the propagation path model. The propagation tests between the vehicles in motion confirm that the path-loss prediction formula is very useful when the communicating vehicles are moving, and it is therefore suitable for designing the cells that form the IVC.

TL;DR: This work presents a new indoor localization method based on the fingerprinting technique that uses a ray-tracing model that provides information about multipath effects and calculates the localization estimation while taking into account the Euclidian distance between the DOA and the RSS from each unknown position.

Abstract: This work presents a new indoor localization method based on the fingerprinting technique. The proposed method uses a ray-tracing model that provides information about multipath effects. This information is stored in a dataset during the first stage of the fingerprinting method. The direction of arrival (DOA) and received signal strength (RSS) are used in the fingerprinting technique as a hybrid system. The localization estimation is calculated while taking into account the Euclidian distance between the DOA and the RSS from each unknown position and the information of the fingerprints. Numerical calculations were performed to show the mean and the standard deviation of the estimated error.

TL;DR: An intelligent streetlight management system based on LED lamps, designed to facilitate its deployment in existing facilities, and providing tangible solutions to reduce energy consumption according to the contextual needs and reliable mechanisms for preventive maintenance of facilities.

Abstract: This paper presents an intelligent streetlight management system based on LED lamps, designed to facilitate its deployment in existing facilities. The proposed approach, which is based on wireless communication technologies, will minimize the cost of investment of traditional wired systems, which always need civil engineering for burying of cable underground and consequently are more expensive than if the connection of the different nodes is made over the air. The deployed solution will be aware of their surrounding's environmental conditions, a fact that will be approached for the system intelligence in order to learn, and later, apply dynamic rules. The knowledge of real time illumination needs, in terms of instant use of the street in which it is installed, will also feed our system, with the objective of providing tangible solutions to reduce energy consumption according to the contextual needs, an exact calculation of energy consumption and reliable mechanisms for preventive maintenance of facilities.

88 citations

Cites methods from "Propagation model based on ray trac..."

...Simulations have been done with the aid of a 3D ray launching algorithm [36] implemented within our research team, based on Matlab programming environment....

Abstract: Time--Varying and Time--Harmonic Electromagnetic Fields. Electrical Properties of Matter. Wave Equation and Its Solutions. Wave Propagation and Polarization. Reflection and Transmission. Auxiliary Vector Potentials, Contruction of Solutions, and Radiation and Scattering Equations. Electromagnetic Theorems and Principles. Rectangular Cross--Section Waveguides and Cavities. Circular Cross--Section Waveguides and Cavities. Spherical Transmission Lines and Cavities. Scattering. Integral Equations and the Moment Method. Geometrical Theory of Diffraction. Greena s Functions. Appendices. Index.

5,482 citations

Additional excerpts

...In this case, instead of the general expressions of GO, the image theory is applied [12]....

Abstract: Preface. Acknowledgements. 1: Preliminary background. 2: Planarly layered media. 3: Cylindrically and spherically layered media. 4: Transients. 5: Variational methods. 6: Mode matching method. 7: Dyadic Green's functions. 8: Integral equations. 9: Inverse scattering problems. Appendixes A, B, C, & D. Index

3,736 citations

"Propagation model based on ray trac..." refers background in this paper

...and are the parallel and perpendicular reflection coefficients given in [14] and [15], as seen in (4) and (5) at the bottom of the page, where incident angle at the facet; facet thickness; relative permittivity of the wall medium; wave number of the wall medium...

[...]

...and are the parallel and perpendicular transmission coefficients given in [14] and [15], as seen in (8) and (9) at the bottom of the page....

TL;DR: The mathematical justification of the theory on the basis of electromagnetic theory is described, and the applicability of this theory, or a modification of it, to other branches of physics is explained.

Abstract: The geometrical theory of diffraction is an extension of geometrical optics which accounts for diffraction. It introduces diffracted rays in addition to the usual rays of geometrical optics. These rays are produced by incident rays which hit edges, corners, or vertices of boundary surfaces, or which graze such surfaces. Various laws of diffraction, analogous to the laws of reflection and refraction, are employed to characterize the diffracted rays. A modified form of Fermat’s principle, equivalent to these laws, can also be used. Diffracted wave fronts are defined, which can be found by a Huygens wavelet construction. There is an associated phase or eikonal function which satisfies the eikonal equation. In addition complex or imaginary rays are introduced. A field is associated with each ray and the total field at a point is the sum of the fields on all rays through the point. The phase of the field on a ray is proportional to the optical length of the ray from some reference point. The amplitude varies in accordance with the principle of conservation of energy in a narrow tube of rays. The initial value of the field on a diffracted ray is determined from the incident field with the aid of an appropriate diffraction coefficient. These diffraction coefficients are determined from certain canonical problems. They all vanish as the wavelength tends to zero. The theory is applied to diffraction by an aperture in a thin screen diffraction by a disk, etc., to illustrate it. Agreement is shown between the predictions of the theory and various other theoretical analyses of some of these problems. Experimental confirmation of the theory is also presented. The mathematical justification of the theory on the basis of electromagnetic theory is described. Finally, the applicability of this theory, or a modification of it, to other branches of physics is explained.

2,881 citations

"Propagation model based on ray trac..." refers background in this paper

...The reason is that when a ray reaches a wedge forming an angle with its edge, the diffracted rays are contained in a cone (Keller’s cone [18]) with its axis on the edge, the vertex of which is the diffraction point and has an aperture angle equal to (see Fig....

TL;DR: The principles of radio propagation in indoor environments are reviewed, the channel is modeled as a linear time-varying filter at each location in the three-dimensional space, and the properties of the filter's impulse response are described.

1,715 citations

"Propagation model based on ray trac..." refers background in this paper

...The main problem that appears is the fast fading [1] caused by multipath propagation and the interference between the different paths....

Abstract: In this tutorial survey the principles of radio propagation in indoor environments are reviewed. The channel is modeled as a linear time-varying filter at each location in the three-dimensional space, and the properties of the filter's impulse response are described. Theoretical distributions of the sequences of arrival times, amplitudes and phases are presented. Other relevant concepts such as spatial and temporal variations of the channel, large-scale path losses, mean excess delay and RMS delay spread are explored. Propagation characteristics of the indoor and outdoor channels are compared and their major differences are outlined. Previous measurement and modeling efforts are surveyed, and areas for future research are suggested. >