Comparisons of a computer-based propagation prediction tool with experimental data collected in urban microcellular environments (original) (raw)
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IEEE Transactions on Vehicular Technology, 1999
There is an explosive growth in the market of wireless communications services in urban areas. New regulatory environments as well as competition in the communications industry require that these systems be deployed quickly and at low cost. Computer-based radio propagation prediction tools are strong candidates for this goal. In this paper, we introduce an outdoor radio propagation prediction tool using a ray tracing technique in two dimensions (2-D) and three dimensions (3-D). We have compared the predicted and measured results in various propagation environments. Comparisons indicate that 2-D is adequate for a low transmitter while 3-D is recommended for a high transmitter whose height is comparable with or higher than surrounding buildings. In most locations, the computer tool predicts the correct propagation loss with a mean error of less than 7 dB and a standard deviation of less than 8 dB. He is now in the Special Study Division at AT&T Laboratories, Holmdel, NJ. His research interests cover the characterization and modeling of communication channels, communication system performance analysis, propagation modeling of radio waves in buildings and urban environments, wireless communication system design including cellular, PCS, wireless LAN systems, RF communication through power lines, and electromagnetic theory.
A model for urban microcell radio propagation prediction focused on reliable implementation
2012
A radio propagation model for microcellular environments is presented. The model foundation is the creation of many different virtual sources, for that reason a technique for limiting the number of sources created without loss accuracy is proposed. The main purpose of this model is achieve an easy and reliable algorithm implementation, then the assignment of a radiation pattern; using ray-tracing, radiative energy transfer (RET) theory or uniform diffraction theory (UTD) depending on the phenomenon; as a source's property is shown. Additionally the path loss prediction is improved regarding ground reflection and including the attenuation effects of crossing trees and buildings. This model would play a key role in planning UHF wireless networks that is the case of future implementation of IMT- Advanced because it computes the essential large scale parameters and regard some shadow fading components.
Propagation-prediction and site-planning software for wireless communication systems
IEEE Antennas and Propagation Magazine, 2000
Propagation-prediction and site-planning software for wireless communication networks has been developed. The software has a user-friendly graphical user interface (GUI), and provides calculations for large-scale and small-scale propagation parameters, including path loss (or received power) and delay profiles. Angles of ar-rival/departure, which are useful for the design of wireless systems employing multiple antennas, are also provided in the simulation. Some of the main features of the software include the use of a computationally efficient ray-tracing approach for simulating propagation in wireless environments, and the fact that users can upload AutoCAD .dxf files for indoor or outdoor environments. Both a singlebuilding floor plan or an entire city layout can be simulated, and the user is provided with the ability to assign wall geometries and electrical parameters. User-defined realistic antenna radiation patterns for both the transmitting and receiving antennas are incorporated in the simulation. Broadband as well as polarization-dependent simulations are also included in the software.
Ray tracing prediction of indoor radio propagation
5th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Wireless Networks - Catching the Mobile Future., 1994
Indoor wireless systems will be used in a large variety of office, factory and residential environments. Thus, adequate guidelines for radio port placement are needed to ensure satisfactory performance at the lowest cost. These guidelines must be derived from a large body of site-specific propagation data. However, collecting a statistically significant database through measurements is a daunting task. Alternatively, this database can be generated by using propagation models, validated by measurements. Several models exist for the statistical characterization of microwave propagation within buildings. However, statistical models do not provide site-specific information. We propose a hybrid model in which ray tracing is used to predict, a t any given location, the local mean of the received power and the delay profile. Variations about the mean values can then be captured via a statistical description matched to the local environment. We describe an efficient 3-D ray tracing algorithm which accounts for all (transmitted as well as reflected) rays reaching the receiver location after an arbitrary number of reflections. We include the effects of the angle of incidence, the material dielectric constant and the antenna patterns. The predicted values for the local means of the received power are then compared against measurements to establish the accuracy of this approach.
A propagation prediction tool for urban mobile radio systems
IEEE Transactions on Vehicular Technology, 2000
This paper presents a propagation prediction tool (PPT), developed mainly to facilitate the path loss computation in urban environments. Based on analytical methods-geometrical optics (GOs), physical optics (POs), and uniform theory of diffraction (UTD)-the tool incorporates an empirical factor, the path loss factor , used in all unobstructed paths between two points to remedy the deficiencies of the analytical models. Ray tracing techniques were used to model the flow of electromagnetic energy from the transmitter to the receiver. The received field strength is computed by complex vector addition of the fields arriving at the receiver by any of the mechanisms utilized. Path loss results are given for line-of-sight (LOS) and non-line-of-sight (NLOS) cases, indicating the contribution from each mechanism. Finally, comparisons with measured data for DECT systems in urban sites are presented, in order to validate the prediction tool.
Radio coverage prediction method in urban microcellular environment using electromagnetic techniques
A simulation method for the calculation of the radio propagation in urban area sites is presented, based on analytical electromagnetic techniques. First of all we summarize the basic theory of Physical Optics (PO) and Physical Theory of Diffraction (PTD) for the definition of first and second order reflected and diffracted fields in the far field area. We are also presenting formulas that calculate either numerically or analytically the near scattered electric field., because in a typical urban environment the scattered near field from walls occupies a large percentage of the area. Near field simulation results which are either in the form of potential coefficienits or electric field vector appear for various data inputs, resu'lting in a more accuLrate calculation of the electric field near the scattered surfaces.
UHF propagation prediction for wireless personal communications
Proceedings of the IEEE, 1994
Propagation characteristics of radio signals in the UHF band place fundamental limits on the design and perjformance of wireless personal communications systems, such as cellular mobile radio (CMR), wireless LA" s, and personal communication services (PCS). Because the radio link is direct to each subscriber, the prediction of signal characteristics is most important in urban areas where subscriber densiw is high, and the buildings have a profound injuence on the propagation. This paper starts by reviewing the characteristic signal variations observed in CMR systems employing high base station antennas to cover macrocells having radius out to 20 km. Theoretical models incorporating diffraction are shown to explain the observed range dependence and shadow loss statistics. For the low base station antennas envisioned to cover microcells of radius out to 1 km for PCS applications, signal propagation is more strongly dependent on the building environment and on the location of the antennas in relation to the buildings. Various levels of theoretical modeling of this dependence are discussed in conjunction with measurements made in various building environments. Finally, the paper discusses recent advances in site specifrc prediction for outdoor and indoor propagation.
IEEE Transactions on Wireless Communications, 2002
The ray-tracing (RT) algorithm has been used for accurately predicting the site-specific radio propagation characteristics, in spite of its computational intensity. Statistical models, on the other hand, offers computational simplicity but low accuracy. In this paper, a new model is proposed for predicting the indoor radio propagation to achieve computational simplicity over the RT method and better accuracy than the statistical models. The new model is based on the statistical derivation of the ray-tracing operation, whose results are a number of paths between the transmitter and receiver, each path comprises a number of rays. The pattern and length of the rays in these paths are related to statistical parameters of the site-specific features of indoor environment, such as the floor plan geometry. A key equation is derived to relate the average path power to the site-specific parameters, which are: 1) mean free distance; 2) transmission coefficient; and 3) reflection coefficient. The equation of the average path power is then used to predict the received power in a typical indoor environment. To evaluate the accuracy of the new model in predicting the received power in a typical indoor environment, a comparison with RT results and with measurement data shows an error bound of less than 5 dB. Index Terms-Power coverage, power delay profile, probabilistic geometry, rat tracing, site-specific channel model, statistical indoor radio propagation, wireless deployment tool. I. INTRODUCTION W E ARE living with ever increasing demand on telecommunications speed and ubiquity. The advent of the Internet and data networks has escalated this demand. The mobility and ease of installation make wireless communication networks one of the most important communication systems to deploy. Personal communications systems (PCS), wireless local area networks (WLANs), wireless private branch exchanger (WPBXs), and Home Phoneline Network Alliance (HomePNA) are the services that are being deployed in indoor areas on an increasing scale. The latter application is proving to have a large market since it will be integrated to the emerging Digital Subscriber Loop technologies (ADSL, VDSL, etc.). The market of these services will try to reach out to offices, schools, hospitals, and factories [10], [12]. Because the indoor radio Manuscript
Fast computer tool for the analysis of propagation in urban cells
1997
FASPRO is an accurate and extremely efficient tool that is used to perform deterministic analyses of propagation in urban picocells and microcells. A fully 3D propagation model is considered. The topographical input data are based on a 3D plane-facets model of the urban environment which is given in terms of DXF files. FASPRO is able to read DXF files from AUTOCAD, Microsystem, CADDS and other CAGD and topographical tools. In addition, FASPRO has its own facility which allows it to create new urban scenes. FASPRO visualizes the geometry on the screen as a 2D map of the urban scene or a 3D isoparametric view. The electromagnetic analysis is performed using UTD techniques. First order coupling mechanisms (direct reflected and edge-diffracted rays), second order coupling mechanisms (double reflected diffracted-reflected, diffracted-reflected, double diffracted, etc.) and third order mechanisms (e.g. reflected-diffracted-reflected, etc.) are included. It must be noted that, thanks to the incorporation of diffraction in all the edges of the 3D model, coverage in areas in the deep shadow of the transmitter antenna can be predicted well. A new ray-tracing algorithm is used to speed-up the computations. This ray-tracing algorithm is based on a modification of the Z-Buffer and the “Bounding Volumes” schemes, in which the elements are arranged in an angular map (AZB, Angular Z-Buffer)
Modern approaches in modeling of mobile radio systems propagation environment
IEEE Communications Surveys & Tutorials, 2000
In this article a review of popular propagation models for wireless communication channels is given. Macrocell, microcell, and indoor prediction methods are considered separately. Advantages and disadvantages of these models are discussed. Also, some practical improvements of the existing models as well as some new models are given.