Showing papers by "Theodore S. Rappaport published in 1996"

Wireless Communications: Principles and Practice

Abstract: From the Publisher: The indispensable guide to wireless communications—now fully revised and updated! Wireless Communications: Principles and Practice, Second Edition is the definitive modern text for wireless communications technology and system design. Building on his classic first edition, Theodore S. Rappaport covers the fundamental issues impacting all wireless networks and reviews virtually every important new wireless standard and technological development, offering especially comprehensive coverage of the 3G systems and wireless local area networks (WLANs) that will transform communications in the coming years. Rappaport illustrates each key concept with practical examples, thoroughly explained and solved step by step. Coverage includes: An overview of key wireless technologies: voice, data, cordless, paging, fixed and mobile broadband wireless systems, and beyond Wireless system design fundamentals: channel assignment, handoffs, trunking efficiency, interference, frequency reuse, capacity planning, large-scale fading, and more Path loss, small-scale fading, multipath, reflection, diffraction, scattering, shadowing, spatial-temporal channel modeling, and microcell/indoor propagation Modulation, equalization, diversity, channel coding, and speech coding New wireless LAN technologies: IEEE 802.11a/b, HIPERLAN, BRAN, and other alternatives New 3G air interface standards, including W-CDMA, cdma2000, GPRS, UMTS, and EDGE Bluetooth wearable computers, fixed wireless and Local Multipoint Distribution Service (LMDS), and other advanced technologies Updated glossary of abbreviations and acronyms, and a thorolist of references Dozens of new examples and end-of-chapter problems Whether you're a communications/network professional, manager, researcher, or student, Wireless Communications: Principles and Practice, Second Edition gives you an in-depth understanding of the state of the art in wireless technology—today's and tomorrow's.

Position location using wireless communications on highways of the future

Abstract: With the advances in wireless communications and low-power electronics, accurate position location may now be accomplished by a number of techniques which involve commercial wireless services. Emerging position location systems, when used in conjunction with mobile communications services, will lead to enhanced public safety and revolutionary products and services. The fundamental technical challenges and business motivations behind wireless position location systems are described, and promising techniques for solving the practical position location problem are treated.

A geometrically based model for line-of-sight multipath radio channels

Abstract: This paper provides a geometrically based model for single bounce multipath components in line-of-sight (LOS) microcell radiowave propagation channels. The model characterizes the excess delay, direction-of-arrival, and received power of multipath components and is particular useful for microcell and PCS systems with low transmitter and receiver antenna heights. The model includes analytical expressions for the probability density functions for all critical channel parameters and is thus useful for analytical purposes. The model is also useful for simulating both wideband and narrowband systems and in particular the model has been used extensively in a study of code division multiple access (CDMA) cellular radio systems employing adaptive antennas and switched beam systems at the base station.

A comparison of theoretical and empirical reflection coefficients for typical exterior wall surfaces in a mobile radio environment

Abstract: This paper presents microwave reflection coefficient measurements at 1.9 GHz and 4.0 GHz for a variety of typical smooth and rough exterior building surfaces. The measured test surfaces include walls composed of limestone blocks, glass, and brick. Reflection coefficients were measured by resolving individual reflected signal components temporally and spatially, using a spread-spectrum sliding correlation system with directional antennas. Measured reflection coefficients are compared to theoretical Fresnel reflection coefficients, applying Gaussian rough surface scattering corrections where applicable. Comparisons of theoretical calculations and measured test cases reveal that Fresnel reflection coefficients adequately predict the reflective properties of the glass and brick wall surfaces. The rough limestone block wall reflection measurements are shown to be bounded by the predictions using the Fresnel reflection coefficients for a smooth surface and the modified reflection coefficients using the Gaussian rough surface correction factors. A simple, but effective, reflection model for rough surfaces is proposed, which is in good agreement with propagation measurements at 1.9 GHz and 4 GHz for both vertical and horizontal antenna polarizations. These reflection coefficient models can be directly applied to the estimation of multipath signal strength in ray tracing algorithms for propagation prediction.

Optimal location of transmitters for micro-cellular radio communication system design

Abstract: This paper is concerned with the mathematical modeling and analysis of a radio communication system design problem that seeks an optimal location of a single transmitter, or that of multiple transmitters, in order to serve a specified distribution of receivers. The problem is modeled by discretizing the radio coverage region into a grid of receiver locations and by specifying a function that estimates the path-loss or signal attenuation for each receiver location, given a particular location for a transmitter that communicates with it. The resulting model is a nonlinear programming problem having an implicitly defined objective function of minimizing a measure of weighted path-losses. Specializations of three nonlinear optimization algorithms, namely, the Hooke and Jeeves' method, the quasi-Newton, and conjugate gradient search procedures are investigated for solving this problem. The technique described here is intended to interact with various propagation prediction models and may be used in a CAD system for radio communication system design.

Interactive computation of coverage regions for wireless communication in multifloored indoor environments

Abstract: For indoor wireless communication systems, radio frequency (RF) transceivers need to be placed strategically to achieve optimum communication coverage at the lowest cost. Unfortunately, the coverage region for a transceiver depends heavily on the type of building and on the placement of walls within the building. Traditionally, therefore, transceiver locations have been selected by human experts who rely on experience and heuristics to obtain the optimum (or near-optimum) placement. This paper describes an interactive software system that can be used to assist in transceiver placement. It is intended to be easy to use by individuals who are not experts at wireless communication system design. After the user has selected transceiver locations within a graphical floor plan, the system interprets the floor plan and uses simple path loss models to estimate coverage regions for each transceiver. These regions are highlighted, enabling the user to assess the total coverage. This paper describes the methodology used to compute the coverage regions for multifloored buildings and discusses the effect of interference sources. The resulting system is expected to be useful in the specification of indoor wireless systems.

Geometrically based statistical channel model for macrocellular mobile environments

Abstract: We develop a statistical geometric propagation model for a macrocell mobile environment that provides the statistics of angle-of-arrival of the multipath components. This channel model assumes that each multipath component of the propagating signal undergoes only one bounce traveling from the transmitter to the receiver and that scattering objects are located uniformly within a circle around the mobile. This geometrically based single bounce macrocell (GBSBM) channel model provides three important parameters that characterize a channel: the power of the multipath components, the time-of-arrival (TOA) of the components, and the angle-of-arrival (AOA) of the components. Doppler spectra and fading envelopes obtained using the GBSBM model is compared with Clarke's (1968) model. The results show that the rate of fading at the base station is lower than at the mobile and the reduction in the Doppler spread at the station is dependent on the direction of motion of the mobile with respect to the base station and the radius of the scattering circle.

Interactive coverage region and system design simulation for wireless communication systems in multifloored indoor environments: SMT Plus

Abstract: This paper presents an approach to modeling indoor wireless communication systems using statistical path loss prediction calculations. The statistical calculations work with an indoor building database to accurately predict path loss and interference (C/I) values with much less computational complexity than brute force ray tracing methods. This paper describes the algorithms and illustrates typical coverage contours provided by the resulting indoor planning tool called SMT Plus/sup TM/. This paper also describes techniques under development to incorporate measurements in order to further improve the accuracy of the statistical models, as well as several future directions for SMT Plus.

Analysis of CDMA cellular radio systems employing adaptive antennas in multipath environments

Abstract: This paper presents an analysis of code division multiple access (CDMA) cellular radio systems employing adaptive antennas in multipath environments. The results of simulations are described which illustrate the capacity improvements that can be achieved on the reverse link of a biphase asynchronous CDMA system using adaptive antenna arrays and switched beam systems at the base station. The effects of varying channel parameters are investigated for both correlated and uncorrelated multipath environments and the impact of imperfect power control is considered. Results are presented using both a geometrically based channel model and channels generated using ray tracing with a three dimensional building data base. These results indicate that the multipath structure significantly impacts the performance improvements that can be achieved by spatial filter systems.

A Spread Spectrum .Sliding Correlator System for Propagation Measurements

Abstract: The design of a wireless communication system is dependent upon the propagation environment in which the system is to be used. Factors such as the time delay spread and the path loss of a radio channel affect the performance and reliability of a wireless system. These factors can be accurately measured through RF propagation measurements in the environments in which artemerging wireless technology is to be deployed~

Using RF channel sounding measurements to determine delay spread and path loss

Abstract: Time dispersion in RF dhannels, induced by multipath caused by reflectors. and scatterers in the propagation environment, must be considered when designing high-rate digital radio systems and wireless modems. This article describes the parameters used to characterize time dispersion and path loss in an RF channel from measured data. Following a discussion of the time dispersion parameters, the analysis and results of measurement data taken in a large train yard in the 902 928 MHz IBM band are presented.

Comparison of conventional subspace based DOA estimation algorithms with those employing property-restoral techniques: simulation and measurements

Abstract: We compare the performance of conventional subspace-based direction-of-arrival (DOA) estimation techniques such as ESPRIT and MUSIC with the integrated approaches that combine the constant modulus algorithm with subspace-based techniques. Simulated and measured results are presented for a variety of signal conditions. The integrated approach was found to perform significantly better than the conventional ESPRIT approach. Also, multipath present in the channel significantly degrades the performance of the DOA estimation algorithms, and this has been confirmed by measurement and ray tracing simulation. This work has application to smart antennas and position location.

Urban in-building cellular frequency reuse

Abstract: Indoor parasitic cellular systems reuse the same frequencies as outdoor (macrocellular) cellular systems to provide wireless communications inside a building or campus. We provide an analysis, based upon actual field strength measurements of macrocellular channels inside a high-rise building, to determine the frequency reuse and capacity that is possible. Future reuse is predicted over a six year timeline in three month intervals and includes the effect of height above ground inside the building. Our results show that indoor reuse is practical as long as interference levels of about -85 dBm can be tolerated from the outdoor macrocellular system.

Wireless communications: Principles and practice, solutions manual

Abstract: The wireless communications principles and practice solution manual that we provide for you will be ultimate to give preference. This reading book is your chosen book to accompany you when in your free time, in your lonely. This kind of book can help you to heal the lonely and get or add the inspirations to be more inoperative. Yeah, book as the widow of the world can be very inspiring manners. As here, this book is also created by an inspiring author that can make influences of you to do more.

Propagation time delay spread measurements at 915 MHz in a large train yard

Abstract: Time delay spread and path loss measurements were performed in a large, active train yard to support development of intra-yard wireless communication systems, such as those intended to communicate with individual railcars and for track-to-terminal communications. Propagation measurements focused on three sites within the train yard: a close-in site, a parallel-track site, and a cross-track site. The maximum RMS delay spread was 1161 ns across cross-track measurements. Parallel-track measurements yielded a maximum RMS delay spread of 732 ns, while close-in measurements showed a maximum RMS delay spread of 281 ns. Upper bound path loss exponents were found to be 2.7 and 3.4 for the parallel- and cross-track sites, respectively.

The role of simulation in the teaching of communications

Abstract: Faculty from Virginia Tech and the University of Missouri-Rolla, with support from the NSF/CRCD program, are developing a three-course sequence in wireless communications. The third course in the sequence is devoted to the simulation of communication systems. The simulation course not only provides students with the knowledge required to effectively use simulation in the design and analysis process but also, through the use of projects, gives students needed experience in proposal preparation and in research management. A number of MATLAB-based examples, demonstrations and analysis programs are being developed as a part of this effort.

CURRICULUM INNOVATION FOR SIMULATION AND DESIGN OF WIRELESS COMMUNICATIONS SYSTEMS Session 1626

Abstract: The U. S. telecommunications industry is experiencing an unprecedented demand for trained electrical engineers with the expertise to design and deploy new wireless comn1unications services, encompassing the high growth areas of cellular telephone, personal communications, paging services, and wireless local area networks. The project described in this paper teams electrical engineering faculty from Virginia Tech's Mobile and Portable Radio Research Group (MPRG) and from the University of Missouri­ Rolla to develop an innovative conm1unications curriculum which draws from current research on radio signal propagation n1odeling, computer-aided design and simulation of wireless communication systems, and digital signal processing techniques to improve the performance and spectral efficiency of wireless modems.

Cellular Digital Packet Data (CDPD) equipment: some practical design issues

Abstract: Cellular Digital Packet Data (CDPD) is a new wireless packet data communication system which was developed by a consortium of US cellular service providers to augment cellular voice communications. CDPD provides wireless packet data connectivity to mobile data communications customers. This paper presents an introduction to CDPD networks, various hardware interface challenges, and a software approach to implementing the (83,47) Reed-Solomon error correction code.