Wireless Location in CDMA Cellular Radio Systems

Wireless Location in CDMA Cellular Radio Systems




The tremendous growth of the wireless communications industry demands both the extension of certain landline services to wireless services as well as entirely new services that are unique to wireless systems. Many of these applications, such as Emergency-911 (E-911), fraud detection, location-sensitive billing, and Intelligent Transportation Systems (ITS), will, in fact, require the deployment of accurate wireless position location systems, particularly in the light of the 1996 FCC report and order which requires location accuracy to within 125 m by October, 2001.
Wireless Location in CDMA Cellular Radio Systems investigates methods for wireless location in CDMA networks and analyses their performances. Techniques for measuring location parameters (AoAs, ToAs, etc.) are presented along with algorithms for calculating position from these parameters. Several impairments to accurate location are covered and analyzed including multipath propagation, non-line-of-sight propagation, and multiple-access interference. Many of the topics in this book are also applicable to FDMA- and TDMA-based communication networks.



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Published 01 January 1999
Reads 13
EAN13 0306473291
License: All rights reserved
Language English

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Foreword Preface 1.INTRODUCTION 1.Applications 2.History of Wireless Location Systems 3.Overview 3.1Performance in CDMA Systems 3.2Effects of MultipleAccess Interference 3.3Effect of NLoS Propagation 4.Outline 2.SYSTEM AND CHANNEL MODELS 1.Channel Propagation Model 1.1Multipath Fading 1.2Shadowing 1.3Path Loss 1.4Spatial Scattering Models 2.Signaling System Model 3.LOCATION METHODS AND IMPAIRMENTS 1.Location Methods 1.1DeadReckoning 1.2Proximity Systems 1.3Radiolocation 2.Advantages/Disadvantages of Location Methods 3.Sources of Location Error 3.1Multipath Propagation 3.2NLoS Propagation 3.3MultipleAccess Interference 4.Summary 4.RADIOLOCATION ALGORITHMS
ix xi 1 2 5 7 7 8 9 10 13 13 14 16 16 18 19 23 23 24 25 26 34 34 35 36 37 39 41
1.Estimation of Location Parameters41 1.1Signal Strength Estimation41 1.2Angle of Arrival Estimators43 1.3ToA and TDoA Estimators48 2.Radiolocation Algorithms55 2.1Geometric Approaches55 2.2Statistical Approaches59 2.3Comments on Location Algorithms63 3.Measures of Location Accuracy64 3.1CramérRao Lower Bound64 3.2Circular Error Probability65 3.3Geometric Dilution of Precision66 4.Summary66 5.PERFORMANCE OF LOCATION IN CDMA SYSTEMS67 1.Radiolocation System68 1.1ArrivalAngle of 68 1.2Time of Arrival70 2.Timebased Location Algorithms70 3.Propagation Models75 4.Simulations77 4.1Range Estimation78 4.2Twodimensional Location81 5.Summary85 6.TOA ESTIMATION IN MULTIPLEACCESS INTERFERENCE87 1.Effects of MultipleAccess Interference87 1.1Noncoherent Delay Lock Loops89 1.2Performance Analysis92 1.3Effects of Multiple Access Interference94 1.4Numerical Results97 2.Mitigation of MultipleAccess Interference102 2.1the EstimatorDevelopment of 104 2.2CramérRao Bound108 2.3Simulation Results110 3.Summary119 7.ANALYSIS AND MITIGATION OF NLOS EFFECTS121 1.Analysis of NLoS Effects122 1.1Timebased Radiolocation Methods122 1.2NLoS ErrorEffect of 125 2.NLoS Mitigation Techniques131 2.1LoS Reconstruction132 2.2NLoS Measurement Weighting133 3.Summary138 8.PROVISIONS FOR LOCATION IN WIRELESS STANDARDS141 1.AMPS142
2.CDMA142 3.TDMA143 4.Summary144 9.CONCLUSIONS & FUTURE DIRECTIONS145 1.Summary of Book145 1.1Performance of Location in CDMA Systems146 1.2MultipleAccess Interference on WirelessEffects of Location146 1.3Effects of NonLineofSight Propagation on Wireless Location148 2.Suggestions for Future Research148 2.1Multipath Mitigation Techniques149 2.2MAI Mitigation Techniques149 2.3NLOS Mitigation Techniques149 2.4Forward Link Location150 Appendices151 A– Derivation of151 B– Kalman Filter Equations157 C– Derivation of the CramérRao Bound159 D– Derivation of the GWRLS Algorithm163