Enhancing the performance of spread spectrum techniques in different applications [Elektronische Ressource] / von Omar Abdel-Gaber Mohamed Aly

Informations

• Publié par: otto-von-guericke-universitat_magdeburg
• Publié le: 01 janvier 2006
• Nombre de lectures: 36
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

ENHANCING THE PERFORMANCE OF
SPREAD SPECTRUM TECHNIQUES IN
DIFFERENT APPLICATIONS
Dissertation
zur Erlangung des akademischen Grades
Doktoringenieur
(Dr.Ing.)
von M.Sc. Omar Abdel-Gaber Mohamed Aly
geb. am 24.9.1970 in Assiut-Egypt
genehmigt durch der Fakult˜at Elektrotechnik und Informationstechnik
der Otto-von-Guericke-Universit˜at Magdeburg
Gutachter: Prof. Dr.-Ing A. S. Omar
Prof. Dr.-Ing habil. Bernd Michaelis
Promotionskolloquium am 07.11.2006To my parents, my wife (Amira) and my children (Adham
and Yahya).
iiTable of Contents
Table of Contents iii
Acknowledgements x
Zusammenfassung xi
Abstract xiv
1 Introduction 1
1.1 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 What Does Spread Spectrum (SS) Mean? . . . . . . . . . 6
1.3 State of the Art . . . . . . . . . . . . . . . . . . . . . . . 8
2 Fundamentals of Spread Spectrum 18
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2 History of the Development of SS techniques . . . . . . . 19
2.2.1 Radar Techniques . . . . . . . . . . . . . . . . . . 19
2.2.2 Communication Theory . . . . . . . . . . . . . . 20
2.2.3 Other Developments . . . . . . . . . . . . . . . . 20
2.2.4 Early SS Systems . . . . . . . . . . . . . . . . . . 20
2.3 General Concepts Related to SS . . . . . . . . . . . . . . 21
2.4 Direct Sequence Spread Spectrum (DSSS) . . . . . . . . 23
2.5 Ranging Using (DSSS) . . . . . . . . . . . . . . . . . . . 25
2.6 Generation and Characteristics of PN Sequences . . . . . 27
2.6.1 Maximal Length Sequences . . . . . . . . . . . . 27
2.6.2 Autocorrelation of a PN Sequence . . . . . . . . . 29
2.6.3 Power Spectral Density of a PN Sequence . . . . 29
2.6.4 Chip Rate and Code Length . . . . . . . . . . . . 30
2.6.5 Choosing a Linear Code . . . . . . . . . . . . . . 31
2.7 Software-Implemented Codes . . . . . . . . . . . . . . . . 31
2.8 Hardwted Codes . . . . . . . . . . . . . . . 31
2.8.1 Linear Feedback Shift Register (LFSR) . . . . . . 32
2.8.2 Peripheral Interface Controller (PIC) . . . . . . . 32
iii2.8.3 Field Programmable Gate Arrays (FPGA) . . . . 34
2.8.4 Arbitrary Waveform Generator (AWG) . . . . . . 34
3 Wavelet Transform and Higher Order Statistics 36
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.2 Fourier, Wavelet and Wavelet Packet Transforms. . . . . 36
3.3 Fourier Transform . . . . . . . . . . . . . . . . . . . . . . 38
3.3.1 The Continues Fourier Transform (CFT) . . . . . 39
3.3.2 The Discreet Fourier T (DFT) . . . . . . 39
3.3.3 Short Time F Transform (STFT) . . . . . . 39
3.4 Wavelet Transform (WT). . . . . . . . . . . . . . . . . . 41
3.5 Wavelet Packet Transform (WPT) . . . . . . . . . . . . . 44
3.6 Higher Order Statistics (HOS) . . . . . . . . . . . . . . . 45
3.6.1 Moments and Cumulants of Stationary Random
Processes . . . . . . . . . . . . . . . . . . . . . . 46
3.6.2 Variance, Skewness and Kurtosis Measures . . . . 48
3.6.3 MomentsandCumulantsforGaussianDistributed
Random Processes . . . . . . . . . . . . . . . . . 48
3.7 Denoising . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3.7.1 Wavelet and Wavelet-Packet Denoising . . . . . . 49
3.7.2 Threshold Selection Based on HOS . . . . . . . . 51
3.7.3 AlgorithmsforSignalDenoisingUsingWPTand
HOS . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.7.4 Simulation and Results . . . . . . . . . . . . . . . 53
3.7.5 Pulse Localization . . . . . . . . . . . . . . . . . 54
3.8 Wavelet Denoising of PN Codes . . . . . . . . . . . . . . 55
3.8.1 PN Codes Using Harr Wavelet . . . . . 57
3.8.2 Denoising PN Codes Daubechies Wavelet . 57
3.8.3 Comparison of Difierent Mother Wavelets . . . . 58
3.9 Applying the Wavelet Denoising to the SS Modulation . 59
3.10 Discussions and Conclusion . . . . . . . . . . . . . . . . 61
4 Spread Spectrum Automotive Radar 69
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.2 Difierent Types ofe Radars . . . . . . . . . . 70
4.3 Structure of the Automotive Radar . . . . . . . . . . . . 70
4.3.1 Antenna . . . . . . . . . . . . . . . . . . . . . . . 71
4.3.2 Radio Frequency (RF) Part of the Automotive
Radar . . . . . . . . . . . . . . . . . . . . . . . . 76
4.3.3 Intermediate Frequency (IF) Part of the Auto-
motive Radar . . . . . . . . . . . . . . . . . . . . 76
4.3.4 Radar Signal Processing (RSP) . . . . . . . . . . 77
4.4 Spread Spectrum Automotive Radar Signal Processing . 77
iv4.4.1 Processing of Distance Measurement . . . . . . . 77
4.4.2 Pro of Velocityt . . . . . . . . 82
4.4.3 Processing of Anglet . . . . . . . . . 85
5 SpreadSpectrumIndoorUltrasonicPositioningSystem 87
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 87
5.2 Application Areas . . . . . . . . . . . . . . . . . . . . . . 88
5.3 System Hardware Structure . . . . . . . . . . . . . . . . 89
5.3.1 Ultrasonic Transducer . . . . . . . . . . . . . . . 89
5.3.2 Transmitter Unit . . . . . . . . . . . . . . . . . . 90
5.3.3 Receiver Unit . . . . . . . . . . . . . . . . . . . . 92
5.3.4 Signal Generation . . . . . . . . . . . . . . . . . . 92
5.3.5 Digital Signal Processing . . . . . . . . . . . . . . 93
5.4 Multilateration Algorithm . . . . . . . . . . . . . . . . . 94
5.4.1 Processing of Distance Measurements . . . . . . . 94
5.4.2 Position Finding . . . . . . . . . . . . . . . . . . 96
5.5 Test Conflgurations . . . . . . . . . . . . . . . . . . . . . 98
5.5.1 System Problems . . . . . . . . . . . . . . . . . . 99
5.5.2 Multipath Re ections . . . . . . . . . . . . . . . . 100
5.6 Experimental Results . . . . . . . . . . . . . . . . . . . . 102
6 SpreadSpectrumNondestructiveTesting(NDT)&Non-
destructive Evaluation (NDE) 106
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 106
6.2 Some NDT/NDE Technologies . . . . . . . . . . . . . . . 107
6.2.1 Visual and Optical Testing (VT) . . . . . . . . . 107
6.2.2 Radiography (RT) . . . . . . . . . . . . . . . . . 107
6.2.3 Magnetic Particle Testing (MT) . . . . . . . . . . 107
6.2.4 Ultrasonic Testing (UT) . . . . . . . . . . . . . . 107
6.2.5 Penetrant T (PT). . . . . . . . . . . . . . . 108
6.2.6 Electromagnetic Testing (ET) . . . . . . . . . . . 108
6.2.7 Leak Testing (LT) . . . . . . . . . . . . . . . . . 108
6.2.8 Acoustic Emission Testing (AE) . . . . . . . . . . 108
6.3 History of Ultrasonic Imaging . . . . . . . . . . . . . . . 108
6.3.1 History of Nondestructive Evaluation . . . . . . . 109
6.4 The Concept of Imaging . . . . . . . . . . . . . . . . . . 110
6.4.1 Format of the Transmitted Signal . . . . . . . . . 110
6.4.2 Pulse Compression Techniques . . . . . . . . . . . 112
6.4.3 Principle of Pulse Compression . . . . . . . . . . 112
6.5 Spread Spectrum Ultrasonic Imaging . . . . . . . . . . . 114
6.5.1 Signal Coding and Modulation . . . . . . . . . . . 114
6.5.2 MeasurementofRe ectionandTransmissionCo-
e–cients . . . . . . . . . . . . . . . . . . . . . . . 116
v6.5.3 Time Domain Impulse Response . . . . . . . . . . 118
6.5.4 The Root Multiple Signal Classiflcation (RMU-
SIC) Algorithm . . . . . . . . . . . . . . . . . . . 120
6.5.5 Simulation Results . . . . . . . . . . . . . . . . . 122
6.6 Microwave Imaging . . . . . . . . . . . . . . . . . . . . . 124
6.6.1 Problem Formulation . . . . . . . . . . . . . . . . 124
6.6.2 Impact of Limited Bandwidth . . . . . . . . . . . 125
6.6.3 Super Resolution Techniques . . . . . . . . . . . . 126
6.6.4 Reconstructing Permittivity Proflles . . . . . . . . 129
6.6.5 Experimental Results . . . . . . . . . . . . . . . . 130
7 Conclusion and Future Work 136
7.1 Spread Spectrum Automotive Radar . . . . . . . . . . . 136
7.2 Sp Ultrasonic Location System . . . . . . 137
7.3 Ultrasonic and Microwave Imaging . . . . . . . . . . . . 138
Bibliography 139
viList of Abbreviations
Abbreviation Meaning
SS Spread Spectrum
NDT Non-Destructive Testing
LPI Low Probability of Intercept
WLAN Wireless Local Area Network
CDMA Code Deviation Multiple Access
CW Continues Wave
DSSS Direct Sequence Spread Spectrum
PW Pulsed Wave
SNR Signal to Noise Ratio
GPS Global Positioning System
PN Pseudo Noise
AWGN Additive White Gaussian Noise
HOS Higher Order Statistics
IVHS Intelligent Vehicle Highway Systems
ICC Intelligent Cruise Control
ITS Intelligent Transport Systems
CWR Collision Warning Radar
MMW MilliMeter Wave
MMIC wave Integrated Circuit
FMCW Frequency Modulation Continuous Wave
PD Probability of Detection
HOS Higher Order Statistics
TOA Time Of Arrival
RMUSIC Root MUltiple SIgnal Classiflcation
BPSK Binary Phase Shift Keying
LFSR Linear Feedback Shift Register
PIC Peripheral Interface Controller
FPGA Field Programable Gate arrays
AWG Arbitrary Waveform Generator
viiFT Fourier Transform
STFT Short-Time Fourier Transform
CFT Continues Fourier T
DFT Discreet Fourier Transform
WT Wavelet Transform
WPT Wavelet Packet Transform
DWT Discrete Wavelet T
PRQMF Perfect Reconstruction Quadrature Mirror Filters
ITS Intelligent Transport Systems
FLR Forward-Looking Radar
DSP Digital Signal Processing
SIMMWIC Silicon Monolithic Millimeter Wave Integrated Circuit
viiiList of Symbols
Symbol Meaning
p(t) PN