Time-Compression Overlap-Add

279 Pages·2016·6.67 MB·English

Time-Compression Overlap-Add (TC-OLA) for Wireless Communications
by
Stephen Harrison
B.Eng., University of Victoria, 2009
A Dissertation Submitted in Partial Fulfillment of the
Requirements for the Degree of
DOCTOR OF PHILOSOPHY
in the Department of Electrical and Computer Engineering
c Stephen Harrison, 2016
(cid:13)
University of Victoria
All rights reserved. This dissertation may not be reproduced in whole or in part, by
photocopying or other means, without the permission of the author.
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Time-Compression Overlap-Add (TC-OLA) for Wireless Communications
by
Stephen Harrison
B.Eng., University of Victoria, 2009
Supervisory Committee
Dr. P. F. Driessen, Supervisor
(Department of Electrical and Computer Engineering)
Dr. W. Page, Departmental Member
(Department of Electrical and Computer Engineering)
Dr. G. Tzanetakis, Outside Member
(Department of Computer Science)
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Supervisory Committee
Dr. P. F. Driessen, Supervisor
(Department of Electrical and Computer Engineering)
Dr. W. Page, Departmental Member
(Department of Electrical and Computer Engineering)
Dr. G. Tzanetakis, Outside Member
(Department of Computer Science)
ABSTRACT
Time-compression overlap-add (TC-OLA) is presented as a novel method of com-
munications over a (wireless) channel, which is shown to have benefits over other
methods in some applications. TC-OLA is initially explored in an experimental con-
text using a custom wideband software-defined radio (SDR) to gain insight into some
of the possibilities of this method. Basic analysis is developed showing the process-
ing gain, transmitted spectrum, and behaviour in fading channels. The method is
considered as a candidate for low power wide area network (LPWAN) applications,
highlighting the equivalent channel property, channel averaging, and ability to handle
more simultaneous users in the uplink than other schemes in this application area.
The method is then considered as an alternative to single carrier frequency domain
equalization (SC-FDE) for ultrawideband (UWB) applications, where the ability to
reduce or eliminate the cyclic prefix (CP) overhead while still using frequency domain
equalization (FDE) techniques is highlighted. Additional application areas for this
technology are briefly considered, including cognitive radio and radar. The process of
patenting this technology is outlined in an appendix. The issued patent can be found
through the United States Patent and Trademark Office (USPTO) as U.S. Patent
9,479,216.
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Contents
Supervisory Committee ii
Abstract iii
Table of Contents iv
List of Tables ix
List of Figures x
Acronyms xiii
Acknowledgements xvii
1 Introduction 1
1.1 Claimed Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Novel UWB and Spread Spectrum System Using Time Compres-
sion and Overlap-Add Techniques 8
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1 Time Compression and Overlap-Add . . . . . . . . . . . . . . 11
2.3.2 Windowing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.3 Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3.4 Channel Effects . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3.5 Interference Rejection . . . . . . . . . . . . . . . . . . . . . . 22
2.3.6 Extension to CDMA . . . . . . . . . . . . . . . . . . . . . . . 22
v
2.3.7 Extension to TDMA . . . . . . . . . . . . . . . . . . . . . . . 24
2.3.8 Complex Baseband and Real Passband Signals . . . . . . . . . 24
2.3.9 System Implementation . . . . . . . . . . . . . . . . . . . . . 26
2.4 Wideband SDR Implementation . . . . . . . . . . . . . . . . . . . . . 27
2.4.1 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.4.2 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.4.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.5 USRP Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2.5.1 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.6 Conclusions and Future Work . . . . . . . . . . . . . . . . . . . . . . 46
3 Time-Compression Overlap Add: Description and Analysis 49
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3.2 Time-Shifting Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.2.1 AWGN Performance . . . . . . . . . . . . . . . . . . . . . . . 53
3.2.2 Multipath Rayleigh Fading Performance . . . . . . . . . . . . 54
3.3 Digital Filter Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.3.1 Transmitted Spectrum . . . . . . . . . . . . . . . . . . . . . . 62
3.4 Conclusion and Future Work . . . . . . . . . . . . . . . . . . . . . . . 67
4 Time-Compression Overlap Add for Low Power Wide Area Net-
works 68
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2 TC-OLA System Model . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.2.1 Code Division . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
4.2.2 Equivalence with DS/CDMA . . . . . . . . . . . . . . . . . . 73
4.3 Multiuser Performance Analysis . . . . . . . . . . . . . . . . . . . . . 76
4.3.1 Generic Multipath Model . . . . . . . . . . . . . . . . . . . . 77
4.3.2 Matrix Notation . . . . . . . . . . . . . . . . . . . . . . . . . 77
4.3.3 In Static Frequency Selective Channels . . . . . . . . . . . . . 81
4.3.4 In Frequency Flat Fading . . . . . . . . . . . . . . . . . . . . 82
4.3.5 In Time-Varying Frequency Selective Channels . . . . . . . . . 90
4.4 System Design and Results . . . . . . . . . . . . . . . . . . . . . . . . 91
4.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
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5 Robust TC-OLA Reception with Frequency Domain Equalization
for UWB Applications 98
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
5.2 TC-OLA System Model . . . . . . . . . . . . . . . . . . . . . . . . . 100
5.3 Frequency-Domain Processing . . . . . . . . . . . . . . . . . . . . . . 100
5.4 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
5.4.1 Indoor Channels . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.4.2 Industrial Channels . . . . . . . . . . . . . . . . . . . . . . . . 106
5.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
6 Discussion and Future Work 109
6.1 Perspectives on TC-OLA . . . . . . . . . . . . . . . . . . . . . . . . . 109
6.1.1 As a Matched Filter Communications System . . . . . . . . . 110
6.1.2 As a Spread Spectrum Method . . . . . . . . . . . . . . . . . 112
6.1.3 As a Multicarrier and Cyclic Prefix Block Processing Method 114
6.1.4 Sample Rearrangement and SC-FDMA . . . . . . . . . . . . . 115
6.2 System Parameter Relationships . . . . . . . . . . . . . . . . . . . . . 116
6.3 Multiple Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
6.3.1 Time Division . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
6.3.2 Code Division . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
6.3.3 Frequency Division . . . . . . . . . . . . . . . . . . . . . . . . 121
6.3.4 Multicarrier Code Division . . . . . . . . . . . . . . . . . . . . 121
6.4 Circular TC-OLA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
6.5 Offset TC-OLA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
6.5.1 Phase and Frequency Synchronization . . . . . . . . . . . . . . 125
6.5.2 Window Synchronization . . . . . . . . . . . . . . . . . . . . . 128
6.6 Timing Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
6.6.1 Sample Frequency Offset . . . . . . . . . . . . . . . . . . . . . 131
6.6.2 Parameter Estimation . . . . . . . . . . . . . . . . . . . . . . 131
6.7 Window Weighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
6.7.1 Channel Inversion . . . . . . . . . . . . . . . . . . . . . . . . . 132
6.7.2 Window Discard . . . . . . . . . . . . . . . . . . . . . . . . . 134
6.8 Hardware Implementation . . . . . . . . . . . . . . . . . . . . . . . . 135
6.9 Multiuser FDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
6.10 Novel Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
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6.10.1 Multiple Antenna Systems . . . . . . . . . . . . . . . . . . . . 140
6.10.2 Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
6.10.3 Cognitive Radio . . . . . . . . . . . . . . . . . . . . . . . . . . 141
6.10.4 Audio Reverb . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
6.10.5 Hybrid Analog/Digital Broadcast . . . . . . . . . . . . . . . . 142
6.11 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
6.11.1 Patent Concepts . . . . . . . . . . . . . . . . . . . . . . . . . 143
6.11.2 Analysis and Design Activities . . . . . . . . . . . . . . . . . . 144
6.11.3 Suggested Publications . . . . . . . . . . . . . . . . . . . . . . 146
7 Conclusions 148
A Glossary of Symbols 150
B Generic Multipath Model 153
C Wideband SDR Receiver 155
Software Usage Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
RFRB-SDR Design Document . . . . . . . . . . . . . . . . . . . . . . . . . 158
D Patent Document 181
Original Claims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
First Office Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Amended Claims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Notice of Allowability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
Issued Patent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
E Comparison of TC-OLA with RPMA 240
E.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
E.2 Uplink Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
E.2.1 Pole Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
E.2.2 Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
E.2.3 Scheduled vs. Random . . . . . . . . . . . . . . . . . . . . . . 245
E.2.4 Time-Dispersive Channels . . . . . . . . . . . . . . . . . . . . 246
E.3 Comparison of RPMA with Slotted ALOHA . . . . . . . . . . . . . . 247
E.4 TC-OLA Compatibility with RPMA . . . . . . . . . . . . . . . . . . 248
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F Publishing Challenges 250
F.1 Reviews of Time-Compression Overlap Add for Low Power Wide Area
Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
F.1.1 Editor’s Comments . . . . . . . . . . . . . . . . . . . . . . . . 250
F.1.2 Reviewer 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
F.1.3 Reviewer 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
F.1.4 Reviewer 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Bibliography 255
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List of Tables
Table 2.1 Example System Parameters for Figures 2.4-2.7 . . . . . . . . . 16
Table 2.2 System Parameters for Wideband SDR Implementation . . . . . 28
Table 2.3 Experimental System Parameters . . . . . . . . . . . . . . . . . 40
Table 2.4 Frequency Selective Channel Model . . . . . . . . . . . . . . . . 44
Table 5.1 Range of TC-OLA Parameters and Effective CP for L = 256 . 104
B
Table A.1 General Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Table A.2 Vectors and Matrices . . . . . . . . . . . . . . . . . . . . . . . . 152
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List of Figures
Figure 2.1 Assembling a Stream of Non-Overlapping Segments . . . . . . 12
Figure 2.2 Assembling a Stream of Non-Overlapping Hanning Windows . 14
Figure 2.3 Effect of Frame Loss, Showing Drop in Output Amplitude . . 16
Figure 2.4 Static Two-Ray Channel Response . . . . . . . . . . . . . . . 17
Figure 2.5 Time-Varying Two-Ray Channel Response, 10 Second Sweep . 18
Figure 2.6 Time-Varying Two-Ray Channel Response, 1 Second Sweep . 20
Figure 2.7 Time-Varying Two-Ray Channel Response, 0.1 Second Sweep 21
Figure 2.8 Basic Code Division Example . . . . . . . . . . . . . . . . . . 23
Figure 2.9 Basic Time Division Example . . . . . . . . . . . . . . . . . . 25
Figure 2.10 Simplified System Diagram . . . . . . . . . . . . . . . . . . . 26
Figure 2.11 Signal Discontinuity Caused by Narrowband Interference . . . 27
Figure 2.12 Wideband SDR System Connection Diagram . . . . . . . . . . 29
Figure 2.13 Transmitted Frame Format . . . . . . . . . . . . . . . . . . . 30
Figure 2.14 Receiver Digital Signal Processing Architecture . . . . . . . . 32
Figure 2.15 Received Samples, Timing Marker and Alignment Window . . 33
Figure 2.16 Impulse Response Averaged Over 8 Sweeps . . . . . . . . . . . 35
Figure 2.17 Impulse Response Averaged Over 8 Sweeps, I/Q Crosstalk . . 36
Figure 2.18 Measured Power Delay Profile at 8, 14, and 20 Feet . . . . . . 38
Figure 2.19 USRP-Based System Hardware Connection Diagram . . . . . 39
Figure 2.20 Recovered Impulse Response with Simple Wired Channel . . . 42
Figure 2.21 Recovered Impulse Response with Two-Ray Model . . . . . . 42
Figure 2.22 BER Floor vs. Maximum Doppler Frequency . . . . . . . . . 43
Figure 2.23 BER Floor vs. Normalized Maximum Doppler Frequency . . . 45
Figure 2.24 BER Floor vs. Normalized Maximum Doppler Frequency . . . 47
Figure 2.25 BER Floor vs. Normalized Maximum Doppler Frequency . . . 47
Figure 3.1 TC-OLA Transmission Concept . . . . . . . . . . . . . . . . . 51
Figure 3.2 Multirate Transmitter Process . . . . . . . . . . . . . . . . . . 56