RFI ISSUE AND SPECTRUM SHARING PARADIGM FOR FUTURE SATELLITE COMMUNICATION AND RADIO ASTRONOMY SYSTEMS by Yucheng Dai APPROVED BY SUPERVISORY COMMITTEE: Dr. Hlaing Minn, Chair Dr. John P. Fonseka Dr. Andrea Fumagalli Dr. Murat Torlak Copyright © 2020 Yucheng Dai All rights reserved Dedicated to my family, I received no more powerful and effective support than the support from my beloved family. RFI ISSUE AND SPECTRUM SHARING PARADIGM FOR FUTURE SATELLITE COMMUNICATION AND RADIO ASTRONOMY SYSTEMS by YUCHENG DAI, BS, MS DISSERTATION Presented to the Faculty of The University of Texas at Dallas in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY IN ELECTRICAL ENGINEERING THE UNIVERSITY OF TEXAS AT DALLAS August 2020 ACKNOWLEDGMENTS I would like to thank my PhD adviser, Dr. Hlaing Minn, for his valuable advice, dedicated guidance, and unparalleled support that made this work possible. I would like to express my deepest appreciation to my committee members, Drs. Andrea Fumagalli, John P. Fonseka, and Murat Torlak. I would like to thank my parents, for their guidance to the way to PhD, and for their support both spiritually and financially. I also want to thank my friend and lab-mate, Dong Han, who shows an example of dedicated and helpful PhD student to me. June 2020 v RFI ISSUE AND SPECTRUM SHARING PARADIGM FOR FUTURE SATELLITE COMMUNICATION AND RADIO ASTRONOMY SYSTEMS Yucheng Dai, PhD The University of Texas at Dallas, 2020 Supervising Professor: Dr. Hlaing Minn, Chair Wireless services, which utilize radio spectrum resources, can be classified into two types: passive wireless services and active wireless services. Some passive wireless services (e.g., Radio Astronomy System (RAS)) are extremely vulnerable to the interference from active wireless services. In addition, the widely-distributed radio astronomical signals in the spec- trum drive the radio astronomers seeking for opportunities to observe in the bands which have been assigned to active wireless systems for primary use. In view of the conflict between the RAS and other active wireless systems, this dissertation focuses on the spectrum sharing paradigm between the two sides which can bring benefits to both sides and thus achieve a harmonious utilization of the spectrum resource. First, we investigate and develop a spectrum sharing paradigm between the RAS and the Geostationary Orbit (GSO) Satellite Communication Systems (SCSs). Via utilizing the idle RAS band(s), the proposed paradigm can bring more throughput/capacity to SCS side while reducing Radio Frequency Interference (RFI) and offering more observation opportunities to RAS side. Next, we propose a new paradigm where SCS and RAS are integrated into the Non-Geostatio- nary Orbit (NGSO) satellite system, thus effectively creating large-scale telescopes in orbit. This integrated system not only avoids SCS's RFI to RAS but also offers more spectrum vi access opportunities to both SCS and RAS. The proposed paradigm several additional ad- vantages in terms of accessible spectrum bands, RAS observation performance, and SCS maximum mean supportable data rate as well as enabling coexistence and growths of both types of services. vii TABLE OF CONTENTS ACKNOWLEDGMENTS . v ABSTRACT . vi LIST OF FIGURES . x LIST OF TABLES . xiii CHAPTER 1 INTRODUCTION . 1 1.1 Background . .1 1.2 Outline and Contributions . .2 CHAPTER 2 A SPECTRUM SHARING PARADIGM FOR GSO SATELLITE SYS- TEM AND RADIO ASTRONOMY SYSTEM . 3 2.1 Introduction . .3 2.2 RFI Analysis for Ground Radio Telescopes under GSO satellites . .9 2.2.1 Interference from GSO Satellites to Ground Radio Telescopes . .9 2.2.2 Ground Telescope Model . 11 2.2.3 GSO Satellite System Model . 13 2.2.4 Unwanted Emission Power of the GSO Satellite's Subband Transmission 15 2.2.5 RFI from Other Active Wireless Systems . 18 2.2.6 RFI and Sample Loss Rate of the Ground Radio Telescopes under GSO SCS .................................... 20 2.3 Existing RFI Reduction methods as Benchmarks . 24 2.4 Proposed Spectrum Sharing Paradigm with Three RFI Reduction Methods . 31 2.4.1 RFI Determination for Ground Radio Telescopes in Different Time Durations . 31 2.4.2 Reorganization of the Spectrum Resource to Minimize the Unwanted Emission Power of the GSO Satellites in the RAO Bands . 34 2.4.3 Rearranging the Subband Allocation of the GSO Satellite's Beams to Minimize the RFI of the GSO Satellites . 40 2.4.4 Cell-based Beam Switch Approach to Suppress the RFI . 44 2.5 Numerical Results of RFI and Sample Loss Rate . 49 2.5.1 Effects of the Parameters of the Three RFI Reduction Methods . 49 viii 2.5.2 RFI and Sample Loss Rate in Different Scenarios . 51 2.6 Conclusions . 62 CHAPTER 3 IMPACTS OF LARGE-SCALE NGSO SATELLITES: RFI AND A NEW PARADIGM FOR SATELLITE COMMUNICATIONS AND RADIO ASTRONOMY SYSTEMS . 65 3.1 Introduction . 65 3.2 RFI Analysis for Ground Radio Telescopes under a Large-Scale LEO SCS . 68 3.2.1 Interference Calculation . 68 3.2.2 Large-Scale LEO SCS Model: OneWeb . 70 3.2.3 Ground Telescopes Model . 72 3.2.4 Guardband and Emission Mask Based RFI Analysis . 73 3.2.5 RFI Analysis Based on OneWeb LEO Constellation . 76 3.3 Guardband, Transmission Muting and Sample Excision Based Solutions under Large-Scale LEO SCS . 81 3.4 A New Paradigm for NGSO SCS and RAS . 83 3.4.1 An Integrated NGSO SCS and RAS . 83 3.4.2 Observability of LEO versus Ground Telescopes . 86 3.4.3 Sensitivity of LEO versus Ground Telescopes . 92 3.5 Data Rate Analysis Based on a Shared RAS Band in the Proposed Paradigm 94 3.5.1 Gateway-Satellite Model Based Data Rate Analysis . 94 3.5.2 Communication System Maximum Mean Supportable Data Rate and RAO Data Rate Results . 98 3.6 RAO Data Transport Design . 101 3.6.1 Development of Data Transport . 101 3.6.2 Data Transport Performance Results . 103 3.7 Conclusions . 104 CHAPTER 4 CONCLUSION . 107 REFERENCES . 109 BIOGRAPHICAL SKETCH . 117 CURRICULUM VITAE ix LIST OF FIGURES 2.1 The 58 existing ground observatories' locations on the earth . 11 2.2 Downlink band allocation of the 3 groups of GSO satellites . 14 2.3 Cell locations of the GSO satellites with the number of spot beams which serve the cells . 14 2.4 Relative PSD attenuation versus different jf − fcj=Bsub values . 17 2.5 Unwanted emission power of the satellites' transmission in subbands centered at different frequencies in different RAS bands . 18 2.6 RFI at the Effelsberg 100-m radio telescope in the RAS band I with different RAO modes and the corresponding beam directions in latitude and longitude . 21 2.7 RFI at the Effelsberg 100-m radio telescope in the RAS band I at different direc- tions in different scenarios . 22 2.8 Average RFI at different telescopes in 200 random realizations . 24 2.9 Average sample loss rate at different telescopes in 200 random realizations . 25 2.10 Sample loss rate and average throughput ratio in case 1 with different guard band bandwidths . 29 2.11 Sample loss rate and average throughput ratio in case 2 with different muting thresholds . 30 2.12 Sample loss rate and average throughput ratio in case 3 with different muting thresholds . 30 2.13 An example of periods and subperiods in an RAO operation duration . 32 2.14 Potential spectrum resource allocation of the SCS in scenario 1 . 35 2.15 Average unwanted emission power versus minimum total SCS required bandwidth BSCS;0 under different Bsub;0 and Bsub;unit values in scenario 1 . 38 2.16 Average unwanted emission power in different scenarios with different BSCS;0 val- ues .......................................... 41 2.17 Procedure diagram for rearranging the subband allocation at period n ...... 45 2.18 RFI generated by the spot beams from different satellites which serve a cell near the Effelsberg 100-m Radio Telescope . 45 2.19 Average RFI and sample loss rate of a realization in scenario 1 among the tele- scopes using the spectrum resource reorganization method with different BSCS;0 requirements . 50 x 2.20 Average RFI among the telescopes of a realization in scenario 1 using the subband allocation method or the beam switch method with different Nsp values . 51 2.21 Average RFI among the telescopes of a realization in scenario 1 using the beam switch method with different Nbeam;ex and Nswitch values . 52 2.22 Average RFI at different telescopes with different RFI reduction methods in sce- nario 1 . 54 2.23 Average sample loss rate versus average throughput ratio with different RFI re- duction methods in scenario 1 . 55 2.24 Average RFI at different telescopes with different RFI reduction methods in sce- narios 2 and 3 . 56 2.25 Average sample loss rate versus average throughput ratio with different RFI re- duction methods in scenarios 2 and 3 . 57 2.26 Average RFI at different telescopes with different RFI reduction methods in sce- nario 4 . 58 2.27 Average sample loss rate versus average throughput ratio with different RFI re- duction methods in scenario 4 . 59 2.28 Average RFI at different telescopes with different RFI reduction methods in sce- nario 5 . 60 2.29 Average sample loss rate versus average throughput ratio with different RFI re- duction methods in scenario 5 . 61 2.30 Average RFI at different telescopes with/without the beam switch method in scenario 6 . 62 2.31 Average sample loss rate versus average throughput ratio in scenario 6 . 63 3.1 An illustrative scenario for angles θT and θR .................... 71 3.2 OneWeb LEO satellite constellation (+ denotes a satellite) . 72 3.3 Existing ground radio astronomy telescopes' locations .