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Pilot Patterns for the Primary Link in a MIMO-OFDM Two-Tier Network

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Pilot Patterns for the Primary Link in a MIMO-OFDM Two-Tier Network Pilot Patterns for the Primary Link in a MIMO-OFDM Two-Tier Network by Sara Al-Kokhon A thesis submitted in conformity with the requirements for the degree of Master of Applied Science Electrical and Computer Engineering University of Toronto © Copyright by Sara Al-Kokhon 2017 Pilot Patterns for the Primary Link in a MIMO-OFDM Two-Tier Network Sara Al-Kokhon Master of Applied Science Electrical and Computer Engineering University of Toronto 2017 Abstract To meet the exponentially growing demand for high data rates in wireless mobile networks, high capacity cells are required. One way of increasing the cell’s capacity is by the use of MIMO- OFDM two-tiered networks. These networks can also be used to efficiently connect IoT devices, of which many are expected to be stationary and deployed within a small area, to the internet. As primary links could create a bottleneck in the system, we focus on increasing the capacity of these links through achieving a more accurate channel estimate without adding overhead to the system- when compared to the 3GPP LTE system. We achieve this by proposing a new Reference Signal (RS) structure that focuses on reducing the effect of the AWGN on the different pilot symbol positions without reducing the amount of power or bandwidth available for data transmission, and without adding complexities to the system. We show the effectiveness of the proposed design and the impact of AWGN at pilot symbol positions on the link’s capacity through mathematical analysis and simulation results. ii Acknowledgements I would like to thank my supervisor Prof. Elvino Sousa for his support and guidance, and for the valuable knowledge he imparted to me. I would also like to thank him for giving me the opportunity to learn, immerse in research, and get this work done. I would also like to thank my committee members: Prof. Raviraj Adve, Prof. Dimitrios Hatzinakos and Prof. Natalie Enright Jerger for their time and valuable feedback; and all UofT professors who I took courses with for their knowledge and inspiration. Finally, I would like to thank my family for their love, motivation, encouragement, and constant support; my lab colleagues for the valuable discussions; and my friends for their continued support and encouragement. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ...................................................................................................................... iii LIST OF TABLES ..................................................................................................................................... vi LIST OF FIGURES ................................................................................................................................. viii LIST OF ACRONYMS ............................................................................................................................. xi 1. INTRODUCTION .................................................................................................................................. 1 LITERATURE REVIEW................................................................................................................. 4 CONTRIBUTION ........................................................................................................................... 8 ORGANIZATION ........................................................................................................................... 9 2. LTE DOWNLINK PHYSICAL CHANNELS AND PHYSICAL SIGNALS ................................. 10 2.0 INTRODUCTION ......................................................................................................................... 10 2.1 LTE DL TRANSMISSION ............................................................................................................ 10 2.2 LTE DL PHYSICAL CHANNELS ................................................................................................ 17 2.3 LTE DL PHYSICAL SIGNALS .................................................................................................... 19 2.4 SUMMARY ................................................................................................................................... 24 3. LTE DL REFERENCE SIGNAL STRUCTURE .............................................................................. 25 3.0 INTRODUCTION ......................................................................................................................... 25 3.1 COMMON RSS.............................................................................................................................. 26 3.2 UE-DEDICATED RSS .................................................................................................................. 33 3.3 MBSFN-REGION DEDICATED RS ............................................................................................ 40 3.4 SUMMARY ................................................................................................................................... 42 4. PROPOSED REFERENCE SIGNAL STRUCTURE ...................................................................... 44 4.0 INTRODUCTION ......................................................................................................................... 44 4.1 BASIC SL-RS STRUCTURE ........................................................................................................ 46 4.2 SUMMARY ................................................................................................................................... 55 5. MATHEMATICAL ANALYSIS ........................................................................................................ 56 5.0 INTRODUCTION ......................................................................................................................... 56 iv 5.1 MIMO SYSTEM MODEL ............................................................................................................. 56 5.2 CHANNEL ESTIMATION ANALYSIS ....................................................................................... 57 5.3 POST-EQUALIZATION SINR ..................................................................................................... 64 6. SIMULATION RESULTS .................................................................................................................. 67 6.0 INTRODUCTION ......................................................................................................................... 67 6.1 SIMULATION PARAMETERS ................................................................................................... 67 6.2 SIMULATION RESULTS............................................................................................................. 70 6.3 CONCLUSION .............................................................................................................................. 98 CONCLUSION ....................................................................................................................................... 102 FUTURE WORK .................................................................................................................................... 103 APPENDIX A- MATLAB CODE FLOW CHART ............................................................................. 105 APPENDIX B-WIM CDL POWER-DELAY PROFILE (PDP) ......................................................... 107 APPENDIX C- ADDITIONAL SIMULATION RESULTS ............................................................... 108 REFERENCES ........................................................................................................................................ 114 v List of Tables TABLE 2-1: LTE TRANSMISSION BANDWIDTH CONFIGURATIONS ............................................................. 13 TABLE 2-2: PHYSICAL RESOURCE BLOCK PARAMETERS ............................................................................ 14 TABLE 2-3: ANTENNA PORT MAPPING FOR DIFFERENT LTE RS TYPES...................................................... 21 TABLE 3-1: RS CATEGORIES, TYPES AND SEQUENCE INITIALIZATION PARAMETERS ................................ 26 TABLE 3-2: COHERENCE BANDWIDTH SUPPORTED BY CSR APS ............................................................... 29 TABLE 3-3: CSR PILOT OVERHEAD ............................................................................................................ 30 TABLE 3-4: CHANNEL PARAMETERS SUPPORTED BY AP5 ......................................................................... 34 TABLE 3-5: AP COMBINATIONS USED FOR MULTI-LAYER BEAMFORMING ................................................. 35 TABLE 3-6: CHANNEL PARAMETERS SUPPORTED BY AP7 AND AP8 RS STRUCTURES .............................. 36 TABLE 3-7: LENGTH-2 OCC CODE USED FOR DUAL-LAYER & 4-LAYER BEAMFORMING .......................... 39 TABLE 3-8: LENGTH-4 OCC CODE USED FOR 8-LAYER BEAMFORMING .................................................... 40 TABLE 3-9: LTE RS STRUCTURE PARAMETERS ......................................................................................... 43 TABLE 4-1: 푁푃푂퐹퐷푀 FOR SISO SL-RS STRUCTURE ................................................................................... 49 TABLE 4-2: 푁푃푂퐹퐷푀 FOR 2X2, 4X4, AND 8X8 MIMO SL-RS STRUCTURES ............................................... 51 TABLE 6-1: WIM PARAMETERS ................................................................................................................. 69 TABLE 6-2: SIMULATION PARAMETERS ....................................................................................................
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