THE UNIVERSITY of HULL Development of a Heterogeneous Microwave Network, Fade Simulation Tool Applicable to Networks That Span E
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THE UNIVERSITY OF HULL Development of a Heterogeneous Microwave Network, Fade Simulation Tool Applicable to Networks that Span Europe being a Thesis submitted for the Degree of Doctor of Philosophy in Electronic Engineering in the University of Hull by HAFIZ BASARUDIN (MEng.) (HND, British Malaysian Institute) January, 2012 ACKNOWLEDGEMENTS First and foremost, my utmost gratitude to Dr. K. S. Paulson, my supervisor, whose sincerity, guidance and encouragement I will never forget and has helped me to finish this work. I would also like to extend my gratitude to others including Mr. N. G. Riley, Dr. Franklin Mung'au, the department and Graduate School. I would also like to acknowledge the support of the British Atmospheric Data Centre and the National Oceanic and Atmospheric Administration, Physical Science Division for providing the critical datasets for this research. Last but not least, my sincere gratitude to my family and friends who helped me a lot in finishing this project through continuous encouragement and support during my study. i ABSTRACT Radio communication systems operating at microwave frequencies are strongly attenuated by hydrometeors such as rain and wet snow (sleet). Hydrometeor attenuation dominates the dynamic fading of most types of radio links operating above 10 GHz, especially high capacity, fixed, terrestrial and Earth-Space links. The International Telecommunication Unions – Radio Section (ITU-R) provides a set of internationally recognized models to predict annual fade distributions for a wide variety of individual radio link. However, these models are not sufficient for the design and optimisation of networks, even as simple as two links. There are considerable potential gains to be achieved from the optimized design of real-time or predictive Dynamic Resource Management systems. The development of these systems requires a joint channel simulation tool applicable to arbitrary, heterogeneous networks. This thesis describes the development of a network fade simulation tool, known as GINSIM, which can simulate joint dynamic fade time-series on heterogeneous networks of arbitrary geometry, spanning Europe. GINSIM uses as input meteorological and topological data from a variety of sources and numerically calculates the joint effects on fading on all links in a specified network. ITU-R models are used to transform rain rate into specific attenuation and to estimate the specific attenuation amplification due to non-liquid hydrometeors. The resulting simulation tool has been verified against ITU-R models of average annual fade distributions, fade slope and fade duration distributions, in the southern UK. Validation has also been performed against measured terrestrial and Earth-space link data, acquired in the Southern UK and Scotland. ii CONTENTS Acknowledgement i Abstract ii Contents iii List of Figures and Tables vii Notation x Glossary of Terms xii CHAPTER 1 INTRODUCTION .................................................................................. 1 1.1 Brief description of GINSIM............................................................................... 6 1.2 Aims and objectives............................................................................................. 8 1.3 Thesis outline....................................................................................................... 8 CHAPTER 2 MICROWAVE FADE MECHANISMS .............................................. 10 2.1 Formation Cloud and Rainfall ........................................................................... 10 2.2 Earth-Space Radio Communication System...................................................... 13 2.3 Absorption by Atmospheric Gasses ................................................................. 14 2.4 Rain Parameters, Scattering and Attenuation .................................................... 16 2.4.1 Rain Scattering ....................................................................................... 17 2.4.2 Raindrop Size Distribution (DSD) ......................................................... 18 2.4.3 Rain Drop Shape and Canting Angle ..................................................... 21 2.4.4 Rain rate ................................................................................................. 23 2.4.5 Specific Attenuation of rain ................................................................... 25 2.4.6 Rain Attenuation .................................................................................... 26 2.5 Sleet Attenuation ............................................................................................... 29 iii 2.6 Cloud Attenuation.............................................................................................. 32 Chapter 2 summary.................................................................................................. 33 CHAPTER 3 METEOROLOGICAL MEASUREMENTS ........................................ 34 3.1 Rainfall Measurements...................................................................................... 34 3.1.1 Rain gauge.............................................................................................. 36 3.1.2 Weather radar ......................................................................................... 38 3.1.3 Meteorological Satellites........................................................................ 43 3.2 Meteorological Measurement Datasets ............................................................. 46 3.2.1 Chilbolton Drop-Counting and Tipping-Bucket Rain Gauge ................ 47 3.2.2 Chilbolton Advance Weather Radar (CAMRa) ..................................... 47 3.2.3 Nimrod and OPERA............................................................................... 48 3.2.4 Multi-Sensor Precipitation Estimate (MPE) .......................................... 50 3.2.5 NCEP/NCAR Reanalysis datasets ......................................................... 51 3.2.6 Shuttle Radar Topography Mission (SRTM).......................................... 52 Chapter 3 Summary................................................................................................. 54 CHAPTER 4 NETWORK FADE SIMULATION .................................................... 56 4.1 General Procedures for Network Fade Simulation............................................ 56 4.2 Different approaches for Network Fade Simulation.......................................... 61 4.2.1 Rain Cell models .................................................................................... 61 4.2.2 Statistical Rain Rate Variation Models ................................................. 64 4.2.3 Downscaling NWP or Meteorological Data........................................... 66 4.2.3a SISTAR .................................................................................... 66 4.2.3b SATCOM ................................................................................. 67 4.2.3c Hull Rain Fade Network Simulator (HRFNS) and GINSIM ... 68 4.3 Downscaling and network simulation processes for GINSIM .......................... 69 iv 4.3.1 Disaggregation ....................................................................................... 71 4.3.2 Interpolation ........................................................................................... 72 4.3.3 Extrapolation into Low Rain Rate Regions............................................ 73 4.3.4 Advection ............................................................................................... 74 4.3.5 Transforming to Specific Attenuation Fields and Pseudo-integration .. 74 4.3.6 Rain Height model ................................................................................. 75 Chapter 4 Summary................................................................................................. 80 CHAPTER 5 VALIDATION WITH ITU-R MODELS ............................................. 81 5.0 Experimental setup ............................................................................................ 81 5.1 Validation of Rain Rate Distribution................................................................. 82 5.2 Validation of First Order Statistics for Annual Hydrometeor Fade .................. 84 5.3 Validation of Second Order Statistics for Hydrometeor Fade........................... 87 5.3.1 Fade Duration......................................................................................... 87 5.3.2 Fade Slope.............................................................................................. 89 Chapter 5 Summary................................................................................................. 93 CHAPTER 6 VALIDATION WITH MEASURED TERRESTRIAL AND EARTH- SPACE LINKS............................................................................................................ 94 6.1 Measurement data.............................................................................................. 94 6.2 Comparison of simulated and measured fade data ............................................ 96 6.2.1 Distributions and Joint Distributions of Fade ........................................ 96 6.2.2 Distributions of Fade at different spatial and temporal scales ............... 98 6.2.3 Site Diversity Comparison ................................................................... 102 6.2.4 Validation of Autocovariance ............................................................. 106 Chapter 6 Summary..............................................................................................