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Modelling and Coverage Improvement of DVB-T Networks A thesis submitted for the degree of Doctor of Philosophy By Kasampalis Stylianos Supervised By: Professor John Cosmas, Dr Lazaridis Pavlos Department of Electronic and Computer Engineering College of Engineering, Design and Physical Sciences Brunel University London Uxbridge, UK March 2018 ABSTRACT The necessity of accurate point-to-area and point-to-point prediction tools arises from the enormous demand in designing broadcasting systems for digital TV and cellular communications. Up to now, a considerable number of coverage prediction models for radio coverage has been developed. In electromagnetic wave propagation theory, there are three types of propagation models. Empirical models that are based on a large quantity of measurement data are elementary but not very accurate. Semi-deterministic models that are based on measurement data and electromagnetic theory of propagation, which are more precise. Finally, deterministic models based on theoretical physics, like diffraction theory and Fresnel theory, that require a significant amount of geometrical data about the propagation terrain profile but are the most accurate. The primary outcomes of this research are the comparative study and improvement of several propagation models, using a significant quantity of measurements and simulations and the deduction of useful conclusions to be used by engineers to improve propagation predictions further. In this research, the Longley-Rice (ITM) Irregular Terrain Model model was used, a classic model used for TV coverage prediction, which model is to date the preferred model of the FCC (Federal Communications Commission) in the US for FM-TV coverage calculations. To run the model, the Radio Mobile program (Radio Propagation and Virtual Mapping Freeware) was used based on the Longley-Rice Model ITM, including the 3-arc-second Satellite Radar Terrain Mission (SRTM) maps and the SPLAT! program (an RF Signal Propagation, Loss, And Terrain analysis tool), which also relies on the Longley-Rice ITM model and makes use of SRTM maps. Both programs work in Windows operating system (Windows7 Professional, 64 bits). Another model used in this research was SPLAT! with ITWOM (Irregular Terrain with Obstructions Model) which combines empirical data from the ITU-R P.1546 model and other ITU recommendations in conjunction with Beer's and Snell's laws. The ITU-R Recommendation P.1546 model and the empirical Hata-Davidson model using HAAT were also utilized in this research. The Single Knife-Edge (SKE) model was coded in MATLAB and utilized in this research as a simple reference model, where only one main obstacle is considered. Other well-known multiple knife-edge diffraction models employed in this study are the Epstein-Peterson, Deygout, and Giovaneli models. For these deterministic models, I individual MATLAB programs were written. Simulations produced by the models were limited to the main two knife-edges of the propagation path for immediate comparison with the Longley-Rice model which uses the “double knife-edge” approach. All measurement campaigns took place in Northern Greece and Southern (F.Y.R.O.M) Former Yugoslav Republic of Macedonia using a Rohde & Schwarz FSH-3 portable spectrum analyser and precision calibrated antennas. II ACKNOWLEDGMENTS I am very thankful to my principal supervisor, Professor John Cosmas, who gave me valuable guidance, and helped me and supported me to complete my research. I am also thankful for my supervisor Pavlos Lazaridis. He helped me in conducting this research and supported me over the last four years regarding technical assistance, proposed ideas and results verifications. He helped me, a lot and encouraged me when I was tired psychologically and I was thinking to abandon. He is a more a friend than a supervisor. I do not forget the hundreds of hours we spent visiting cities and climbing mountains to take our measurements. Lastly, I owe my most profound gratitude to my wife and children, for their patience, without whom I would not have made it through my Ph.D. studies. Thank you all. III DEDICATION Dedicated to my wife Eleni, my sons Apostolos and Nikolaos and my mother Panagiota. IV TABLE OF CONTENTS ABSTRACT…………………………………………………………………………………....….I ACKNOWLEDGMENTS………………………………………………………………........... .III DEDICATION………………………………………………………………………………..… IV LIST OF FIGURES………………………………………………………………………….... VII LIST OF TABLES…………………………………………………………………………...... XII LIST OF ABBREVIATION…………………………………………………………………..XI V AUTHOR'S DECLARATION………………………………………………………………..X VI STATEMENT OF COPYRIGHT………………………………………………………….. XVII CHAPTER 1 INTRODUCTION………………………………………………………….….. 1 1.1 OVERVIEW……………………………………………………………………….…… .….1 1.2 BACKGROUND……………………………………………………………………….. .….1 1.3 AIMS AND OBJECTIVES…………………………………………………………….. .….7 1.4 CONTRIBUTION TO KNOWLEDGE…………………………………………………. ….8 1.5 RESEARCH METHODOLOGY………………………………………………………. .….9 1.6 RESEARCH OUTPUT………………………………………………………………… .….9 1.7 REFERENCES…………………………………………………………………………. ....11 CHAPTER 2 LITERATURE REVIEW………………………………………………........ ..14 2.1 LITERATURE REVIEW......................……………………………………………....... ....14 2.1.1 Overview………….……………………………………………………………….. ...14 2.1.2 Papers and books studied for this survey………………………………….………... ..15 2.2 SUMMARY……………………………………………………………………………. ....22 2.3 REFERENCES…………………………………………………………………………. ....23 CHAPTER 3 A SURVEY ON PROPAGATION MODELS…………………………….. ...29 3.1 OVERVIEW……………………………………………………………………………. ....29 3.2 THE FREE SPACE PROPAGATION MODEL………………………………………. ....29 3.3 EMPIRICAL-STATISTICAL MODELS……………………………………………….. ...30 3.3.1 The Okumura Model…………………………………………………………....... ....30 3.3.2 The Okumura-Hata Model……………………………………………………….. ....32 3.3.3 The COST 231-Hata Model……………………………………………………… ....33 3.3.4 The Hata-Davidson Model………………………………………………………….. ..33 3.3.5 The Lee Model…………………………………………………………………… ....35 3.3.6 The ECC-33 Model………………………………………………………………. ....36 3.3.7 ITU-R Models……………………………………………………………………. ....36 3.3.8 The ITU-R P.370 Recommendation……………………………………………….. ...36 3.3.9 The ITU-R P.1411 Recommendation…………………………………………….. ....37 3.3.10 The ITU-R P.1546 Recommendation…………………………………………….. ...38 3.3.11 The Walfisch-Bertoni Model……………………………………………………. ....39 3.4 DETERMINISTIC-GEOMETRICAL MODELS……………………………………….. ...40 3.4.1 Single Knife-Edge Diffraction Model……………………………………............. ....40 3.4.2 The Bullington Model………………………………………………………........... ...41 3.4.3 Deygout's Approach……………………………………………………………….. ...41 3.4.4 The Causebrook Correction……………………………………………………….... ..42 3.4.5 Epstein's-Peterson Method………………………………………………………….....43 3.4.6 Giovaneli's Method…………………………………………………………………....44 3.4.7 The ITU-R P.526 Model Propagation by diffraction……………………………….. ..46 3.4.8 The Longley-Rice Model………………………………………………………….... ..46 3.4.9 The Ikegami Model………………………………………………………………... ...54 V 3.4.10 The Flat Edge Model……………………………………………………………. ....54 3.5 SUMMARY……………………………………………………………………………... ...56 3.6 REFERENCES…………………………………………………………………………... ...57 CHAPTER 4 BASIC THEORY, PROPAGATION MODELS, AND SOFTWARE USED IN THIS STUDY…………………………….. ...60 4.1 OVERVIEW…………………………………………………………………………….. ...60 4.2 PROPAGATION MODELS USED IN THIS STUDY…………………………………... ..60 4.2.1 The Longley-Rice Model………………………………………………………….... ..60 4.2.2 The ITWOM Model……………………………………………………………….. ...60 4.2.3 The Hata-Davidson Model…………………………………………………….…... ...61 4.2.4 ITU-R P.1546 Recommendation…………………………………………………. ....62 4.2.5 Deygout's Model…………………………………………………………………. ....62 4.2.6 Epstein's-Peterson Model………………………………………………………….. ...62 4.2.7 Giovaneli's Model…………………………………………………………………. ...62 4.2.8 Recommendation ITU-R P.526-13………………………………………………... ...62 4.3 FUNDAMENTAL CONCEPTS………………………………………………………….. ..62 4.3.1 Plotting the Fresnel zones – Ellipses………………………………………………... ..62 4.3.2 The command zi……………………………………………………………….…... ...65 4.3.3 Equirectangular Approximation………………………………………………........ ...66 4.3.4 Earth's Bulge - The k factor………………………………………………………... ...67 4.3.5 Finding the Intersection Points in MATLAB between two lines using an Algebraic Method…………………………………... ....70 4.3.6 Calculating Field Strength Signal………………………………………………….....72 4.3.7 Conversions between Watt, dBW, dBm, E.R.P, E.I.R.P…………………….…… ....74 4.3.8 Finding the Maximum Height (Knife-Edge) of an Obstacle in Elevation Profile……………………………………………….. ....76 4.4 EXPLANATION OF THE PROGRAMS OPERATION……………………………….. ...78 4.4.1 The Single Knife-Edges programs………………………………………………….... .78 4.4.2 The Double Knife-Edges programs……………………………………………….. ...84 4.4.3 Case Study for Three Obstacles with Deygout's Method………………………….... ..90 4.4.4 Case Study for Four Obstacles with Deygout's Method…………………………... ...96 4.5 ASSUMPTIONS………………………………………………………………………….. 102 4.6 SUMMARY…………………………………………………………………………....... .103 4.7 REFERENCES…………………………………………………………………………. ..103 CHAPTER 5 LONGLEY-RICE MODEL PREDICTION INACCURACIES IN THE UHF AND VHF TV BANDS, IN MOUNTAINOUS TERRAIN………………………………………… ..105 5.1 INTRODUCTION……………………………………………………………………….. .105 5.2 MEASUREMENTS AND COMPARISONS…………………………………………….. 106 5.3 SUMMARY…....………………………………………………………………………... .124 5.4 REFERENCES…………………………………………………………………………. ..125 CHAPTER 6 COMPARISON OF LONGLEY-RICE, ITU-R P.1546 AND HATA-DAVIDSON PROPAGATION MODELS FOR DVB-T COVERAGE PREDICTION………………………………. .127 6.1 INTRODUCTION…………………………………………………………………........ ..127 6.2 MEASUREMENTS AND COMPARISONS…………………………………………….. 128 6.3 SUMMARY……………………………………………………………………………... .143 6.4 REFERENCES…………………………………………………………………………..
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