RAIN FADE ANALYSIS at C, Ku and Ka BANDS in NIGERIA
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RAIN FADE ANALYSIS AT C, Ku AND Ka BANDS IN NIGERIA BY SANYAOLU, MODUPE EUNICE PHY/14/5847 A DISSERTATION SUBMITTED IN THE DEPARTMENT OF PHYSICAL SCIENCES TO THE SCHOOL OF POSTGRADUATE STUDIES, REDEEMER’S UNIVERSITY EDE, OSUN STATE, NIGERIA IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTERS OF SCIENCE (M. Sc) IN COMMUNICATION PHYSICS JULY, 2016 CERTIFICATION This is to certify that this research work was carried out by Sanyaolu, Modupe Euniceof the Department of Physical Sciences, Redeemer’s University, Ede, Osun state. …………………………… ………………………… Prof.L.B Kolawole Date Supervisor DEDICATION This work is dedicated to my beloved husband, Mr. Sanyaolu Olufemi Oluseunand my children; Ayomide, Anjolaoluwa and Temiloluwa. ABSTRACT Telecommunication systems are rapidly moving to higher frequencies due to the congestion at the lower frequency bands. In the design of telecommunication systems, the dynamic characteristics of fading due to atmospheric effects are essential in order to optimize system capacity and meet quality and reliability of signal reception. This study pertains to the analysis of rain fades at C, Ku and Ka bands at some selected stations covering the main geographical zones of Nigeria.The propagation model recommended by the International Telecommunication Union (ITU-RP) was used to calculate the fade depth at 6 GHz, 8 GHz, 12 GHz, 16 GHz, 20 GHz, 30 GHz and 40 GHz. The result shows that the higher the frequency, the higher the fade depth, andit is most severe in Port Harcourt, followed in descending order, by Lagos, Nsukka, Akure, Yola, Minna and Ayingba. Port Harcourt has the highest rain rate and was seen to have the highest fade depth. The rain fade correlate with signal attenuation. Attenuationdistribution for a percentage of time unavailability and availability were estimated. The results therefore show thatthe attenuations for vertically and circularly polarized signal are less than that of the horizontal polarization at all the frequencies.This shows that rain fade is less severe in the Northern part of the country and is more severe in the southern part of Nigeria, with Port Harcourt, Lagos and Nsukka experiencing the highest rain impairment. Attenuation due to effective path lengths is of little effect due to other dominant factors such as frequency and local rain rate. The fade durations showing the number of events for which duration exceeds threshold at 1, 3, 6, 9, 12, 15 and 18 dB levelswere also determined. It isseenthat when the attenuation is increased the fade duration decreases. ACKNOWLEDGEMENTS I appreciate the Almighty God for seeing me through this course. He is my help and strength. It has been His grace all the way. I wish to express my profound gratitude to Professor L.B. Kolawole for his fatherly love.He encouraged me and thoroughly supervised this work. The support of the National Space Research and Development Agency (NASDRA) is gratefully acknowledged for establishing The NigeriaEnvironmental and Climatic Observatory Programme (NECOP)and for donating the equipment used for this study. My sincere appreciation also goes to Dr. E.U. Vincent, Dr. Falade, Engr. Dairo, Mr Osinowo, Mr Akinyemi and every other member of staff of the Department of Physical Sciences. I wish to show my sincere appreciation to the management of Redeemer’s University for the staff development scholarship offered me for this Master’s degree programme. I am expressing my deep gratitude to God on behalf of my late father Mr L.A. Owoseni. Daddy, your children are doing well, and may your soul rest in peace. I want to say a big thank you to my sweet mother, Mrs Emily Owoseni and my siblings- Mrs Bola Ogunniyi, Kayode, Seun, and Tosin Owoseni for their love and support. Many thanks also to my in laws: Daddy and Mummy Sanyaolu. I appreciate my husband Olufemi Sanyaolu and our God’s gifts; Ayomide, Anjolaoluwa and Temiloluwa, for their love, prayers, understanding, support and encouragement during the period of this work. TABLE OF CONTENT Certification i Dedication ii Abstract iii Acknowledgements iv Table of contents v List of Figures vii List of Tables ix List of Abbreviation x CHAPTER ONE: 1.0 Introduction 1 1.1 Background of study 1 1.2 Statement of the problem 13 1.3 Objectives 13 1.4 Scope of study 14 CHAPTER TWO 2.0 Literature review 15 2.1 Raindrop size and shape 18 2.2 Rain rate prediction models 18 2.3 Rain fade mitigation techniques 22 2.4 Fixed wireless link power budget 26 2.5 Rain attenuation models 27 2.6 ITU-R prediction of rainfall over tropical region 28 2.7 Rain height and noise temperature 30 2.8 Fade depth prediction 30 2.9 Fade duration distribution models 31 CHAPTER THREE Materials and methodology 3.0 Equipment 33 3.1 Instrumentation 34 3.2 Data 36 3.3 Rainfades calculations 38 CHAPTER FOUR 4.0 Data analysis 49 4.1 Results 51 CHAPTER FIVE 5.0 Discussion of Results 78 5.1 Conclusion and Recommendation 82 References 84 LIST OF FIGURES Figure 1.1 Features characterizing the dynamic of fade events 9 Figure 1.1 Map of Nigeria showing study areas 14 Figure 3.1 The TRODAN station at the Redemption Camp, Mowe, Ogun State 34 Figure 3.2 The locations where data were taken for this work 37 Figure 3.3 A schematic diagram of slant range below freezing point 39 Figure 3.4 A schematic diagram of earth-space path 42 Figure4.1 The average monthly rainfall accumulations during the observation period 50 Figure 4.2 Rain rate for the eight stations in Nigeria 52 Figure 4.3 Rain rate for Mowe and Minna 53 Figure 4.4 Rain rate for Lagos and Nsukka 54 Figure 4.5 Rain rate for Port Harcourt and Yola 55 Figure 4.6 Rain rate for Ayingba and Akure 56 Figure 4.7 Fade depth of all location 55 Figure 4.8 Attenuation at 0.01% exceedance for all locations 64 Figure 4.9 The effective path length for attenuations at 0.01% 67 Figure 4.10 Attenuation at C-band for horizontal polarization for all locations 68 Figure4.11 Attenuation at Ku-band for vertical polarization for all locations 69 Figure 4.12 Attenuation at Ka band for circular polarization for all locations 70 Figure4.13 Fade duration grouping by attenuation levels in (a) Port Harcourt(b) Lagos 71 Figure 4.14 Fade duration grouping by attenuation levels in (a) Mowe (b) Minna 72 Figure 4.15 Fade duration grouping by attenuation levels in (a) Akure (b) Nsukka 73 Figure 4.16 Fade duration grouping by attenuation levels in (a) Yola (b) Ayingba 74 LIST OF TABLES Table 1.1: Frequency bands 5 Table3.1: Site characteristics of locations used 36 Table3.2 The values of k and α found from ITU-RRecommendation p.838. 45 Table4.1 Geometrical Parameters 60 Table 4.2 Estimates of specific attenuation and fade depth for all polarizations 62 Table4.3 attenuations (in dB) for 0.01% of the time and the effective path lengths 65 Table 4.4 Number of events for which duration exceeds threshold in Lagos 75 Table 4.5 Number of events for which duration exceeds threshold in Port Harcourt 75 Table 4.6 Number of events for which duration exceeds threshold in Yola 75 Table 4.7 Number of events for which duration exceeds threshold in Mowe 76 Table 4.8 Number of events for which duration exceeds threshold in Minna 76 Table 4.9 Number of events for which duration exceeds threshold in Akure 76 Table 4.10 Number of events for which duration exceeds threshold in Ayingba 77 Table 4.11 Number of events for which duration exceeds threshold in Nsukka 77 LIST OF ABBREVIATIONS SATCOM Satellite Communications DSD Rain Drop Size Distribution UPC Uplink Power Control ITU International Telecommunication Union ACM Adaptive Code Modulation VSAT Very Small Aperture Terminal FMT Fade Mitigation Technique SW South West SS South South SE South East MB Middle Belt NE North East NASDRA National Space Research and Development Agency TRODAN Tropospheric Data Acquisition Network LOS Line-of-sight CDs Cumulative distributions ITCZ Inter Tropical Convergence Zone CHAPTER ONE INTRODUCTION 1.0 BACKGROUND TO THE STUDY Telecommunications transmission facilities are the physical means of communicating large amounts of information over distance. Without exception, communication signals (speech, images, video, or computer data) are electromagnetic waves traveling along transmission lines such as 2-wire line, coaxial line, optical fiber and microwave link. For a given route, the type of transmission line selected dependson the topography, the amount of information to transmit, and the cost(Garlington,2006). The presence of various forms of precipitation such as rain, snow, cloud and fog in a radio wave or microwave path is always capable of producing major impairment to terrestrial communications. Hydrometeors can introduce significant attenuation and depolarization, through their ability to absorb and scatter radio waves. (Shoewu and Edeko, 2011). Consumer diversity, demands for bandwidth, and service convergence have led to a tremendous growth in communication systems. These have resulted in congestion at lower frequency bands, and consequently increased the need for higher frequency band usage. At these frequencies, however, the presence of rain causes degradation of signals, especially above 10 GHz. The many advantages of telecommunications systems operating at higher frequencies include: large bandwidth, increased frequency reuse, small device size and wide range of spectrum availability. The major obstacle to these frequency ranges is rain ( Malinga, Owolawi and Afullo, 2013). The impacts of rain rate along the satellite path in regions where mixed climate conditions (tropical, sub-tropical and temperate) are common demand special attention with respect torain attenuation modeling.