ABSTRACT
This research studies the propagation prediction variations of
three models over a Nigerian urban environment and the development
of a suitable propagation prediction model for the environment. The
measurements of the received signal strength at various distances for
nine base stations were conducted at Celtel,Kano. The measurement
equipment used consists of a Test Mobile System (TEMS) connected to
GPS and radio antennas. The TEMS was mounted inside a car that
was driven along an open route for each of the sectors selected from
the nine base stations. Three macro cell propagation models: COST-
231 Hata, Lee and COST-231 Walfisch-Ikegami models were examined
with respect to nine base stations of Celtel, Kano. The results gave
mean prediction error values of –0.7dB,-4.2dB and 8.9dB for COST-
231 Hata, Lee and COST-231Walfisch-Ikegami models respectively.
The analysis show that the COST-231 Hata and Lee models
underestimate the path loss for this environment, while the COST-231
Walfisch-Ikegami model over predict the environment. The new
propagation prediction model was developed from the three modified
propagation models.
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TABLE OF CONTENTS
Title page — — — — — — — — — i
Declaration — — — — — — — — ii
Certification — — — — — — — — iii
Dedication — — — — — — — — iv
Acknowledgement — — — — — — — v
Abstract — — — — — — — — — vi
Table of Contents — — — — — — — vii
List of Figures — — — — — — — — xi
List of Tables — — — — — — — — xiii
List of Abbreviations — — — — — — — xviii
CHAPTER ONE: GENERAL INTRODUCTION
1.1 Introduction — — — — — — — 1
1.2 Motivation — — — — — — — — 2
1.3 Problem Definition and Methodology — — — 2
1.4 Thesis Outline — — — — — — — 2
CHAPTER TWO: LITERATURE REVIEW AND THEORETICAL
BACKGROUND
2.0 Introduction — — — — — — — 4
2.1 Literature Review — — — — — — — 4
2.2 The Cellular system — — — — — — 5
2.2.1 Macro cell — — — — — — — — 6
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2.3 The GSM Network Architecture — — — — 6
2.3.1 The Mobile Station — — — — — — 7
2.3.2 The Base Station Subsystem — — — 8
2.3.3 GSM Frequency Management — — — — 10
2.4 Radio Propagation Characteristics — — 10
2.4.1 Free Space Loss — — — — — — — 10
2.4.2 Diffraction — — — — — — — — 11
2.4.3 Scattering — — — — — — — — 12
2.4.4 Fading — — — — — — — — 12
2.5 Macro cell Propagation Models — — — — 12
2.5.1 The COST-231 Hata Model — — — — — 13
2.5.2 The Lee Model — — — — — — –. 14
2.5.3 The COST-231 Walfish-Ikegami Model — — — 15
CHAPTER THREE: METHODOLOGY
3.0 Introduction — — — — — — — 18
3.1 Measurement Technique — — — — — 18
3.2 Measurement Environment — — — — — 19
3.3 Base Station Parameters — — — — — 19
3.4 Data Presentation — — — — — — — 21
CHAPTER FOUR: ANALYSIS AND RESULTS
4.0 Introduction — — — — — — — 24
4.1 Analysis of the COST-231 Hata Model — — — 24
4.2 Analysis of the Lee Model — — — — — — 25
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4.3 Analysis of the COST- 231 Walfisch –Ikegami Model — 27
4.4 Propagation Loss Models Predictions — — — 29
4.4.1 Results obtained using the COST – 231 Hata Model — 29
4.4.2 Results obtained using the Lee Model — — — 30
4.4.3 Results obtained using the COST-231Walfisch-Ikegami
Model– — — — — — — — — — — — — — — — — 30
4.5 Comparison of Measured and Predicted Results– — — 30
4.6 Differences between Measured and Predicted Results — 40
4.7 Propagation Loss prediction Statistics — — — — — — 40
4.8 Proposed Propagation Prediction Models — — — — — 41
4.9 Comparison of the Proposed Prediction Model
with Measured Results — — — — — — 44
4.10 Discussion and Interpretation of Results — — — — 49
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
5.0 Introduction — — — — — — — 51
5.1 Summary of Results — — — — — — 51
5.2 Significance of Results and Applications — — 51
5.3 Problems Encountered and Limitations — — 52
5.4 Conclusion — — — — — — — 53
5.5 Recommendations for further work — — — 53
REFERENCES — — — — — — — — 54
APPENDICES — — — — — — — — — 56
APPENDIX A: Computed Signal Strength and Path Loss using
the COST-231 Hata Model — — — — — — 56
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CHAPTER ONE
GENERAL INTRODUCTION
1.1 INTRODUCTION
Propagation models have become an inevitable tool for network coverage
prediction and planning. This is even more paramount for macro cells since they
accommodate majority of the subscribers due to the large area they are expected to
cover. However, research has shown that the problems faced by most network
operators are the lack of a fast and suitable propagation prediction model for network
coverage prediction and planning especially in urban areas.[8]
Propagation models are based on measurements and observations over a
particular environment. There is the need to examine the propagation prediction
variation of these models over the environment. The analysis of these propagation
models will aid the provision of a fast and suitable propagation prediction model for
the urban environment under consideration.
This research work involves the collection of the received signal strength at
various locations for nine base stations of Celtel; Kano. The measurement equipment
used by the radio frequency personnel of the network operator consists of a Test
Mobile System (TEMS) connected to GPS and radio antennas. The TEMS was
mounted inside a car that was driven along open routes for each of the sectors selected
from the nine base stations. The result of this analysis was used to provide
propagation prediction models that can be used for fast network coverage prediction
and optimization of radio resources in this environment.
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1.2 MOTIVATION
Standardized propagation models are based on measurements carried out over a
particular environment. There is the need to examine the propagation prediction
variations of these models over a Nigerian urban environment. The results of this
analysis will aid the provision of a fast and suitable means of predicting the network
coverage for the environment.
1.3 PROBLEM DEFINITION AND METHODOLOGY
The performance of any cellular mobile network depends to a large extent on
the availability of fast and suitable network coverage prediction tool. This is even
more paramount in macro cells where the area intended to cover is large .The ability
to predict the network coverage between the transmitter and receiver is a very
important aspect of any cellular network planning and optimization.
The methodology adopted involves the collection of the received signal
strength data at various locations for nine base stations of Celtel Network conducted
by the radio frequency personnel through drive tests using the Test Mobile System
(TEMS).These data were analyzed using other base station parameters and compared
with the predictions from the three models considered: COST-231 Hata, Lee and
COST-231 Walfisch-Ikegami models. The results of this analysis were used to obtain
modified coverage prediction models.
1.4 THESIS OUTLINE
The whole work is divided into five chapters. Chapter One contains the
introduction to the thesis. Chapter Two explains the theoretical background of the
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cellular mobile system, radio propagation characteristics and models for macro cells.
In chapter Three, the methodology adopted in carrying out the research is discussed.
Chapter Four presents the analysis of the data collected and the results. Chapter Five
contains the problems encountered, limitations, applications, recommendation for
further work and conclusion.
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