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THE NELSON MANDELA AFRICAN INSTITUTION OF SCIENCE AND TECHNOLOGY (NM-AIST) COVERAGE IMPROVEMENTS FOR MOBILE COMMUNICATION IN RURAL AREAS OF TANZANIA Adolph Kasegenya A Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of (Masters of Science in Information and Communication Science and Engineering) of the Nelson Mandela African Institution of Science and Technology. Arusha, Tanzania. October, 2014
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THE NELSON MANDELA AFRICAN INSTITUTION OF SCIENCE AND

TECHNOLOGY (NM-AIST)

COVERAGE IMPROVEMENTS FOR MOBILE COMMUNICATION

IN RURAL AREAS OF TANZANIA

Adolph Kasegenya

A Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of

(Masters of Science in Information and Communication Science and Engineering) of the

Nelson Mandela African Institution of Science and Technology.

Arusha, Tanzania.

October, 2014

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ABSTRACT

This dissertation looks at how network operators operate in Tanzania. It examines how they set

up their networks, and the services offered so far. First thing first was to evaluate the Quality of

Services (QoS) offered by telecommunications network vendors in Lake Zone and to access their

coverage ranges. The assessments were done through a keen feasibility study of the selected area

done in Mwanza region as a study area, followed by the drive test field measurements performed

by the help of TEMS Investigation tools and software, the log files collected were evaluated by

using both Map Info software and Actix Analyzer. The study shows only 24.02% of the sample

area had a good coverage, while the poor coverage beyond threshold was recorded at 23.24%.

Also, when it comes to the case of QoS, it was observed that only 27.61% had a good QoS, while

the poor threshold was 2.76% of the entire sample area. This analysis was done in both rural and

urban areas, moreover the other aspect of this dissertation was to assess the planning and

optimization phases of the telecommunication networks done by the vendors and looked at the

conducive environment for Base Station Installation and it was done with the help of Map Info,

Asset, Google Earth and Measurements Reading Reports (MRR) tool. The Third generation (3G)

Planning was done for both coverage and capacity in Wideband Code Division Multiple Access

(WCDMA), which resulted into a better coverage with good performance of QoS and also

Optimization was done for power control mechanism to increase coverage through better

Received Signal Code Power (RSCP) value, better QoS through good ration of Received Power

to Noise (Ec/No) value. Lastly, different wireless technology services offered by

telecommunication vendors were evaluated based on their coverage and suggestions on how to

improve them were given out.

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DECLARATION

I, Adolph Kasegenya do hereby declare to the Senate of Nelson Mandela African Institution of

Science and Technology that this dissertation is my own original work and that it has neither

been submitted nor being concurrently submitted for degree award in any other institution.

_________________________________________ ________________

Name and signature of candidate Date

The above declaration is confirmed

________________________________________ _________________

Name and signature of supervisor1 Date

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COPYRIGHT

This dissertation is copyright material protected under the Berne Convention, the Copyright Act

of 1999 and other international and national enactments, in that behalf, on intellectual property.

It must not be reproduced by any means, in full or in part, except for short extracts in fair

dealing; for researcher, private study, critical scholarly review or discourse with an

acknowledgement, without a written permission of the Deputy Vice Chancellor for Academic,

Research and Innovation, on behalf of both the author and the Nelson Mandela African

Institution of Science and Technology.

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CERTIFICATION

The undersigned certify that they have read and hereby recommend for acceptance by the Nelson

Mandela African Institution of Science and Technology a dissertation entitled: Coverage

Improvements for Mobile Communication in Rural Areas of Tanzania, in fulfilment of the

requirements for the degree of Master of Science (Information and Communication Science and

Engineering (ICSE)) of the Nelson Mandela African Institution of Science and Technology.

...........................................................

Dr. Anael Sam

(Principal Supervisor)

Date: …………………………….

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ACKNOWLEDGEMENT

I’m so grateful to Almighty God for giving me life, health and for his mighty doings in my life. I

express my heartfelt gratitude to my Supervisor at the Nelson Mandela African Institution of

Science and Technology (NMAIST), Dr. Anael Sam for his knowledge, experience, expertise,

valuable suggestions and comments, effective support where I couldn’t find an answer by

myself, gratitude to all the staff of school of Computation and Communication Science and

Engineering (CoCSE) since has there been providing valuable support whenever I needed it.

Then my gratitude goes to the management of NMAIST, for all the material and financial

support during course work and research, I have nothing to repay you, but am praying for the

name of NMAIST to fly high and the sky to be its limit towards the success of its mission and

vision.

I Wish also to thank my supervisor at Tigo company, Mr. Steven Katamba for allowing me to

use their resources during my research whenever I needed them. Also, I can’t forget Mr. Rodgers

Bajungu who was another supervisor in my side from Tigo. We work daily with him and he was

ready to help whenever I needed it. Thank you very much. Also, all Tigo staff in the department

of Planning just to mention few, Mr. Gasper Clement, Mr. Exaud Sudda and Mr. Raymaker

Sadick for working hand with hand and always gave me the support I needed despite of their

busy schedule. It was great working with such nice people and high level professionals in this

field of communication. I wish all of you all the best in your professional careers and in your

personal life. You have been such great friends. Thank you all very much.

May I express my gratitude to all my classmates, including Mr. Josia Nombo (PhD student), for

standing there with me during my two years of study here at NMAIST. They were so nice

provided me with all necessary help whenever I stumble through academic and life obstacles. Be

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blessed all. I’ll miss you very much. They were friends at times and also parents in another way

for whatever they thought it was beneficial to my life. Am forever indebted to you all.

And last but not least, I want to thank my family for the support and such great understanding to

allow me to perform my master’s study, being patient when they needed me and For encouraging

me to pursue higher goals and the dreams of my life with their moral and material support.

May the Almighty God bless you all abundantly.

Adolph kasegenya

October, 2014

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DEDICATION

This work is dedicated to Mrs. Regina Kasegenya and the late Mr. Aloyce Paul Kasegenya for

believing in me and providing all the necessary support through high moral standards, ethics,

and prayers which kept me going always. Also to all my family members for understanding and

supporting me in every way they can.

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TABLE OF CONTENTS

ABSTRACT ..................................................................................................................................... i

DECLARATION ............................................................................................................................ ii

COPYRIGHT ................................................................................................................................. iii

CERTIFICATION ......................................................................................................................... iv

ACKNOWLEDGEMENT .............................................................................................................. v

DEDICATION .............................................................................................................................. vii

CHAPTER ONE: GENERAL INTRODUCTION ...................................................................... 3

1. Introduction ............................................................................................................................. 3

1.1. Background Information .......................................................................................................... 5

1.2. Research problem and justification of study ............................................................................ 6

1.2.1. Research Problem ................................................................................................................. 6

1.2.2. Research Justification ........................................................................................................... 6

1.3. Objectives ................................................................................................................................ 7

1.3.1. General objective .................................................................................................................. 7

1.3.2. Specific objectives ................................................................................................................ 7

1.4. Hypotheses/Research questions ............................................................................................... 7

1.6. Research methodology ........................................................................................................... 10

1.6.1. Analysis of Quality of Service (QoS) ................................................................................. 10

1.6.2. Site Selection ...................................................................................................................... 11

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1.6.3. Planning and Optimization ................................................................................................. 11

CHAPTER TWO: REVIEW OF SCHEMES FOR ANALYZING QUALITYOF SERVICES

IN WIRELESS NETWORK ENVIRONMENT .......................................................................... 13

Abstract ......................................................................................................................................... 13

2.1. Introduction ............................................................................................................................ 14

2.1.1. Problem statement ............................................................................................................... 15

2.1.2. Challenges associated with quality of service .................................................................... 15

2.2. Methodologies........................................................................................................................ 16

2.2.1. Different QoS scheme for wireless network ....................................................................... 16

2.2.2. Fault Tolerant Dynamic Channel Allocation Scheme ........................................................ 16

2.2.2.1. Centralized approach ....................................................................................................... 16

2.2.2.2. Distributed approach ........................................................................................................ 16

2.2.3. Call Admission Control (CAC) Scheme ............................................................................. 17

2.2.4. Mobility Prediction Scheme ............................................................................................... 19

2.2.5. Dynamic Allocation Scheme using Renegotiation ............................................................. 21

2.3. Discussion and Conclusion .................................................................................................... 22

2.3.1. Results Discussion .............................................................................................................. 22

2.3.2 Conclusion ........................................................................................................................... 23

2.3.4. Future work ......................................................................................................................... 24

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CHAPTER THREE: CHAPTER THREE: ANALYSIS OF QUALITY OF SERVICE FOR

WCDMA NETWORK IN MWANZA, TANZANIA .................................................................. 25

Abstract ......................................................................................................................................... 25

3.1. Introduction ............................................................................................................................ 25

3.1.1. Received Signal Code Power (RSCP) ................................................................................ 26

3.1.2. Ration of Received Power to Noise (𝑬𝒄/𝑵𝒐) .................................................................... 27

3.1.3. Speech Quality Index (SQI) ............................................................................................... 27

3.1.4. Transmitting Power (TX power) ........................................................................................ 27

3.2. Methodologies........................................................................................................................ 28

3.2.1 Feasibility Study .................................................................................................................. 28

3.2.2. Drive Test............................................................................................................................ 28

3.3. Results and Discussion .......................................................................................................... 28

3.3.1. Coverage in terms of RSCP ................................................................................................ 29

3.3.2 Coverage in terms of EC/No ................................................................................................ 30

3.3.3. Transmission Power ............................................................................................................ 32

3.3.4. Call Information Overview ................................................................................................. 34

3.3.5. Low Received signal level .................................................................................................. 34

3.3.6. Lack of Dominant Server .................................................................................................... 35

3.3.7. Sudden appearance and disappearance of neighbour .......................................................... 35

3.3.8. Drop Call due to Bad Coverage: ......................................................................................... 35

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3.4. Recommendation ................................................................................................................... 35

3.5. Conclusion ............................................................................................................................. 36

CHAPTER FOUR: PLANNING AND OPTIMIZATION OF 3G NETWORK WITH

PERFORMANCE COMPARISON BETWEEN THE OPERATORS OF MOBILE

COMMUNICATION SERVICES ................................................................................................ 37

Abstract ......................................................................................................................................... 37

4.1. Introduction ............................................................................................................................ 38

4.2. Radio network Planning Process ........................................................................................... 39

4.2.1. Radio Link Budget (RLB) .................................................................................................. 40

4.2.1.1. Interference margin: ......................................................................................................... 41

4.2.1.2. Fast fading margin (= power control headroom): ............................................................ 41

4.2.1.3. Soft handover gain, as was discussed by (Laiho, 2002): ................................................. 41

4.2.2. Downlink Load Factor ........................................................................................................ 46

4.3. Capacity and Coverage Planning ........................................................................................... 48

4.3.1. Iterative Capacity and Coverage Prediction ....................................................................... 48

4.3.2. Detailed Coverage Planning ............................................................................................... 50

4.3.3. Detailed Capacity Analysis ................................................................................................. 50

4.4. Results and Discussion .......................................................................................................... 51

4.4.1. Results for planning ............................................................................................................ 51

4.4.2. Network Optimization ........................................................................................................ 60

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4.4.2.1. Received Signal Code Power (RSCP) ............................................................................. 62

4.4.2.2. Received Signal Strength Indicator (RSSI) ..................................................................... 62

4.4.2.3. Ration of Received Power to Noise (EC/N0) ................................................................... 63

4.5. Performance comparison for all network operators ............................................................... 64

4.5.1. WCDMA Benchmarking Objectives .................................................................................. 64

4.5.2. Number of 3G sites ............................................................................................................. 65

4.5.3. Coverage Statistics .............................................................................................................. 66

4.5.4. Accessibility Statistics ........................................................................................................ 66

4.5.5. Retainability Statistics ........................................................................................................ 67

4.5.6. Soft Handover Statistics ...................................................................................................... 68

4.5.7. Coverage RSCP .................................................................................................................. 69

4.5.8. Quality EC/No .................................................................................................................... 70

4.5.9. Summary of all Comparison ............................................................................................... 70

4.6. Conclusion ............................................................................................................................. 71

CHAPTER FIVE: GENERAL DISCUSSION AND CONCLUSION ...................................... 73

5.1. General Discussion ................................................................................................................ 73

5.1.1. 2G network analysis ............................................................................................................ 75

5.1.2. 3G network analysis ............................................................................................................ 77

5.1.3 Environment, Planning and Optimization............................................................................ 80

5.2. Conclusion ............................................................................................................................. 82

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5.3. General Recommendations .................................................................................................... 85

REFERENCES ............................................................................................................................. 87

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LIST OF TABLES

Table 1.1: Summary description of research specific objective and the methodology used. ....... 12

Table 3.1: Mean, Mode, Median, Variance, Standard deviation and maximum and minimum

ranges of both RSCP and Ec/N0 in active set count ..................................................................... 32

Table 4.1: Parameters used in Uplink load factor calculations as described in (Laiho, 2002) ..... 45

Table 4.2: As was argued by (Laiho, 2002) and (Holma et al., 2010), Parameters used in the

downlink load factor calculation. .................................................................................................. 47

Table 4.3: Benchmarking Objectives ............................................................................................ 64

Table 4.4 Summary Comparison of voice, data, coverage and QoS ............................................ 70

Table 5.1 KPI’s for 2G network performance comparison. .......................................................... 75

Table 5.2: Data statistics comparison for 2G network operators ................................................. 76

Table 5.3: Summary of 3G analysis on voice, coverage and quality ............................................ 77

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LIST OF FIGURES

Figure 1.1: Trend of Mobile and Fixed line subscription in Tanzania as for report from TCRA .. 4

Figure 1.2: Voice telecom subscription for each operator up to June 2014 by the courtesy of

TCRA .............................................................................................................................................. 4

Figure 2.1: Distribution channel allocation model (source: http://en.kioskea.net) ....................... 17

Figure 2.2: Call Admission Control Algorithm (Kovvuri) ........................................................... 19

Figure 3.1: Coverage KPIs _RSCP_Long Call Mode .................................................................. 29

Figure 3.2: RSCP in active set count ............................................................................................ 31

Figure 3.3: Transmission Power from the base stations ............................................................... 32

Figure 3.4: Coverage summary of the whole sample region ........................................................ 33

Figure 3.5: Quality of Service summary of the entire sample region ........................................... 33

Figure 3.6: Summary of the call information overview ................................................................ 34

Figure 4.1: WCDMA radio network planning process ................................................................. 39

Figure 4.2: UpLink Iteration Process ............................................................................................ 42

Figure 4.3. Downlink iteration Process........................................................................................ 43

Figure 4.4: Area of interest which needs to be covered ................................................................ 52

Figure 4.5: Depiction of environmental terrain from our area of interest .................................... 53

Figure 4.6: Geographical environmental features of the area of interest, side view .................... 54

Figure 4.7: Geographical environmental pattern for consideration while planning ..................... 55

Figure 4.8:Timing Advance distribution....................................................................................... 57

Figure 4.9:RX Quality for downlink channel ............................................................................... 58

Figure 4.10: RX level Uplink channel .......................................................................................... 58

Figure 4.11: RX level downlink channel ...................................................................................... 59

Figure 4.12: Design layout of the BTS position ........................................................................... 60

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Figure 4.13: CPICH RSSCP ......................................................................................................... 62

Figure 4.14: CPICH RSSI ............................................................................................................. 63

Figure 4.15: CPICH Ec/N0 ........................................................................................................... 64

Figure 4.16: Site comparison for all operators in Mwanza region up to June 2014 ..................... 65

Figure 4.17: Coverage statistics of all 3G operators ..................................................................... 66

Figure 4.18: Accessibility of 3G sites ........................................................................................... 67

Figure 4.19: Retainability Statistics .............................................................................................. 68

Figure 4.20: Soft Handover statistics ............................................................................................ 68

Figure 4.21: Coverage RSCP Statistics ........................................................................................ 69

Figure 4.22: Quality Ec/No statistics ............................................................................................ 70

Figure 5.1: Geographical view of Mwanza and its salient features .............................................. 73

Figure 5.2: Mwanza view of the local residence settlement ......................................................... 74

Figure 5.3: Data Technology distribution ..................................................................................... 78

Figure 5.4: Modulation Schemes used .......................................................................................... 79

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LIST OF ABBREVIATIONS AND SYMBOLS

3G- 3rd Generation

BER – Bit Error Rate

BS- Base Station

BTS- Base Transceiver Station

CAC- Call Admission Control

CBR – Call Blocking Rate

CDMA – Code Division Multiple Access

CDR – Call Dropping Rate

CST – Call Setup Time

DL – Downlink

Ec/No – Ration of Received Power per Noise Density

FACH – Forward Access Channel

FDMA – Frequency Division Multiple Access

FTP- Forced Termination Probability

GGSN – Gateway GPRS Serving Node

GPRS – General Packet Radio Service

GPS - Global Positioning System

GPS – Global Positioning System

HLR- Home Location Register

HO – Handover

HSDPA – High Speed Downlink Packet Access

HSPA – High Speed Packet Access

HSR – Handover Successful Rate

ITU – International Telecommunication Union

KPI – Key Performance Indicator

LFG- Limited Fractional Guard Channel

MAC- Medium Access Control

MH- Mobile Host

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MMM- Mobility Management Module

MS- Mobile Station

MSC- Mobile Switching Centre

MSS- Mobile Service Station

MT - Mobile Terminal

QAM – Quadrature Amplitude Modulation

QoS- Quality of Service

QPSK – Quadrature Phase Shift Keying

RF – Radio Frequency

RLB – Radio Link Budget

RNC- Radio Network Controller

RSCP – Received Signal Code Power

RSSI – Received Signal Strength Indicator

RX Power – Received power

RXQUAL – Received Quality

SAP- Service Access Point

SCCR- Successful Call Completion Rate

SGSN – Serving GPRS Serving Node

SQI – Speech Quality Index

TA – Timing Advance

TDMA – Time Division Multiple Access

TDSCDMA– Time Division Synchronous CDMA

TE- Terminal Equipment

TX Power – Transmission power

UL – Uplink

UMTS – Universal Mobile Telecommunication System

WCDMA – Wideband CDMA

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CHAPTER ONE: GENERAL INTRODUCTION

1.Introduction

The massive growth of mobile phone communications in the developing world has changed the

way we used to look on our daily life. Most countries in the developing world have abandoned

their old ways of communication through wired technology and now they have catapulted into

wireless technology through mobile phone communication. For most people in the world if not

all the prevalent means of communication is through mobile phones. Since the beginning of the

new millennium the use of it is averaged for every 100 occupants in Africa, Latin America,

Caribbean and Asia to have reached 100 to 400% in a short period of only five years. This is

explained in (Orbicom, 2007).

Mobile communication continues to grow diversely throughout the world. According to (Forlin

et al., 2008; Rashid and Elder, 2009), the speed of mobile phone penetration as a necessary

device is ascribed by the influence of liberalization of telecommunication sector itself has easy

to use application, basic knowledge in normal usage of phones and the ability to communicate by

any language including the native ones.

In Tanzania the telecommunication industry continues to shine and dominate the ICT Subsector

in the contribution of day to day life and the GDP of the country (TCRA 2006). The country's

population is about 45 million people (National Census 2012), almost 28 million people are

mobile phone subscribers in different companies, namely Vodacom Tanzania, Airtel, Tigo,

Zantel, TTCL and Benson (Statistics of June 2014 TCRA).

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Figure 1.1: Trend of Mobile and Fixed line subscription in Tanzania as for report from TCRA

Figure 1.2: Voice telecom subscription for each operator up to June 2014 by the courtesy of

TCRA

Many Tanzanians lives in the villages since the backbone of the economy is agriculture.

Coverage of the telecommunication networks in most of the rural areas in the country is very

poor. One reason being the scattered settlement of the indigenous, so it makes it difficult for

service providers to install many base stations as in urban areas. The cost of installation,

operation (most of the time by power generator since the power supply is not reliable) and

maintenance in rural areas provide a very small profit margin or a loss to the company most of

the time.

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According to (Tacchi et al., 2003) Mobile phones capability to communicate is not limited

tphone'sser space, volume, medium or time, and therefore it makes the continuation of

communicative ecologies.

The main challenge when planning and designing the telecommunication network is

approximating the actual amount of cells needed to provide sufficient coverage in the area of

interest with capacity constraint. When we refer to coverage of the cell it means the actual area

covered by the Base Transceiver Station (BTS) and for the capacity of the cell it means the real

number of subscribers which can be supported by the BTS.

1.1. Background Information

According to (Sood, 2006), there is enough proof of the new mobile users to be rural area's

settlers, while according to ITU report in 2006 it shows Africa has the world fastest mobile

subscription in the world. Tanzania is currently estimated to be the fourth country in the

continent for mobile subscription with South Africa, Nigeria and Kenya are leading respectively

(ITU Report 2012).

As telecommunication markets mature and continue to diversify, in Africa mobile phones are

now mostly used as service delivery platforms instead of just a simple communication tool. In

2007 Connect Africa Summit, the President of Rwanda, said; “In 10 short years, what was once

an object of luxury and privilege, the mobile phone, has become a basic necessity in Africa”.

Also, due to (The Economist, 2008), “A device that was a yuppie toy not so long ago has now

become a potent force for economic development in the world’s poorest countries.”

The growth of mobile phone usage has simply reduced communication and coordination

expenses and it is now changing lives through the state-of-the-art applications and services.

Samuel et al. (2005) assessed the socioeconomic impacts of mobile communications on

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households, rural communities and small businesses in South Africa, Tanzania and Egypt and

found out mobile phones helps to cut down the travelling necessity, supporting employment seek

out, increasing awareness of business information, and easy the communication into our inner

circle.

1.2. Research problem and justification of study

1.2.1. Research Problem

The scattered settlement and population in rural areas makes it difficult for proper planning of

radio frequency coverage. The installation of new base station in most of these areas is of low

profit margin to the network operators since most of the places lack permanent electricity, hence

needs to be operated by power generator, this calls for a proper design for better maximization of

performance throughput and capacity of the network.

1.2.2. Research Justification

Mobile phone usage is of much help in the development of rural settlers as it was depicted in the

study of “Contribution of mobile phones to rural livelihoods and poverty reduction in Morogoro

region, Tanzania.” The Study reports on the crucial role of mobile phones in lessening the

hardships of life as well as refining rural livings through the use of social networking, boost

people’s capability of dealing with an urgent situation, reduces travel expenses, capitalize on the

result of required trips, amplify secular user friendliness, and increase effectiveness of doing

things. Mobile phone lowers business expenditures and escalate production by supporting rural

traders and farmers to find suitable market and prices (Sife et al., 2010).

Coverage and capacity can be improved through the addition of new cells into a network. But

addition of new sites goes with hefty additional costs to network operators which most of the

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time are not ready to incur. This calls for a proper research on finding new ways and technique to

augment coverage by lowering the costs.

According to the (GSMA- 2011) report it is anticipated that by 2015 there will be a large number

of people owning mobile phones in the sub-Saharan Africa than electricity in their homes as the

use of mobile phone services will surpass the provision of other primary infrastructure therefore

communication industry will have larger significance into social life and society. Apart from

making communication more meaningful and easier, it will expedite sectors like education,

banking, agriculture, health care and women empowerment to be delivered with simplicity to the

society.

1.3. Objectives

The objectives of this research were laid down as follows;

1.3.1. General objective

The main objective of this research is to study network coverage of different wireless

technologies used by telecommunications vendors in rural areas and to give suggestions for

improving them.

1.3.2. Specific objectives

i. To analyse the quality of service (QoS) of the mobile network operators in rural areas

ii. To identify the geographic terrain pattern of the area needed for the selected telecom site.

iii. To plan and optimize for best radio coverage of the specific area

1.4. Hypotheses/Research questions

i. What is the quality of mobile network services in rural areas of Tanzania?

ii. What is the geographical terrain profile needed for better planning?

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iii. How can a radio coverage be planned to achieve better optimization of the Base Transceiver

Station (BTS)?

The main goal of the RF planning is to achieve greater coverage and capacity with the resource

at hand while preserving a great deal of quality of service. Planning undeveloped network for the

purpose of serving a certain number of subscribers is not the major challenge to discuss, but the

main issue is to carry a real network planning which will allow the forthcoming expansion in

case there is a need so as to help trimming down the cost for the operator while continuing to

provide good service.

According to (Tutschku et al., 1996), planning means projecting the way the network it’s going

to serve the customers. This is done by describing the actual number of cell sites needed and

their location to be placed, the kind of configuration needs to be done for the system to run and

lastly the types of hardware and software needed. All these should be detailed by experienced

and knowledgeable radio frequency engineers.

The principle activity in planning process decides on the amount of cell sites from all the

possible sites that have been evaluated to cover the targeted market. As for (Hurley, 2002), the

chosen cell sites should meet the predefined criteria of the network operator normally to have

good coverage area with maximum capacity that cost less. In order for the criteria to work, the

necessity of defining suitable configuration parameter comes into effect.

The World today witness the massive use of advance technology in both mobile communication

and internet. The new advance technology offers a different quality of service to each user

depending on their location and the predefined network capacity. (Kajackas et al., 2011),

urgues that, it causes the unsettled quality of arguese to individual subscribers and the QoS of

the individual customer can not be generalized.

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As planning seems to be a complex process (Tutschku et al., 1996), discuss the novel idea of

analytical planning. This approach gives attention to the ability of the radio engineers to

handpick the suitable places for cell sites and to designate frequency on the new sites by

inspecting the radio wave propagation and the nature of the environment with regards to

interference among adjacent cells. The method considers the inclusion of subscriber’s behaviour

and Tele Traffic in later stages of the planning process.

The study of radio propagation in rural residential areas with vegetation by (Blaunstein et al.,

2003) reveals that, the trees have both absorbing effects (instigated by scattering from foliage)

and diffraction effect ( which is due to lateral wave produced by the top l(er of the tree) which

affect the radio wave propagation at large.

(Dawy et al., 2003) defines the coverage of the cell as the geographical area which reach out to

the limit of Base Station (BS), and the capacity of the cell is described as the amount of Mobile

stations (MS) that can be served by the BS.

In defining coverage, it is indicated that due to the very rapid transition from near perfect to no

reception at all, it is necessary that the minimum required signal level is achieved at a high

percentage of locations. For mobile reception the percentages defined to be 99% for good and

90% for acceptable (ITU Report, 2012). Due to the high costs and the scarcity of radio resources,

an accurate and efficient mobile network planning procedure is required. The objective of

network planning is to maximize the coverage, capacity and the quality of service (Guo et al.,

2003).

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1.6. Research methodology

1.6.1. Analysis of Quality of Service (QoS)

This study aims to collect opinions from subscribed customers of telecommunication operators

on how satisfied they are with the services provided in rural areas, Also the customers will state

what they are expecting to get in their areas from most network operators, or what they think

these operators should do and currently they are not doing, in terms of customer services, signal

reception and transmission i.e. Making and receiving a call, services like text messages and data

for those interested in data services. The study also is expected to evaluate the strength of signals

from different base stations in Lake Victoria Zone (Mwanza, Geita, Shinyaga, Mara and Kagera

regions). The Lake, Victoria Zone is depicted as a case study due to its complexity in its

geographical terrain pattern (i.e., the presence of the Lake Victoria itself and also the rocks

surrounding the area). The geographical feature hinders the propagation of signal at large extent

and also the electromagnetic waves tend to behave differently where transferred across the lake

zone. This calls for a proper research in the area to maximize the coverage despite of all the

challenges of the area.

A drive test is going to be conducted from selected rural areas of the mentioned regions. Data of

signal strength will be taken starting from a distance of 100 meters to at least 6 kilometres on

each side of the directional antenna allocated to the particular base station. The process will be

repeated for each sector of the base station for the entire coverage zone of the base station. This

process will be facilitated by the use of TEMS Investigation tools. Whereby the TEMS mobile

phone will collect these data and send them to TEMS log file where they will be manipulated to

analyse the quality of services from those areas.

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1.6.2. Site Selection

The study also is expected to cover the range of processes involved in the selection of the

particular areas to mount a base station, knowing the longitude, latitude and altitude required

through proper surveys will be used to identify the modes of propagation which the area is

suitable for. Propagation in the land mobile service at frequencies from 300 to 1800MHz is

affected in varying degrees by topography, Morphography, ground constants and atmospheric

conditions. Upon getting a clear clarification of all the effects which will be present in the areas,

a single site will be depicted from among the several candidate sites. This process will involve

the use of software like MapInfo and tools like GPS at large extent.

1.6.3. Planning and Optimization

The next phase will be to plan for Radio Frequency (RF) coverage and optimization. Network

planning can be explained as devising the system which will enable customers to communicate

within the limit such system. The planning process is detailed into few steps as follows;

• Network dimensioning involves;

o Defining network requirements

o Defining the network configuration

o Projecting coverage area

o Projecting capacity of the channel

• Network planning and implementation which deals with;

o Coverage planning and Site selection which gives;

Defining number of sites and site acquisition.

Defining propagation models based on geographical, environmental nature.

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o Capacity requirement which deals with;

Traffic and service distribution

o Parameter planning

Network optimization

The planning process always starts from the subscriber’s point of view, the need to cater for the

new emerging market or to easy traffic on the overloaded site. The customer’s views give an

insight what kind of network to be planned and integrated into the core network.

After the planning process being incorporated as full-fledged running network, then comes the

work of conforming the predefined criteria on QoS to whether they are met.

Table 1.1: Summary description of research specific objective and the methodology used.

S.no. Objective Methodology

1 To analyse the quality of service (QoS)

of the mobile network operator in rural

areas

Feasibility Study.

Drive test, measured by using TEMS

Automatic tools, devices and software.

2 To identify the geographic terrain

pattern of the area needed for the

selected telecom site.

Feasibility Study

MapInfo software

GPS

Google Earth

3 To plan and optimize for best radio

coverage of the specific area

MapInfo Software

TEMS Automatic

Asset

Google Earth

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CHAPTER TWO: 1REVIEW OF SCHEMES FOR ANALYZING QUALITYOF SERVICES IN

WIRELESS NETWORK ENVIRONMENT Adolph kasegenya1, Anael Sam2

Abstract

Resource allocation and management is the fundamental key in providing better service using

mobile communication systems. This paper reviews the schemes for providing Quality of

Service (QoS) in the mobile wireless network environment. The paper will evaluate a total of

four schemes; this includes Fault Tolerant Dynamic Allocation Scheme, which deals with the

methods of reusing the channels effectively between two adjacent cells to avoid co-channel

interference. The second is a Call Admission Control Scheme, which deals with pre-blocking of

calls based on the available bandwidth for handling calls. Third scheme is Mobility Prediction

Scheme, which collects the information of the mobile host while travelling in a vehicle and store

the information into a database. And lastly Dynamic Allocation using Renegotiation Scheme

where the bandwidth usage changes dynamically depending on its availability. These schemes

are used in different environments to increase the quality of services of mobile communication.

Each scheme has its strong and weak point, depending on the parameters they are to analyse.

Key words: Quality of Service (QoS), Resource allocation, voice and data services, wireless

network.

1A. T. Kasegenya, Dr. A. Sam, “Review of Schemes for Analyzing Quality of Service in Wireless Network

Environment”, Conference Proceedings of the Pan African Conference on Science, Computing and

Telecommunications (PACT 2014), July 14 -18, 2014, Arusha – Tanzania.

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2.1. Introduction

Quality of Service (QoS) in cellular networks is defined as the capability of the cellular service

providers to provide a satisfactory service which includes voice quality, signal strength, low call

blocking and dropping probability, high data rates for multimedia and data applications etc. For

network based services QoS depends on the following factors;

Throughput: The rate at which the packets go through the network. The maximum rate is

always preferred.

Delay: This is the time which a packet takes to travel from one end to the other.

Minimum delay is always preferred.

Packet Loss Rate: The rate at which a packet is lost. This should also be as minimum as

possible.

Packet Error Rate: These are the errors which are present in a packet due to corrupted

bits. This should be as minimum as possible

Reliability: The ability of the network to carry it’s functionality as desired or per

specification.

If infinite network resources were available, then all application traffic could be carried at the

required bandwidth, with zero latency, zero jitter and zero loss. However, network resources are

not infinite. As a result, there are parts of the network in which resources are unable to meet

demand. QoS mechanisms work by controlling the allocation of network resources to application

traffic in a manner that meets the application's service requirements. [7]

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2.1.1. Problem statement

Imagine the scenario where you are talking with your friend and you suddenly experience a call

drop or maybe you can’t hear properly with what your friend is talking due to signal scrambling.

It is highly undesirable and you do not want to be in a network of such kind while you’re paying

for the desired service. To realize the conducive environment for communication in wireless

network, effective QoS schemes are needed. Scheme and issues related to better QoS is the main

subject of this paper.

2.1.2. Challenges associated with quality of service

The main challenges when considering the issue of QoS in mobile phone network environment

are issues like bandwidth allocation, varying rates, channel characteristics, fault tolerance level

and handoff support in heterogeneous wireless networks. Each layer of the OSI architecture has

its mechanism to provide a better QoS so as to attain network flexibility and tolerance. One of

the biggest challenges in the cellular network in today’s world is the proper and efficient usage

of the spectrum. Bandwidth allocation plays a vital role in this aspect. While designing we

should take into account the issue of bandwidth allocation by imploring schemes like

Renegotiation scheme for allocating the bandwidth to lower priority class just to make sure

everything is utilized to its fullest. The issue of QoS gets much more complicated when we deal

with the QoS of both voice and data at the same time and in the same network. Voice services

are very delay sensitive and require real time service while on the other hand, data services are

less sensitive to delay, but very sensitive to loss of data that is why there is a need of error free

packets all the time. All issues of bandwidth, latency, jitter and loss need to be considered for a

proper designing in order to obtain a better quality of service of the network. [6 – 7], [9], [15].

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2.2. Methodologies

2.2.1. Different QoS scheme for wireless network

There are so many QoS schemes deployed to be used in cellular network depending on the

application it’s going to serve. Some of these schemes are such as Fault Tolerant Dynamic

Allocation scheme, Call Admission Control (CAC), Mobility prediction scheme, and

Renegotiation Scheme.. [1 – 5].

2.2.2. Fault Tolerant Dynamic Channel Allocation Scheme

2.2.2.1. Centralized approach

In this approach the mobile station (MS) sends a request to the central controller, which is called

Mobile Switching Centre (MSC). The MSC is the only component which is responsible for

channel allocation and distribution of all resources to avoid co- channel interference between

cells. When the MSC encounters a problem and fails, then the entire network of that MSC it also

fails to operate. This approach is not scalable because the MSC can become a bottleneck when

the traffic load of the system is heavy.

2.2.2.2. Distributed approach

This approach does not depend on MSC as the centralized one rather the nearby base station

share the responsibility to allocate channels through the use of Mobile Service Station (MSS).

The base stations are independent to communicate with each other by using the MSS component

and to share information. The base station that wants to borrow a channel it will send the request

to all the nearby base stations through the communication of the MSS and when the reply come

that there is a free channel in any one of the nearby channels then it uses that channel. This is

done in collaboration with all nearby channels by sharing the information thus to avoid the co-

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channel interference which might occur. This approach is scalable, reliable and robust and thus it

guarantees the QoS of the cellular network. [1],[6],[19 – 24].

Figure 2.1: Distribution channel allocation model (source: http://en.kioskea.net)

2.2.3. Call Admission Control (CAC) Scheme

In the CAC algorithm scheme the new call arriving will be processed by comparing the

estimated rate of call arriving with the predetermined rate of call arriving. If the estimated rate is

higher compared to the predetermined level then the fraction of calls will be blocked regardless

of the availability of the channels in the cells. The main objective of this scheme is to avoid the

bottleneck of the incoming traffic. The QoS on this scheme is achieved through the use of

parameters like Forced Termination Probability (FTP), which is defined as the ration of the

number of calls which are forced to terminate due to failed handoff to the number of calls that

successfully entered the network. Another parameter is the Successful Call Completion Rate

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(SCCR), which is defined as the number of calls which are completed successfully in a unit time

by each cell. [2],[25 – 28]

When the new call arrives the algorithm check whether the acceptable load is less compared to

the estimated load. If the answer is less then it check for the availability of a free channel in the

cell otherwise if the estimated load is greater than the acceptable load, then the algorithm will

calculate the fractional amount of calls which will be allowed and the remaining fraction which

is exceeded will be discarded even if there are available channels. This is called pre-blocking of

channels and through this the scheme improves the FTP and SCCR of the profiled users. [2],[30]

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Figure 2.2: Call Admission Control Algorithm (Kovvuri)

2.2.4. Mobility Prediction Scheme

The Mobility Prediction Scheme is used to determine the path of the trajectory of a mobile node

and this path information is stored in the database from time to time. Normally there are channels

reserved for handoff process, so this scheme, there is prioritization of resources before handoff

occur so as to decrease the call probability rate at the handoff. Through this the handoff can be

predicted earlier and the resources will be reserved for the same. [3],[25 – 28],[30].

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While travelling in the vehicles the mobile host (MH) will encounter a number of handoff when

communicating. By studying the information about the road topology and to store them in the

database from time to time, then the prediction algorithm will prove to be suitable. The figure

above shows a number of base stations when the MH is moving in a vehicle. This database of the

base station, it records information’s such as average time to transit a segment, neighbouring

segments at each junction and the probability of the MH to do a handoff. Every time the base

station is able to collect the information of the moving node, then it will update its database to

prepare resource incase this node will require a handoff in the near future while communicating.

Through this the management of handoff is done precisely by reducing the probability of call

block and forced termination due to lack of resource, hence improved QoS of the entire system

[3], [28 – 30]

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Figure 2.1: Topology information for Mobility Prediction Scheme (Soh)

2.2.5. Dynamic Allocation Scheme using Renegotiation

In this scheme when the medium level is free of using its resources, then the low level priority is

given those resources. This scheme increases the QoS of the over whole network system by

making sure the high priority they are served effectively while also the low priority doesn’t

execute for a long time.

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With the massive development of mobile phone technology now the world is trying to find its

feet in 4G technology, therefore the battle for resources between conversational and streaming

classes is becoming intense. With services like video telephony, Telnet, voice and video we

expect the network to employ real time traffic data which are delay sensitive while the

application like emails, news, FTP and all kinds of surfing over the web browser are less delay

sensitive. [10 – 13]

In Renegotiation scheme the conversational classes are assigned with maximum priority say

class 1. While the streaming classes are also given high priority say class 2. But the priority class

1 and 2 when arrived at the first time will be served if there are enough resources to

accommodate them, if not they won’t be admitted. But lower priority class, let’s assume class 3

which has interactive services like chart messages and emails will be admitted at any time they

knock in since they require lesser bandwidth compared to class 1 and 2. The big advantage of

these schemes is when bandwidth is allocated to high class priority it can be transferred when

that particular task is completed. Also lower priority class they can use more resources than they

previously asked if the resources are available. And at this time when the higher priority class

arrives, it won’t be blocked even if there are no enough resources, but rather it will take those

resources allocated to low class from the high class and reuse them. [4 – 6],[16],[18]

2.3. Discussion and Conclusion

2.3.1. Results Discussion

The Dynamic channel allocation Scheme is fault tolerant since it gives us an opportunity to reuse

the channels. Also, since it doesn’t use the MSC as the centre of its operation as the cell

communicate with each other then we have seen there is no need to get the response from all the

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adjacent cells for borrowing a channel. Therefore, this scheme, it helps to reduce the overall

congestion in the network.

The CAC scheme utilizes the combination of the pre-request scheme and guard channel scheme

to avoid the bottleneck of the incoming calls, hence it helps to reduce the number of blocking

calls.

The Mobility Prediction Scheme it uses the information it collects from the mobile host when

travelling and prepare the resources for handoff when needed. This helps to avoid unnecessary

call drops during the handoff procedure.

The Renegotiation Scheme it makes sure the QoS of highest priority is not disturbed while

allocating the unused resources to the low priority. Through this the overall QoS of the network

is improved through idle resource distribution even though they didn’t ask for that amount of

resource

2.3.2 Conclusion

Quality of service as an essential tool in wireless network communication depends on the choice

of the scheme for a certain application. We have seen scheme like Fault Tolerant Dynamic

Allocation reduces the overall network traffic congestion. And Call Admission Control balances

the network load by blocking the incoming calls even if there were available channels. While the

Mobility Prediction Scheme uses the information it collects in advance to set the room for

handoff to occur without causing dropped calls. Lastly the Renegotiation Scheme, which

guarantees the QoS of low priority by reallocating the unused resource. These schemes are

essential tools in analysing the quality of service the network can provide to its users.

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2.3.4. Future work

In the near future the drive test, measurement will be conducted in Mwanza region to collect data

about Network Fault related parameters such as Fault Incidence rate, Mean Time to repair,

Network availability (coverage) also Network reliability with parameters like Call set-up success

rate (within own network), Service Access Delay, Signal strength and voice quality, Call Drop

rate percentage of connections with good voice quality and data quality. This data will help me

to examine these schemes of QoS into details.

Acknowledgement

I sincerely thank the Almighty God for giving me the will and courage to complete this work.

Then my supervisor Dr. Anael Sam for working hand with hand to the completion of this work.

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CHAPTER THREE: CHAPTER THREE: 2ANALYSIS OF QUALITY OF SERVICE FOR

WCDMA NETWORK IN MWANZA, TANZANIA

Adolph kasegenya1, Anael Sam2

Abstract

This paper presents an analysis and evaluation of a WCDMA network in both rural and urban

areas of Mwanza, Tanzania. The analysis of data starts by collecting data through a drive test,

measurement by using TEMS Investigation tool. The parameters which are analysed in this

paper are such are Received Signal Code Power (RSCP), Transmitted Power (TX), Speech

Quality Index (SQI) and the ration of received power to noise (Ec/N0). The data collected

shows that only 24.02% of the region has got the best coverage, 23.24% has poor coverage and

the 52.74% has a fair coverage. Also by using the basic Key Performance Indicators (KPI’s) we

analysed the data for the quality of service (QoS) of the area which shows only 27.61% of the

region has good QoS, while the poor value recorded with 2.76% of the region. We can use the

analysis done in this work to stage and support system optimization for telecom service

providers so as to improve their performance of services in this area.

Keywords: WCDMA, Received Signal Code Power, Coverage and Quality of Service

3.1. Introduction

Quality of Services in mobile environment can be defined as the proficiency of mobile operators

to deliver acceptable services to mobile subscribers as for the predefined key performance

2International Journal of Information Engineering and Application (IJIEA). Volume 4 Issue 10, October, 2014,

ISSN: 2225 - 0506; Accepted and ready for publication by Adolph Kasegenya and Anael Sam from the school of

Computational Communication Sciences and Engineering (NMAIST).

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indicators set. The services delivered include good voice services with low blocking and

dropping probability, good signal strength with high data rates.

Tremendous growth of the mobile phone market in Africa and the introduction of smart phone

for communication have changed the way we used to look for cellular network services. There is

an increase demand for converged services supporting multimedia such as video and audio in

mobile communication systems. Provisioning of quality of service (QoS) in converged networks

is becoming much more complex.

The main challenges when considering the issue of QoS in mobile phone environment are issues

like bandwidth allocation, varying rates, channel characteristics, fault tolerance level and handoff

support in heterogeneous wireless networks. Each layer of the Open System Interconnection

(OSI) model has its own mechanism to provide better QoS so as to attain interoperability,

various standards, network flexibility and tolerance. One of the biggest challenges in the mobile

phone network in today’s world is the proper and efficient usage of the spectrum resource such

as frequencies, scrambling codes, spreading factors, power for common and dedicated channels

Bandwidth allocation plays a vital role in this aspect. There is a great challenge when the issue of

data and its application is evaluated for better QoS of the mobile network. Supporting both data

and voice application needs a better understanding of how they work. Voice need real time

operation since they are delay sensitive. While on the other side data are sensitive to loss of data.

The following parameters were the keys of this analysis;

3.1.1. Received Signal Code Power (RSCP)

The “Received Signal Code Power” (RSCP) means the power measured by the receiver on a

physical communication channel. This power denotes the strength of the signal measured, the

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condition for handover to occur, how to find path loss and moreover it’s a power control in

downlink channel.

3.1.2. Ration of Received Power to Noise (𝑬𝒄/𝑵𝒐)

𝐸𝑐𝑁𝑜Account for all received energy per chip from the Node B when divided by the power

spectral density in the given band of operation. ‘No’ contains the actual power of a particular cell

from the designated total received power. Hence 𝐸𝑐/𝑁𝑜 is decreasing the value for ‘No’

increase. It is expressed into 𝑑𝐵.

EC/No for a UE is the measure of PCPICH (code power) over Total Wide Band Power on that

particular carrier. Measure of PCPICH (RSCP) 𝑑𝐵𝑚 and measure of Total Wideband power

(RSSI) 𝑑𝐵𝑚. So the𝐸𝑐/𝑁𝑜 will become;

EC/No = RSCP / RSSI (1)

(By applying logarithmic rule) into (1) then we get

Ec/No = RSCP – RSSI (dB) (2)

3.1.3. Speech Quality Index (SQI)

SQI is a performance metric for voice quality in telecommunication. It is specific only to the

TEMS family of drive testing/field testing tools. SQI aims to provide a reasonable estimate of

the voice quality, as perceived by a human ear.

3.1.4. Transmitting Power (TX power)

The kind of power which carries the signal from Node B (BTS) and transmitting it to User

Equipment (UE) or mobile communication device. TX power needs to be sufficient enough to

ensure the reliable communication between the Node B and UE.

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3.2. Methodologies

3.2.1 Feasibility Study

While conducting analysis of QoS in Mwanza, a keen feasibility study was conducted to gather

information about; system parameters of equipment which have been installed in Mwanza,

including the transmission capacity for sites, class of services offered and network configuration

in terms of data rates, Number of sites, prospective customers and criteria for addition of sites,

Frequency Band (Uplink and Downlink), Modulation schemes, and factors which degrades

Quality of Service.

3.2.2. Drive Test

The analysis of QoS in Mwanza region was done through Drive Test, measurement where the

tester collected log files through the TEMS investigation tool and analyses them through Actix

Analyzer and Map Info. The main objectives of this DT were to check the coverage of the area,

accessibility, handover success rate and retain-ability of the cellular network in general.

3.3. Results and Discussion

The following graphs were obtained after the log files collected from the drive test was simulated

and analysed in Actix Analyzer and Map Info software.

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3.3.1. Coverage in terms of RSCP

Figure 3.1: Coverage KPIs _RSCP_Long Call Mode

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3.3.2 Coverage in terms of EC/No

Figure 3.1: Coverage KPIs _CPICH Ec/No

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Below is the summary of the above findings from the maps

Figure 3.2: RSCP in active set count

Figure 3.1: The 𝐸𝑐/𝑁0 in active set count

0%

5%

10%

15%

20%

25%

30%

35%

40%

0

2000

4000

6000

8000

10000

12000

< -130.0 -130.0 to-115.0

-115.0 to-100.0

-100.0 to-90.0

-90.0 to -80.0

-80.0 to -70.0

-70.0 to -60.0

-60.0 to20.0

> 20.0

% S

am

ple

s

Sam

ple

Co

un

t

RSCP (dBm)

Strongest RSCP in Active Set

0%

10%

20%

30%

40%

50%

60%

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

< -20.0 -20.0 to -17.0

-17.0 to -15.0

-15.0 to -13.0

-13.0 to -11.0

-11.0 to -9.0

-9.0 to -5.0

-5.0 to0.0

% S

am

ple

s

Sam

ple

Co

un

t

EcIo (dB)

Strongest EcNo in Active Set

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Table 3.1: Mean, Mode, Median, Variance, Standard deviation and maximum and minimum

ranges of both RSCP and Ec/N0 in active set count

Statistic Strongest EcNo in AS Strongest RSCP in AS

Mean -9.3 -87.4

Mode -9.0 -89.0

Median -9.0 -87.0

Maximum -2.5 -50.0

Minimum -24.0 -121.0

Count 31792 31792

Standard Deviation 2.7 12.7

Variance 7.1 161.9

3.3.3. Transmission Power

Figure 3.3: Transmission Power from the base stations

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Coverage summary

Figure 3.4: Coverage summary of the whole sample region

The results show the best coverage in the entire sample of evaluation was only 24.02%, while the

poor coverage below the minimum value was 23.24% of the whole region. This shows the rest of

the region has a fair coverage, which is not enough for the good quality of service of the whole

region.

Quality of Service Summary

Figure 3.5: Quality of Service summary of the entire sample region

24.02

52.74

23.24

Coverage

Good RSCP > -80 dBm Fair -80 to -95 Poor below -95 dBm

27.61

69.62

2.76

Quality

Good Ec/No > -8 dB Fair -8 to -15 Poor below -15 dB

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The overall QoS which is greater than -8dB was only 27.61% and the poor quality of service

which is below the -15dB was 2.76%. The results show most of the region is under fair quality of

service of about 69.62%.

3.3.4. Call Information Overview

Figure 3.6: Summary of the call information overview

Bad quality of service of the entire region shows the rate of call drop was above 60%, while the

rate of the overall call success rate was below 40%.

Now from the above graphs we can say that;

3.3.5. Low Received signal level

Most of the places of this region are covered by different types of terrain, structures like hills,

mountains and tall rocks which results in loss of line of sight to the transmitted signal. In places

where the signal received level is below the threshold, then there are coverage holes and those

places can be seen with the red colour on the above two maps. Attenuation of signal due to high

mountains, hills and valleys contributes much to downlink low level signal strength. Also the

low number of serving sites and path loss due the effect of Rayleigh Fading was another reason

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for reduced signal strength. Poor coverage due to the low received signal level results into bad

quality of service and hence call drops.

3.3.6. Lack of Dominant Server

Due to the low value of CPICH power, the MS was experiencing a high number of handover.

This was because the MS was located at the border of the cell and there was no BTS with strong

signal to support and keeping the call. It keeps on receiving signals from more than one cell,

hence results in interference and handover.

3.3.7. Sudden appearance and disappearance of neighbour

Due to different terrain changes and obstacles from tall rocks the neighbour cells were popping

up with high levels of signal, hence resulting into a lot of handover over a short period of time to

the BSC. The effect is famously known as “The ping pong effect”.

3.3.8. Drop Call due to Bad Coverage:

The signal level goes down beyond the minimum RX Access level to which prevents the on-

going call to drop. This is mostly due to bad coverage as it is shown on both coverage maps of

RSCP and CPCIH.

3.4. Recommendation

The best solution in most of the coverage problems will be installations of new base station. But

due to budget limits and operations under low profit margins in most of this area, it is difficult to

be implemented.

Therefore, it is better to do site auditing to check for corrects antenna orientations, antenna tilts

and antenna type as for specific environments. Also to check the possible attenuation of the cells

through faulty feeders, jumpers, connectors and other faulty equipment.

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To increase strong received signal it is better to deal with unnecessary down tilts, proper

investigation of the existence of natural diversity like forest hills, tall rocks and valleys as well as

to increase the height of the site. Putting high gain antennas and increasing output power could

improve the coverage.

3.5. Conclusion

The coverage of this region is bad in most of the places due to poor RSCP as it is shown in the

above analysis of the map extracted from the log files. The transmitting power also degrades as

the User Equipment moves away from the BTS. All of this and other factors which have been

discussed above results into call drops, muted calls and fluctuation on coverage for both data and

voice. Even though the quality of service is not that much bad, but there are many problems due

to coverage and they need to be taken care as soon as possible. Proper optimization is needed to

be done in most of the area to increase the quality of service in the region. New sites can be

added to complement the problems of coverage, especially in areas where they lack dominant

server.

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CHAPTER FOUR: 3PLANNING AND OPTIMIZATION OF 3G NETWORK WITH

PERFORMANCE COMPARISON BETWEEN THE OPERATORS OF MOBILE

COMMUNICATION SERVICES

Adolph kasegenya1, Anael Sam2

Abstract

This paper presents WCDMA radio network planning. The Planning process involves network

dimensioning, thorough capacity planning and coverage planning as well as network

optimisation. The WCDMA network dimensioning comprises of the information’s of base

stations and their design criterion and other network elements as for the operator’s preferences

and the radio propagation of the selected area. The dimensioning of the network needs to achieve

the operator’s prerequisites intended for coverage of the cell, traffic capacity and the basic

Quality of Service (QoS) projected. These two aspects are attentively correlated in WCDMA

networks, consequently all of them need to be reflected concurrently in the process of network

dimensioning. With the help of network planning tools like Asset software, Google Earth, Map

Info and Tems Investigation kit both channel capacity planning and coverage planning of the cell

are assessed simultaneously for WCDMA networks. With detailed planning, the actual

propagation plots and operator’s traffic assessments in respective areas are of crucial importance.

After the planning process being commissioned, then the network implementation comes into

effect, and here the network operation and its performance were observed through network

performance tests, and the outcomes of these tests were used as the foundation stage for network

optimisation. Also the comparison of performance of services between all the operators in terms

of voice services, data services and its application, coverage through Received Signal Code

3International Journal of Technology Enhancements and Emerging Engineering Research (IJTEEE). Volume 2

Issue 11, November, 2014, ISSN (Online): 2347 - 4289; Accepted for publication by Adolph Kasegenya and Anael

Sam from the school of Computational Communication Sciences and Engineering (NMAIST).

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Power (RSCP) and Quality of Service through the ration of Received Power to Noise (EC/No)

was conducted for all operators.

4.1. Introduction

The Third Generation networks which are based on Code Division Multiple Access (CDMA) is

also referred as Universal Mobile Telecommunication System (UMTS) is categorized into three

standards as per International Telecommunication Union (ITU) specification, these standards are

such as Wideband CDMA (WCDMA), CDMA2000, and Time Division Synchronous CDMA

(TDSCDMA). CDMA is a digital mobile communication technology that employs spread-

spectrum methods. It doesn’t allocate frequency explicit to individual subscriber, but it ensures

each channel exploit the disposal of efficient usage of complete spectrum. Distinctive colloquies

are encrypted with a pseudo-random digital system (Eisenblatter et al., 2008)and (Guo et al.,

2003).

As was elaborated by (Toskala et al., 2001), the first commercial 3G network was launched in

Japan in 2001, while in Europe was launched in 2003 in parts of the Uk and Italy. The

commercial launch in Africa took place in 2006 by EMTEL Company in Mauritius. The spread

of WCDMA networks in most countries was hindered by the huge superfluous cost of licensing

spectrum fees. Since WCDMA operates with different frequency range when compared to GSM,

then network vendors in many countries were required to build their networks with new

specification which conforms to new frequencies of UMTS. The licence fees for the new

frequencies in these countries were predominantly high due to the limited number of frequency

sold by most governments and also early agitation of 3G’s prospective. Other holdups were due

to the overhead of setting up a new network.

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The main components of 3G network include BS (Base Station) or node B, RNC (Radio

Network Controller), together with Wideband CDMA Mobile Switching Centre (WMSC) and

the Serving GPRS Support Node (SGSN) /Gateway GPRS Support Node (GGSN). WCDMA

network aid vendors to operate with the maximum spectral efficiency with better management of

traffic capacity and a variety of improved sophisticated services. These services are such as

video calls, broadband wireless data and voice telephony in a conducive and efficiently manner.

Additional features such as High Speed Packet Access (HSPA), it has ability of transmitting data

with speed up to 14.4Mbps on the downlink and 5.8 Mbps in the uplink.

4.2. Radio network Planning Process

WCDMA radio network Planning process as it was described by (Laiho et al., 2006). The below

graph depicts the necessary footsteps for WCDMA planning methods.

Figure 4.1: WCDMA radio network planning process

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System dimensioning is a key task in network planning. It provides an early assessment into

network environment count as well as the supplementary channel capacity components. These

components are such as radio network and the core network. Due to time constraints, this paper

will deal with the radio network section exclusively.

The initial stage of planning requires the planner to evaluate the special features like the

population density of the area, morphographic features (environmental area types), topographic

features (terrain heights), natural vegetation and network configuration parameters and sub

parameters of the area. This stage consists of the activity like Radio Link Budget (RLB) were the

uplink and downlink power are estimated, coverage prediction were the area to be covered is

plotted with all the salient features required, capacity prediction were the ability of BTS is

compared to the traffic density of the area, and lastly the number of required BTS to handler all

the traffic in accordance with the estimated population density of the area, Radio Network

Controller (RNC), equipment for different interfaces and the core network elements needed.

Network dimensioning outlays how the traffic will be distributed in the network, the future

expected traffic growth and the basic QoS needed. This stage also introduces the Call Admission

Control (CAC) algorithms for managing the blocking probability.

4.2.1. Radio Link Budget (RLB)

The RLB in UMTS networks, is a little more complex, as every user is generating interference to

others in the same network. (Laiho et al., 2006) describes that, the RLB takes into account the

existence of parameters like antenna gains, cable losses, diversity gains, fading margins and

handovers while dimensioning the radio network. The RLB computation yields to maximum

tolerable propagation path loss, which is deemed to determine cell range and the highest number

of cell sites required. Thus the cell radius is reliant on the traffic capacity at any absolute time,

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and the outcome of this has to be projected on a series of repeated methods for uplink and

downlink evaluation. Both uplink and downlink estimation will yield in a cell range value which

the final value will be the lower of the two iterations on average.

The following parameters are the additional from the link budget equation of the TDMA-GSM

based.

4.2.1.1. Interference margin:

The importance of the interference margin in this link budget is clearly depicted by (Mahato,

2007), due to the presence of features like loading of the cell and the load factor in effect of

coverage analysis. The more loading capacity is sanctioned in the system, the larger is the

interference margin needed in the uplink, and the smaller is the coverage area. In coverage

limited cases, a smaller interference margin is used while in capacity limited cases we used a

larger interference margin. Also (Glisic, 2003), explains coverage limited cases whereby the cell

size is limited by the maximum allowed path loss in the link budget, while the maximum air

interface capacity of the base station is not used. The typical values for the interference margin in

coverage limited cases are 1.0 to 3.0dB, which corresponds to 20 to 50% loading.

4.2.1.2. Fast fading margin (= power control headroom):

For keeping up sufficient closed loop fast power control, the headroom is needed in the mobile

station transmission power. This is especially for slow moving pedestrian mobiles where fast

power control is able to compensate the fast fading. The typical value for the fast fading margin

are 2.0 to 5.0dB for slow moving mobiles.

4.2.1.3. Soft handover gain, as was discussed by (Laiho, 2002):

The soft handover gives a gain contrary to slow fading by diminishing needed log-normal fading

margin. This is due to the reason that the slow fading is partly uncorrelated between the base

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stations and by making handover the mobile can select a better base station for its operations.

This gain provides extra macro diversity gain contrary to fast fading by decreasing the needed

Eb/N0 in relation to a particular radio link. The extent of gain can be expressed in terms of

mobile phase, the types of algorithms deployed into the receiver and supplementary gains which

are presented into the received signal. The absolute soft handover gains it’s in the range of 2.0

and 3.0 dB. The following graph depicts the Uplink iteration process for RLB calculation as was

discussed by (Laiho et al., 2006)

Figure 4.2: UpLink Iteration Process

Connect MSs to best server, calculate needed

MS TX Power and SHO gains

Check UL loading and possibly move MSs to

new other carrier of outage

Calculate adjusted MS TX powers, check MSs

for outage Calculate new i = ioth / lown

Set old Threshold to the default/ new coverage

threshold

Calculate new coverage threshold

Check hard blocking and possibly take links

out if too few HW resources

Evaluate UL break criterion

Initialisation

End

Post Processing

DL Iteration step

Convergence

No

n

Co

nv

er

ge

nc

e

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The Downlink iteration process takes into consideration the total downlink power as its reference

point and not the level of interference in the system as its counterpart Uplink iteration process it

considers. The keen descriptive data for both the process are not shown for the sake of brevity of

the concerning company. The graph of the downlink iteration process was explained by (Laiho et

al., 2006)

Figure 4.3. Downlink iteration Process

Initialise

Iterations

Calculate target C/I’s

Calculate Initial TX Powers

for all links

Determine the SHO

connections

Calculate the MS

Sensitivities

Calculate the received perch

levels and determine the best

server in DL

Allocate the CPICH powers

Global Initialisation

Initialise deltaCloid

Calculate the SHO

diversity combining gains;

adjust the required change

to C/I

Check CPICH Ec/Io

Calculate the C/I for each

connection

Calculate C/I for each MS

UL iteration setup

Check UL and DL break

criteria

Fulfil

led

End

Post Processing

Update deltaCloid

Adjust TX powers of

each remaining link

accordingly to deltaCl

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The cell range value is calculated by using equation (3) as was depicted by (Hurtado, October

2005), were the minimum required power level at the receiver(sensitivity) is defined for a

reference user i of each service k.

RXlevel_i [dBm] = NF + 10 log (No) + 10 log (i_oi ) + 10 log [Eb/(No_k )] + 10log (R_k)

(3)

Where

• NF = Node B noise Figure [dB]

• No = thermal noise density, normally assumed to be -174 dBm/Hz

• Eb/No k = Eb/No for the service k

• Rk: Service k bit rate (bps)

• ioi = Noise Rise due to interference

To calculate the Maximum path loss, equation (4) is used

Lmax, i = PULk – Required_Leveli – Σ losses – Σ margins + Σ gains (4)

Where:

PULk is the mobile power valid for service k [dBm]. In this equation, all the losses, margins and

gains are given in dB.

After getting the maximum path loss (Lmax), then we apply a propagation model like Okumura-

Hata to determine the corresponding cell range. Then we are supposed to calculate the ability of

the cell to carry traffic so as to get the interference over noise rise and to make a comparison

with the figure at the end of the uplink iteration process.

Traffic per cell can be computed for each service, since the number of subscribers per square

kilometre is renowned from preceding processes of network dimensioning and the area of the

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cell is conveyed from the cell range found previously. For example, for the standard hexagonal

cell with the type of antenna which radiates equally in all directions, then the area is

approximated to be 2.6R2, where R is the cell range in Kilometres.

By using modified Stochastic Knapsack model as was depicted by (Kumar et al., 2010) and

(Hodge, 2006), the capacity of cell can be computed by using equation (5);

η_UL (Uplink load factor) = (the number of active users) /(pole capacity) (5)

Where “Pole Capacity” means 100 % cell load and is given by equation (6);

𝑁𝑝𝑜𝑙𝑒 ,𝑈𝐿 = 𝑤/(1 + 𝑓𝑢𝑙) ∑ 𝑗 = 1 … 𝑘 𝑉𝑗 ∗ 𝑅𝑗 ∗ 𝑃𝑗 [𝐸𝑏/𝑁0 𝑗/(1 +𝐸𝑏

𝑁0𝑗

∗𝑅𝑗

𝑊)]

(6)

Where:

• W : chip rate, in W-CDMA is fixed to 3.84 Mchips/sec

• K = number of offered services

• Eb/No j is the required Eb/No for the service j (j=1… k)

• Rj is the bit rate of service j

• vj is the activity factor of the service j.

• Pj is the percentage of the total active users who are using service j

• 𝑓𝑢𝑙 = other cell / own cell interference ratio,

As they are received from Node B, For the ideal antenna which radiates equally in all sides, then

this value is approximated to be 55% (0.55).

Table 4.1: Parameters used in Uplink load factor calculations as described in (Laiho, 2002)

Definitions Recommended Values

N Number of users per cell

Activity factor of user j at physical layer

0.67 for speech, assumed 50% voice

activity and DPCCH overhead during

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DTX

1.0 for data

Eb/N0 Signal energy per bit divided by the

noise spectral density that is required to

meet a predefined Quality of Service

(e.g. Bit error rate). Noise includes both

thermal noise and interference

Dependent on service, bit rate,

multipath fading channel, mobile

speed, etc.

W WCDMA chip rate

3.84 Mcps

Rj Bit rate of user j Dependent on service

i Other cell to own cell interference ratio

seen by the base station receiver

Macro cell with omnidirectional

antennas: 55%

Lastly after having the cell load, then we need to calculate the Interference Noise rise as it is

given by equation (7);

𝑁𝑅 [𝑑𝐵] = − 10 𝐿𝑜𝑔10 (1 − 𝜂𝑢𝑙) (7)

Then we need to approximate the conjunction of the resultant value with the presumed one in the

preliminary stage. The computation of Radio Link Budget (RLB) and the analysis of coverage

gives out the cell range value and its subsequent cell area coverage

4.2.2. Downlink Load Factor

As was described in (Holma et al., 2010), the downlink load factor η, Can be explained on the

ground of comparable analysis as the uplink factor even though they are considerably unlike.

The downlink factor can be calculated by using equation (8);

𝜂𝐷𝐿 = ∑ 𝜐𝑗 .(

𝐸𝑏𝑁0

)𝑗

𝑊/𝑅𝑗

𝑁𝑗=1 . [(1 − 𝛼𝑗) + 𝑖𝑗] (8)

Where−10 ⋅ 𝑙𝑜𝑔10(1 − 𝜂𝐷𝐿) is equal to the noise rise over thermal noise due to multiple access

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Interference. As explained by (Laiho, 2002), the new parameter 𝛼𝑗 , Symbolize the orthogonality

factor in the downlink channel. The WCDMA employs orthogonal codes to distinct subscribers,

despite being deprived of any multipath propagation the orthogonality persists the signal is

received by the UE. By any chance when the delay is of large extent, then, the UE will receive

this signal as multiple access interference. The orthogonality of 1 corresponds to perfectly

orthogonal users (Toskala et al., 2001). The typical value of orthogonal ranges between 0.4 and

0.9 in multipath channel (Sipila et al., 1999).

Table 4.2: As was argued by (Laiho, 2002) and (Holma et al., 2010), Parameters used in the

downlink load factor calculation.

Definition Recommended values for dimensioning

N Number of connections per cell =

number of users per cell x (1 + soft

handover overhead)

Activity factor at physical layer 0.67 for speech, assumed 50% voice

activity and DPCCH overhead during

DTX

1.0 for data

Eb/N0

Signal energy per bit divided by noise

spectral density, required to meet a

predefined Quality of Service (e.g. Bit

error rate). Noise includes both thermal

noise and interference

Dependent on service, bit rate,

multipath fading channel, mobile speed,

etc.

W WCDMA chip rate

3.84 Mcps

Rj Bit rate of user j Dependent on service

αj Orthogonality of user j

Dependent on the multipath propagation

1: fully orthogonal 1-path channel

0: no orthogonality

ij Ratio of other cell to own cell base

station

Each user sees a different ij, depending on

its location in the cell and log-normal

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power, received by user j

shadowing

Average orthogonality factor in the cell ITU Vehicular A channel: ~60%

ITU Pedestrian A channel: ~90%

The average ratio of other cell to own

cell base station power received by the

user. Own cell interference is here

wideband

Macro cell with omnidirectional

antennas: 55%

4.3. Capacity and Coverage Planning

4.3.1. Iterative Capacity and Coverage Prediction

The network dimensioning phase enabled us to obtain the cell count, which now will be used in

network planning by taking into account the radio frequency and its associated favourable

environmental conditions with digital maps of high resolution, which shows all necessary

geographical data and precise propagation models, to simplify to exercise of estimating the

optimum number of base station required.

In order to come up with a meticulous channel capacity and coverage planning, as explained by

(Laiho, 2002), the actual propagation information from the selected site are indispensable

collectively with the anticipated user density and projected traffic load. Meanwhile the

knowledge of the surrounding Node B’s is highly required with their performance data so as to

evaluate the option of reusing the existing cell sites in the area. The outcome of these two

processes of planning for capacity and coverage are such as the exact location to install a Node B

as well as the necessary constraints required.

Since users in WCDMA share the similar resources in the air interface for the interference, then

these users they cannot be analysed independently. The influence between each user interference

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causes their transmission power to change. As a result the whole extrapolation process becomes

iteratively until the transmission power is steady. The multipath channel profiles, bit rates and

mobile speeds play a vital role in both capacity and coverage planning. Also the WCDMA, it

includes features like fast power control in both uplink and downlink, soft and softer handover

and orthogonal downlink channels to enhance its performance. Other things to note in coverage

and capacity planning in WCDMA are, things like interference estimation which is crucial in

coverage prediction phase, also the base station sensitivity depend on the number of users and

used bit rates in all cells.

In WCDMA, coverage and capacity need to be analysed concurrently due to the fact that they are

both influencing each other and they result in phenomena like cell breathing where the cell

coverage area shrinks (i.e., mobile phones which are transmitting at their maximum power in the

cell border cannot increase their power levels more and eventually they get disconnected unless

the handover takes place with the help of the nearby cell) if there is higher interference in the

cells (intra-cell/ inter-cell interference).

The tangible specified planning stage on WCDMA network it looks similar to TDMA/FDMA

planning in GSM network. The BTS or Node B spot and their region segments are deployed in

planning software were the significance of the transport layer is evaluated. The mobile station

densities in different cells are based on the actual traffic information. The hotspots should be

identified as an input for accurate analysis.

In 3G networks the prerequisite number of cells to cover a particular area can be calculated based

on the capacity and the radio link budget. The network usually acts as either coverage limited

(i.e., there is an adequate amount of capacity resources in the cell to sustain the traffic forecasted,

even though the maximum cell range of a mobile transmission power limits it) or capacity

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limited (i.e., the maximum cell radius cannot support the total traffic offered because of

insufficient resources). [ITU]

4.3.2. Detailed Coverage Planning

Once we have the geographic data, clutter information and accurate propagation models, then the

coverage planning starts so as to identify the number of base stations and their locations by using

proper planning tools like Asset software. Also the advanced features are evaluated to avoid

undesirable phenomena like pilot pollution (where the presence of too many pilots with

maximum power levels in the same area, cause interference and higher error rates as a receiver

are designed to handle the maximum of only 4 pilots) and Ping-Pong effect which causes the

excessive handovers and increased dropped call rates.

Thus the coverage planning includes the following activities;

Channel power planning (to avoid pilot pollution)

Detailed characterization of the radio environment

Soft handover parameter planning

Iterative network coverage analysis based on the simulation tools and

Network optimization to ensure efficient usage of network resources

4.3.3. Detailed Capacity Analysis

While planning the 3G network in capacity aspect we should note that it is very important to

ensure that the current resource meet the current traffic demand for a greater quality of service

(capacity management) without forgetting to plan for the future load dimensioning (capacity

planning). One of the reason for planning these two factors coverage and capacity

simultaneously is that the detection of capacity complications in the network is unconventional

in WCDMA, since the load system depends on several parameters like traffic load of individual

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service (data influx route), user mobility profile, spatial distribution of traffic demand, the

geographical environment (urban, suburban and rural) and other physical radio parameters like

efficiency of Rake receivers and macro diversity gains. According to (Hurtado, October

2005),the capacity planning need to adhere to the following fundamental issues;

To guarantee that the presented resources are used to deliver the uppermost performance

(capacity management)

In addition, there will be enough resources to encounter the upcoming workload

requirements (capacity planning).

Detailed capacity analysis is the process to ensure the above two fundamental issues are certain

while planning.

4.4. Results and Discussion

4.4.1. Results for planning

The output from network dimensioning gave us the clear picture of both capacity, coverage and

quality predictions. From capacity planning, we knew the spectrum available, the subscriber

growth forecast and the traffic density map. While in coverage planning, we determined the

coverage regions and the area, type of information associated with the regions we want to cover,

preferred antenna line system specifications, suitable propagation model, field strength

predictions and coverage threshold values on per regions (outdoor, in-car and indoor). Finally,

both capacity and coverage ensure we had better quality of service by having low blocking

probability and good threshold values on per regions coverage for most of the area.

Normally planning is done in two scenarios where it is either the capacity planning which

originates from technical department through customer complaints or coverage planning which

originates from the marketing department for expansion of the network.

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Coverage planning is done where the area does not have a pre-existing site from the core

network and there is demand from the new market prediction. A polygon of the area is drawn to

show the dimensions of the area needed to be covered. Coverage prediction goes hand in hand

with the development of digital map where the information like topography (terrain heights) and

morphography (area types) are evaluated.

The capacity planning is done through optimizing the existing infrastructure by looking at ways

to ease traffic to the overloaded BTS. Capacity planning examines the capacity of each sector by

comparing its actual capacity and the estimated capacity. If the subscriber densities are much

greater compared to the entire capacity of the BTS then that is the call of adding new sites to

accommodate the traffic needed.

The following Nyarugusu area was planned for both coverage and capacity planning as the area

is illustrated in the given polygon below due to its potential new market.

Figure 4.4: Area of interest which needs to be covered

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The blue colour shows the entire area which needs to covered by the new sites. Therefore the

first work was to define the features of the area through network dimensioning. The planning

gave out the details of how many BTS are needed to cover the whole area and where to place

those BTS with their sectors.

From the below digital map we can describe the topographical features (terrain heights) and

morphographical features (area types).

Figure 4.5: Depiction of environmental terrain from our area of interest

The digital map shows us that the area is not a smooth area, but it contains mountains and

valleys, as it can be seen by following the red line. Hence putting the BTS along this line, it’s too

risk as it may result in biased transmission of signal by covering one side and hindering the

signal in another side. The geographical terrain of this area from the line drawn shows it’s not

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suitable for BTS installation and sectorization and hence we have to try to plot the coverage in

another direction.

Figure 4.6: Geographical environmental features of the area of interest, side view

From the above map it shows the line was drawn from the high mountain to the valley. At least

the terrain of this area gives us a hope of mounting a BTS as attitude from the sea level continue

to decrease as we go down the line. From the starting point, it’s a high mountain, but coming

down, it’s a valley up to the end of the polygon where the line ends.

The mere description of the area is as follows through the below figure;

Diffraction:

Point to point communication system (i.e., line of sight) is galvanized by the fundamental

principle of radio path consent in the middle of antennas. Moreover is the main determinant

components of propagation requirements of communication system. When a large object exists

in the signal path between two broadcasting antennas, it normally reduces the signal strength due

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to the fact that the radio link depends on the amount of energy bent nearby the blocking target,

and not on direct line of sight.

Radio frequency signals in diffraction can propagate behind any hindering objects, even though

the received signal strength will be promptly reduced as a receiver is moving closer into the

hindered object (shadowed) region. In this area of interest of which we planned for the new BTS,

the diffraction occurs due to the presence of big rocks, mountains and valleys.

Figure 4.7: Geographical environmental pattern for consideration while planning

Reflection:

Reflection takes place when the angle of incidence is equal to the angle of reflection in a

conducting surface. Loss of signal in reflection is caused by either absorption or direct passing of

light into a conducting material or medium. In long distance communications, wet areas, sea and

lakes are the best reflectors while the desert and landfall areas are poor reflectors. While in short

range communication the good reflectors are buildings and any other metallic structures. The

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presence of forest trees and other natural vegetation were of great concerns when planning for

better coverage in our area of interest.

Refraction:

The Snell’s Law states that 𝑛1 𝑠𝑖𝑛𝜃1 = 𝑛2 sin 𝜃2 Whereby we know if 𝑛1 has got the refractive

index, which differs to 𝑛2, then when electromagnetic waves move between these two media it

will change the direction as it cross from media with refractive index one to refractive index 2.

When it comes to a radio frequency signal, the direction of signal will abruptly bend rather than

undergoing a quick change in direction.

Scattering:

Scattering happens when the radio frequency signal hits a rough surface (within homogeneities)

and as a result the signal get dispersed instead of being absorbed. The resulting signal is less

significant than the original signal. Scattering of RF signals in this region occur much when they

encounter things like rocky terrain, leafy trees, chain link fencing rain as well as dust.

Absorption:

Absorption occurs when the Radio Frequency signal is transformed into heat. The RF waves

move faster than the molecules of the media where the RF is passing and causes absorption to

occur. In this area where the planning was done the absorption occur since the area is rich in

water and there are wood forest.

After examining the environment into details and its nature description, then it follows the design

process of how the antennas will be placed. Here we look at the antenna orientation, antenna

heights, antenna tilt and the antenna types.

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The following graphs show the detailed planning for power estimation and the quality of power

received

Figure 4.8:Timing Advance distribution

From the figure above, we know Timing advance (TA) value corresponds to the length of time

a signal takes to reach the base station from a mobile phone. The TA value used was between 0

and 63, with each step representing an advance of one bit period (approximately 3.69

microseconds).

RX Quality

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Figure 4.9:RX Quality for downlink channel

Rx Quality this is the other name for Bit Error Rate (BER), so BER defines the Rx quality. It

means that the lower the percentage of the BER, the better the Rx quality. The extents of full and

sub samples are contingent on the speech activity elements which is renowned as DTX factor.

The variance in the BER averaging methods, results into considerable dissimilarities in the

RXQUAL distributions.

UL RX level

Figure 4.10: RX level Uplink channel

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From the figure above the BTS was set with the operating range of power from -50dBm up to

less than -100dBm. But the signal was more efficient in the range of -70dBm to -95dBm.

DL RX level

Figure 4.11: RX level downlink channel

The figure above shows the range of downlink RX power which goes to the UE from the Node B

or BTS was from -50dBm to -100dBm. But for convenient communication link the UE needs to

receive the power in the range of -60dBm to -95dBm.

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Figure 4.12: Design layout of the BTS position

The figure above shows the coverage of our sample area. Where the entire given area was

successfully covered as for the description of colours. The BTS were placed at a distance of 6km

from each other and we had a total of 3 BTS for the whole area to be covered.

4.4.2. Network Optimization

When the network is already in place and its running, then comes the work of checking if the

predictions made were correctly and the basic KPI’s for quality analysis as for the operator’s

rxlev>=-75

Good

-95<=rxlev<-75 Fair

rxlev<-95 Bad

Legend

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settings were met. Here we look at how network resources are shared and distributed as for the

services offered. The key performance indicator for the operational network were evaluated by

using network status analysis tools like Measurement Reading Report (MRR), and the radio

resource parameters were tuned for best performance. Based on definite data, the ability of the

new defined network will be assessed on its adeptness to predict the traffic load.

Optimisation needs to be evaluated based on the KPI’s defined in early stage. The field measured

data were compared to the measurement from network management system data and the

comparison were used to describe the quality of service of the new network. The performance of

radio resource management algorithms (i.e., handovers, power control, admission and load

control and packet scheduling) were analysed by using the KPI’s results.

For the WCDMA networks, optimisation can be done automatically instead of being done

manually as for second generation GSM networks.

The following graphs are the results of optimisation done

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4.4.2.1. Received Signal Code Power (RSCP)

Figure 4.13: CPICH RSSCP

The figure above shows the graph of Received Signal Code Power (RSCP) as the measure of

CPICH, with the standard deviation of 12.6, mean of -81.0 and a median of -82.0 for the total

active set count of 7101.

4.4.2.2. Received Signal Strength Indicator (RSSI)

The figure above shows the Received Signal Strength Indicator (RSSI). This is a value that takes

into account both RSCP and Ec/I0. RSSI is usually given in dBm and can be calculated as

through an equation;

RSSI[dBm] = 𝑅𝑆𝐶𝑃[𝑑𝐵𝑚] − 𝐸𝑐/𝐼𝑜[𝑑𝐵] (9)

The RSSI records the mean of -60.81, Median of -61.05 and the Standard deviation of 5.18

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Figure 4.14: CPICH RSSI

4.4.2.3. Ration of Received Power to Noise (EC/N0)

The below graph shows the ration of Received Power to Noise (Ec/N0). EC/No for a UE is the

measure of PCPICH (code power) over Total Wide Band Power on that particular carrier.

Measure of PCPICH = RSCP dBm and measure of Total Wideband power = RSSI dBm

EC/No will become 𝐸𝑐/𝑁𝑜 = 𝑅𝑆𝐶𝑃 / 𝑅𝑆𝑆𝐼

𝐸𝑐/𝑁𝑜 = 𝑅𝑆𝐶𝑃 – 𝑅𝑆𝑆𝐼 (𝑑𝐵) (By applying logarithmic rule)

The graph shows the Mean of -10.04, the Median of -10.00 and the Standard deviation of 1.93.

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Figure 4.15: CPICH Ec/N0

4.5. Performance comparison for all network operators

After the network was up and running, then comes the part of checking the performance of all

network operators in Mwanza region to see how they are providing their services.

4.5.1. WCDMA Benchmarking Objectives

Table 4.3: Benchmarking Objectives

Mode Objective

Idle -Compare Coverage

Dedicated mode

-Compare: Call Setup Time

-Compare: Accessibility

-Compare: Retainability

-Compare: Handover Success Rate

-Compare: Received Quality

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The objective of this benchmarking was to compare coverage, call setup time, accessibility,

Retainability, handover success rate and received quality for Airtel, Vodacom and Tigo who are

currently the dominant operators in the region.

4.5.2. Number of 3G sites

The test covers the area of 425 square kilometres and it involves providing mobile

communication to at least 363,452 people. There are currently about 100 3G sites in the region,

and the distribution of sites for each operator are as in the graph below;

Figure 4.16: Site comparison for all operators in Mwanza region up to June 2014

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4.5.3. Coverage Statistics

Figure 4.17: Coverage statistics of all 3G operators

From the figure above, it can be seen that Vodacom is the leading operator in this region when it

comes for good coverage, followed by Tigo which also had a remarkable coverage even though

they are short with a number of BTS when compared to Vodacom. And Airtel is lagging behind

in good coverage.

4.5.4. Accessibility Statistics

Operators

Total Call

Attempts

Total Call

Blocked

Accessibility-

CSSR%

Ranking

Airtel 97 18 81.44% 3

Vodacom 73 5 93.15% 2

Tigo 69 0 100.00% 1

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Figure 4.18: Accessibility of 3G sites

The data show a good ratio of Call Setup Successful Rate (CSSR), for Tigo as they didn’t record

any call block. However, Vodacom they recorded 5 call drops for a total of 69 attempted calls,

while Airtel they had 18 calls blocked for a total of 97 attempted calls.

4.5.5. Retainability Statistics

Operators

Total Call

Established

Total Call Drop

Retainability-

DCR%

Ranking

Airtel 79 6 92.41% 2

Vodacom 68 0 100.00% 1

Tigo 69 0 100.00% 1

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Figure 4.19: Retainability Statistics

From the figure it can be depicted that Vodacom and Tigo they have a good ratio of the Call

Completion rate for all their attempted calls 68 and 69 respectively. While Airtel had only 6

dropped calls out of 79 attempted.

4.5.6. Soft Handover Statistics

Operators Total HO OK Total HO Fail HO SR Ranking

Airtel 1746 0 100.00% 1

Vodacom 1701 0 100.00% 1

Tigo 1566 0 100.00% 1

Figure 4.20: Soft Handover statistics

In the case of soft handover, all operators had a perfect score without handover failure.

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4.5.7. Coverage RSCP

Figure 4.21: Coverage RSCP Statistics

Coverage in terms of Received signal Code Power (RSCP), was better for Vodacom as they

recorded an average of 81.2%, followed by Airtel for having 58.1% of good ratio of RSCP

received. While Tigo lag behind for recording only 57.4% of good signal received.

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4.5.8. Quality EC/No

Figure 4.22: Quality Ec/No statistics

The Quality of Service (QoS) in terms of ration of Received Power to Noise (EC/No) shows a

little prospect for Vodacom with a record of 43.9%. While Airtel and Tigo recorded 34.6% and

32.6% respectively. Both companies need to strengthen this area of QoS.

4.5.9. Summary of all Comparison

Table 4.4 Summary Comparison of voice, data, coverage and QoS

No. KPI Score Ranking

AIRTEL VODACOM TIGO AIRTEL VODACOM TIGO

1 Voice Score (%) 74.46% 89.92% 92.65% 3 2 1

2 Data Score (%) 87.10% 24.30% 27.60% 1 3 2

3

Coverage (% of

samples RSCP > -

82dbm)

58.10% 81.20% 57.40% 2 1 3

4 EcNo (% of

samples 0-8) 34.60% 43.90% 32.60% 2 1 3

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The above table summarises all comparison where it shows the strength and weakness of every

operator in the region so far. Were Tigo are leading in Voice services followed by Vodacom and

Airtel are the last. While in terms of data services and applications, Airtel is the leading operator

followed by Tigo and Vodacom are the last. In the case of Coverage through RSCP, Vodacom is

leading with its 47 Node B’s, and is followed by Airtel with its 26 Node B’s and Tigo are closing

the curtains with its 27 Node B’s. Lastly the case of QoS through the EC /No, again Vodacom is

leading, followed by Airtel and Tigo are in the last position.

4.6. Conclusion

The planning and optimisation process for the WCDMA was done successfully. In dimensioning

the network we looked into how the Radio link budget can be calculated, the range between

cells, which for better coverage, we decided for it to be 6km up to 9km apart for rural areas

where for urban area it is better to be situated to 1km distance. Also the capacity estimation by

looking onto the total number of sites required to cover the area given by comparing to the total

traffic density of the area. Lastly, we explore the suitability of the geographical environment for

positioning the Base Station. Lastly, we optimised the power through RSCP, RSSI, and EC/No

so as to obtain a better quality of service to places where there where the demand was not met.

After considering all necessary parameters while looking at the nature of environment the

coverage, capacity and quality of service of the given area were so much better. While at the start

of this research Tigo was last in comparison in every category, but after going through a proper

ways of planning and optimisation procedure, now they are the leading operators in terms of

Voice and they are also in second place when it comes to data services and its application.

Acknowledgment

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My heartfelt gratitude to my Supervisor Dr. Anael Sam for being with me and guiding me

through the completion of this work without getting tired. Also to all Tigo staffs who participated

in one way or another in the completion of this work. From planning the network, analysing the

suitable environment, optimising the network and lastly is correcting data and do the keen

analysis of performance of all operators in the region. I have nothing to repay for your kindness

and support, but am praying to God, May you succeed in your endeavour.

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CHAPTER FIVE: GENERAL DISCUSSION AND CONCLUSION

5.1. General Discussion

Coverage problems are so wide in the interlacustrine region. The Lake, Victoria coast is famous

for its natural vegetation and the physical nature, bringing in complexity in mobile network

planning, designing and implementation. The presence of huge rocks gives Mwanza a famous

name of Rock city. Other geographical salient features of the area are like deep valleys, forest

trees, long rivers, hills and mountains covered by tall rocks. The native people of this area

reside in the wide valleys, slopes of the mountains and hills where they have built up houses and

make living in such environments.

Figure 5.1: Geographical view of Mwanza and its salient features

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Figure 5.2: Mwanza view of the local residence settlement

This area has three giant network operators, namely Vodacom, Airtel and Tigo. Zantel is present,

but not so popular. These three operators cover the region with about 100 Node B’s for 3G

technology covering an area of 425 square kilometres and a population of 363,452. The

distribution of the Node B’s is 47, 26 and 27 for Vodacom, Airtel and Tigo respectively. They

both operate in the frequency of 2100 GHz for single carrier. In the case of GSM technology, the

BTS are 43 for Vodacom, 29 for Airtel and 24 for Tigo, which add to a total of 96. Therefore the

total number of BTS and Node B in the region is 196.

This research examines the QoS of the area on the basis of the basic KPI’s set by the Tanzania

Communication Regulatory Authority (TCRA), for both GSM technology (2G network) and

UMTS technology (3G network).

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5.1.1. 2G network analysis

The analysis indicates that Tigo is doing better in terms of coverage recorded an average of

96.6%, followed by Vodacom recording 95.8% and Airtel is lagging with only 92.7%. The

quality of the received signal (RXQUAL), Tigo has done a good job with 98% of good quality,

followed by Airtel with 95% and Vodacom is lagging with 88.7%%.

In the case of Call Setup Success Rate (CSSR), Tigo has 96.63%, Vodacom 93.41%, and Airtel

86.00%, for Call Drop Rate (CDR), Tigo has a drop rate of 3.49%, Airtel 4.65% and Vodacom

recorded a drop rate of 11.76%. Then for Call Blocking Rate (CBR), Tigo recorded a blocking

rate of 3.37%, Vodacom 6.59% and Airtel 14.00%. The analysis of the Call Setup Time (CST),

Airtel had the lowest CST of 2.4 Seconds, Tigo 2.5 Seconds, and Vodacom with 3.4 Seconds.

Lastly, we analysed Handover Success Rate (HSR), were Vodacom had no handover failure for

all the samples, Tigo had a failure of only 0.51%, which means it recorded HSR about 99.49%,

and Airtel 96.82 with a failure of 3.18%.

The analysis for Voice, coverage and Quality, the table below summarises the analysis

Table 5.1 KPI’s for 2G network performance comparison.

2G - Airtel

2G - Vodacom

2G - Tigo

KPI Mwanza KPI Mwanza KPI Mwanza

No. of Sites 29 No. of Sites 43 No. of Sites 24

Number of Blocked

calls 14

Number of Blocked

calls 6

Number of Blocked

calls 3

Number of Drop

calls 4

Number of Drop

calls 10

Number of Drop

calls 3

% of Rxlevel

sample better than -

75 dBm

92.70%

% of Rxlevel

sample better than -

75 dBm

95.80%

% of Rxlevel

sample better than -

75 dBm

96.60%

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% of Rxlevel

sample between -75

dBm to -85 dBm

6.10%

% of Rxlevel

sample between -75

dBm to -85 dBm

3.90%

% of Rxlevel

sample between -75

dBm to -85 dBm

3.10%

% of Rxlevel

sample between -85

dBm to -95 dBm

1.10%

% of Rxlevel

sample between -85

dBm to -95 dBm

0.30%

% of Rxlevel

sample between -85

dBm to -95 dBm

0.30%

% of Rxlevel

sample below -95

dBm

0.10%

% of Rxlevel

sample below -95

dBm

0.00%

% of Rxlevel

sample below -95

dBm

0.00%

% of RX Qual

samples < 6 95%

% of RX Qual

samples < 6 88.70%

% of RX Qual

samples < 6 98.00%

The analysis of data and its application had a total of three KPI’s, analysed Radio Link Control

(RLC) throughput Downlink is greater than 60kbps were Tigo recorded 19.60%, Airtel 19.50%

and Vodacom had 10.20%. For Uplink Vodacom had 0.1%, while both Tigo and Airtel had 0%.

Another KPI was the File Transfer Protocol (FTP) Throughput where Airtel recorded 67.46%,

Tigo 43.92 percent and Vodacom had only 28.18%. The FTP Success Rate, Tigo had 15.38%,

Airtel 12.50 and Vodacom had 4.7%. Lastly, we analysed the Ratio of Carrier to Interference

(C/I) for the ratio which is greater than 9 and the statistics were as follows, Tigo had a ratio of

96.90%, Airtel 94.90% and Vodacom 80.40%.

Table 5.2: Data statistics comparison for 2G network operators

No. KPI Score Ranking

Airtel Vodacom Tigo Airtel Vodacom Tigo

1 RLC throughput DL >60

(kbps) 19.50% 10.20% 19.60% 2 3 1

2 RLC throughput UL > 60 0 0.1 0 2 1 3

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(kbps)

3 FTP Throughput 67.46 28.18 43.92 1 3 2

4 FTP Success Rate 12.50% 4.70% 15.38% 2 3 1

5 C/I Ratio > 9 94.90% 80.40% 96.90% 2 3 1

Recommendations as for above observation

These are general recommendation for the sake of brevity in individual operator.

In some places where cell did not give coverage as per desired direction the following

recommendation was given out;

o Site audit to check physical parameter and site configuration.

For the case of poor quality patch due to overshooting;

o Site audit for antenna orientation and also handover definition.

Overshooting cell which creates missing neighbours;

o Needs to check frequency planning and site neighbour planning.

Poor quality due to abnormal overlaid (OL)/under laid (UL) coverage distribution;

o Need to check the Site for OL/UL settings, which cause abnormal coverage

patterns.

5.1.2. 3G network analysis

Since the entire research analysed in details the 3G network. Here is the summary of all the

discussion.

Table 5.3: Summary of 3G analysis on voice, coverage and quality

3G - Airtel

3G – Vodacom

3G - Tigo

KPI Mwanza KPI Mwanza KPI Mwanza

No. of NodeB in

Town 26

No. of NodeB in

Town 47

No. of NodeB in

Town 27

Number of

Blocked calls 18

Number of

Blocked calls 5

Number of

Blocked calls 0

Number of Drop

calls 6

Number of Drop

calls 0

Number of Drop

calls 0

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% of Rxlevel

sample better than

-75 dBm

38.1%

% of Rxlevel

sample better than

-75 dBm

56.4%

% of Rxlevel

sample better than

-75 dBm

38.7%

% of Rxlevel

sample between -

75 dBm to -85

dBm

29.8%

% of Rxlevel

sample between -

75 dBm to -85

dBm

31.1%

% of Rxlevel

sample between -

75 dBm to -85

dBm

30.1%

% of Rxlevel

sample between -

85 dBm to -95

dBm

18.7%

% of Rxlevel

sample between -

85 dBm to -95

dBm

10.4%

% of Rxlevel

sample between -

85 dBm to -95

dBm

25.4%

% of Rxlevel

sample below -95

dBm

13.4%

% of Rxlevel

sample below -95

dBm

2.1%

% of Rxlevel

sample below -95

dBm

5.8%

% of Ec/Io sample

better than -13 93.2%

% of Ec/Io sample

better than -13 92.1%

% of Ec/Io sample

better than -13 94.4%

Average App DL

Throughput -Kbps 1764.84

Average App DL

Throughput -Kbps 1194.16

Average App DL

Throughput -Kbps 1696.22

Figure 5.3: Data Technology distribution

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Data technologies widely used are Forward Access Channel (FACH), High Speed Downlink

Packet Access (HSDPA), High Speed Packet Access (HSPA), HSPA Plus (HSPA+), PS DCH

R99 AND UMTS PS idle. All these technologies are used on the basis of environmental and

operator’s preferences. For example, Vodacom is good, mostly in HSPA+, UMTS PS idle and

FACH, while Tigo they strengthen themselves into FACH, HSPA, and UMTS PS idle. Airtel is

strong in HSPA+ and UMTS PS idle.

Figure 5.4: Modulation Schemes used

Both operators used mostly QPSK and 16QAM as their modulation schemes and introduction of

64QAM as the new technology. The world today in communication is more on multimedia than

voice communication. The operators need to adhere to this circumstance by increasing their

ability to accommodate more users while providing reliable data communication with high

downlink and uplink capacity.

Recommendations on 3G analysis

Poor RSCP coverage;

o Need to audit antenna orientation (azimuth).

o Antenna placement (electrical and mechanical tilt).

o Physical audit on hardware fault.

Poor quality

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o Call latched due to poor server; check the cell neighbour planning

o Pilot pollution in the region; physical site audit to change antenna electrical and

mechanical tilt.

The analysis of the QoS enables the evaluation of different schemes which are used to provide

better QoS in mobile communication environment, four schemes were evaluated based on their

strength and weakness. These schemes are as follows;

Fault Tolerant Dynamic channel Allocation Scheme

Call Admission Control Scheme

Mobility Prediction Scheme and

Dynamic Allocation Scheme using Renegotiation

And it was concluded that these schemes they do depend on each other for their functionality.

5.1.3 Environment, Planning and Optimization

The issue of coverage and capacity planning which goes concomitant with selecting the best

place for putting Node B, which is based on favourable geographical environment pattern.

Planning for coverage and capacity is done concurrently.

There is still a room for research on the case of environmental pattern which causes the mobile

phone signal to be degraded. One of the reasons identified in this research is the presence of

blackspot.

Blackspot is described as the geographic, environmental area where the signal of the mobile

phones is degraded but not because the mobile phone is far from the transmission tower. The

study shows both the act of the mobile phone being far from a cell tower and being at blackspot

area they resemble in features. The following are the special features associated with both

phenomena;

High intensity of power usage

Call drops

Interference from another call when you’re making yours.

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Signal scrambling

High call setup time

Slow connection for internet

High number of handover failure

These characteristics and many others describe the same scenario, whether is blackspot or being

far from transmission tower. Both courses can be evaluated on environmental terrain basis or

non-terrain basis. There are additional factors like antenna placement (electrical and mechanical

tilt) as well as antenna orientation.

The suitable place for a cell tower mounting should consider also the presence of atmospheric

and tropospheric effects of electromagnetic and radio signal, Presence of forest trees and natural

vegetation at large extent in one area could be a problem, also the costs of Lake and oceans are

not so friendly with radio signal. Features like mountainous rocks and deep valley cause

diffraction, scattering effects, reflection and refraction of radio signal.

For planning, efforts should be on network dimensioning and defining the network parameter

configuration. Enough time should be spent with skilled and experienced engineers for site

information collection, devising the proper approach on ways for coverage, capacity and quality

planning, designing and optimization.

Operators in this region offer a wide range of wireless technologies, which help to ease the life of

local citizens. Such services are like SimBanking, services like M-PESA, AIRTEL MONEY and

TIGO PESA prove to be very beneficial to normal citizens. Now it’s easy to send or receive

money from one user to another, banking transactions and with the introduction of the M-PAWA

and TIGO WEKEZA as the new ways of storing money for subscribers of Vodacom and Tigo

respectively.

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The use of mobile apps facilitated by the introduction of Android as the new operating systems

for mobile phone have revolutionized the way we use to think of mobile phones services and

applications. The wide spread of mobile phone technology has now reached into sectors like

education where the use m-learning facilitates education deliverance, in agriculture the use of

m-Agri good example is tigokilimo a new Tigo service for farmers to tap the opportunity to

expand their crop production, markets and healthcare services through mobile applications.

All these are needed by the rural settlers probably more that urban settlers, Since education is

well delivered in urban, more schools with better teachers than in rural areas, therefore there is a

need to enable the use of m-learning to deliver the same education in rural as in urban areas.

Hospital services are also not so good in rural areas while in town there are a number of hospitals

with good services. Now it’s time to use m-healthy to deliver such services.

5.2. Conclusion

Proper planning and designing is the key to coverage and performance improvement in the world

of telecommunication networks. The process of planning and designing telecommunication

network requires more experienced radio frequency engineers who are strongly equipped,

knowledgeable and skilled in defining networks at its initial stage. Network definition laid the

foundations for the network parameters and sub parameters required for configurations of the

new site, the type of hardware required for the new site and the relation between the new site and

the existing nearby sites. In network definition, it’s where the new site information was described

and the strategies of the whole planning were drawn. Understanding the geographical,

environmental pattern surrounding the area was another key feature for increasing coverage of

mobile phones especially in rural areas. The geographical pattern had significant impact on how

the radio frequency is transmitted and received. The degradation of the efficiency of the

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communication links where possible and to the large extent contributed by neglecting thorough

investigation of the importance of geographical environmental pattern in the planning process.

The propagation models were defined based on the nature of the environment of the new site.

The number of sites was defined based on the population density of the area which also gave a

picture of how the settlement of subscribers were found. The distance between sites depends

solely on the population density distribution. Antenna placement on cell tower considered again

the distribution of the population density of the area and the geographical hindrance if any.

Having a proper antenna orientation to subscriber’s daily activity areas and their settlement

places also gave a better point into coverage and performance evaluation.

Capacity estimation was another key feature in determining the coverage of the network and its

performance. Unlike 2G network 3G network capacity and coverage where planned together at

the same time. The observation revealed that it’s not possible to separate the two, by planning for

coverage and then capacity later on. For the network to work effectively both capacity and

coverage were dependent on each other while planning. Capacity estimation also depends on the

population density. Sectoring of the antenna was done with consideration of how the population

is distributed. The number of resources available was a criteria for capacity prediction. The

definition of bandwidth usage and channel allocation appeared to have a strong impact on

capacity estimation. The problems like dropped calls were largely minimized through proper

capacity estimation by considering the resources at hand.

Another very important aspect which contributed significantly in improving coverage was site

neighbouring planning. The site neighbouring planning gave a clearer picture of how resource

are distributed, shared and managed. It was the key in minimizing the handover failure while

subscribers communicated.

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Network evaluation and analysis through basic predefined key performance indicators were

carried with the help of the QoS schemes. The schemes were first evaluated on their strength and

weakness and it was found that in the case of Fault Tolerant Dynamic channel Allocation

Scheme it was possible to reuse the channel and hence was suitable for reducing traffic

congestion in the network. Therefore the issue of channel capacity depends on this scheme. Next

Call was Admission Control Scheme used to avoid the bottleneck of the incoming calls and

hence it reduces the rate of blocking probability. The capacity related problems can be

minimized through the use of this scheme, then we had Mobility Prediction Scheme, which

collected the subscriber’s information who are moving from one point to another and then it

store them into the database. The collected information was used to prepare resources when there

was handover. This was very important to be highlighted in site neighbouring plan. Lastly, we

had a Dynamic Allocation Scheme using Renegotiation which made sure that the low priority

services do not starve and can be served at any time without affecting the QoS of high priority

services. It distributes the unused resource for low priority services and takes them when needed

without causing much effect since the low priority didn’t need those resources even though it

gave them since they were idle resources. The capacity planning came into effect in this scheme.

And all these schemes depends on one another in their operation.

When the QoS where analysed based on the data collected through drive test measurements at

first there were problems in every category, There were high number of call drops, blocking

calls, handover failure, poor quality and bad coverage for the entire sample area, Through this

analysis the optimisation was done and for the new sites which were constructed after proper

planning were considered all necessary factors like improving coverage, capacity and QoS, then

another analysis were performed to confirm the results. The new analysis based on the

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benchmarking data for all the operators in the area of interest. The data revealed the high level of

improvement where the area with good coverage improved from being 24.02% to 57.40%, the

good quality moved from 27.61% to 32.60%, voice services at first had almost 33% of CSSR

and 67% of CDR. The new results revealed the overall voice performance of 92.65% with 100%

of the CSSR and there were no call drops or call blocking for all the attempted calls, and no

handover failure.

This research proves that, it is possible to improve coverage, especially in rural areas which is

less marketable area compared to urban areas. What is needed is proper network planning from

the initial stage. Good coverage helps in resource effective utilization and maximum

performance efficiency of the network.

5.3. General Recommendations

At the beginning of 2014, the government announced a major plan to empower the mobile

operators by providing funds so as they can build their infrastructure into less marketable wards

in the country. The government disbursed a total of $ 10milion to TTCL, TIGO, VODACOM

and AIRTEL through TCRA.

Due to the need of sharing resources, TCRA should put a rule that instead of finding both

companies in one place, then whenever let’s say company X has put the resources in a certain

area, then all the remaining companies should use all the resources of company X instead of

building the resources of their own. This will enable larger areas to be covered than it was

anticipated.

Use of an experienced and skilled radio engineers in early stages of planning. These mobile

operators usually outsource their work into other companies. It's time to review the experience

and skills of the company they outsource their work to, because there are some places the

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problems are due to either poor planning and designing or bad installation of equipment due to

lack of sufficient knowledge with the growing technology.

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