Solomon WiMAX

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DECLARATION

I Ddumba Solomon John hereby declare to the best of my knowledge that the work presented in

this report is original and has not been presented in any institution anywhere for any degree,

diploma or any award.

Signed

DDUMBA SOLOMON JOHN

DATE ..

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APPROVAL

This project proposal has been submitted with the approval of my supervisor

Signed..... Date

Mr. Kigozi John

Signed Date

Mr. Odong Steven

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ABBREVIATIONS

WiMAX - Wide Area Interoperability of Microwave Access

UTL - Uganda Telecom

BS -Base Station

FM -Frequency Modulation

VoIP -Voice over Internet Protocol

VPN - Virtual Private Networks.

BER - Bit Error Rate

ASN -Access Service Network

CSN -Connectivity Service Network

LOS -Line of sight

NLOS - Non Line of Sight

RF -Radio Frequency

3G - Third Generation

4G -Fourth Generation.

HARQ - Hybrid Automatic Repeat Request

ODFM -Orthogonal Frequency Division Multiplexing

MIMO -Multiple-Input Multiple-Output

QoS -Quality of Service

AMC -Adaptive Modulation and Coding

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TABLE OF CONTENTS

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

.................................................................................................................................. ii

APPROVAL ............................................................................................................ iii

ABBREVIATIONS ......................................................................................................... iv

TABLE OF CONTENTS .................................................................................................. v

CHAPTER ONE: INTRODUCTION .................................................................................. 1

1.1 Background ...................................................................................................... 1

1.2 Problem statement ............................................................................................ 1

1.3 Objectives ....................................................................................................... 2

1.3.1 Main Objective ............................................................................................ 2

1.3.2 Specific Objectives ...................................................................................... 2

Significance ............................................................................................................. 2

Justification .............................................................................................................. 2

1.6 Scope ............................................................................................................... 3

CHAPTER TWO: LITERATURE REVIEW ......................................................................... 3

2.1 Related projects ................................................................................................ 4

2.1.1. The Uganda Telecom 3G Project. ............................................................. 4

2.3 The Proposed Project ......................................................................................... 4

2.3.1 WiMAX 802.16 ............................................................................................. 4

2.3.2 The WiMAX IEEE 802.16 Architecture ......................................................... 5

2.4 Interference in Wimax Networks ....................................................................... 6

2.6 Line Of Sight Communication (LOS) .................................................................. 7

2.7 Non Line of Sight Communication (NLOS) ......................................................... 7

2.8 WiMAX Frequencies ........................................................................................... 8

2.9 Hybrid Automatic Repeat Request (HARQ) ........................................................ 8

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3.0 More on Wimax ................................................................................................ 9

3.1 Multiple-Input Multiple-Output (MIMO) Technology ........................................9

3.2 Adaptive Modulation and Coding (AMC) ......................................................... 9

3.3 IEEE 802.16 WiMAX Model Layers ................................................................ 9

3.4 Quality of Service (QOS) .................................................................................. 10

CHAPTER THREE: METHODOLOGY ............................................................................ 11

3.1 Procedures ...................................................................................................... 11

Reviewing of the existing literature on WiMAX IEEE 802.16, this is going to be done

through detailed research and in-depth analysis of the data that has been collected

from various sources which include: the internet, books, similar projects and

documentation related to WiMAX ............................................................................. 11

3.2 Data Collection ............................................................................................... 11

3.2 Data Analysis .................................................................................................. 12

3.3 System Design and Simulation ........................................................................ 12

3.3.1 The WiMAX Base Station ........................................................................... 13

3.3.2 The WiMAX Access Service Network (ASN) ................................................ 13

3.3.3 WiMAX Customer Premise Equipment ...................................................... 13

3.3.4 Proposed Optimization tools and mechanisms .......................................... 13

3.4 Expected Results ............................................................................................. 14

REFERENCES ............................................................................................................. 14

WiMax.com Broadband Solutions (2011) ............................................................. 15

Does WiMAX have quality of service (QOS)? Retrieved October 13 2011 from

http://www.WiMAX .com/ quality-of-service.htm, 2011 ......................................... 15

Appendix 1 TIME FRAME ........................................................................................... 15

Appendix 2 BUDGET ................................................................................................ 16

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CHAPTER ONE: INTRODUCTION

1.1 Background

Uganda Telecom LTD (UTL) is the Leading Telecommunication Service provider in Uganda

offering voice and data communication services to its customers and subscribers country wide.

Uganda Telecom has deployed Huawei WiMAX equipment on over 50 base stations

countrywide ensuring broadband connectivity to subscribers countrywide offering services like

High-speed Internet, Voice over Internet Protocol (VOIP), Virtual Private Networks.

WiMAX (IEEE 802.16) stands for World Wide Interoperability of Microwave Access and it is a

leading technology that is used in providing last mile broadband connectivity by radio link.

WiMAX is a packet based wireless technology that provides fixed and mobile high speedconnection to end users, IEEE 802.16d for fixed WiMAX and IEEE 802.16e which has support

for mobility and hence referred to as Mobile WiMAX. WiMAX is preferred because of its High

data rates, low cost of deployment, wide coverage which makes it the most suitable option for

support of business critical services and applications.

1.2 Problem statement

The performance of WiMAX in the Uganda Telecoms Network is not at its optimum level in

comparison to the expected standards of IEEE 802.16 quality of service (QoS) requirements. The

optimum performance of WiMAX networks as specified by the Institution of Electrical and

Electronic Engineers (IEEE) is to provide connectivity to customers with data rates of up to

70mbps to a range of 50 km for fixed stations (IEEE 802.16d) and up to 15km for mobile

stations (IEEE 802.16e) which is not the case for the existing UTL WiMAX network. There exist

a number of factors that limit that overall system capacity of the WiMAX radio channel for

example attenuation over the air interface due to fading effects, interference and obstruction,

high bit error rates(BER) and congestion at the R6 interface (Between the WiMAX base station

and the Access Service Network. (Iwan A, Rosario G & Garroppo S, 2009) These cause delay in

the access of business critical services like high speed Internet, Voice Over Internet protocol

(VoIP), Virtual Private Networks (VPN) and other multimedia applications by UTL customers.

This reduces on the quality of service of the Network and in turn it reduces on the income that is

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generated by the Company (Low returns on investment) and also pauses a threat of loss of

customers who are always looking out for better services.

1.3 Objectives

1.3.1 Main Objective

To optimize the system capacity and application delay in Uganda Telecoms WiMAX network

1.3.2 Specific Objectives

To review the existing literature on WiMAX Technology.

To survey the existing system of the Uganda Telecoms WiMAX Network in order to

enable me to clearly identify the impairments to communication over the WiMAX Air

Interface (Interface between the WiMAX Base Station and the User equipment) and the

R6 interface (Interface between the Base station and the ASN)

To establish measures that should be taken to mitigate the identified problems.

To design an optimized WiMAX System for UTL using OPNET simulation software.

Significance

The Uganda Telecom WiMAX Network will be optimized after the implementation of my

project. The system capacity of the WiMAX communication channel is going to be optimumly

utilized and delays are going to be greatly reduced when the optimization mechanisms specified

in this project are put into consideration.

Justification

WiMAX technology is designed to provide data rates of up to 70mbps to ranges of up to 50km

for fixed WiMAX and 15 km for mobile users and my projects is going to conform the existing

UTL Network to the ideal WiMAX communication system. My project should be carried out

because it is going to ensure increased data rates and improved network performance for the

UTL WiMAX network which is necessary to ensure the support of the increasing demand of

business critical applications and services that are accessed by WiMAX subscribers. Some of

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these services include high speed internet connectivity, Voice over Internet Protocol (VoIP),

Virtual Private Networks (VPN) and Video Streaming.

1.6 Scope

This study is going to be done with Uganda Telecom LTD. It will involve identifying current

problems with the current WiMAX communication over the AIR interface and the R6 Interface.

Some of these problems include: attenuation caused by fading effects, interference, obstruction,

traffic congestion and high bit error rate (BER) among others. The project will also involve

establishing measures to mitigate the above mentioned problems and coming up with a design of

the optimized WiMAX network using OPNET simulation software.

CHAPTER TWO: LITERATURE REVIEW

In this chapter, I am going to review the existing work that has been done as far as WiMAX

Optimization is concerned. It will review existing literature and related projects and identify any

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issues that could have been left out in the previous work. It is also going to clearly elaborate the

proposed project and how it covers the gaps that are existent in some of the current work that has

been done on WiMAX.

2.1 Related projects

2.1.1. The Uganda Telecom 3G Project.

According to Edris Kisambira, (June 2011), Uganda Telecom has deployed Third Generation

(3G) broadband wireless technology in the capital city Kampala and several other districts. The

porpoise was to offer mobile broadband services to users which included high speed internet

access, video and audio streaming among others.

Farouk Kiwala (2008), The Uganda Telecoms Business Solutions Manager further emphasizesthe need for people to maintain connectivity and data access even when they are out of their

formal office environment which usually have fixed data connections. He also specifies Third

Generation Technology (3G) that has just been deployed by Uganda Telecom as the best option

for providing such services.

Contrary to that WiMAX IEEE 802.16 stands to be the optimum technology in the delivery of

high speed connectivity and data access with data rates of up to 70Mbps.

2.2 The Need For Optimization

Wireless operators are increasingly pressured to enhance their networks and service capabilities

in order to keep pace with the accelerating growth in wireless utilization and increasing demand

for high performing connections. As bandwidth intensive, rich media applications are introduced,

larger volumes of subscribers consume ever-growing quantities of data packets while continuing

to utilize more minutes of voice. Simply acquiring more spectrum channels and deploying more

sites to resolve capacity issues can be decidedly inefficient and costly, (Mukherjee, S. July 2010)

2.3 The Proposed Project

2.3.1 WiMAX 802.16

WiMAX stands for World Wide Interoperability of microwave access and it is a leading

technology that is used in the provision of last mile wireless broadband connectivity by radio

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link to subscribers. The name WIMAX was created by the WiMAX Forum in June 2001 and the

major purpose was to promote conformity and interoperability of the IEEE 802.16 standard.

WiMAX provides both Fixed and mobile connectivity to subscribers with the capability of

providing data rates of 70mbps over a distance of around 50 km fixed stations. IEEE 802.16d

standard was published in 2001 as a technology that was used for providing fixed WiMAX

access to customers. IEEE 802.16e is has support for mobility and it is thus referred to as Mobile

WiMAX. It offers Broadband connectivity to mobile users to a range of up to 15km. The IEEE

802.16 technology is a leading technology in the provision of Wireless broadband access because

of its advantages which include high data rates, wide coverage, improved mobile performance,

wide coverage and low costs of deployment for both line of sight (LOS) and non line of sight

communication (NLOS). WiMAX technology is very efficient in supporting high speed business

critical services to users for example Voice over internet protocol (VoIP), high speed Internet

connectivity, Virtual Private Networks (VPN), audio and Video streaming

2.3.2 The WiMAX IEEE 802.16 Architecture

The WiMAX network comprises of a number of components and Interfaces which include:

The Air Interface (R1) This is the interface between the WiMAX Base station and the

Mobile Station

The R2 interface. this is the interface between the Mobile Station and the Connectivity

Service Network (CSN)

The R6 Interface This is the Interface between the WiMAX base station and the Access

Service Network (ASN)

The R3 Interface This is the Interface between the Access Service Network (ASN) and

the Connectivity Service Network (CSN)

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Figure 1 Showing the main interfaces and module in the WiMAX Architecture

2.4 Interference in Wimax Networks

In short, the degree to which WiMAX succeeds will depend in large part on the ability to

minimize channel interference. This positions the base station antenna system as critical to

WiMAX long term success. Going forward, antenna pattern shaping and interference control will

play a significant role in successful WiMAX deployments. (Andrew. 2008)

2.5 Orthogonal Frequency Division Modulation (ODFM)

WiMAX Technology applies Orthogonal Frequency division multiplexing technique which is a

special multicarrier transmission mode where a single data stream is transmitted over a number

of lower rate orthogonal sub carriers. It is a technique that is used to increase the robustness of

the transmission link against frequency selective fading. In single carrier radio transmission,

channel fading affects the entire transmission link and this is solved by using multicarrier

transmission techniques like orthogonal frequency division Modulation where only a few

subcarriers will be affected. Error correction mechanisms and coding can be applied to only the

few subcarriers that have encountered transmission errors.

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ODFM subcarriers are individually modulated by Phase shift Keying (PSK) or Quadrature

Amplitude Modulation (QAM). Some of the advantages of using Orthogonal Frequency Division

Modulation include:

ODFM as a modulation scheme is divides the transmission channel into smaller

narrowband sub channels and this makes the transmission link more resistant to

frequency selective fading as compared to single carrier transmission systems.

Channel equalization in OFDM schemes is much simpler as compared to using adaptive

equalization techniques which is the case for single carrier

ODFM modulation scheme also provides good protection against co channel interference

and parasitic noise

Orthogonal Frequency division Modulation scheme also makes efficient use of the

spectrum by allowing overlap

OFDM is less sensitive to sample timing offsets as compared single carrier systems

2.6 Line Of Sight Communication (LOS)

Line of sight communication refers to communication in which the transmitting and receiving

antenna have visual contact with each other in the absence of any obstacles like buildings, trees,or hills that could impair signal transmission over the radio link.

In WiMAX communication this usually involves a receiving antenna at the customer premises

that is appropriately oriented towards the transmitting antenna at the WiMAX Base station. This

mode of signal transmission usually encounters attenuation on the Air interface due to

atmospheric weather conditions, fading effects and interference.

2.7 Non Line of Sight Communication (NLOS)

Non Line of sight communication refers to the transmission of radio signals over a path that is

partially obstructed. In this mode of communication, the radio signals have to penetrate physical

objects which usually include Buildings, trees, and hills among others. Theses obstructions

usually impair the transmission of signals over the radio channel especially when it is being done

at low transmission power.

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2.8 WiMAX Frequencies

The most recent versions of WiMAX standards in 802.16 operate in frequencies ranging from

2GHz to 66GHz which is a wide spectrum range. However the practical market considerations of

the WiMAX forum members dictated that the first product profiles focus on spectrum ranges that

offered Forum vendors the most utility and sales potential. The International standard of 3.5GHz

spectrum was the first to enjoy WiMAX products. (WiMax.com Broadband Solutions, 2011)

The US license free spectrum at 5.8GHz has a few WiMAX vendors building products. The

physics of radio signals typically place two primary constrictions on spectrum. To generalize, the

higher the spectrum frequency the greater the amount of bandwidth that can be transported;

lower frequencies transport less bandwidth. Secondly, the lower the frequency the greater the

carry range and penetration of a signal. For example: A 900 MHz license free radio will travelfarther and penetrate some tree cover fairly easily at ranges up to one to two miles. But it can

carry much less bandwidth than a 2.4 GHz signal which cannot penetrate any tree cover

whatsoever, but can deliver a lot more data. The caveat that can somewhat alter this equation is

power. Licensed band spectrum such as 2.5 GHz by virtue of being dedicated to one user is

allotted significantly higher power levels which aids in tree and building wall penetration.

2.9 Hybrid Automatic Repeat Request (HARQ)

Hybrid automatic repeat request (HARQ) is a combination of high-rate forward error correcting

coding and ARQ error-control for detectable-but-uncorrectable errors. In standard ARQ,

redundant bits are added to data to be transmitted using an error-detecting code such as cyclic

redundancy check (CRC). In hybrid ARQ, a code is used that can perform both forward error

correction(FEC) in addition to error detection (ED)(Such as Reed-Solomon, convolutional code

or Turbo code), to correct a subset of errors while relying on ARQ to correct that are

uncorrectable using only the redundancy sent in the initial transmission. As a result Hybrid ARQ

performs better than ordinary ARQ in poor signal conditions, but in its simplest form this comes

at the expense of significantly lower throughput in good signal conditions. There is typically a

signal quality cross-over point below which simple Hybrid ARQ is better, and above which basic

ARQ is better.

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3.0 More on Wimax

3.1 Multiple-Input Multiple-Output (MIMO) Technology

Multiple-Input Multiple-Output (MIMO) technology is the foundation of the next generation of

4G mobile products like WiMAX, LTE, UMB and 802.16m. By leveraging multiple transmit

and receive antennas to employ spatial multiplexing, adaptive antenna processing, and space

time coding, MIMO products deliver greater wireless throughput and range enabling ubiquitous

high-speed voice, video and data services. Channel emulation is required to accurately

characterize the effect of multi-channel RF interactions on the conformance, performance and

interoperability of MIMO systems. The ACE 400WB is a fully featured channel emulator

designed for ease of test that can accurately create complex fading channels to test the most

advanced MIMO technology (MIMO Channel Emulator for WiMAX Testing.mht)

3.2 Adaptive Modulation and Coding (AMC)

The adaptive modulation and coding (AMC) technique is used in order to compensate for

variations in radio transmission conditions, while the transmission power remains constant.

(Ajay, R. 2007).

3.3 IEEE 802.16 WiMAX Model Layers

WiMAX operates on two layers which are the Physical Layer (PHY) and the Media Access

Layer (MAC).Some of the services of the WiMAX MAC layer include: Automatic Repeat

request Enhanced Version, Connection established Channel Quality Indicator Channel

(CQICH), Idle mode, sleep mode alterations, Multicasting and Broadcasting Services (MBS) and

Mobility services (Hand off and Mobile IP).

The WiMAX physical layer also carries out a number of services which include orthogonal

frequency division multiplexing, Power Control and Hybrid automatic Repeat Request (HARQ),

Multiple input Multiple Output (MIMO) operations and Exponential Effective SIR mapping

(EESM) among others.

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3.4 Quality of Service (QOS)

Quality of Service is what determines if a wireless technology can successfully deliver high

value services such as voice and video. The chief detractors from good QoS are latency, jitter

and packet loss. Solve these issue and you have a carrier-grade service. (WiMax.com Broadband

Solutions, 2011)

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CHAPTER THREE: METHODOLOGY

This Chapter is going to specify the methods and procedures that I will undertake in order to

achieve the objectives of my project.

3.1 Procedures

Reviewing of the existing literature on WiMAX IEEE 802.16, this is going to be done through

detailed research and in-depth analysis of the data that has been collected from various

sources which include: the internet, books, similar projects and documentation related to

WiMAX

Surveying the existing WiMAX communication system of Uganda Telecom.

Clearly specifying the impairments to communication over the WiMAX Air Interface

(Interface between the WiMAX Base Station and the User equipment) and the R6

interface (Between the Base Station and the Radio Access Network)

Identifying the measures that should be taken to mitigate the specified problems.

Designing of an optimized WiMAX Network for Uganda Telecom using OPNET

simulation software.

3.2 Data Collection

The data and information resource to be used in my project is going to be collected in the

following ways:

Interviewing of Uganda telecoms WiMAX customers and finding out what exact

problems they face in the access of high speed data services and applications over the

WiMAX Network.

Interacting and consulting Uganda Telecom and Huawei WiMAX Optimization

Engineers on the challenges that are experienced in the use of WiMAX Technology from

a technical perspective.

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Surveying and analyzing of the existing WiMAX technology and equipment that has

been deployed in various parts of the country by UTL.

Technically analyzing the physical environmental characteristics and terrain features in

which the UTL WiMAX technology is operating.

Clearly identifying and analyzing the operation parameters that are currently being

implemented in Uganda Telecoms WiMAX Network for example Carrier frequencies,

transmit power, bandwidth allocation mechanisms and modulation schemes.

3.2 Data Analysis

Data that will be collected from the above mentioned sources will be analyzed in various ways

which include the following:

From the problems experienced by the WiMAX customers, deductions will be made as to

what exactly is the cause of the problems.

From the technical perspectives of the WiMAX Engineers, I will establish the appropriate

mechanisms and tools that are necessary for the Optimization work

The different network and equipment parameters are going to be adjusted so as to

establish their effect on the WiMAX Network performance

The performance of the proposed WiMAX network is also going to be analyzed by

simulation after the necessary adjustments have been done.

3.3 System Design and Simulation

The proposed Optimized WiMAX communication system is going to be designed and simulated

using OPNET simulation software and it is going to clearly elaborate the different major

components of the WiMAX Network Architecture along with the optimization mechanism thathas been applied on each module.

Some of the WiMAX Network equipment and modules on which optimization will be carried out

include:

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3.4 Expected Results

After my project has been carried out the, the expected results are:

A detailed review of the existing literature on WiMAX will have been done.

A thorough system study of Uganda Telecoms WiMAX network architecture.

A clear identification of the impairments to communication over the WiMAX Air

Interface (Interface between the WiMAX Base Station and the user equipment) and the

Rs interface (Interface between the WiMAX Base station and the Access Service

Network).

Measures to mitigate the identified problems will be identified and implemented.

An Optimized WiMAX Network will be designed for UTL with enhanced system

capacity and reduced application delay

REFERENCES

Ajay, R. (2007), Advanced Cellular Network Planning and Optimization, Nokia

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Networks, 468)

Andrew. (2008). Patterns of Success, Antenna Patterns to Play a Key Role in

WiMAX Success, 1-4.

Kisambira Edris (June 2008)

Uganda Telecom Deploys 3G Data service Retrieved 3 October from

http://www.cio.com/article/418013/Uganda_Telecom_Deploys_3G_Data_Service

Mukherjee, S. (10 July 2010 18:30). WiMAX Antennas Primer, A guide to

MIMO and Beamforming, 3.

Wikipedia (2011)

WiMAX. Retrieved 2 November 2011 from http://en.wikipedia.org/wiki/WiMAX

WiMax.com Broadband Solutions (2011)

Does WiMAX have quality of service (QOS)? Retrieved October 13 2011 from

http://www.WiMAX .com/ quality-of-service.htm, 2011

WiMax.com Broadband Solutions (2011)

What RF Frequencies does WiMAX work in? Retrieved September 18 2011 from

http://www.WiMAX.com/WiMAX FAQ rangee.freguencies.html.

Appendix 1 TIME FRAME

No Activity

2011 2012

SEPT OCT NOV DEC JAN FEB MAR APR MAY

15
http://www.cio.com/article/418013/Uganda_Telecom_Deploys_3G_Data_Servicehttp://www.wimax/http://www.wimax.com/WiMax%20FAQ%20rangee.freguencies.htmhttp://www.cio.com/article/418013/Uganda_Telecom_Deploys_3G_Data_Servicehttp://www.wimax/http://www.wimax.com/WiMax%20FAQ%20rangee.freguencies.htm


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1 Identifying

Project Title

2 Proposal Writing

3 Seeing supervisors

4 Proposal

Presentation

5 Collecting

Information

6 Field Study

7 System Design

and Simulation

8 Final Report

Writing

9 Final Presentation

10 Submission of

Report

Appendix 2 BUDGET

S/N ITEM QUANTITY PRICE / UNIT

(USH)

TOTAL COST

(USH)

1. USB Modem 1 100,000 100,000

2. TRANSPORT AND AIR

TIME

10 trips 50,000 500,000

3. OPNET Simulation Software 1 License 650,000 650,000

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4. SECTRETARIAL

SERVICES

Reams of paper

Pens and Pencils

Printing for Report and

Presentation slides

2 Reams

3 copies

200,000 200,000

5. LAPTOP 1 1,300,000 1,300,000

TOTAL 2,750,000

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