INDOOR PROPAGATION PREDICTION AND MEASUREMENTS WITHIN

MULTISTORY BUILDING FOR WIRELESS LAN APPLICATIONS

ABDUSAMEA I.A OMER

UNIVERSITI TEKNOLOGI MALAYSIA

iii

To

My Beloved Parents , Brothers and Sisters

iv

ACKNOWLEDGMENT

In the name of Allah, Most Gracious, and Most Merciful

Praise be to Almighty Allah (Subhanahu Wa Ta’ala) who gave me the

courage and patience to carry out this work. Pease and blessing of Allah be upon his

last prophet Mohammed (Sallulaho-Alaihe Wassalam) and all his companions

(Sahaba), (Razi-Allaho-Anhum) who devoted their lives towards the prosperity and

spread of Islam.

My deep appreciation and heartfelt gratitude goes to my supervisor,

PROF.DR THAREK BIN ABDUL RAHMAN for his kindness, constant endeavor,

and guidance and the numerous moments of attention he devoted through out this

work.

I extend my deepest gratitude to my close friend, Eng. Ibrahim Abuharba for

his encouragement and motivation. Also I would like to thank friends and stuff in

wireless communication center (WCC) for their help facilities and for providing

conductive working environment

Family support plays a vital role in the success of any individual. I would like

to convey a heartfelt thanks to my parents, brothers, and other family members

including all my uncles, ants and their families; their prayers and encouragement

always helped me take the right step in life.

A heartfelt gratitude and acknowledgement are due to the Libyan community

in UTM, Skudai for their kindness, care, valuable advices and cooperation, which

generates a similar environment as what I left.

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ABSTRACT

In recent years, the possibility of using radio for data and voice

communications inside the buildings has become an attractive proposition. A

prerequisite to the design of indoor radio communication systems is knowledge of

indoor propagation characteristics. These characteristics can be used to determine the

optimum location of the base station antenna for a desired coverage within a

building. Propagation prediction within buildings is made difficult by the occurrence

of various propagation phenomena which depend on specific building structures. In

this project the investigation for WLAN system is done for three different buildings

inside University of Technology Malaysia. The Site Ware Technology's site specific

propagation prediction tool is a three-dimensional (3-D) ray tracing code employing

modified shoot and bounce ray(SBR) method know as the Vertical Plane Launch

(VPL) will be used to predict indoor propagation effects with different building

structures to show the prediction of the path loss and the time delay spread for

WLAN system inside these buildings, also a comparison between the real time

measurements using AirMagnet software and the prediction using VPL software

has been done for verification and the AutoCAD tool with the help of Ms Excel, was

used to measure all the building's dimensions for highly accurate building database.

The results from both prediction and measurement are in form of numbers, so Matlab

has been used to present these outputs in 2D display. Finally, based on the evaluation

results, we provide a set of recommendations that might help to improve this work

and fulfill the indoor user requirements.

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ABSTRAK

Syak kebelakangan ini , penggunaan radio untuk komunikasi data dan suara

dalam bangunan telah menjadi suatu proposisi yang menarik . factor yang diperlukan

dalam rekaan sistem komunikasi radio dalaman adalah pengetahuan tentang karakter-

karakter perambatan dalaman . karakter- karakter ini boleh digunakan dalam

penentuan lokasi optima antena stesen asas bagi sesuatu , rangkuman dalam

bangunan yang diinginkan ramalan perambatan dalam bangunan menjadi sukar

dengan kejadian pelhagi fenomena perambatan yang bergantung kepda struktu

struktu spesifik bangunuan . dalam projek ini ,siasatan sistem WLAN dilaksanakan

untuk tiga bangunan yang berbeza dalam Universiti Teknologi Malaysia . alat

ramalan perambatan lokasi spesifik oleh site ware technology ialah tiga dimensi

(3D)”ray tracing “ kod yang menggunakam modifikasi “shoot” dan “bounce ray

“(SBR) cara yang juga dikenali sebagai “ Vertical Plane Launch” (VPL). la akan

digunakan dalam meramal efek-efek perambatan dalaman dengan pelbagai Stnrkuer

beugunan berbeza whtuk menunjukkan ramalan ″path loss″ dan ″time delay opread″

bagi sistem WLAN dalam bengunan serta perbandingan antara pengukuran sebener

menggunalcan software dilaksanakan untuk tujuan verifikasi. Dengan bantuan Ms

Excel, alat antocad digunakam untuk mengukur samua dimensi bengunan untuk

memperoleh dadbase bangunan yang dalam bentuk numbor-nombor. Oleh itu,

Matlab digunakan untuk menunjuklcan output-output ini dalam pameran secara 2D.

Akhir sekali dengan berpandutcan hasil-hasil evausasi, satu set cadangan membina

dalam meningkatkan kerja ini dan mencapai kehendak-kehendak pengguna dalaman

akan dibekalkan.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENTS iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xi

LIST OF FIGURES xii

LIST OF SYMBOLS xv

LIST OF APPENDENCES xvii

1 INTRODUCTION 1

1.1 Overview 1

1.2 Problem Statement 2

1.3 Objective of the Project 2

1.4 Scope of the Project 2

1.5 Methodology of the Project 3

1.5.1 Site Survey 3

1.5.2 Data Collection of Multistory building

using AutoCAD 3

1.5.3 Excel Files 3

1.5.4 VPL Simulation 3

1.5.5 Real time measurement 4

1.6 Organization of the Thesis 6

2 LITERATURE REVIEW 7

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2.1 Wireless Local Area Network (WLAN) 7 2.1.1 Introduction 7 2.1.2 Benefits of Wireless LANs 7

2.1.3 Architecture of a Wireless LAN 8

2.1.3.1 Stations 8

2.1.3.2 Access Points (AP’s) 8

2.1.3.3 Wireless Clients 9

2.1.3.4 Basic Service Set 9

2.1.3.5 Independent Basic Service

Set

9

2.1.3.6 Infrastructure Basic Service

Set 9

2.1.3.7 Extended Service Set 10

2.1.3.8 Distribution System 10

2.2 IEEE 802.11 Standards 10

2.3 Indoor Radio Wave Propagation 12

2.3.1 Reflection: 13

2.3.2 Diffraction: 14

2.3.3 Refraction 15

2.3.4 Scattering 15

2.3.5 Indoor Path Loss 16

2.3.6 Free Space Los 16

2.3.7 Line of Site Path Loss 18

2.3.8 Obstructed Path Loss 19

2.3.9 Doppler frequency shift 20

2.3.10 Multipath and Fading Effects 22

2.3.11 Delay Spread 24 2.3.12 Raleigh Fading 25

2.3.13 Rician Fading 25

2.3.14 Related work 26

3 RAY TRACING SOFTWARE AND 30

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SIMULATION

3.1 Propagation Models 30

3.1.1 Two-Ray tracing Model 30

3.1.2 Vertical-Plane-Launch Method 32

3.1.3 Algorithm of Simulation Software 33

3.2 Databases for Simulation 35

3.2.1 Building database 35

3.2.2 Receiver Database 37

3.2.3 Building Interior Database Format 38

3.3 Simulation Command Input 39

3.4 Output of the Prediction Tool 40

4 RESULTS AND DISCUSSION 42

4.1 Over view 42

4.2 Output Result from VPL Software 42

4.2.1 Power and Delay Spread Output 43

4.2.2 Impulse Response Output 43

4.2.3 Ray Path Information Output

43

4.3 Measurements result using AirMagnet 47

4.4 Result Visualization 48

4.4.1 Path Loss and Time delay spread

Visualization for WCC 48

4.4.2 Path Loss and Time Delay Spread

For KOLEJ PERDANA 50

4.4.3 Path Loss and Time Delay Spread

For KOLEJ 11 MA7 building 59

4.5 Result Analysis 60

4.5.1 Path Loss and Time Delay Spread 60

4.5.2 Comparison between Prediction and

Measurement Result 61

5 CONCLUSION 63

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5.1 Conclusion 63

5.2 Future Work

64

REFERENCES 65

Appendices A - F 67-167

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LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 WLAN standards 12

2.2 2.4 GHz Signal Attenuation 20

2.3 Diffierent Between two types of ray tracing models 29

3.1 Part of WCC building database 36

3.2 Example of the receivers database 37

3.3 Interior building database 39

3.4 Simulation Command input 40

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LIST OF FIGURES

FIGURE NO. TITLE PAGE

1.1 AirMagnet Software with Laptop 4

1.2 Flow chart of the methodology 5

2.1 Access Point infrastructure 8

2.2 Wireless Local Area Network Architecture using an

Infrastructure BSS 10

2.3a Reflected Signal on partial reflective surface 13

2.3b Reflected Signal on perfect reflective surface 13

2.4 Diffraction of a Signal 14

2.5 Refracted wave 15

2.6 Scattered Wave front on an I-beam 16

2.7 Free Space Radiating Point Source 17

2.8 2.4GHz Typical Path Loss 18

2.9 Multiple Floors Indoor Path Loss 19

2.10 Doppler frequency shift effect 22

2.11 Multipath signal in indoor environment 22

2.12 Small Scale Fading 24

2.13 Impulse response and frequency transfer function of a

multipath channel. 24

2.14 Measurement system by “Symbol” 26

2.15 Signal level without pepole 27

2.16 Signal level with present pepole 27

2.17 Effect opening and closing the door 28

3.1 Two-Ray Model 31

3.2 Ray generation in horizontal plane (Liang and Bertoni

1998) 33

3.3 Flow chart of ray-tracing simulation based on the VPL 34

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method (Liang and Bertoni 1998)

3.4 Sample of the AUTOCAD Building map of WCC 36

3.5 AutoCAD Receiver location map 37

3.6 Command input simulation 41

4.1 Example of power and delay spread output 44

4.2 Example of impulse response output 45

4.3 Example of ray path information output 46

4.4 Example of AirMagnet measurement (Kolej Perdana) 47

4.5 Simulation Path Loss for Mobile Lab room (WCC) 48

4.6 Time delay spread for Mobile Lab room (WCC) 49

4.7 Simulation Propagation predictions Path Loss for

(WCC) 49

4.8 Time delay spread for WCC 50

4.9 Kolej Perdana First floor Path loss propagation

predication at 2400MHz Carrier Frequency 50

4.10 Kolej Perdana Second floor Path loss propagation

predication at 2400MHz Carrier Frequency 51

4.11 Kolej Perdana Third floor Path loss propagation

predication at 2400MHz Carrier Frequency 51

4.12 Kolej Perdana Forth floor Path loss propagation

predication at 2400MHz Carrier Frequency 52

4.13 Kolej Perdana Fifth floor Path loss propagation

predication at 2400MHz Carrier Frequency 52

4.14 Kolej Perdana Sixth Floor Path loss propagation

predication at 2400MHz Carrier Frequency 53

4.15 Kolej Perdana Seventh Floor Path loss propagation

predication at 2400MHz Carrier Frequency 53

4.16 Kolej Perdana All the seven Floors Path loss

propagation predication at 2400MHz Carrier Frequency 54

4.17 Kolej Perdana-One Floor Path loss propagation

predication at 2400MHz Carrier Frequency (Based on

assumption that the building is only one floor) 54

4.18 Kolej Perdana One Floor Path losses Comparison 55

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between 1 ray (blue) model and 2 ray model (red)

propagation predication at 2400MHz Carrier Frequency

4.19 Time delay spread for the First Floor Kolej Perdana 55

4.20 Time delay spread for the Second Floor Kolej Perdana 56

4.21 Time delay spread for the Third Floor Kolej Perdana 56

4.22 Time delay spread for the Fourth Floor Kolej Perdana 57

4.23 Time delay spread for the Fifth Floor Kolej Perdana 57

4.24 Time delay spread for the Sixth Floor Kolej Perdana 58

4.25 Time delay spread for the Seventh Floor Kolej Perdana 58

4.26 Time delay spread for All the Seven Floors Kolej

Perdana 59

4.27 Kolej 11 All the four Floors Path loss propagation

predication at 2400MHz Carrier Frequency 59

4.28 Time delay spread for all the four Floors Kolej 11 MA7 60

4.29 comparison between real-time measurements and

simulation for Kolej Perdana 61

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LIST OF SYMBOLS

WLAN - wireless local area networks

WCC - Wireless Communications Center

IEEE - Institute of Electrical and Electronic Engineering

ETSI - European Telecommunications Standards Institute

VPL - Vertical Plane Launch

Wi-Fi - Wireless Fidelity

LOS - Line of sight

OFDM - Orthogonal frequency division multiplexing

DSSS - Direct sequence spread spectrum

Pt - Transmitting power

Pr - Receiving power

Gt - Transmitter antenna gain

Gr - Receiver antenna gain

Ar - Effective aperture of antenna

λ - Wavelength

C - Velocity of light

dB - Decibels

θ - Incidence angle

f - Frequency

ht - High of receiver antenna

hr - High of transmitter antenna

A - Attenuation factor

ρ - Ground reflection coefficient

r1, r2 - Phase path distance along

h - Fresnel zone radius to the knife edge

oλ - Free space wavelength

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dΔ - Distance difference

1d - Distance from transmitter to obstacle

2d - Distance from transmitter to obstacle

τ - Delay spread

v - Speed of portable

fc - Carrier frequency

L - Path loss

L0 - Reference loss

Li - Floor loss factor

D - Distance

h(t) - Impulse response

nA - Amplitude of signal

nτ - Arrival time

nϑ - Arrival phase

iE - Received field amplitude

oE - Transmitting field strength

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LIST OF APPENDICES

APPENDIX TITLE PAGE

A WIRELESS COMMUNICATION CENTER SIMULATION DATABASES

67

B KOLEJ PERDANA SIMULATION DATABASES 76

C KOLEJ 11 MA7 BUILDING SIMULATION

DATABASES

91

D RAY TRACING PROPAGATION PREDICTION 104

E AIR MAGNET SOFTWARE

F AUTOCAD IMPLEMINTATION 130

CHAPTER 1

INTRODUCTION

1.1 Overview

The past decade has witnessed a phenomenal growth in wireless

communication. Indoor wireless communication - such as is associated with personal

communication (PCS) and wireless local- area networks (LANs) - is exploding

rapidly. The need for an efficient way to evaluate radio propagation in buildings is

increasing. It is also critical to optimize the locations of the base stations required to

ensure satisfactory system performance. Consequently, radio-propagation prediction

for indoor environments, which forms the basis for optimizing the location of the

base stations, has become an important research topic.

Indoor radio propagation is not influenced by weather conditions, such as

rain, snow, or clouds, as is outdoor propagation, but it can be affected by the layout

in a building, and especially by the use of different building materials. Owing to the

reflection, refraction, and diffraction of radio waves by objects such as walls,

windows, doors, and furniture inside the building, the transmitted signal often

reaches the receiver through more than one path, resulting in a phenomenon known

as multipath fading [1].

2

1.2 Problem Statement

Wireless LAN have become widely spread over the last few years, it has been

one of the most significant research topics to investigate how radio wave’s propagate

inside office environments, since local objects like pillars, walls, doors and windows

may reduce the link performance of such low power systems.

The existing for indoor environments is that the signal propagated from the

transmitter antenna will experience many different signal transformations and paths

with a small portion reaching the receiver antenna. Awareness of this process will

assist the user to better understand radio performance limitations.

1.3 Objective

This project is aiming to predict and measure the signal strength of wireless

LAN in a multi storey building (Kolej Perdana) in the University Of Technology

Malaysia in order to Obtain best efficiency and coverage of indoor propagation for

wireless LAN systems.

1.4 Scope of project

To provide proper study of wireless LAN propagation signal in multi storey

building, in which the signals are traced , and to build the database of a multi storey

building by using AUTOCAD and MS EXCEL Software; the simulation results will

be Presented by using MATLAB software for visualizing; The prediction will be

done at a carrier frequency 2.4GHz (based on IEEE 802.11 b/g standards) the

simulated result will be compared with the real time measurements that obtained

using Air magnet software In order to Analyze the simulated result.

3

1.5 Project Methodology

1.5.1 Site Survey

Site survey involved in locating the place to be measured. As initial stage of

this project Wireless Communication Center (WCC) in Universiti Teknologi

Malaysia was the first place to be tested.

In the second stage of this project (kolej perdana) will be our target in the

following sections the procedures that have been taken in order provide a good

evaluation of coverage are introduced.

1.5.2 Data Collection of Multistory building

Building data base was provided by WCC as DWG file (DraWinG) witch

will be imported to CAD so all the measurements of the building dimensions can be

obtained easily.

1.5.3 Excel Files

Upon having the dimensions of the multistory building with the help of

AUTOCAD the dimensions are entered into an excel file , after words a file.txt can

be generated to be imported to VPL .

1.5.4 VPL Simulation

Firstly selecting up the parameters for VPL such as increment angel between

successive rays, operating frequency (in our case 2.4 GHZ), fresnel zone width first

4

and second zone, antenna type (in our case monopole) Secondly, simulation is

carried out and the outcome of the simulation is tested If no errors, the results can be

plotted by using MATLAB two of the most graphs that will be plotted are path loss

and time delay spread .

If error occurs, then simulation must be repeated by changing either the

parameters of the VPL or the TXT file that was generated by Excel.

1.5.5 Real time measurement

Figure1.1 AirMagnet Software with Laptop

With the use of Air Magnet software, real time measurements can be conducted to

measure the actual strength and path loss of the signal.

Once the real time test has finished a comparison will be done with the predicted

result, the comparison will be in terms of path loss and time spread delay Upon this

comparison, an analysis can be done to evaluate the tested positions for Access

Points and Receivers to be located for best coverage Final recommendations can be

made to improve the performance of the network.

5

Compare between measured &

simulated results

Data Collection Using AutoCAD

NO

Result Analysis

Collecting parameters

Done

Measurements usingAir magnet software

Generate Excel files • Building database • Receiver point database • Interior building data base

YES Simulation Using VPL

Success

UPDATING DATABASE

Illustrate simulation result using "MATLAB"

Site Survey

Figure1.2 Flow chart of the methodology

For Simulation

6

1.6 Organization of the Thesis

Chapter 1 contains some brief overview of WLAN systems In addition to this, the

problem statement , objective and the scope of the research have been described.

Finally, the flow chart of how the work of this project has been carried out was also

illustrated.

The literature review is performed in chapter 2. Some introduction about the

WLAN architecture and propagation paths and WLAN propagation mechanism are

introduced such as reflection, refraction, diffraction, delay spread and multipath

fading, the last part shows a summary of some related works.

Chapter 3 contains the some Propagation Models and brief explanation about

vertical plane launch method , the types of databases needed for the simulation are

described and some examples are provided also the outputs of the simulation

software are briefly described and the command input for the simulation software

have been provided.

Chapter 4 contains the results from VPL, result from AirMagnet software,

Visualization result in 2D by Matlab, in this chapter also include some analysis that

is done based on the wireless communication principles and fundamentals.

Finally, Chapter 5 contains the summary of the thesis and also includes some

suggestions for future work.