modelos empiricos teoricos y fisicos
TRANSCRIPT
OUTDOOR PROPAGATION PREDICTION AND MEASUREMENT
FOR WLAN APPLICATION
SAURDI BIN ISHAK
UNVERSITI TEKNOLOGI MALAYSIA
PSZ 19:16 (Pind. 1/97)
UNIVERSITI TEKNOLOGI MALAYSIA
BORANG PENGESAHAN STATUS TESIS
JUDUL: OUTDOOR PROPAGATION PREDICTION AND MEASUREMENTS FOR WLAN APPLICATION
SESI PENGAJIAN: 2005/2006
Saya SAURDI BIN ISHAK
(HURUF BESAR)
mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah)* ini disimpan di Perpustakaan Universiti Teknologi Malaysia dengan syarat-syarat kegunaan seperti berikut:
1. Tesis adalah hakmilik Universiti Teknologi Malaysia. 2. Perpustakaan Universiti Teknologi Malaysia dibenarkan membuat salinan untuk
tujuan pengajian sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sabagai pertukaran antara institusi
pengajian tinggi. 4. **Sila tandakan ( )
SULIT (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam (AKTA RAHSIA RASMI 1972)
TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)
TIDAK TERHAD Disahkan oleh
(TANDATANGAN PENULIS) (TANDATANGAN PENYELIA)
Alamat tetap: Nama Penyelia:
LOT 1183, JALAN HELANG, PROF. DR. THAREK ABD. RAHMAN KPG. SEMERAH PADI, 93050KUCHING, SARAWAK.
Tarikh: 25 APRIL 2006 Tarikh: 25 APRIL 2006
CATATAN: * Potong yang tidak berkenaan. ** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak
berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.
Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).
“I hereby, declare that I have read this thesis and in my
opinion this thesis is sufficient in terms of scope
and quality for the award of degree of
Master of Engineering (Electrical-Electronic & Telecommunication Engineering)
Signature : ______________________
Name of Supervisor : PROF.DR.THAREK BIN ABD.RAHMAN
Date : 25 APRIL 2006
OUTDOOR PROPAGATION PREDICTION AND MEASUREMENT
FOR WLAN APPLICATION
SAURDI BIN ISHAK
A project report submitted in partial fulfilment of the
requirements for a award of the degree of
Master of Engineering (Electrical-Electronics & Telecommunication)
Faculty of Electrical Engineering
Universiti Teknologi Malaysia
MAY 2006
ii
I declare that this thesis “Outdoor Propagation Prediction and Measurements for
WLAN Application” is the result of my own research except for works that have
been cited in the reference. The thesis has not been accepted any degree and not
concurrently submitted in candidature of any other degree.
Signature : ______________________
Name of Author : SAURDI BIN ISHAK
Date : 25 APRIL 2006
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To my dearest mother, father and family for their encouragement and blessing
To my beloved classmate for their support and caring … … …
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ACKNOWLEDGEMENT
Alhamdullillah, I am grateful to ALLAH SWT on His blessing in completing
this project.
I would like to express my gratitude to honourable Professor Dr. Tharek
Abdul Rahman my supervisor of Master’s project. Under his supervision, many
aspects regarding on this project has been explored, and with the knowledge, idea
and support received from him, this thesis can be presented in the time given.
Finally, I would like to dedicate my gratitude to my parents, my family and
friends especially my classmate Ibrahim, Abdul Rahman, Masrul, Ilyasak, Sabrina
and Ismail who helped me directly or indirectly in the completion of this project .
Their encouragement and guidance mean a lot to me. Their sharing and experience
foster my belief in overcoming every obstacle encountered in this project.
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ABSTRACT
Propagation prediction and measurement plays an important role in the
design and implementation of outdoor WLAN application. In this project, a three-
dimensional (3-D) ray tracing technique: Site Specific Outdoor / Indoor Propagation
Prediction Code will be used to predict outdoor propagation effect in Tun Chancellor
Hostel, University Technology Malaysia. Propagation prediction will be done within
five blocks of building which area covers 215 X 235 meter consists of 11 locations
receiver . The carrier frequencies are 2.4 GHz (IEEE 802.11b) and Patch antenna as a
transmiter. Then measurements of signal strength using AirMagnet software will be
carried out within the research area.
2
The objective of this project is to study on the losses of signal strength when
it travels through Line of Sight (LOS) and effect on building (NLOS). Then do
simulation of signal propagation and signal strength prediction at Tun chancellor
Hostel (KTC) building and measurement of signal strength in determines places in
KTC. In order to show the Propagation of signal the simulation code will be
visualized using Matlab. The Airmagnet tool will be used for the measurements and
results between simulations will be compared.
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ABSTRAK
Ramalan perambatan memainkan peranan yang penting dalam rekabentuk
dan pemasangan system Wlireless LAN terbuka. Dalam projeck ini, perisian jenis 3
dimensi ray tracing-Site specific Outdoor / Indoor Propagation Prediction Code
akan digunakan untuk melakukan ramalan perambatan dan kekuatan signal pada lima
blok bangunan di Kolej Tun Chencellor, Universiti Teknologi Malaysia, dengan
keluasan tempat ramalan 215 X 235meter mengandugi 11 lokasi penerima.
Frekuensi pembawa ialah 2400MHz (IEEE 802.11b) dengan Pacth antenna sebagai
pemencar.
2
Objectif project ini adalah untuk mengkaji kecekapan dan liputan (coverage)
bagi kawasan terbuka dan kesan bangunan kepada kekuatan signal. Keputusan yang
didapati daripada perisian ini dalam bentuk teks dan dengan menggunakan Perisian
Matlab perambatan gelombang radio dapat dipaparkan. Kemudian satu pengukuran
kekuatan signal akan dilakukan dengan mengunakan perisin Airmagnet dan
keputusan ramalan dan pengukuran kekuatan signal akan dibuat perbandingan .
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CONTENTS
SUBJECT PAGE
TITLE i
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT IV
ABSTRACT v
ABSTRAK vi
CONTENTS vii
LIST OF TABLES xi
LIST OF FIGURES xii
LIST OF ABBREVIATIONS xvi
CHAPTER 1 INTRODUCTION 1
1.1 Overview 1
1.2 Objective 2
1.3 Scope of Project 3
1.4 Layout of Thesis 3
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CHAPTER 2 WIRELESS COMMUNICATION TECHNOLOGY 5
AND WIRELESS LAN
2.1 Introduction 5
2.2 Wireless Networks 6
2.2.1 Cellular Networks 7
2.2.2 Wireless Local Area Networks 8
2.3 Wireless Local Area Network (WLAN) Standard 10
2.3.1 Current IEEE Standards 11
2.3.1.1 802.11 Standard 11
2.3.1.2 802.11b Standard 11
2.3.1.3 802.11a Standard 11
2.3.1.4 802.11g Standard 12
2.3.2 The IEEE 802.11b/g 12
2.4 Wireless Local Area Network (WLAN) Architecture 13
2.5 Benefits of WLANS 14
2.6 Summary 15
CHAPTER 3 RADIO WAVE PROPAGATION 16
3.1 Introduction 16
3.2 Free Space Propagation 17
3.3 Basic Propagation Mechanisms 19
3.4 Multipath Fading 20
3.5 Classifications of Propagation and Channel Models 23
3.5.1 Empirical Model 23
3.5.2 Theoretical Model 24
3.5.3 Physical Model 24
3.6 Classic Propagation Model 25
ix
3.6.1 Diffraction losses and Fresnel Zone 26
3.6.2 The Okumura Model 27
3.6.3 The Lee Model 27
3.7 Development of Ray Tracing Modelling 27
3.8 Accuracy of Ray Tracing Modelling 33
3.9 Summary 34
CHAPTER 4 PROPAGATION PREDICTION AND MEASUREMENTS 35
4.1 Introduction 35
4.2 Site Survey 37
4.3 Introduction to Ray Tracing Simulation Tool 39
4.4 Algorithm of Simulation Software 41
4.5 Databases for Simulation 43
4.5.1 Building database 43
4.5.2 Receiver Database 44
4.5.3 Terrain Elevation Database 44
4.5.4 Antenna Radiation Pattern Database 45
4.6 Simulation Command Input 46
4.7 Output of the prediction Tool 47
4.7.1 Impulse Response Output 48
4.7.2 Power and Delay Spread Output 49
4.7.3 Ray Path Information Output 49
4.8 Result Visualization 51
4.9 Field Measurement 53
4.9.1 AirMagnet WLAN Analyzer 53
4.9.2 Field Measurement Flow Chart 54
4.9.3 The AirMagnet WLAN Analyzer Measurement 55
4.10 Summary 57
x
CHAPTER 5 SIMULATION AND MEASUREMENTS RESULTS 58
5.1 Introduction 58
5.2 The Vertical-Plane-Launch output and code Visualization 59
5.3 AirMagnet and characteristics of signal strength. 62
5.4 The simulation and measurement result 63
5.5 Summay 67
CHAPTER 6 CONCLUSION & FUTURE WORKS 68
6.1 Conclusion 68
6.2 Future work 69
REFERENCES 70
APPENDICES A-B 76-111
xi
LIST OF TABLES
TABLE NUMBER TITLE PAGE
4.1 Command input simulation 47
5.1 Simulation and Measurement 64
xii
LIST OF FIGURES
FIGURE NUMBER TITLE PAGE
2.1 Cellular Network 7
2.2 Typical LAN and WLAN configuration 9
3.1 Short term and long term fading 22
3.2 Fresnel Zone 25
4.1 Methodology Process 36
4.2 Photo one of KTC Hostel 37
4.3 Rolling hills and Trees at KTC 38
4.4 Site Map Plan 38
4.5 Approximation 3D ray tracing using vertical plane 39
4.6 Rays Generation in horizontal plane 40
4.7 Flow Chart of VPL method 42
4.8 Databases Visualization 45
4.9 Antenna radiation pattern 46
4.10 Example of impulse response output 50
4.11 Example of power delay spread output 50
4.12 Example of ray path information output 51
4.13 VPL ray tracing visualization using Matlab 52
4.14 AirMagnet Laptop Analyzer 53
4.15 Field Measurement Flow Chart 54
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4.16 Transmitters and Receiver Location 55
4.17 Wireless Multi-client Bridge/AP 56
4.18 Patch Antenna 56
4.19 S15 and S14 viewfrom S01 57
5.1 Power and delay spread output 59
5.2 Characteristics Power and spread out 60
5.3 Ray paths visualization for buildings S15, S14, S13, S12,
S11and S01 61
5.4 The reflection and diffraction of ray at locations 9,10 and11 61
5.5 (a) Signal strength versus time at location 1 62
(b) Signal strength versus time at location 2 62
5.6 Average power received Vs location 63
5.7 Signal strength as a function of distance 64
5.8 Best-Fit-Line 65
5.9 shows the measurement of signal strength in Tun
Chancellor Hostel 66
5.10 Comparison result of Measurement and simulation
Of signal strength 66
xiv
LIST OF ABBREVIATIONS
1G first generation
2G second generation
3G third generation
2D two-dimensional
3D three-dimensional
AM amplitude modulation
AP access point
BS base station
DSSS direct sequence spread spectrum
EIRP effective isotropic radiated power
FCC Federal Communication Commision
FM frequency modulation
GBSBM Geometricall theory of diffraction
GTD geomettrical theory protocol
GUI graphic user interface
I/O input output
IDU indoor unit
IEEE Instituteuf Electrical and Electronics Engineers
IP Interenet Protocol
ISM industrial, scientific and medical
LAN Local Area Network
LOS line of sight
MAS Mobile Switching Center
NLOS non line of sight
xv
ODU outdoor unit
PDF probability density function
PSTN Public Switched Telephone Network
rms root mean square
SBR shooting and bouncing ray
UHF ultra high frequency
UNII unlicensed national information infrastructure
UTD uniform theory of diffraction
UTM Universiti Teknologi Mara
VPL vertical plane launch
WCC Wireless Communication centre
WLANs Wireless Local Area Network
CHAPTER 1
INTRODUCTION
1.1 Overview
The basic components of the WLAN are access points (AP) and the
mobile clients (MC), typically a laptop or a PDA with a WLAN card. To create a wired
network infrastructure, Ethernet cables are placed through out the building and then
buildings reconnected together using fiber optic cables. With a Wireless LAN, in order
to create the network infrastructure APs are placed in various locations throughout a
building and even outdoors. Various mobile clients then communicate with each other
by first communicating with these access points.
One of the primary principles of WLAN connections is that network data is
transmitted as modulated electromagnetic waves using antennas. When the radio waves
propagate or travel from one device to another there are several issues has to highlight.
The radio energy attenuate when it propagates and the radio signal also attenuated when
they pass through obstacles such as trees and buildings. There are three basic
2
mechanisms that occurred when radio waves propagates reflection, diffraction and
scattering. The scattering problem occurs when RF can reflect off many thing and the
direct signal combines with the signals have reflected off of object that are not in direct
path. This problem usually described as multipath, fading, Rayleigh fading or signal
dispersion.
In this project the radio waves propagation for outdoor environments will be
investigated using the Wireless LAN 802.11b at the frequency band 2.4 GHz. This
project involved the study of the effect on building within the access point install
outdoors and than get the propagation prediction and measurements. To determine the
electromagnetic interaction with the surrounding environment a ray vertical code
employing a modified shoot and bounce ray (SBR) method known as the Vertical Plane
Launch (VPL) will be used for the prediction. Software called Matlab will be used to
visualize a ray tracing code. The field measurement can be done using AirMagnet
Wireless LAN Analyzer than the prediction and measurement result will be compared.
1.2 Objective
The objectives of this research are to investigate the outdoor propagation for
WLAN 802.11b application that involved the prediction and measurement of signal
strength in an outdoor environment at Kolej Tun Chancellor with taking account of the
building effects. In other words this research aim for a site specific signal strength study
and then observe effect of obstacle, but here only taking account of building effects.
3
1.3 Scope of Project
1- The physical model is to predict propagation effect in the related site by using ray
ray tracing simulation program based on vertical-plane-Launch (VPL) technique
courtesy of Bertoni, Xia, and Liang.
2- Collect four types of databases (building, terrain, receiver and antenna radiation
antenna radiation pattern ) that needed in the simulation.
3- The VPL ray tracing code visualized using MATLAB.
4- The AirMagnet HANDHELD Wireless Lan Analyzer that installed in Laptop used
for field measurement.
5- Observe the effect of building to the signal direction in Matlab Visualization
as well as signal strength degradation due to building.
6- Analyze the signal strength of two methods, prediction and field measurement.
1.4 Layout of Thesis
This section outlines the structure of the thesis.
The first chapter briefly introduces this project by elaborating on the project
overview, objectives, and scope of project. Second and third chapter are written based
on the findings from the literature. Chapter two discuss the wireless communication
4
technology and concentrates on Wireless LAN and its application, whereas chapter three
discuss about the Radio Wave Propagation and the development ray tracing Modeling.
Chapter 4 contains the methodology process for the propagation prediction and
measurements by showing up the detailed diagram of the project methodology and
highlights briefly the steps have been taken to meet the objectives of this project.
Chapter 5 discusses the simulation and measurements results. The performance of signal
strength between simulation and measurements will be analyzed for LOS and NLOS.
Chapter 6 concludes the topics and suggests recommendation for future works.
CHAPTER 2
WIRELESS COMMUNICATION TECHNOLOGY AND WIRELESS LAN
2.1 Introduction
The world of wireless technology has come a very long way since Gudlielmo
Marconi first demonstrated radio’s ability to provide continuous contact ships sailing the
English Channel on 1897. Over the past century, wireless transmission has progressed
through the development of radio, radar, television, satellite and mobile telephone [1].
In early years of wireless communication, radio was the most intensively
deployed technology, both in the public domain and by law enforcements
establishments. In 1934, 194 municipal police radio system and 58 state police stations
had adopted amplitude modulation (AM) mobile communication system for public
safety in the U.S. It was estimated that 5000 radios were installed in mobiles in the mid
1930s.
6
AM was the transmission used Edwin Armstrong demonstrated the feasibility of
frequency modulation (FM) in 1935. Subsequently, Fm has been the main modulation
method deployed for mobile communication system worldwide since the late 1930s.
World war II accelerated the improvements of the world’s deployment of one-way and
two-way radio and television systems flourished [2].
The space age opened many new opportunities for radio communications
between widely separated locations. Instead of high frequency terrestrial system with
limited bandwidth or a large number of short-range microwave relays, Satellite can link
distant locations from a point high above the earth. By the mid-1960s, launch vehicles
were delivering communications to locations in the geostationary satellite orbit. Today
geostationary communications satellites continue to play a major role in
telecommunications. Another wireless communication technology is the Low Earth
Orbit (LEO), made up of satellites that communicate directly with handheld telephones
on earth [3].
The growth of cellular radio and personal communication systems began to
accelerate in the late 1970s. The growth was spurred on with the successive introduction
of the first generation (1G), second generation (2G and third generation (3G) cellular
systems.
2.2 Wireless Networks
Wireless networking is currently the fastest growing technology in
communication and computing. The past decade has seen new technologies develop,
ranging from digital cellular phones to WLANs. New protocols and standards are
constantly being developed, making the network more efficient and secure. Even the
7
devices used on such networks are getting increasingly ‘smart’. Newer mobile devices
are smaller but more powerful and offer a range of flexible features with some
technologies often overlapping. Some new cellular phones, for instance, are flexible
enough to be used as mobile computers, PDAs and GPS Receivers with applications
ranging from telecommunications and wireless internet access to location sensing. The
following sections provide a brief overview of some of these wireless technologies.
2.2.1 Cellular Networks
Cellular networks have fast developed into an extensive wireless communication
infrastructure providing wireless voice and data communications with almost world-
wide coverage. Use of cellular phones is greatly increasing worldwide, and the number
of cell phone subscribers has quadrupled to over half a billion in the past five years. A
cellular network is a wireless communication service area subdivided into hexagonal
areas termed as cells. These cells vary in size from a few kilometers in diameter, in
modern digital networks, to around a hundred kilometers in older analog networks. Each
of these cells has a base station (cellular tower) associated with it.
Figure 2.1 shows a simplified cellular architecture [2].
Figure 2.1 Cellular Network
8
Each base station has a certain range of radio frequency channels associated with
it. To avoid overlap and radio interference, these channels are different from channels
associated with all of its neighboring cells. Channels can be reused in cells that are far
enough so that no interference occurs. These cells are grouped together as clusters for
required coverage area.
All the Base Stations (BS) are connected to a Mobile Switching Center (MSC)
using fixed links. Each MSC of a cluster is then connected to the MSCs of other clusters
and a Public Switched Telephone Network (PSTN) switching centre. The MSC stores
information about the subscribers located within the cluster and is responsible for
directing calls to them.
One of the most important issues in cellular networks is tracking of a mobile
client when it is moving through a network. To counter this, cellular networks use
Location Management techniques. Location Management essentially involves two
processes, location update and paging. Location update is the information provided by
the mobile device to the network about its current location. Paging, on the other hand, is
done by the network where it actively queries the mobile device to find out what cell it is
located in, so that the incoming call can be routed correctly to the appropriate BS [2].
2.2.2 Wireless Local Area Networks
The Local Area Networks (LAN) are the next common type of network, when
two computers are connected together they form a network of computers. A LAN can be
composed of anywhere from just a few to several hundred computers connected together
by physical Ethernet cables. The motivation for the growth of LANs started in the 1970s
9
to make it possible to share expensive resources such as printers. By connecting all the
computer terminals in an office to the LAN, and then connecting one printer to the LAN,
all the terminals could share one printer. Eventually LANs were connected to other
LANs; such as a home office and a remote office. Networks of geographically
distributed LANs are also known as Wide Area Networks (WAN). The most familiar
WAN is the Internet which interconnects computers and LANs world wide [5].
A Wireless LAN (WLAN) is a network in which the medium for connecting
nodes or computers is wireless. A WLAN is conceptually very similar to both a cellular
network and a LAN. The major differences between cellular and WLAN are in how they
are implemented and include “the method of delivery of data to users, data rate
limitations and frequency band regulations” . While a cellular network was designed to
serve similar functions to that of traditional telephone networks, a WLAN was designed
to serve the functions of a Wired LAN. The breakthrough in both of these networks is
that devices on the network do not need to be connected together by a physical wire in
order to communicate and instead use radio waves as the communication medium.
Figure 2.2 shows typical LAN and WLAN Configuration relates WLANs, LANs, and
clients. One possible WAN configuration might connect two or more of these
LAN/WLANs that are separated by a long distance.
Figure 2.2 Typical LAN and WLAN configuration
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The original motivation behind these networks was to reduce the cost and
complexity involved in laying down wires. Though that is still a major part of choosing
to deploy a wireless network, more and more it is about the convenience it that provides
to the user and the new applications that have emerged through the availability of
WLANs. One particular benefit can be seen when setting up a network in a historical
building. In such building the physical impact of creating a network is minimized by not
having to lay down LAN cables. The benefits also lie in the multitude of devices can be
connected to WLANs which include traditional PCs, notebook computers, PDAs, and
appliances such as televisions and stereo systems. There are two main categories of
WLANs: infrastructure networks in which there is a backbone and ad hoc networks with
no backbone.
2.3 Wireless Local Area Network (WLAN) Standard
Most common wireless network equipment is subject to IEEE standardization.
The IEEE standards for wireless LAN s describe the specifications for the physical layer
and the Wireless LAN Medium Access Control (MAC) Layer. The standards describe
these layers in detail in order to allow chip manufacturers to use it as a guideline for
producing wireless LAN card chips.
11
2.3.1 Current IEEE Standards
2.3.1.1 802.11 Standard
This is the original standard no longer applicable to new products. Still found in
several existing systems. Its main features include:
Frequency Hopping (FH) and Direct Sequence (DS)
Systems using 802.11 over bandwidth to 2 Mbps using the 2,4 GHz frequency.
2.3.1.2 802.11b Standard
This is the current standard used, especially in Europe because 802.11a still isn’t
ratified.
Its main features include:
Direct Sequence (DS)
11 Mbps, 2,4 GHz
Backward compatibility to 802.11 (DS)
2.3.1.3 802.11a Standard
This is the new standard, already available in the United States, but not in
Europe. One reason is that the 5 GHz frequency band is used by several other
technologies in some European states and not only wireless LANs. Also the
ETSI decides if such a standard can be used in Europe and as yet have not
12
ratified it as it does not support Dynamic Frequency Selection (DFS) and
Transmit Power Control (TPC). The (American) 802.11.a Standard includes the
following main features:
Orthogonal Frequency-Division Multiplexing (OFDM)
54 Mbps, 5 GHz
No support for Backward Compatibility
2.3.1.4 802.11g Standard
Standard that supports a higher data rate for 2,4 GHz with maximum 22 Mbps,
offering compatibility with existing 802.11b systems
There are various ways how this can be solved and it looks like developers are
not quite sure about which way to turn. Therefore, it is unsure if 802.11g will
ever actually be finished
2.3.2 The IEEE 802.11b/g
When the wireless LAN industry began the transition 900 MHz to 2.4GHz in the
mid-1990s, many underestimated the challenges associated. While the benefits of
operation in 2.4GHz relative to 900 MHz were well understood (international operation
and a greater number of available channels), the peculiarities of 2.4GHz tended to less
well defined by vendors. When the 802.11g that has more data rate 53 Mb/s appropriate
with 802.11b in the same 2.4 GHz band the 802.11b/g tended to be more power full
Wireless LAN.
13
The benefit of 802.11g is higher performance with backward compatibility. The
802.11g uses the same transmission type and modulation as 802.11a and therefore
support the same data rates. The 802.11g uses the orthogonal frequency division
multiplexing (OFDM) transmission whereas fairly robust in terms of term interference
and multipath distortion and makes efficient use of a given amount of spectrum, in
another word the 802.11g more efficient than 802.11b that used (DSSS). The backward
compatibility gives advantage to the 8092.11b/g[4].
2.4 Wireless Local Area Network (WLAN) Architecture
The basic components of the WLAN are access points (AP) and the mobile
clients (MC), typically a laptop or a PDA with a WLAN card. To create a wired network
infrastructure, Ethernet cables are placed through out the building and then buildings are
connected together using fiber optic cables. With a Wireless LAN, in order to create the
network infrastructure APs are placed in various locations throughout a building and
even outdoors. Various mobile clients then communicate with each other by first
communicating with these access points [4].
In the simplest configuration there is one AP at the center and one or more MCs
spread out around the AP. When additional APs are added the coverage area of the
network increases and the MC selects to closest AP to communicate with. The entire
WLAN could consist solely of APs and MCs but it is common to find APs connected to
other APs by Ethernet cable, and the network of APs then connected to a LAN or the
internet through other networking devices. Such an arrangement is especially beneficial
if a wired network is already deployed at a site. APs can be placed at locations far from
each other where they provide local coverage, but the MCs in each local coverage area
can still communicate with each other since the APs are connected to the wired network.
14
2.5 Benefits of WLANS
There are many obvious benefits to using a WLAN design, most of which hinge
around the problems with typical wired LANs. Convenience is certainly a benefit to
using wireless communications. With wireless, as long as you are in range of an AP, you
have a connection to the network. This is a tremendous advantage to mobile sales forces,
personnel performing physical inventories of a warehouse, or IT professionals who may
need to get access to data from anywhere in a building. Using wireless technology
makes it easy and effective to let people physically go wherever they need to go and still
be able to access any data that they need from the network.
Another benefit to using a WLAN is that cable distance limitations become less
of an issue. There are many situations where the distance between the network link and
the end user is such that the signal strength is degraded by the time the cable has been
routed up walls, through floors, and around permanent objects [5]. Wireless
communications negate this by doing direct “line-of-sight” connections to a system. The
signal strength from a wireless AP or network card is typically between 150 to 300 feet
indoors (depending on the design and structure of the building) and up to 1000 feet
outdoors. Obviously, the 1000-foot outdoor range outdistances the maximum unshielded
twisted pair (UTP) cable length of 328 feet. In addition, a wireless signal can be boosted
by using more than one AP or by using a wireless relay to extend the range even farther.
15
2.6 Summary
This chapter provides the literature on the wireless communication technology
that has been the most rapidly deployed technology in this century’s. The WLAN is one
of the very famous wireless network and most of private sector and also education center
implement this system. The IEEE standards for wireless LAN describe the specification
for the physical layer and Medium Access Control (MAC) Layer. The Standards
describe these layers in detail in order to allow chip manufacturers to use it as a
guideline for producing wireless LAN card chips. From the various types of WLAN
standards, the 802.11b will be chosen for the propagation prediction and measurements.
CHAPTER 3
RADIO WAVE PROPAGATION
3.1 Introduction
An understanding of radio propagation is essential for coming up with
appropriate design, deployment, and management strategies for any wireless network. In
effect, it is the nature of the radio channel that makes wireless networks far more
complicated then their wired counterparts. Radio propagation is heavily site-specific and
can vary significantly depending on the terrain, frequency of operation, velocity of the
mobile terminal, interface sources, and other dynamic factors. Accurate the
characterization of the radio channel through key parameters and a mathematical model
is important for predicting signal coverage, achievable data, specific performance
attributes of alternative signalling and reception schemes, analysis of interference from
different systems, and determining the optimum location for installing base station
antennas [17].
Nowadays most of people or companies interested to use WLAN for their work
because it’s more economical, easier and consumes a less time. One of the parameter of
17
WLAN is the wavelength of the radio waves used by a WLAN is significantly smaller
than the obstructions that the radio waves encounter; therefore, we can simplify the
study of these waves by treating them as rays traveling in straight lines. The shortest
path that a wave can take is the unobstructed path or the Line-Of-Sight (LOS). When
obstructions are encountered, the signal has to take multiple paths to travel from the
transmitter to the receiver. This behavior, called Multipath Delay Spread, introduces a
delay in the transmission time when compared to LOS. Another property of the radio
propagation that can cause delays is the Doppler Spread which quantifies the
fluctuations caused by the movement of the transmitter, receiver, or the objects in
between them. The Doppler spread is especially relevant when considering moving
vehicles and airplanes. Two concepts that are prerequisite to the mathematical modeling
of radio propagation are transmission power and signal strength. Radio propagation is
the transfer of energy and is measured in terms of units of power or Watts. This power is
measured at the transmitter (transmission power) and also measured at the receiver; the
signal strength is the total amount of power measured at the receiver. Due to the nature
of radio wave propagation the latter measurement is less than the former because the
signal looses power as it moves through the air in the form of radio waves.
3.2 Free Space Propagation
Free space transmission is primary consideration in essentially wireless
communication system. In this case of line of sight (LOS) propagation, there are no
obstructions due earth’s surface or other obstacles. The received power, , at the
receiving antenna located at a distance, , from transmitter is given by Friss free space
propagation as (2.1)
rp
d
18
2
4 dGGPP rttr (2.1)
The equation of path loss for Friss space model, is written as
24
.1 d
GGP
PL
rtr
tf (2.2)
dfGGdBL rtf log20log20log10log1045.32)( (2.3)
Where
rP received power
tP transmitted power
wavelength =f
c
c speed of light (3x10 m/s) 8
f carrier frequency in Mega Hertz
tG gain of the transmitter
tG gain of the reciver
d antenna separation distance in Kilometer
fL free space loss
Equation (2.2) and (2.3) indicate that free space path loss is frequency
dependence and is increasing against distance. The free space attenuation increases by 6
dB whenever the length of the path or the frequency is doubled.
19
3.3 Basic Propagation Mechanisms
Reflection, diffraction, and scattering are the three basic propagation
mechanisms in wireless communication system. These mechanisms cause radio signal
distorts and give rise to signal fading, as well as additional signal propagation losses.
These mechanisms are briefly explained in this section.
Reflection occurs when a propagating electromagnetic wave impinges upon an
object that has very large dimensions compared to the wavelength of the propagating
wave. Reflection occurs from the surface of the ground, from walls, and from furniture.
When reflection occurs, the wave may also be partially refracted. The coefficients of
reflection and refraction are functions of the material properties of the medium, and
generally depend on the wave polarization, the angle of incidence, and the frequency of
the propagating wave [6].
Diffraction occurs when the radio path between the transmitter and receiver is
obstructed by a surface that has sharp edges. The waves produced by the obstructing
surface are present throughout space and even behind the obstacle, giving rise to the
bending of waves around the obstacle, even when a line of sight (LOS) path does not
exist between the transmitter and receiver. At high frequencies, diffraction - like
reflection - depends on the geometry of the object, as well as on the amplitude, phase,
and polarization of the incident wave at the point of diffraction [2], [6].
In many practical situations, the propagation path may consist of more than one
obstruction. Hence, Billington’s method, Epstein-peterson method, and Deygout method
had been suggested many approximate approaches to find multiple knife-methods had
been many approximate approaches to find multiple knife-edge diffraction loss.
However, extending to more knife-edges, it becomes a formidable mathematical
problem. Hence, T.F. Eibert and P. Kuhlmann had combined the result of empirical
model with own measurements results and applied a modified diffraction algorithm in
20
order to obtain good radio propagation prediction with very low consumption of
computational resources [7].
Scattering occurs when the medium through which the wave impinges upon an
object with dimensions that are small compared to the wavelength, such as rough
surfaces, small objects, of other irregularities in the channel. When a radio wave
impinges on a rough in all directions and providing additional radio energy at a receiver.
This leads to the actual received signal is often stronger than what is predicted by
reflection and diffraction models alone, when the additional radio energy is in phase
with received signal [8].
3.4 Multipath Fading
In most radio channels, the transmitted signal arrives at the receiver from various
directions over a multiplicity of paths. The phase and amplitude of a signal arriving on
each different path are related to the path length and conditions o the path. Solving the
Maxwell’s equations with boundary conditions representing the physical properties and
architecture of te environment can do an exact analysis of the multipath propagation.
Unfortunately, this method is computationally burdensome, and even with today’s most
sophisticated computers, only the simplest structure can be treated.
Hence, in order to be able to assess the performance capabilities of various
wireless systems, root mean square (rms) delay spread is a good measure to grossly
quantify the different multipath channels. The equation for rms delay spread ( ) used is
22 )( (2.4)
21
With mean excess delay ( )
kk
kkk
P
P
)(
)( (2.5)
and
KK
kKK
p
P
)(
)( 2
2 (2.6)
where )(P is the relative amplitudes of the multipath components and is the time
delay during multipath energy falls..
In addition to the delay, the channel provides a tome varying gain to the
transmitted signal. In general, the channel gain can be decomposed into a path loss with
large scale (long term) shadowing component and a small scale (short term) fading
component. The path loss represents the local mean of the channels gain and is therefore
dependent on the distance between transmitter and receiver and also on the propagation
environment. The short term fading and long term fading are due to multipath
propagation and independent of the distance between transmitters and receiver sees
Figure 3.1. Reyleigh or Rician distribution can characterize the short term fading [1].
These fading models are typical for mobile and cellular networks. The fading is due is
due to unknown local changes in the propagation environment such people moving
around the room, passing vehicles, and tree moving in the wind.
22
Figure 3.1 Short term and long term fading
For channel with dominant signal component present, the effect of the dominant
signal arriving with weaker multipoath signals gives rise to the Rician distribution. To
specify the Rician distribution, we have parameter K that is defined as the ratio between
the deterministic signal power and the variance of the multipath. The equation used is
expressed in (2.7).
dBA
dBK2
2
2log10)( (2.7)
Where
A peak amplitude of dominant signal
standard deviation of the local power
As the dominant signal becomes weaker ( and ), the Rician
distribution degenerates to a Rayleigh distribution. Rayleigh distribution is the most
commonly used for multipath fading all signals suffers nearly same attenuation, but
arrive with different phases.
0A K
23
3.5 Classifications of Propagation and Channel Models
Propagation model basically predicts what will happen to the transmitted signal
from transmitter to the receiver. According to Rapport and Sandhu [9], propagations
models are not only needed for installation guidelines, but they are a key part of any
analysis or design that strives to mitigate interference. Also, capacity and system
performance prediction are only as good as the channel models upon are based. There is
an extensive with paper published as early as the mid-1930s [10]. Here, propagation and
channel models are divided into three basic classifications that are empirical, theoretical
and physical models.
3.5.1 Empirical Models
Empirical models fundamentally use experimental measurement data to produce
a relationship between the propagation circumstances and expected field strength or time
dispersion results. It can also be developed from measurements made in laboratory or
with scale models of propagation environments. This approach is based on fitting curves
or analytical expressions that recreate set of measured data. This has advantage of taking
account all propagation factors, both known and unknown through actual field
measurements. However, the validity of an empirical model at transmission frequencies
or environments other than those used to derive the model can only be established by
additional measured data in new environment at the required transmission frequency.
24
3.5.2 Theoretical models
Theoretical models are based on same theoretical assumptions about the
propagation environment. These models are also called statistical model. These models
are useful for analytical studies of the behavior of communication systems under a wide
variety of channel response circumstances. Though, due to they do not deal with any
specific propagation information, they are not suitable for planning communication
systems to serve a particular area. Hence, they usually rely on assumptions that lead to
mathematical formulations. The Geometrically Based Single Bounce Marcrocell
(GBSBM) channel model by Petrus et al. [11] and Quasai – wide- sense stationary
uncorrelated scattering (Quasi-WSSUS) channel model by Bello [12] are examples of
theoretical models.
3.5.3 Physical Models
Physical model rely on the basic principles of physics and take into account the
propagation environment. These models can be either site specific or not site specific. A
physical and not site specific model uses physical principles of electromagnetic wave
propagation to predict signal levels in a generic environment in order to develop some
simple relationship between the characteristics of that environment and propagation . An
example of this model by W.Ikegami and H.L. Bertoni for mobile radio systems in urban
areas, where roof edges are considered as a series of diffracting screens with final
diffraction from building roof to the street level being included [13].
In opposition, a physical and site specific channel model not only uses the
physical law of electromagnetic wave propagation but also have a systematic technique
25
for mapping the real propagation environment into the model propagation environment.
Epstein-Peterson method, Deygout Method, Longley Rice model, and Anderson two
dimensional (2D) model which only predict signal attenuation over terrain, and also ray
tracing model which provides time dispersion information and angle of arrival
information are the examples of physical and site specific channel model [14 ].
3.6 Classic Propagation Model
Initial techniques to predict signal strength in shadowed regions relied heavily on
classical Fresnel theory and the concept of single knife-edge diffraction. As a simple
explanation, a Fresnel Zone is the area around the visual line-of-sight that radio waves
spread out into after they leave the transmitting antenna as shown in Figure 3.2. This
area must be clear or else signal strength will weaken. A Fresnel zone can be simplified
as an ellipsoid indicating Radio Line of Sight from the transmitter to receiver. In this
project, a blockage refers to an obstacle blocking the radio line of sight instead of visual
line of sight to implement the effect of Fresnel Zone.
Figure 3.2 Fresnel Zone
26
3.6.1 Diffraction losses and Fresnel Zone
A wave front expands as it travels, causing reflections and phase changes as it
passes over an obstacle [15].This result in a diffraction loss of signal. The Fresnel
Phenomenon occurs in zones. The accepted added clearance to an obstacle is 0.6 of the
first Fresnel zone. The added clearance can be calculated
Added clearance (ft) = 0.6(2280) 2
1
21
21
( ddL
dd (2.8)
Where
d =distance from transmitter antenna to path obstacle, kilometer
2d =distance from receiver antenna to obstacle, kilometer
L =wavelength, ft
Below is the introduction of some popular radio wave propagation models
3.6.2 The Okumura Model
The Okumura et al. method is based on empirical data collected in
detailed propagation tests over various situations of an irregular terrain and
environmental clutter. The results are analyzed statistically and compiled into diagrams.
The basic prediction of the median field strength is obtained for the quasi-smooth terrain
27
in an urban area. A correction factor for either an open area or a suburban area is also
taken into account. Additional correction factors, such as for a rolling hilly terrain, an
isolated mountain, mixed land-sea paths, street direction, general slope of the terrain
etc., make the final prediction closer to the actual field strength values [16].
3.6.3 The Lee Model
W. C. Y. Lee proposed this model in 1982. In a very short time it became widely
popular among researchers and system engineers (especially among those employed by
U.S. companies) mainly because the parameters of the model can be easily adjusted to
the local environment by additional field calibration measurements (drive tests). By
doing so, greater accuracy of the model can be achieved. In addition [16], the prediction
algorithm is simple and fast.
3.7 Development of Ray Tracing Modeling
The application of ray tracing methods to propagation prediction for
communication systems has been around several decades. It is a widely used technique
to predict propagation effects in mobile and personal communication environments. This
section describes some of the ray tracing modeling and current development of this
modeling.
28
Ray tracing is used to identify all possible ray paths between transmitter and a
receiver in multipath channels, compute their amplitude and delay and finally perform
the coherent combination of all the taking into account antenna pattern and gain. [19].
In order words, it approximates electromagnetic waves as discrete propagating rays that
undergo attenuation, reflection, and diffuse scattering phenomena due to the presence of
buildings, walls, and other obstructions. The total received electric field at a point is the
summation of the electric fields of each multipath component that illuminates the
receiver. These models have the advantage of taking 3D environments into account, and
are thus theoretically more precise. In addition, they are adaptable to environment
changes such as transmitter location, antenna position and frequency and predict
wideband behavior as well as the wave’s direction arrival.
A ray tracing technique that incorporates site-specific environmental data, such
as location, the orientation, and electrical properties of building has been used to predict
path loss and delay spread in Virginia Tech campus, USA [20]. The researchers
concentrated on the determination of power delay profiles at fixed receiver locations.
The ray tracing methodology discussed by Thomas Kurner [21] focused on the average
propagation loss, associated with a receiver as it moves through an urban environment.
An excellent agreement between measured and predicted path loss and multipath time
delay profiles has been obtained [21].
In 1996, Orlando Landon et al. highlighted that propagation studies in
microcellular environments have shown that significant nultipath components arise from
reflection off building surfaces [22]. Hence, ray tracing techniques must reliably the
influence of these building and other obstructions. For specularly reflected ray path
(reflection for which parallel incident rays remain parallel after reflection), the Fresnel
reflection coefficients can be used to predict the reflection loss of building surface,
provided its dielectric properties are known. In order to provide enhanced reflection
coefficient models for buildings, measurements at 1.9 GHz and 4.0 GHz have been
made for a variety of typical smooth and rough exterior building surfaces. The measured
29
test surfaces include walls composed of limestone blocks, glass, and brick. Comparison
of theoretical calculations and measured test cases that reflection coefficients adequately
predict the reflective properties of the mentioned building surfaces. These results cab be
applied to ray tracing algorithm for the purpose of propagation prediction microcellular
environment.
Besides, Catedra et al, have reviewed commonly used tracing techniques and has
developed a new method called Angular Z-Buffer (AZB) technique in 1998 [23].
According to the authors, ray tracing cab classified into 2 groups, which are direct
algorithms and inverse algorithm. Direct algorithms (pincushion, shooting and bouncing
ray) are those in which the ray tubes are shot from the source to all the space directions.
The models that proposed by Schaubach [20] and Seidel [24] are grouped as direct
algorithms. These algorithms have been widely used in urban scene. In general, they
work well for visualization problems. However, the computation of the field transported
by each one o the ray tubes generated in the diffraction is very cumbersome, because the
diffracted field is not a spherical wave, as is usually assumed in most pincushion
algorithms. Another difficulty is unable to find the accurate phase when the stigmatic
tube is not spherical. Inverse algorithm is a more complicated algorithm, which checks
all possible paths and well suited to compute diffraction, phase and polarization
accurately. For these reasons, they have selected the inverse method [25], [26] for the
UHF band propagation analysis. From comparison among measurement and prediction,
the AZB ray-tracing algorithm is efficient for design purpose in mobile communication
application.
At the same year, George Liang and Henry L. Bertoni have presented a VPL
technique for approximating a full three-dimensional (3D) site-specific ray trace to
predict propagation effects in cities [18]. The VPL approach for specular reflections
from vertical surfaces and diffraction at vertical edges and approximates diffractions at
horizontal edge by restricting the diffracted rays to lie in the plane incidence. Compared
to the 3D shooting and bouncing ray (SBR) method or the 3D image method that can
30
handle at most one or two diffractions at horizontal edges. Due to the use of reflection
coefficient for a dielectric half space with 75r give the least error with
measurements, 6r is used for the reflection coefficient at walls. The model proposed
was validated with a large number of measurements for both rooftop and street level
transmitters in various locations in Rosslyn, V.A., USA. Besides, the prediction results
are very good in comparison to the other theoretical empirical methods used for site
specific propagation prediction.
In addition, S.Y. Tan and C.L. Chua emphasized that the factors must be taken
into account in a comprehensive propagation model including direct diffraction over
propagation model, multiple diffraction at edges of the building, and scattering from
surrounding building [27]. They applied a ray tracing model and showed good
agreement in the comparison between the measured and predicted wideband delay
profiles and path loss at different locations in cellular scene where the base station is
mounted on a rooftop.
In 2001, Blaunstein ei al. concentrated on the influence of buildings’ overlay
profile on signal spatial decay and on path loss dependence in frequency domain with
UHF/X-band urban propagation channel [28]. The researchers suggested some models to
be employed in cases where buildings are randomly distributed on a hilly terrain. The
suggested models include the well-known 2D deterministic model [29]-[30] and
mathematical ray tracing model by George Liang and Henry L. Bertoni [18].
Alternatively, they introduced the statistical description of the actual building pattern
inside the city and determine the field intensity based on the pattern as done as models
suggested above. Theoretical predictions have been compared with the experimental
data, which obtained from measurements in different kind of built up areas. It is found
that the 3D model is a very good prediction with a mean error of 5 or 6 dB for the loss
characteristic and their frequency dependence in built up area.
31
The accuracy of a ray tracing technique based on a full 3D implementation of
GO/UTD (Geometrical Optics/ Uniform Theory of Diffraction) had been analyzed [31].
Comparison between measurements and simulations has been carried out for different
campus buildings of Cantabria, Spain in 1.8 GHz and 2.5 GHz. The authors had been
presented a set of results with the average error of prediction was 0.0045 dB and its
standard deviation was 2.54 dB for narrowband analysis. This showed a good agreement
between measurements simulations. Besides, nine local power delay profiles were
averaged. The comparison of measured and simulated power delay profiles showed that
the amplitudes and arrival times of the main multipath component could be well
predicted.
Zhong et al. shows the extension of the method used by Jan and Jeng 1997 and
proposed a new 3D model for indoor communications [32]. The researchers have
presented the application of several ray tracing techniques, in combination with UTD in
the propagation prediction for UHF (Ultra High Frequency) band in an indoor
environment. The proposed model took just 1% of the computational time compared to
traditional 3D model. Measurements were carried out at Sheng Jio Tong University,
Shanghai. To ensure that propagation channel were stationary in time, the measured data
was average over ten instantaneously sampled values. The predicted and measured
results for path loss matched closely.
Besides, the development of ray tracing launching tools in [18], [26], [33], and
[34] is highlighted [35]. However, since ray tracing accounts only for rays that undergo
specular reflection and diffractions, it still fails to properly describe diffuse scattering
phenomena, which can have significant impact on propagation. Hence, Degli-Eposti et
al. have presented an efficient diffuse scattering model using simple and analytic
formulas [35]. This model based on ray approach and can be easily integrated into a ray
tracing field prediction tool.
32
In order to overcome the limitations of the existing diffraction coefficient used in
ray tracing programs, a new diffraction coefficient has been developed [36]. The author
presented the influence of the diffraction coefficient and the shape and electrical
properties of building corners on the prediction of received power and the Liang and
Henry L. Bertoni [18] has been applied to incorporate with new developed diffraction
coefficient.
Benard De Backer et al. explored the propagation properties of UHF wave
traveling through building structures, in particular windows. [37]. The rat tracing is
benchmarked against both narrow band measurements and the results of a full wave
moment method technique. This is due to propagation, into and around the building
structure is governed by complex propagation mechanism, and may not be cooperated
into high frequency approximation that ray tracing provides.
As there are so many ways of ray tracing implementation, [19], [38]– [39] divide
the ray tracing software module into two main options, known as ray launching, and
point-to point ray tracing approach. Both of them have their individual advantages and
disadvantaged. Ray tracing computes all rays receiver point individually but require an
extremely high computation times. Thus, to make this technique computationally
feasible, many acceleration techniques had been proposed to be implementing in this
approach. On the other hand, ray launching approach as applied in [40] - [41] is an
option that the casting of rays from traveling long distance. A small constant angle
separation between launched rays needs to be specified to produce reliable results.
Though, this technique is very efficient computationally.
Besides, there are many others authors studied the accuracy of the ray tracing
technique in predicting coverage through the quantification of the mean error and the
standard deviation of the error in urban, microcellular and indoor environment for
different frequency band channel.
33
3.8 Accuracy of Ray Tracing Modeling
Regarding the ray tracing modeling accuracy, there are two kinds of error can be
distinguished, that are the input data and errors due to computer UTD and ray tracing
approach. Among the input data errors, the inaccuracies the topographical tracing
approach. Among the input data errors, the inaccuracies in the topographical and
morphological data of the urban scene and antenna input data such as radiation pattern,
position and orientation can be mentioned. The inaccuracy of the building database and
the lack of information about material characteristic may cause the discrepancies
founded between simulation and measured results.
On the other hand, the UTD/GTD (Geometrical Theory of Diffraction) model
may introduce several errors, among them are the error inherent in UTD due to the finite
size of the obstacles, the approximation in the treatment of reflection and diffraction in
dielectric material and also the assumption that surfaces are smooth and do not give
diffuse scattering. Besides, errors in the ray tracing algorithm in its code implementation
also appear. The code and the ray tracing algorithm can be never be sure that they run as
they were planned. Nevertheless, most times these errors are so evident that they are
very easy to identify and consequently to correct.
34
3.9 Summary
This chapter provides a brief summary on fundamental treatment about practical
and theoretical concepts towards propagation prediction and measurements. There
are three basic mechanisms in wireless system that caused the signal distorts and
give rise to signal fading, as well as additional signal propagation losses. The ray
tracing methods widely used technique to predict propagation effects in mobile and
personal communication environments. Due to the ability of the ray tracing
technique to obtain site specific channel information with taking into consideration
of 3D environment, it best for propagation prediction of radio wave.
CHAPTER 4
PROPAGATION PREDICTION AND MEASUREMENTS
4.1 Introduction
The measurement of the signal strength is to predict the performance of
wireless radio system. Because of the important to predict the performance the
wireless radio system, there have been researchers over past several decades. From
the three basic model classification explained in the site-pacific ray tracing prediction
model, which is one of the physical models, is the best choice for predict WLAN
802.11b radio signals strength. This chapter will discuss about the whole process,
from entering the database, running the simulator, to outputting the simulation and
measurement result in graph form for better analyze. The simulation will be done
using Site Specific Outdoor/ Indoor Prediction Code, Matlab will be used for
visualized the VPL code in order to show the propagating of signal, AirMagnet
Software used for measurement that installed into Laptop, the WLAN 802.11b card
was used for interface, Wireless Multi-client Bridge/AP WLAN 802.11b (AP) and
Patch antenna as the transmitter.
36
The site-specific ray tracing prediction models find dominant propagation
paths and exhibit accuracy efficiency over small ranges in urban area. These methods
model the physical paths and the mechanisms by which radio signals propagate from
transmitter to receiver.
In this chapter the site survey and an introduction towards the ray tracing
simulation technique that applied in this research. This propagation model is based
on VPL technique. It is developed by Liang and Bertoni [17]. The VPL technique
covers frequencies 100 MHz and above. The input parameters and databases for this
simulation tool are described. The Flowchart below shown the Methodology Process
Study on Signal Strength, Site Survey (802.11b)
AirMagnet WLAN Analyzer VPL Propagation Prediction (Databases needed for simulation)
Simulation and Visualization Matlab Result Comparison due to
Signal strength
Figure 4.1 Methodology Process
37
4.2 Site Survey
The related specific-site has been decided before ray tracing propagation
prediction. There are five blocks three floors building and one double floors building
(S15, S014, S13, S12, S11, S01). The Access point (AP) deployed at double floor
building (S01). There were 11 locations of receivers placed at five blocks three floors
building, whereas prediction and measurement will be carried out.
The WLAN 802.11b can give an access to home, businesses, etc [1], based of
this theory the ray tracing propagation prediction will de done. The contour around
the KTC hostels are looks like rolling hill geographically with the height of tree
significantly for the prediction and measurement testing. Figure 4.2, Figure 4.3,
show the photos that captured at the KTC hostel and Figure 4.4 shows the transmitter
location and receiver’s location.
Figure 4.2 Photo one of KTC Hostel
38
Figure 4.3 Rolling hills and Trees at KTC
Receiver Transmitter
Figure 4.4 Site Map Plan
39
4.3 Introduction to Ray Tracing Simulation Tool
The ray tracing simulation used in this research is based on vertical plane
launch technique developed by Liang and Bertoni (1998) [18]. The VPL frequencies
cover from 100 MHz and above. To know the concept of VPL technique see Figure
4.5, this shows half planes originating from a vertical line through the transmitter and
extending outward in one direction.
The VPL method takes account the nearly universal use of vertical walls in
building construction and differentiates the horizontal and vertical directions. In the
horizontal directions, 2D rays representing the vertical planes are launched from the
source. This method generates a binary tree at the point where the vertical plane
intersects an exterior face of building wall, with one plane continuing along the
incident direction and a second plane going off in the direction secular reflection as
shown in Figure 4.6.
Figure 4.5 Approximation 3D ray tracing using vertical plane
40
Figure 4.6 Rays Generation in horizontal plane
The plane that continues in the incident direction contains rays that propagate
directly over the building and rays that are diffracted over the buildings at its
horizontal edges. The plane that is spawned in the reflected direction contains rays
that are either specularly reflected from the building face or are diffracted at the top
horizontal edge of the wall. The path that a ray travels in the vertical direction is
found by examining the profile of all the building in the unfolded set of vertical plane
segments between the source and receiver and uses deterministic equation to
calculate the vertical displacement and received signal strength. A vertical plane
segment is considered to have illuminated the receiver if the ray intersects the
capture circle of a receiver and lies in the wedge of the illumination.
41
4.4 Algorithm of Simulation Software
To understand on how the VPL ray tracing simulation, Figure 4.7 shows the
ray architecture. Firstly, the functionalities used to determine if a vertical plane
intersects with the walls of building. Secondly, it determines whether a receiver will
be illuminated by the vertical plane and calculates the path loss associated with this
path. And thirdly, it finds the vertical building corners that will be necessary to
subsequently determine the diffracted field at a receiver.
In this ray-tracing program, each of the vertical plane generated from a source
goes through all of the above three modules. Several assumptions have been made in
this program. The VPL methods neglects diffuse scattering from, rays travel away
from building and receivers. These simplifications are made because it’s believed
that rays do not contribute to the total received power in a micro substantially
increase the model complexity and computation time.
42
Figure 4.7 Flow Chart of VPL method [18]
43
4.5 Databases for Simulation
The Vertical ray tracing simulation needs three types of databases to run the
simulation completely: building database, terrain, and receiver data base. The
building database gives relative locations of the building g within the prediction are,
whereas the receiver database contains the coordinates of the receiver points. Terrain
elevation database is used to model the effect of the ground on the ray path. Building
interior database in simulation it is only needed when a receiver or transmitter is
placed inside a building interior database is neglected.
4.5.1 Building database
The building database is a single American Standard Code for Information
Interchange (ASCII) file, which contains six columns of integer and floating-point
numbers that represent the building. The first column is a unique building identity
number that must be from the building number before and after. The X and Y
coordinates are entered as a relative position from an arbitrary fixed reference
position of the database coordinate system in next two columns. The Z coordinates
represent the height of the building above the reference plane, and the vertical
distance that building extends downward from Z are in the forth and fifth column.
Integer of the final columns in the database is representing the relative dielectric
constant. The recommended dielectric constant is 6 because it provides the least error
compared to other values [18].
Actually in the reality many of buildings have more complex composition.
The representation of these multi-structure building is similar to the case for the
single structure building. Each distinct Structure of the building is treated separately
and entered into the database in the same convention as in the single building even if
it is merely a part of complex building. The program also has the capability to handle
44
slant and peaked roofs for the buildings with the prediction area. The procedure for
handling this type of structure is similar to that for a flat roof except that we now
partition the roof of a single building into two slanted surfaces.
4.5.2 Receiver Database
The receiver file is also in multi-column format, with each line containing the
coordinates of a single receiver point. The first column represents the receiver
number and the following three columns represent the location of the receiver in x, y
and z coordinates, with respect to the building database coordinate system. The z
value of the receiver point is the height of the ground at the point and not the
absolute height of the receiver. The height of the receiver above the ground, which is
specified by the user in the command lines input, is added to the z value to get the
actual height of the receiver. The receiver database for simulation contains all the
possible locations for receiver.
4.5.3 Terrain Elevation Database
The other database that needed for the simulation is Terrain elevation
database is similar to a commercial used digital elevation map. It is representing the
terrain information to model the effect of the wound on the ray path. Coordinates z at
a particular (x, y) position is representing the height of the ground above the fix
reference. The complete file of these terrain points (x, y, z) cab be viewed as a grid
for simulation area. The terrain database should be large as possible to support the
rays propagating from the transmitter to the receiver.
This prediction area covers 215 X 235 meter . The same building database and
terrain database will be used in this simulation to predict and analyze the result on
2
45
different placements of the receiver points. The rays can be visualized using the
Matlab. Part of the actual databases, which are used for simulation, can be seen from
Appendix B.2.1 to C.2.3. Figure 4.8 shows the visualization of the building and
terrain databases for the software.
Figure 4.8 Databases Visualization
4.5.4 Antenna Radiation Pattern Database
The patch antenna has been used as a transmitter for transmits the signal. The
patch antenna with description and characteristics given in the Appendix A. As
needed in the ray tracing simulation, measurement of radiation pattern and gain of
antenna at 2.4 GHz has been carried out in an anechoic chamber. Two 2D patterns
have been measured. They are the x-z plane (elevation plane = 0), which
represents the principal E-plane and the x-y plane (azimuthal plane; = 2 ); which
represents the principal H-plane. The antenna radiation pattern database is presented
in Appendix B.2.4. Figure 4.9 (a) and (b) show the principal E-plane and H-plane
radiation pattern in polar –logarithmic form.
46
E-Plane (Elevation) Radiation pattern H-Plane (Azimuthal) Radiation Pattern
(a) (b)
Figure 4.9 Antenna radiation pattern. a) Principle E-plane b) Principle H-Plane
4.6 Simulation Command Input
In the VPL method the ray-tracing program is run in DOS mode where it
performs command line execution. Three arguments are required to initialize the
program as shown in the Table 4.1. The first argument is building database file name,
the second argument is receiver location file name and the third argument is output
file name. The associated directory of each file name must be defined correctly. After
the program has been initialized correctly, two lines of information are displayed as
second command input in Table 4.1. If the preprocessed input file name is not given
at the initialization stage, a question will prompt user to decide whether to have a
preprocess run again.
Then, the program starts requesting a series of input parameter as listed in Table
4.1.The input parameters are in Italic font. Details of each input command line and
explanations are available in Appendix B.1. The number of grids in x and y, grid
size, and transmitter coordinates are varying depending on the input information such
as building and receiver database information. Once all required input parameters
have been entered correctly, the program stars executing the ray-tracing simulation.
While the program is running, information is continuously displayed and scrolled up.
47
At the end of the simulation, the program is terminated end returned back to DOS
prompt again.
4.7 Output of the Prediction Tool
The prediction program generated 3 types of output. They are delay spread
output, power delay output, and ray paths information output. To produce both
output files the simulation has to do twice. On the other hand, ray path information
outputs that contain the individual ray paths for the receiver can be obtained together
with any of the two output files. Here, I give the example of result propagation wave
prediction because the propagation wave prediction for kolej KTC in progress due to
collect the databases.
Table 4.1: Command input simulation
No Command Input
1 C:\...........\runvpl<building database file><receiver location file><output file>
[<preprocessed input>]
2 Site Ware Techologies Inc.
Site Specific Propagation Prediction Tool, ver 1.0 28SEP99
No preprocessed file was specified.
Do you want to do a preprocess run? [y/n]:n
3 Enter the angle that the ray trace will increase by: 1
4 Enter the maximum number of reflection to calculate: 6
5 Enter the number of diffraction at vertical edges that will be computed: 2
6 Enter the number of operating frequencies: 1
7 Enter the value of frequency I [MHz] : 2440
8 Enter the Fresnel zone width used to test screens: 1
48
9 Consider terrain using digital elevation database? [y/n]: y
10 Enter the filename of digital elevation database? :
11 Impulse response or power & delay spread output? [ i/p] :p
12 Is directional antenna used? [ y/n] :
13 Output individual ray path data? [y/n]: n
14 Enter the x coordinate of the transmitter:
15 Enter the y coordinate of the transmitter:
16 Enter the z coordinate of the transmitter:
17 Number of different transmitter heights at ( x, y, z): 1
18 Enter height 1 of the transmitter: 0.3
19 Enter the height of the receivers: 0.3
20 Use polynomial fit or read data file for the radiation pattern? [p/f]:f
21 Enter the name of radiation pattern data file for 2440MHz: an.txt
22 Enter the antenna gain at 2440MHz<dB>:12
23 Enter tilt angle of the main beam relative to horizontal<E-plane>:0
24 Enter azimuth angle of the main beam relative to due east<H-plane>:0
4.7.1 Impulse Response Output
In the Impulse Response Output result, the individual path information
according to the receiver. The first line is the receiver number and the x, y, and z
coordinates of the receiver. Listed below the receiver are the individual ray
contributed at the receiver. The columns represent the angle at which the ray left the
transmitter and path length of the ray in meters, the propagation time seconds and the
predicted path loss in dB. The fifth and final column is numerical representation of
the type or class of ray. Example of impulse response output is displayed in Figure
4.10.
49
4.7.2 Power and Delay Spread Output
The power and delay spread output file contains the predicted path loss for
receiver, a section that contains the different components that add together to get the
total power received, rms delay spread and mean excess delay. The results for each
receiver are listed in multicolumn format on a single line with brief heading
describing the program execution parameters. The fifth column is the predicted path
loss value in dB. The column after in between vertical line ( ) separators is
breakdown of the total power received into its separate components. The first two
columns indicate value in watt and number of LOS rays. The second two columns
show value in watt and number of reflected rays that arrived at receiver. The third
and forth two columns indicate value in watt and number of rays that undergo 1 and
2 vertical edge diffraction beside on top of reflection. The final two columns of data
represent the rms delay spread and the mean excess delay in seconds. Figure 4.11 is
an example of power and delay spread output. Complete output for the prediction in
the related sites is given in Appendix B.2.
4.7.3 Ray Path Information Output
The ray path information is stored in separate file for each receiver every
simulation. These outputs generate details of each ray path that arrive at a particular
receiving poin. There are a list of information x, y, z coordinates for all ray segments
that combines together to form a complete path from source to receiving point see
Figure 4.12. The number of ray paths that arrives at particular receiving point on the
simulation output.
50
1 10.0 20.0 30.3
3.05 6.20 1.099552 71.71 2.39e-007 -110.13 1
2 40.0 5.0 30.3
5.08 1.94 1.307271 68.34 2.28e-007 -113.24 1
3 40.0 60.0 30.3
1.47 4.61 0.577952 84.83 2.83e-007 -106.59 1
Rayscontributedat receiver
Propagation
Classof ray
Path Loss (dB)
Time (seconds)
Pathlength(meter)
Angle
Receivernumber andcoordinates
Figure 4.10 Example of impulse response output
1 10.0 20.0 30.3 -110.13 | 0.00e+000 0 9.70e-012 1 0.00e+000 0 0.00e+000 0 | 4.29e-011 2.39e-007
2 40.0 5.0 30.3 -113.24 | 0.00e+000 0 4.74e-012 1 0.00e+000 0 0.00e+000 0 | 4.09e-011 2.28e-007
3 40.0 60.0 30.3 -106.59 | 0.00e+000 0 2.19e-011 1 0.00e+000 0 0.00e+000 0 | 5.08e-011 2.83e-007
4 80.0 90.0 30.3 -91.58 | 0.00e+000 0 6.95e-010 1 0.00e+000 0 0.00e+000 0 | 7.34e-011 4.09e-007
ReceiverCoordinate
ReceiverNumber
PathLoss
Power received for different components
Rms delay spread
MeanExcessDelay
Figure 4.11 Example of power delay spread output
51
#71.71 -110.13
35.20 17.80 2.80
Length and path loss of each ray
Coordinateof each ray 20.00 19.13 50.00
10.00 20.00 30.30
#68.34 -113.24
35.20 17.80 2.80
38.19 10.00 50.00
40.10 5.04 30.30
#84.83 -106.59
35.20 17.80 2.80
36.48 30.00 50.00
39.64 60.04 30.30
#122.62 -91.58
35.20 17.80 2.80
42.82 30.00 50.00
80.23 89.86 30.30
Figure 4.12 Example of ray path information output
4.8 Result Visualization
Matlab is a high-level technical computing language and interactive
environment for algorithm development, data visualization, data analysis, and
numerical computation. It includes a set of low-level file input output (I/0) functions
that are based on the I/0 functions of the American National Standards Institute
(ANSI) Standard C Library.
52
Here, a Matlab Code that is similar to C language is written to extract data
from the numerical input and output files from the VPL ray tracing software. The
data are then presented in a 3D graphic display. The Matlab code written is presented
in Appendix B.4. Figure 4.13 shows the window of Matlab when the written Matlab
running.
Figure 4.13 VPL ray tracing visualization using Matlab
53
4.9 Filed Measurement
As with any other radio propagation model, ray tracing techniques need to be
verified and enhanced with actual RF measurements, which are representative of the
possible installation scenarios. The AirMagnet WLAN Analyzer was used to measure the
signal strength of 11 receivers at Tun Chancellors Hostels.
4.9.1 AirMagnet WLAN Analyzer
The AirMagnet Laptop WLAN Analyzer Figure 4.14 is the industry's most
advanced stand-alone solution for wireless security and troubleshooting. Built from
the ground up to meet the challenges of 802.11a/b/g WLANs, the AirMagnet Laptop
provides a direct automated analysis of any WLAN, proactively detects over 130+
network problems, and delivers a set of active wireless troubleshooting tools that
simply aren't available anywhere else.
Figure 4.14 AirMagnet Laptop Analyzer
54
4.9.2 Field Measurement Flow Chart
Figure 4.15 Field Measurement Flow Chart
There were 11 locations of receivers whereas the signal strength had been
measured. From the 11 locations of receivers we have to identify the LOS and
NLOS. The effect of building can be detected using the concept of LOS and NLOS
and the degradation of signal strength can be obtained.
55
4.9.3 The AirMagnet WLAN Analyzer Measurement
The AirMagnet WLAN Analyzer measurement had been carried out from 11
locations of receivers. The signals transmit from building S01 to S15, S14, S13, S12
and S11 buildings, the transmitter placed on rooftop of building S01. The Figure
4.16 shows transmitter (AP) and receivers for AirMagnet WLAN Measurement,
Figure 4.18 shows the Patch Antenna for the signal transmission and Figure 4.19 the
KTC hostel, S15 and S14 view from transmitter location (S01).
The Wireless Multi-Client Bridge/Access Point operates in the 2.4 GHz
frequency spectrum supporting the 802.11b (2.4GHz, 11Mbps) wireless standard
sees Figure 4.17
Figure 4.16 Transmitters and Receiver Location
56
Figure 4.17 Wireless Multi-client Bridge/AP
4.18 Patch Antenna
Figure 4.19 S15 and S14 view from S01
57
4.10 Summary
This chapter presents the propagation prediction and measurements in Tun
Chancellor Hostel. There are brief explanations about the VPL method as a
prediction tool and AirMagnet WLAN Analyzer as a measurements tool. The Matlab
has been used for code visualization. The ability to understand the concepts of
theoretical and practical VPL tool and the AirMagnet WLAN Analyzer tool can be
used for the propagation prediction and measurements in Tun Chencellor Hostel.
CHAPTER 5
SIMULATION AND MEASUREMENTS RESULTS
5.1 Introduction
This chapter will discuss about the simulation and measurement result. Actually
there are two parts in this project: simulation and measurements. From the simulation
part we can study the propagation of wave whereas the VPL ray code can be visualized
using the Matlab and then study the signal strength (in unit of dBm) for each receiver
from different of location as well as the effect on building. The field measurement is
carried out using the AirMagnet WLAN Analyzer tool. In the theory there are so many
factors that can cause the degradation of signal strength in an outdoor environment, but
in this project we just concentrated about the effect on building.
Before we go further on the result analysis between simulation and measurement,
the results of prediction tool and visualization using Matlab have to discuss and also the
signal strength results of receivers from AirMagnet WLAN Analyzer also will be
discussed.
59
5.2 The Vertical-Plane-Launch output and code visualization
In order to prove the existing of degradation signal strength in an outdoor
environment, the location of receiver has to be in Line-of-Sight (LOS) or Non-Line-of
Sight (NLOS). There are four types databases needed to run this simulation completely:
terrain database, building database, receiver database and antenna radiation pattern
database. Figure 5.1 Shows the power and delay spread output from the simulation tool.
From chapter 4 the power and spread out has been explained in detail and from this
output we can obtain the power received sees Figure 5.2.
Figure 5.1 Power and delay spread output
60
Figure 5.2 Characteristics Power and spread out
The Simulation code in Figure 5.1 had been visualized using the Matlab. The
Matblab code that is similar to C language is written to extract data from the input and
output files from VPL ray tracing software. The Figure 5.3 shows the window for ray
path visualization at the four blocks of building whereas 11 location of receiver placed
LOS and NLOS. In order to see more clearly the effect of building from the ray path
visualization, Figure 5.4 shows the reflection and diffraction of rays due to building
effect at locations 9, 10 and 11.
61
Figure 5.3 Ray paths visualization for buildings S15, S14, S13, S12, S11and S01
Figure 5.4 The reflection and diffraction of ray at locations 9, 10 and 11
62
5.3 AirMagnet and characteristics of signal strength
The patch antenna (directional antenna) is placed above the roof at building S01
and transmits the signal over the five blocks S15, S14, S13, S12 and S11. There are 11
location receiver placed at the four blocks. By using the AirMagnet WLAN Analyzer
the signal strength can be obtained by measuring signal strength at the 11 location of
receiver that had been decided, the AP MAC address is 00026f370AB2 and SSID
WWC2. Figures 5.5 (a), 5.5 (b) show the graph of signal strength for a certain length
times (for 45 seconds duration with a 5 seconds interval) in location 1 and 2.
Signal strength (dBm)
-90
-88
-86
-84
-82
-800 10 20 30 40 50
Time (sec)
Pr (d
Bm
)
Signal (dBm)
Figure 5.5 (a) Signal strength versus time at location 1
Signal Strength (dBm)
-84
-82
-80
-78
-76
-740 10 20 30 40 50
Time (sec)
Pr (d
Bm
)
Series1
Figure 5.5 (b) Signal strength versus time at location 2
63
From the graph in Figure 5.5 (a), it shows the signal strength fluctuated around (1 – 3 dB)
for every 5 seconds for LOS. Also from the figure 5.5 (b) shows the signal strength
fluctuated around 1-8 (dB) for every 5 seconds for NLOS, here the existing of building
effect can cause the degradation of signal strength. In order to verify the all location,
Figure 5.6 below show the average power received at 11 locations receiver, this graph
gives the characteristic of signal strength for each location.
signal strength
-100
-80
-60
-40
-20
00 5 10 15
Location
Ave
rage
pow
er
rece
ived
(dBm
)
Series1
Figure 5.6 Average power received Vs location
5.4 The simulation and measurements result
The Table 5.1 shows the result of signal strength between the simulation and
measurement at 11 locations receiver that has a different distance between each other
and also show the types of propagation whether LOS or NLOS. Both simulation and
measurement in LOS or NLOS, in order to discuss the occurrence of building effect by
referring the Table 5.1 the highest signal strength for the simulation at location 2 (LOS)
and the lowest at location 10 (NLOS), but from the measurement the highest signal
64
strength at location 3 (LOS) and the lowest at location 10 (NLOS) these both quietly
match each other.
Location Types Distance Path Loss (dB)
Signal Strength (Simulation )
Signal Strength (Measured)
1 NLOS 127 -62.16 -64 dBm -70 dBm 2 LOS 117 -57.63 -55 dBm -80 dBm 3 LOS 128 -58.28 -57 dBm -71 dBm 4 LOS 133 -61.38 -63 dBm -72 dBm 5 NLOS 116 -67.4 -75 dBm -75 dBm 6 NLOS 140 -91.83 -124 dBm -82 dBm 7 LOS 119 -57.73 -56 dBm -86 dBm 8 NLOS 129 -59.72 -59 dBm -83 dBm 9 NLOS 143 -89.54 -119 dBm -66 dBm
10 NLOS 168 -92.41 -125 dBm -87 dBm 11 NLOS 157 -61.38 -63 dBm -67 dBm
Table 5.1 Simulation and Measurement
Then a measurement of signal strength for different location that have different
distance each other have been carried out. The result is shown in Figure 5.7.
Distance-Signal Strength Chart
-150
-100
-50
00 50 100 150 200
meter
dB
m
SimulationMeasurementLinear (Measurement)Linear (Simulation)
Distance-Signal Strength Chart
-150
-100
-50
00 50 100 150 200
meter
dB
m
SimulationMeasurementLinear (Measurement)Linear (Simulation)
Figure 5.7 Signal strength as a function of distance
65
Distance - Signal Strength Chart
-150
-100
-50
0
0 50 100 150 200
metersd
Bm
Pr Linear (Pr )
Figure 5.8 Best –Fit-line
From the graph Figure 5.7 the gradient of signal strength varies over distance,
mostly the nearest location gave a highest signal strength and sometimes vice-versa
because of the building effect that considered for degradation of signal strength. The
simulation and measurement signal strength for all location actually quite match each
others, but a slightly different occurs for location 6, location 9 and location 10. Figure
5.8 shows best-fit-line between simulation and measurement over distance using line
regression. The different results between simulation and measurements because in the
simulation (VPL) there are two kinds of errors can be distinguished, that are the input
data and errors due to computer UTD and ray tracing approach.
Among the input data errors, the inaccuracies in the topographical and
morphological data of the urban scene and antenna input data such as radiation pattern,
position and orientation can be mentioned. The inaccuracy of the building database and
the lack information about material characteristic may cause the discrepancies founded
between simulation and measurements result. Figure 5.9 shows the measurement of
signal strength in Tun Chancellor Hostel
66
Figure 5.9 shows the measurement of signal strength in Tun Chancellor Hostel
comparison measurement & simulation Signal strength (dBm)
-150
-100
-50
01 2 3 4 5 6 7 8 9 10 11
Location
Pr (d
Bm
)
SimulationMeasurement
Figure 5.10 Comparison result of Measurement and simulation of signal strength
Figure 5.10 is the comparison result of measurement and simulation of signal strength
from transmitter at S01 building to 11 locations of receiver. The results show it quite
match other accept at location 6, 9 and 10.
Signal strength can be used to determine location and tracking function because
the different value of signal strength for every location can show us whether that
location received a good signal or not. The good signal strength meaning that location
67
has a good performance of WLAN and vice-versa. By knowing a good and worst signal
strength each of location we can determine whether the part of location that has a worst
signal need any deployment of access point or not to ensure that a more good coverage
and performance everybody can get. From this project we can say that the building can
affect the performance of signal although there are other parts of environment also affect
the performance signal that had been proved from other researchers.
5.5 Summary
This chapter provides the simulation and measurements result, the Matlab
successfully visualized the VPL code and show the direction of signal to all receivers
and also the effect on building. There are different levels of signal strength for each
receiver due to NLOS and LOS. The comparison between simulation and measurements
had been done and analyzed. The best-fit-line had been plotted to show the relationship
between simulation and measurements result. There are factors that affected the result
between simulation and measurements that have been discussed in this chapter.
CHAPTER 6
CONCLUSION AND FUTURE WORK
6.1 Conclusion
The objectives of this project have been achieved. The study on the signal
strength and the effect on building have been done and discussed in previous chapters
respectively. The objective to measure and simulate signal strength in Tun Chancellor
Hostel and compare it has been archived and then the ray tracing code has been
visualized using Matlab and shown the direction of signal and the effect on building .
The prediction and measurements give a slightly different of results because
some factors that we have to be considered, regarding the ray tracing modeling accuracy,
there are two kinds of error can be distinguished, that are the input data and errors due to
computer UTD and ray tracing approach. Among the input data errors, the inaccuracies
the topographical tracing approach. Among the input data errors, the inaccuracies in the
topographical and morphological data of the urban scene and antenna input data such as
radiation pattern, position and orientation can be mentioned. The inaccuracy of the
building database and the lack of information about material characteristic may cause
69
the discrepancies founded between simulation and measured results. For the
measurements using the AirMagnet WLAN Analyzer the ability to use this tool in the
proper way can give an accurate result and vice-versa.
Actually it is found that the simulation software: Site Specific Outdoor/ Indoor
propagation Prediction Code is a highly reliable and accurate prediction tool, Since gives
simulation results that are closer to the value given by measurement result, some of
results between simulation and measurements gives a slightly different this problem
occurs because there are two kinds of errors can be distinguished, that are the input data
and errors due to computer UTD and ray tracing approach.
6.2 Future Work
The leaves and branches of tress offer significant attenuation to UHF and
microwave signals. Foliage loss or vegetation loss is very complicated topic that many
parameters and variations. The sizes of leaves, branches, and trunks, the density and
distribution of leaves, branches, and trunks, and the height of tress relative to the antenna
height will all be considered.
In this research I didn’t include the vegetation effect or foliage effect due to time
constraint. For the future work it is best if it can be realize and include for further works
of this related research.
70
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Channel: Comparison Criteria and Results. IEEE Transactions on Antennas and
Propagation. 2001. 49(7): 1101-1110
36. El-Sallabi, H. M., Liang, G., Bertoni, H. L., Rekanos, I. T. Vainikainen, P.
Influence of Diffraction Voefficient and Corner Shape on Ray Prediction of
power and Delay Spreads in Urban Microcells. IEEE Transactions on Antenna
and Propagation. May 2002. 50(5): 703-712.
37. De Backer, B., Borjeson, H., De Zutter, D. and Olyeslager, F. Propagation
Mechanisms for UHF Wave Transmission Through Walls and Windows. IEEE
Transactions on Vehicular Technology. September 2003. 52(5): 1297-1307.
38. Toscano, A., Bilotti, F. and Vegni, L. Fast Ray-Tracing Method for Modeling
Electromagnetic Field Prediction in Mobile Communications. IEEE Transactions
on Magnetics. 2003. 39(3): 1238-1241.
75
39. Yang, C. F., Wu, B. C. and Ko, C. J. A Ray-Tracing Method for Modeling Indoor
Wave Propagation and Penetration. IEEE Transactions on Antennas and
Propagation. 1998. 46(6): 907-919.
40. Chen, S. H. and Jeng, S. K. An SBR/image Approach for Radio Wave
Propagation in Indoor Environments with Metallic Furniture. IEEE Transactions
on Antennas and Propagation. 1997. 45(1): 98-106.
41. Costa, E. Ray Tracing Based on the Method of Images for Propagation Simulation
in Cellular Environments. 10th International Conference Antennas and
Propagation. April 14-17, 1997. Edinburgh: IEEE. 1997. 204-209.
76
Appendix A: The Patch Antenna description and characteristics
77
Appendix B: Ray Tracing Propagation Prediction
B.1 Simulation Command Input
Site Specific Code is available for different types of simulation. The runtime
parameters will be determined from the command line inputs during the simulation and
the simulation results are different depending on the input. An example of running the
prediction program is shown in figure B.1 Firstly; we begin the execution of the
prediction program by typing the following:
runvpl <building file> <receiver points file> <output file> [<preprocessed input
file>]
The command inputs are as follow:
Enter the angle that the ray trace will increment by:
The question prompts the user for the incremental angle between successive rays when
launched from a source. A number which is a integer fraction of 360o should be entered.
Enter the maximum number of reflections to calculate:
This parameter set the maximum number of reflections that a ray will undergo during
the execution of the program. The number does not represent the total number of
reflections but rather the number of reflections allowed for each branch between vertical
diffractions, i.e. if this number is 6 and there is 1 vertical edge diffraction, then 6
reflections are calculated before and after the diffraction. The input should be an integer
which can be greater than or equal to 0. Currently there is no upper limit.
78
Enter the number of diffractions at vertical edges that will be computed:
This input represents the number of levels of vertical edge diffractions that the program
will perform. Only 0, 1 or 2 are valid inputs for this parameter.
Enter the number of operating frequencies:
This question prompts the user for the number of frequencies that the program will
predict for simultaneously. Since the geometrical ray trace is identical at all frequencies
it is possible to perform one ray trace while producing results at a number of frequencies.
The responds to this question should be an integer number. Currently there is no upper
limit to the number of frequencies that can by simultaneously spec-
Enter the value of frequency 1 [MHz]:
. . .
Enter the value of frequency n [MHz]:
This question will be asked n number of times for each frequency(ies) in MHz de
pending on the number of frequencies entering for the previous question. It is the usual
convention to enter the frequencies from lowest to highest although this is not absolutely
required.
Enter the Fresnel zone width used to test screens:
The answer to this question sets the width of the Fresnel zone use within the program.
The program uses this criterion to test which screens are taken into accounted when
calculating diffraction over buildings. The input represents the Fresnel width with input
of 1 representing the first Fresnel zone. Any positive real number may be entered, while
entering 0 represents zero width.
Consider terrain using digital elevation database? [y/n]:
The parameter requires an alpha input with a case insensitive y or Y representing yes
and n or N representing no. Answer yes if actual terrain data from a file will be used.
Enter the filename of digital elevation database:
The name of the file that contains the terrain elevation database should be entered.
79
The complete path of the file can be entered to specify the relative location of the file.
Impulse Response or Power & Delay Spread Output? [i/p]:
This question prompts the user for one of 2 possible alpha responses which determines
the type of output that is produce by the program. A lowercase "i" response will direct
the program to produce a impulse response output while a lowercase "p" will give an
output that states the total power received at each receiver point.
Is a directional antenna used? [y/n]:
This question asks if a directional antenna is used in the prediction. If the response is an
affirmative then additional question regarding the radiation pattern, gain and direction
will be asked later on.
Output individual ray path data? [y/n]:
This question asks the user whether individual ray paths for each receiver point should
be output to a file so that a visual picture can be constructed. The ray paths for each
receiver points are outputted into separate files labeled "ray paths rx#" where # is the
receiver number. Refer to the chapter on the output file format for details and
information contain in the ray paths file.
Enter the x coordinate of the transmitter:
Enter the y coordinate of the transmitter:
Enter the z coordinate of the transmitter:
These questions prompt for a numerical input and set the location of the transmitter
within the program. The inputs can be any number which can include negative
coordinates for the transmitter. The value for the z coordinate should be the value of z at
ground level at the (x,y) location. If the transmitter is on a rooftop location the z value
should be the z of the position at the top of the roof (i.e. the height of the roof) above
some fix reference.
80
Number of different transmitter heights at (x,y,z):
This question asks the user to enter the number of transmitter heights that the program
will simultaneously simulated.
Enter height 1 of the transmitter:
……………
Enter height n of the transmitter:
This question prompts the user for the height(s) (in meters) of the transmitter above the
ground at transmitter location (x,y,z) which was entered previously. This value is added
to the z location value to obtain the absolute location of the transmitter in a 3dimensional
Cartesian coordinates system.
Enter the height of the receivers:
This question prompts the user to enter the height (usually in meters) of the receiver(s)
above the ground. This value is added to the z value of each receiver point which exists
in the receiver points in the receiver database.
The following set of questions appears after the previous set of questions if yes is
answered for the question regarding whether a directional is used.
Use polynomial fit or read data file for the radiation pattern?:[p/f]
This question prompts the user for the polynomial order for the radiation pattern fit in
the H field plane.
Enter the name of the radiation pattern data file for xxx MHz:
The name of the file that contains the antenna radiation pattern database should be
entered. The complete path of the file can be specifying the relative location of the file.
Enter the antenna gain at xxx MHz(dB):
This question sets the antenna gain for the antenna used at the xxx frequency.
81
Enter the tilt angle of the main beam relative to horizontal (E-plane):
This question prompts the user to set the tilt of the boresight of the radiation pattern in
the E plane. The tilt angle is specified in degrees relative to a horizontal boresight with a
positive value is used for an upward tilt and a negative value for a downward tilt.
Enter the azimuth angle of the main beam relative to due east (H-plane):
This question prompts the user for the boresight azimuth direction relative to the positive
x-axis and is specified degrees.
Figure B.1 Display of Program
82
B.2 Databases for simulation
.2.1 Building Database (Part of bs.txt)
70.8 143.7 21.9 10.1 6
B
1
1 66 150.7 21.9 10.1 6
1 61.8 157 21.9 10.1 6
1 61.2 158 20.72 7.62 6
1 59.6 160.6 20.72 7.62 6
1 50.3 155.1 20.72 7.62 6
1 44.7 164.1 20.72 7.62 6
1 66.9 177.6 20.72 7.62 6
1 74.3 166.7 20.72 7.62 6
1 69.1 163.6 20.72 7.62 6
1 70.9 161.9 21.9 10.1 6
1 79 167.3 21.9 10.1 6
1 86.2 157.8 21.9 10.1 6
1 76.8 152.9 21.9 10.1 6
1 79.5 148.4 21.9 10.1 6
2 47.4 159.3 24.47 10.97 6
2 44.7 164.1 20.72 7.62 6
2 66.9 177.6 20.72 7.62 6
2 69.8 173.7 24.47 10.97 6
3 50.3 155.1 20.72 7.62 6
3 47.4 159.3 24.47 10.97 6
3 69.8 173.7 24.47 10.97 6
3 74.3 166.7 20.72 7.62 6
3 69.1 163.6 20.72 7.62 6
3 61.2 158 20.72 7.62 6
3 59.6 160.6 20.72 7.62 6
4 63.7 153.8 25.21 13.41 6
83
4 62 156.5 21.9 10.1 6
4 70.9 161.9 21.9 10.1 6
4 79 167.3 21.9 10.1 6
4 81.4 164.5 25.21 13.41 6
5 70.8 143.7 21.9 10.1 6
5 66 150.7 21.9 10.1 6
5 63.7 153.8 25.21 13.41 6
5 81.4 164.5 25.21 13.41 6
5 86.2 157.8 21.9 10.1 6
5 76.8 152.9 21.9 10.1 6
5 79.5 148.4 21.9 10.1 6
5 70.8 143.7 21.9 10.1 6
6 66 150.7 15.15 3.35 6
6 64.2 149.7 15.15 3.35 6
6 60 155.9 15.15 3.35 6
6 61.8 157 15.15 3.35 6
7 33.6 120 21.4 10.1 6
7 31.4 122.7 21.4 10.1 6
7 22.4 115.7 21.4 10.1 6
7 15.6 125 21.4 10.1 6
7 24.4 131.9 21.4 10.1 6
7 23.5 133.4 20.22 7.62 6
7 18.5 129.5 20.22 7.62 6
7 10.4 140.7 20.22 7.62 6
7 31.5 156.9 20.22 7.62 6
7 37.5 148.5 20.22 7.62 6
7 29.3 141.9 20.22 7.62 6
7 31.1 139.4 20.22 7.62 6
7 31.8 138.4 21.4 10.1 6
7 36.2 132.4 21.4 10.1 6
7 40.8 125.4 21.4 10.1 6
84
8 13.4 136.5 23.57 10.97 6
8 10.4 140.7 20.22 7.62 6
8 31.5 156.9 20.22 7.62 6
8 34.5 152.7 23.57 10.97 6
9 23.5 133.4 20.22 7.62 6
9 18.5 129.5 20.22 7.62 6
9 13.4 136.5 23.57 10.97 6
9 34.5 152.7 23.57 10.97 6
9 37.5 148.5 20.22 7.62 6
9 29.3 141.9 20.22 7.62 6
9 31.1 139.4 20.22 7.62 6
10 34 135.4 24.71 13.41 6
10 17.5 122.5 24.71 13.41 6
10 15.6 125 21.4 10.1 6
10 24.4 131.9 21.4 10.1 6
10 32.2 138 21.4 10.1 6
11 33.6 120 21.3 10.1 6
11 31.4 122.7 21.4 10.1 6
11 22.4 115.7 21.4 10.1 6
11 17.5 122.5 24.61 13.41 6
11 34 135.4 24.61 13.41 6
11 36.2 132.4 21.4 10.1 6
11 40.8 125.4 21.4 10.1 6
11 33.6 120 21.4 10.1 6
12 31.8 138.4 14.65 3.35 6
12 33.5 139.6 14.65 3.35 6
12 37.9 133.7 14.65 3.35 6
12 36.2 132.4 14.65 3.35 6
13 106.9 169.8 21.9 10.1 6
13 104.6 173 21.9 10.1 6
13 95.6 166.1 21.9 10.1 6
85
13 89.2 175.5 21.9 10.1 6
13 97.8 182.3 21.9 10.1 6
13 96.8 183.8 21.12 7.62 6
13 91.9 179.9 21.12 7.62 6
13 84.1 191.1 21.12 7.62 6
13 104.9 207.3 21.12 7.62 6
13 110.9 199.3 21.12 7.62 6
13 102.4 192.1 20.12 7.62 6
13 105.2 188.8 21.9 10.1 6
13 106.8 190.1 15.15 3.35 6
13 111.3 184.1 15.15 3.35 6
13 109.6 182.8 21.9 10.1 6
13 114.5 175.9 21.9 10.1 6
14 86.8 186.9 24.17 10.97 6
14 84.1 191.1 21.9 7.62 6
14 104.9 207.3 21.9 7.62 6
14 107.9 203.1 24.17 10.97 6
15 96.8 183.8 20.82 7.62 6
15 91.9 179.9 20.82 7.62 6
15 86.8 186.9 24.17 10.97 6
15 107.9 203.1 24.17 10.97 6
15 110.9 199.3 20.82 7.62 6
15 102.4 192.1 20.82 7.62 6
15 104.4 189.8 20.82 7.62 6
16 91 172.7 25.21 13.41 6
16 89.2 175.5 21.9 10.1 6
16 97.8 182.3 21.9 10.1 6
16 105.5 188.4 21.9 10.1 6
16 107.3 185.7 25.21 13.41 6
17 106.9 169.8 21.9 10.1 6
17 104.6 173 21.9 10.1 6
86
17 95.6 166.1 21.9 10.1 6
17 91 172.7 25.21 13.41 6
17 107.3 185.7 25.21 13.41 6
17 109.6 182.8 21.9 10.1 6
17 114.5 175.9 21.9 10.1 6
17 106.9 169.8 21.9 10.1 6
18 105.2 188.8 15.15 3.35 6
18 106.8 190.1 15.15 3.35 6
18 111.3 184.1 15.15 3.35 6
18 109.6 182.8 15.15 3.35 6
19 145.6 192 21.9 10.1 6
19 143 200.1 21.9 10.1 6
19 140.8 207.2 21.9 10.1 6
19 139.5 211.1 21.12 7.62 6
19 129.2 208.5 21.12 7.62 6
19 126.2 218.2 21.12 7.62 6
19 151.5 225.9 20.72 7.62 6
19 155.8 212.8 20.72 7.62 6
19 149.8 210.9 20.72 7.62 6
19 150.3 209.5 21.9 10.1 6
19 161.2 212.2 21.9 10.1 6
19 164.7 201.7 21.9 10.1 6
19 154.1 198.4 21.9 10.1 6
19 154.7 195 21.9 10.1 6
20 127.6 213.5 24.47 10.97 6
20 126.2 218.2 21.12 7.62 6
20 151.5 225.9 21.12 7.62 6
20 153.1 221 24.47 10.97 6
21 140.5 208.3 21.12 7.62 6
21 139.5 211.1 21.12 7.62 6
21 129.2 208.5 21.12 7.62 6
87
21 127.6 213.5 24.47 10.97 6
21 153.1 221 24.47 10.97 6
21 155.8 212.8 20.72 7.62 6
21 149.5 210.9 20.72 7.62 6
22 141.8 203.8 25.21 13.41 6
22 141 206.7 21.9 10.1 6
22 150.3 209.5 21.9 10.1 6
22 161.2 212.2 21.9 10.1 6
22 162.1 209.3 25.21 13.41 6
23 145.6 192 21.9 10.1 6
23 143 200.1 21.9 10.1 6
23 141.8 203.8 25.21 13.41 6
23 162.1 209.3 25.21 13.41 6
23 164.7 201.7 21.9 10.1 6
23 154.1 198.4 21.9 10.1 6
23 154.7 195 21.9 10.1 6
23 145.6 192 21.9 10.1 6
24 143 200.1 15.15 3.35 6
24 141 199.8 15.15 3.35 6
24 138.8 206.7 15.15 3.35 6
24 140.8 207.2 15.15 3.35 6
25 187.2 199.4 22.2 10.1 6
25 187.5 203.3 22.2 10.1 6
25 176.6 204.4 22.2 10.1 6
25 178.1 215.7 22.2 10.1 6
25 189.1 214.8 22.2 10.1 6
25 189.4 216.5 21.12 7.62 6
25 183.1 217 21.12 7.62 6
25 184.8 230.8 21.12 7.62 6
25 211.2 228.5 21.12 7.62 6
25 210 218.2 21.12 7.62 6
88
25 199.5 218.9 21.12 7.62 6
25 199 214.5 22.2 10.1 6
25 198.2 207.2 22.2 10.1 6
25 197.3 198.7 22.2 10.1 6
26 184.1 225.6 24.47 10.97 6
26 184.8 230.8 21.12 7.62 6
26 211.2 228.5 21.12 7.62 6
26 210.6 223.3 24.47 10.97 6
27 189.4 216.5 21.12 7.62 6
27 183.1 217 21.12 7.62 6
27 184.1 225.6 24.37 10.97 6
27 210.6 223.3 24.37 10.97 6
27 210 218.2 21.12 7.62 6
27 199.5 218.9 21.12 7.62 6
27 199 215.7 21.12 7.62 6
28 177.6 212.5 25.51 13.41 6
28 178.1 215.7 22.2 10.1 6
28 189.1 214.8 22.2 10.1 6
28 198.9 214 22.2 10.1 6
28 198.5 210.9 25.51 13.41 6
29 187.2 199.4 22.2 10.1 6
29 187.5 203.3 22.2 10.1 6
29 176.6 204.4 22.2 10.1 6
29 177.6 212.5 25.51 13.41 6
29 198.5 210.9 25.51 13.41 6
29 198.2 207.2 22.2 10.1 6
29 197.3 198.7 22.2 10.1 6
29 187.2 199.4 22.2 10.1 6
30 199 214.5 15.45 3.35 6
30 201 214.4 15.45 3.35 6
30 200.2 207 15.45 3.35 6
89
30 198.2 207.2 15.45 3.35 6
31 101.2 44.7 13.115 6.1 6
31 89.1 49.7 13.115 6.1 6
31 82.7 65.3 13.115 6.1 6
31 88.9 78.3 13.115 6.1 6
31 111.3 86.4 13.115 6.1 6
31 118.3 78.9 13.115 6.1 6
31 125 81.4 13.115 6.1 6
31 124.7 92 13.115 6.1 6
31 147.3 98.7 13.115 6.1 6
31 159.3 94.1 13.115 6.1 6
31 165.8 76.8 13.115 6.1 6
31 160.1 65.2 13.115 6.1 6
31 165.9 50.4 13.115 6.1 6
31 177.7 44.3 13.115 6.1 6
31 181.3 36.4 13.115 6.1 6
31 175.6 23.9 13.115 6.1 6
31 154.3 17.9 13.115 6.1 6
31 147 24.1 13.115 6.1 6
31 139.5 21.5 13.115 6.1 6
31 139.9 11.6 13.115 6.1 6
31 116.1 3.4 13.115 6.1 6
31 103.3 9.4 13.115 6.1 6
31 97.6 26.5 13.115 6.1 6
31 102.8 37.9 13.115 6.1 6
32 82.7 65.3 13.115 6.1 6
32 88.9 78.3 13.115 6.1 6
32 111.3 86.4 13.115 6.1 6
32 103.7 65.2 20.265 13.25 6
32 89.1 49.7 13.115 6.1 6
33 111.3 86.4 13.115 6.1 6
90
33 118.3 78.9 13.115 6.1 6
33 122.9 63.7 13.115 6.1 6
33 121.7 51.4 13.115 6.1 6
33 103.7 65.2 20.265 13.25 6
34 121.7 51.4 13.115 6.1 6
34 101.2 44.7 13.115 6.1 6
34 89.1 49.7 13.115 6.1 6
34 103.7 65.2 20.265 13.25 6
35 125 81.4 13.115 6.1 6
35 124.7 92 13.115 6.1 6
35 142.5 78.1 16.565 9.55 6
35 140.6 62.5 13.115 6.1 6
35 130 68.8 13.115 6.1 6
36 124.7 92 13.115 6.1 6
36 147.3 98.7 13.115 6.1 6
36 159.3 94.1 13.115 6.1 6
36 165.8 76.8 13.115 6.1 6
36 142.8 78.1 16.565 9.55 6
37 165.8 76.8 13.115 6.1 6
37 160.1 65.2 13.115 6.1 6
37 140.6 62.5 13.115 6.1 6
37 142.5 78.1 16.565 9.55 6
38 165.9 50.4 13.115 6.1 6
38 177.7 44.3 13.115 6.1 6
38 160.9 32.2 16.565 9.55 6
38 142.5 36.5 13.115 6.1 6
38 151.3 44.2 13.115 6.1 6
39 177.7 44.3 13.115 6.1 6
39 181.3 36.4 13.115 6.1 6
39 175.6 23.9 13.115 6.1 6
39 160.9 32.2 16.565 9.55 6
91
40 175.6 23.9 13.115 6.1 6
40 154.3 17.9 13.115 6.1 6
40 147 24.1 13.115 6.1 6
40 142.5 36.5 13.115 6.1 6
40 160.9 32.2 16.565 9.55 6
41 139.5 21.5 13.115 6.1 6
41 139.9 11.6 13.115 6.1 6
41 119 24.9 16.565 9.55 6
41 122.7 44 13.115 6.1 6
41 133.1 36.7 13.115 6.1 6
42 139.9 11.6 13.115 6.1 6
42 116.1 3.4 13.115 6.1 6
42 103.3 9.4 13.115 6.1 6
42 119 24.9 16.565 9.55 6
43 103.3 9.4 13.115 6.1 6
43 97.6 26.5 13.115 6.1 6
43 102.8 37.9 13.115 6.1 6
43 122.7 44 13.115 6.1 6
43 119 24.9 16.565 9.55 6
31 181.3 36.4 11.015 4 6
31 187.3 33.1 11.015 4 6
31 181.4 21.4 11.015 4 6
31 175.6 23.9 11.015 4 6
92
B.2.2 Receiver Database (one of the simulation receiver databases: re1.txt)
1 21.04 116.5 21.3 2 32.3 120.3 21.3 3 40.8 156.9 24.07 4 71.7 191.2 21.12 5 87.5 180.2 24.47 6 104 212.6 22.12 7 156 196.7 21.9 8 165.4 205 21.9 9 179.5 216 22.2 10 213.5 230.2 21.12 11 211.3 219.6 24.47
B.2.3 Terrain Elevation Database (Part of te.txt)
0 0 9.834 5 0 9.834 10 0 9.834 15 0 9.834 20 0 9.834 25 0 9.834 30 0 9.834 35 0 9.834 40 0 9.834 45 0 9.834 50 0 9.834 55 0 9.834 60 0 9.834 65 0 9.834 70 0 9.834 75 0 9.834 80 0 9.834 85 0 9.834 90 0 9.834 95 0 9.834 100 0 7.015 105 0 7.015 110 0 7.015 115 0 7.015 120 0 7.015 125 0 7.015 130 0 7.015
93
135 0 7.015 140 0 7.015 145 0 7.015 150 0 7.015 155 0 7.015 160 0 7.015 165 0 7.015 170 0 7.015 175 0 7.015 180 0 7.015 185 0 7.015 190 0 7.015 195 0 7.015 200 0 7.015 205 0 7.015 210 0 7.015 215 0 7.015 0 5 9.838 5 5 9.838 10 5 9.838 15 5 9.838 20 5 9.838 25 5 9.838 30 5 9.838 35 5 9.838 40 5 9.838 45 5 9.838 50 5 9.838 55 5 9.838 60 5 9.838 65 5 9.838 70 5 9.838 75 5 9.838 80 5 9.838 85 5 9.838 90 5 9.838 95 5 9.838 100 5 7.015 105 5 7.015 110 5 7.015 115 5 7.015 120 5 7.015 125 5 7.015 130 5 7.015 135 5 7.015 140 5 7.015 145 5 7.015
94
150 5 7.015 155 5 7.015 160 5 7.015 165 5 7.015 170 5 7.015 175 5 7.015 180 5 7.015 185 5 7.015 190 5 7.015 195 5 7.015 200 5 7.015 205 5 7.015 210 5 7.015 215 5 7.015 0 10 9.838 5 10 9.838 10 10 9.838 15 10 9.838 20 10 9.838 25 10 9.838 30 10 9.838 35 10 9.838 40 10 9.838 45 10 9.838 50 10 9.838 55 10 9.838 60 10 9.838 65 10 9.838 70 10 9.838 75 10 9.838 80 10 9.838 85 10 9.838 90 10 9.838 95 10 9.838 100 10 7.015 105 10 7.015 110 10 7.015 115 10 7.015 120 10 7.015 125 10 7.015 130 10 7.015 135 10 7.015 140 10 7.015 145 10 7.015 150 10 7.015 155 10 7.015 160 10 7.015
95
165 10 7.015 170 10 7.015 175 10 7.015 180 10 7.015 185 10 7.015 190 10 7.015 195 10 7.015 200 10 7.015 205 10 7.015 210 10 7.015 215 10 7.015 0 15 9.838 5 15 9.838 10 15 9.838 15 15 9.838 20 15 9.838 25 15 9.838 30 15 9.838 35 15 9.838 40 15 9.838 45 15 9.838 50 15 9.838 55 15 9.838 60 15 9.838 65 15 9.838 70 15 9.838 75 15 9.838 80 15 9.838 85 15 9.838 90 15 9.838 95 15 9.838 100 15 7.015 105 15 7.015 110 15 7.015 115 15 7.015 120 15 7.015 125 15 7.015 130 15 7.015 135 15 7.015 140 15 7.015 145 15 7.015 150 15 7.015 155 15 7.015 160 15 7.015 165 15 7.015 170 15 7.015 175 15 7.015
96
180 15 7.015 185 15 7.015 190 15 7.015 195 15 7.015 200 15 7.015 205 15 7.015 210 15 7.015 215 15 7.015 0 20 9.838 5 20 9.838 10 20 9.838 15 20 9.838 20 20 9.838 25 20 9.838 30 20 9.838 35 20 9.838 40 20 9.838 45 20 9.838 50 20 9.838 55 20 9.838 60 20 9.838 65 20 9.838 70 20 9.838 75 20 9.838 80 20 9.838 85 20 9.838 90 20 9.838 95 20 9.838 100 20 7.015 105 20 7.015 110 20 7.015 115 20 7.015 120 20 7.015 125 20 7.015 130 20 7.015 135 20 7.015 140 20 7.015 145 20 7.015 150 20 7.015 155 20 7.015 160 20 7.015 165 20 7.015 170 20 7.015 175 20 7.015 180 20 7.015 185 20 7.015 190 20 7.015
97
195 20 7.015 200 20 7.015 205 20 7.015 210 20 7.015 215 20 7.015 . . . . . . . . . . . . 60 210 13.5 65 210 13.5 70 210 13.5 75 210 13.5 80 210 13.5 85 210 13.5 90 210 13.5 95 210 13.5 100 210 13.5 105 210 13.5 110 210 13.2 115 210 13.2 120 210 13.2 125 210 13.5 130 210 13.5 135 210 11.8 140 210 11.8 145 210 11.8 150 210 11.8 155 210 11.8 160 210 11.8 165 210 11.8 170 210 11.8 175 210 12.1 180 210 12.1 185 210 12.1 190 210 12.1 195 210 12.1 200 210 12.1 205 210 12.1 210 210 12.1 215 210 12.1 0 215 13.5 5 215 13.5 10 215 13.5 15 215 13.5 20 215 13.5 25 215 13.5
98
30 215 13.5 35 215 13.5 40 215 13.5 45 215 13.5 50 215 13.5 55 215 13.5 60 215 13.5 65 215 13.5 70 215 13.5 75 215 13.5 80 215 13.5 85 215 13.5 90 215 13.5 95 215 13.5 100 215 13.5 105 215 13.5 110 215 13.5 115 215 13.5 120 215 13.5 125 215 13.5 130 215 13.1 135 215 13.1 140 215 13.1 145 215 13.1 150 215 13.1 155 215 13.1 160 215 13.1 165 215 13.1 170 215 13.1 175 215 13.1 180 215 12.1 185 215 12.1 190 215 12.1 195 215 12.1 200 215 12.1 205 215 12.1 210 215 12.1 215 215 12.1 0 220 13.5 5 220 13.5 10 220 13.5 15 220 13.5 20 220 13.5 25 220 13.5 30 220 13.5 35 220 13.5 40 220 13.5
99
45 220 13.5 50 220 13.5 55 220 13.5 60 220 13.5 65 220 13.5 70 220 13.5 75 220 13.5 80 220 13.5 85 220 13.5 90 220 13.5 95 220 13.5 100 220 13.5 105 220 13.5 110 220 13.5 115 220 13.5 120 220 13.5 125 220 13.1 130 220 13.1 135 220 13.1 140 220 13.1 145 220 13.1 150 220 13.1 155 220 13.1 160 220 13.1 165 220 13.4 170 220 13.4 175 220 13.4 180 220 13.4 185 220 13.4 190 220 13.4 195 220 13.4 200 220 13.4 205 220 13.8 210 220 13.8 215 220 13.8
0 225 13.5 5 225 13.5 10 225 13.5 15 225 13.5 20 225 13.5 25 225 13.5 30 225 13.5 35 225 13.5 40 225 13.5 45 225 13.5 50 225 13.5
100
55 225 13.5 60 225 13.5 65 225 13.5 70 225 13.5 75 225 13.5 80 225 13.5 85 225 13.5 90 225 13.5 95 225 13.5 100 225 13.5 105 225 13.5 110 225 13.5 115 225 13.5 120 225 13.5 125 225 13.5 130 225 13.1 135 225 13.1 140 225 13.1 145 225 13.1 150 225 13.1 155 225 13.1 160 225 13.1 165 225 13.1 170 225 13.1 175 225 13.4 180 225 13.4 185 225 13.4 190 225 13.4 195 225 13.4 200 225 13.4 205 225 13.4 210 225 13.8 215 225 13.8 0 230 13.5 5 230 13.5 10 230 13.5 15 230 13.5 20 230 13.5 25 230 13.5 30 230 13.5 35 230 13.5 40 230 13.5 45 230 13.5 50 230 13.5 55 230 13.5 60 230 13.5 65 230 13.5
101
70 230 13.5 75 230 13.5 80 230 13.5 85 230 13.5 90 230 13.5 95 230 13.5 100 230 13.5 105 230 13.5 110 230 13.5 115 230 13.5 120 230 13.5 125 230 13.5 130 230 13.5 135 230 13.5 140 230 13.5 145 230 13.5 150 230 13.5 155 230 13.5 160 230 13.5 165 230 13.5 170 230 13.4 175 230 13.4 180 230 13.4 185 230 13.4 190 230 13.4 195 230 13.4 200 230 13.4 205 230 13.4 210 230 13.8 215 230 13.8 0 235 13.5 5 235 13.5 10 235 13.5 15 235 13.5 20 235 13.5 25 235 13.5 30 235 13.5 35 235 13.5 40 235 13.5 45 235 13.5 50 235 13.5 55 235 13.5 60 235 13.5 65 235 13.5 70 235 13.5 75 235 13.5 80 235 13.5
102
85 235 13.5 90 235 13.5 95 235 13.5 100 235 13.5 105 235 13.5 110 235 13.5 115 235 13.5 120 235 13.5 125 235 13.5 130 235 13.5 135 235 13.5 140 235 13.5 145 235 13.5 150 235 13.5 155 235 13.5 160 235 13.5 165 235 13.5 170 235 13.5 175 235 13.5 180 235 13.5 185 235 13.5 190 235 13.5 195 235 13.5 200 235 13.5 205 235 13.5 210 235 13.5 215 235 13.5
103
B.2.4 Antenna Radiation Pattern Database (Part of an.txt)
H,0,1.78E-06
H,1,1.78E-06
H,2,2.24E-06
H,3,2.24E-06
H,4,2.51E-06
H,5,2.51E-06
H,6,2.51E-06
H,7,2.51E-06
H,8,2.51E-06
H,9,2.51E-06
H,10,2.51E-06
H,11,2.51E-06
H,12,2.51E-06
H,13,2.51E-06
H,14,2.00E-06
H,15,2.00E-06
H,16,1.78E-06
H,17,1.78E-06
H,18,1.41E-06
H,19,1.41E-06
H,20,1.12E-06
H,21,1.12E-06
H,22,1.00E-06
H,23,1.00E-06
H,24,8.91E-07
H,25,8.91E-07
H,26,1.12E-06
H,27,1.12E-06
H,28,1.59E-06
104
H,29,1.59E-06
H,30,2.00E-06
H,31,2.00E-06
H,32,2.24E-06
H,33,2.24E-06
H,34,2.51E-06
H,35,2.51E-06
H,36,2.82E-06
H,37,2.82E-06
V,320,2.82E-07
. . .
. . .
. . . V,321,2.82E-07
V,322,2.51E-07
V,323,2.51E-07
V,324,2.24E-07
V,325,2.24E-07
V,326,2.51E-07
V,327,2.51E-07
V,328,2.82E-07
V,329,2.82E-07
V,330,2.82E-07
V,331,2.82E-07
V,332,2.82E-07
V,333,2.82E-07
V,334,3.16E-07
V,335,3.16E-07
V,336,3.55E-07
V,337,3.55E-07
V,338,3.55E-07
V,339,3.55E-07
105
V,340,3.55E-07
V,341,3.55E-07
V,342,3.55E-07
V,343,3.55E-07
V,344,3.55E-07
V,345,3.55E-07
V,346,3.16E-07
V,347,3.16E-07
V,348,2.82E-07
V,349,2.82E-07
V,350,2.82E-07
V,351,2.82E-07
V,352,2.51E-07
V,353,2.51E-07
V,354,2.82E-07
V,355,2.82E-07
V,356,3.55E-07
V,357,3.55E-07
V,358,2.24E-07
V,359,2.24E-07
106
B.3 Output of the Prediction Tool
#Start Time: Tue Mar 07 22:37:53 2006 #End Time: Tue Mar 07 22:38:16 2006 #****************************************#*** INPUT FILES #*** Buildings: bs.txt #*** Receivers: re1.txt #*** Terrain: te.txt #*** Indoor Features: none #*** Preprocessed Data: none #****************************************#*** INPUT PARAMETERS #*** Incremental angle 1.000 #*** Number of Reflections 6 #*** Number of Diffractions 2 #*** Prediction Frequency 2440.0MHz #*** Fresnel Width Used n=1.00 #*** Single Ray Model Was Used #*** Transmitter Located at x=142.5 y=78.1 z=16.9 #*** Height of Transmitter 0.3 #*** Height of Receivers 0.3 #****************************************
1 21.0 116.5 21.6 -62.14 | 6.11e-007 1 0.00e+000 0 0.00e+000 0 0.00e+000 0 | 7.63e-011 4.25e-007
2 32.3 120.3 21.6 -57.63 | 1.72e-006 1 0.00e+000 0 0.00e+000 0 0.00e+000 0 | 7.07e-011 3.94e-007
3 40.8 156.9 24.4 -58.28 | 1.48e-006 1 0.00e+000 0 0.00e+000 0 0.00e+000 0 | 7.71e-011 4.30e-007
4 71.7 191.2 21.4 -61.38 | 7.27e-007 1 0.00e+000 0 0.00e+000 0 0.00e+000 0 | 7.99e-011 4.45e-007
5 87.5 180.2 24.8 -67.39 | 0.00e+000 0 1.83e-007 1 0.00e+000 0 0.00e+000 0 | 6.96e-011 3.88e-007
6 104.0 212.6 22.4 -91.73 | 0.00e+000 0 6.72e-010 1 0.00e+000 0 0.00e+000 0 | 8.39e-011 4.67e007
7 156.0 196.7 22.2 -57.73 | 1.68e-006 1 0.00e+000 0 0.00e+000 0 0.00e+000 0 | 7.15e-011 3.98e007
8 165.4 205.0 22.2 -59.71 | 0.00e+000 0 1.07e-006 1 0.00e+000 0 0.00e+000 0 | 7.73e-011 4.30e007
9 179.5 216.0 22.5 -89.53 | 0.00e+000 0 1.11e-009 1 0.00e+000 0 0.00e+000 0 | 8.63e-011 4.80e007
10 213.5 230.2 21.4 -92.40 | 0.00e+000 0 5.75e-010 1 0.00e+000 0 0.00e+000 0 | 1.01e-010 5.62e007
11 211.3 219.6 24.8 -61.38 | 7.14e-007 1 1.40e-008 1 0.00e+000 0 0.00e+000 0 | 3.11e-009 5.26e007
107
B.4 VPL Ray Tracing Visualization Code
format short
disp('***************Program is running. **************’)
bd=input('Please insert a building database filename: ','s');
te=input('Please insert a terrain database filename: ','s');
name=input('Please insert simulation result filename: ','s');
startno=input('Ray trace at receiver number (start) : ','s');
stopno=input('Ray trace at receiver number (end) : ','s');
freq=input('Please insert frequency used [MHz] during simulation (eg:2000) :','s');
file1=fopen(bd,'r');
file2=fopen('build.txt','w');
build=fscanf(file1,'%d %f %f %f %f %*f \n')';
fprintf(file2,'%d %f %f %f %f \n',build);
build=[reshape(build,5,[])]';
fclose(file1);
fclose(file2);
figure;
file3=fopen(te,'r');
te=fscanf(file3,'%f %f %f \n')';
te=[reshape(te,3,[])]';
[Y,X] = meshgrid(0:5:235,0:5:215);
Z = te(:,3);
Z=[reshape(Z,44,[])];
[C,h] = contour3(X,Y,Z,100);
hold on;
% surface(X,Y,Z,'EdgeColor',[.8 .8 .8],'FaceColor','interp','CDataMapping','direct')
surface(X,Y,Z,'EdgeColor',[.8 .8 .8],'FaceColor','none','CDataMapping','direct')
108
% colormap cool
% clabel(C,h)
colormap copper
fclose(file3);
data=[name,'_tx1_',freq,'MHz'];
file5=fopen(data,'rt');
file6=fopen('rxpoint.txt','w');
status=fseek(file5,685,-1);
result=fscanf(file5,'%d %f %f %f %*4d %*s %*s %*4d %*s %*d %*4d %*s %*d
%*4d %*s %*d %*4d %*s %*d %*s %*4d %*s %*4d %*s\n')';
fprintf(file6,'%d %f %f %f \n',result);
result=[reshape(result,4,[])]';
fclose(file5);
fclose(file6);
data=[name,'_tx1_',freq,'MHz'];
file3=fopen(data,'rt');
status=fseek(file3,542,-1);
Xt=fscanf(file3,'%*4s %*11s %*7s %*2s %f');
status=fseek(file3,542,-1);
Yt=fscanf(file3,'%*4s %*11s %*7s %*2s %*f %*2s %f');
status=fseek(file3,542,-1);
Zt=fscanf(file3,'%*4s %*11s %*7s %*2s %*f %*2s %*f %*2s %f');
status=fseek(file3,542,-1);
height=fscanf(file3,'%*4s %*11s %*7s %*2s %*f %*2s %*f %*2s %*f\n %*4s %*6s
%*2s %*11s %f');
fclose(file3);
plot3(Xt,Yt,Zt,'*b')
plot3([Xt Xt],[Yt Yt],[Zt Zt+height],'-g*','LineWidth',1,'MarkerEdgeColor',[0 0
0],'MarkerFaceColor',[0 0 0])
109
plot3([Xt Xt],[Yt Yt],[Zt Zt+height],'-g','LineWidth',5);
plot3(Xt,Yt,Zt,'*k')
plot3(Xt,Yt,Zt+height,'*k')
legend('Receiver Point','Transmitter',4);
% Building drawing %
n=length(build);
i=1;
m=0;
while i<=n-1
if build(i+1,1)==build(i,1)
xa=[build(i,2) build(i,2) build(i+1,2) build(i+1,2)];
ya=[build(i,3) build(i,3) build(i+1,3) build(i+1,3)];
za=[build(i,4)-build(i,5) build(i,4) build(i+1,4) build(i+1,4)-build(i+1,5)];
fill3(xa,ya,za,'y')
m=m+1;
else
xa=[build(i,2) build(i,2) build(i-m,2) build(i-m,2)];
ya=[build(i,3) build(i,3) build(i-m,3) build(i-m,3)];
za=[build(i,4)-build(i,5) build(i,4) build(i-m,4) build(i-m,4)-build(i-m,5) ];
fill3(xa,ya,za,'y')
xb=build(i-m:i,2);
yb=[build(i-m:i,3)];
zb=[build(i-m:i,4)-build(i-m:i,5)];
fill3(xb,yb,zb,'y')
xc=build(i-m:i,2);
yc=[build(i-m:i,3)];
zc=[build(i-m:i,4)];
fill3(xc,yc,zc,'y')
m=0;
end
i=i+1;
110
end
xa=[build(i,2) build(i,2) build(i-m,2) build(i-m,2)];
ya=[build(i,3) build(i,3) build(i-m,3) build(i-m,3)];
za=[build(i,4)-build(i,5) build(i,4) build(i-m,4) build(i-m,4)-build(i-m,5) ];
fill3(xa,ya,za,'y')
xb=build(i-m:i,2);
yb=[build(i-m:i,3)];
zb=[build(i-m:i,4)-build(i-m:i,5)];
fill3(xb,yb,zb,'y')
xc=build(i-m:i,2);
yc=[build(i-m:i,3)];
zc=[build(i-m:i,4)];
fill3(xc,yc,zc,'y')
% set(gca,'dataaspectratio',[2 2 1],'plotboxaspectratio',[320 320 100])
% set(gca,'cameraviewanglemode','manual')
yd=[256.0 257.5 253.0 257.5];
xd=[536.0 538.6 536.0 533.4];
zd=[90 60 60 60];
fill3(xd,yd,zd,'w')
startno=strread(startno,'%u');
stopno=strread(stopno,'%u');
num=startno;
while num<=stopno
number=int2str(num);
file4=fopen('ray_edit.txt','w');
rayfile=['C:\ray_paths_tx1_rx',number,'_',freq,'MHz'];
[x,y,z]=textread(rayfile,'%f %f %f','whitespace','\n','commentstyle','shell');
ray=[x,y,z];
fprintf(file4,'%f %f %f \n',ray);
fclose(file4);
111
plot3(result(num,2),result(num,3),result(num,4),'*b');
n=length(ray);
i=2;
while i<=n
if i==n
plot3([ray(i,1) ray(i-1,1)],[ray(i,2) ray(i-1,2)],[ray(i,3) ray(i-1,3)],'r');
plot3([ray(i,1) result(num,2)],[ray(i,2) result(num,3)],[ray(i,3) result(num,4)],'r');
i=i+1;
elseif n==3&i==2
plot3([ray(i,1) ray(i-1,1)],[ray(i,2) ray(i-1,2)],[ray(i,3) ray(i-1,3)],'r');
plot3([ray(i,1) result(num,2)],[ray(i,2) result(num,3)],[ray(i,3) result(num,4)],'r');
i=i+2;
elseif ray(i,1)==ray(1,1)&ray(i,2)==ray(1,2)&ray(i,3)==ray(1,3)
plot3([ray(i-1,1) result(num,2)],[ray(i-1,2) result(num,3)],[ray(i-1,3)
result(num,4)],'r');
i=i+1;
else
plot3([ray(i,1) ray(i-1,1)],[ray(i,2) ray(i-1,2)],[ray(i,3) ray(i-1,3)],'r');
i=i+1;
end
end
num=num+1;
end
hold off
disp('********************Ray Trace Successfully. ********************’)