BIT ERROR RATE FOR PRIVATE MOBILE RADIO (PMR)
DUE TO LIGHTNING ELECTROMAGNETIC FIELD RADIATION (LEMR)
MONA RIZA BINTI MOHD ESA
UNIVERSITI TEKNOLOGI MALAYSIA
BIT ERROR RATE FOR PRIVATE MOBILE RADIO (PMR)
DUE TO LIGHTNING ELECTROMAGNETIC FIELD RADIATION (LEMR)
MONA RIZA BINTI MOHD ESA
A thesis submitted in fulfillment of the requirements for the award of the degree of
Master of Engineering in Electrical – Electronic & Telecommunication
Faculty of Electrical Engineering Universiti Teknologi Malaysia
November 2005
iii
Dedicated to the dearest persons in my heart and the idol of my life
Puan Hajah Rosminah Mahmud
Encik Mohd Esa b. Ali
Mohd Ridhwan b. Mohd Esa
Mohd Redza Ezzaq b. Mohd Esa
Mohd Raffiq Azriq b. Mohd Esa
iv
ACKNOWLEDGMENT
I would like to express my highly gratitude and appreciation to:
1. Prof. Dr. Hussein Ahmad, for the supervision, assistance, encouragement and
advices that enable me to successfully complete this project with great
experience in this field, High Voltage and High Current. The support and full
attention that enable me to build up a good quality of a researcher in myself
2. Assoc. Prof. Dr. Ahmad Zuri, for the supervision, a lot of guidance to start
the simulation programming and advices in realizing and solving problem
arises.
3. Technician of IVAT that contributes lots of help and kindness in setting up
the high voltage and high current equipments in order to execute the
measurement and achieve the target of the project.
4. My best colleagues, for the ideas, moral supports and great indirect helps
during accomplishing this project.
5. My parents, for the love, care and understanding during the whole period of
completing the research and theses.
Last but not least, I would like to thank Allah for giving me motivation, strength
and guidance to successfully complete this research as planned.
v
ABSTRACT
The conceptual implementation to access the extend influence of lightning
electromagnetic radiation (LEMR) on mobile radio communication. Binary data has
been transmitted through a pair of Motorola Talkabout T5420 walkie-talkie with 14
channels and 38 eliminator codes and operates on 14 UHF Family Radio Service (FRS)
Frequencies. Two types of induced interferences which are high voltage and high
current experiment has been conducted in High Voltage Laboratory, Institute of High
Voltage and High Current, UTM. In order to achieve the implementation mention
above, a research has been conducted with the title of the project is “Bit Error Rate for
Private Mobile Radio (PMR) Due to Lightning Electromagnetic Field Radiation
(LEMP)”. The objective of the first part of the research is to determine whether the
lightning could produce the error of the bit in term of bit error rate in digital
communication. If there any errors, the research will continue to ascertain how much it
damage or influence the data. In optical communication, in practice, a low bit error rate
in the region 10-7 to 10-10 may be tolerated with pulse code modulation (PCM)
transmission. Although, in wireless communication, the receiver will face much higher
bit error rate due to the environment and nature phenomena such as rain drops, fogs,
thunderstorm and lightning.
vi
ABSTRAK
Konsep yang diimplementasi bagi mendalami kejadian yang dipengaruhi oleh
radiasi elektromagnet kilat (LEMR) ke atas perhubungan radio bergerak. Penghantaran
data binari melalui sepasang radio (Walkie-talkie) Motorola Talkablout T5420 dengan
14 saluran dan 38 penyahkodan serta 14 UHF FRS. Dua jenis gangguan tambahan iaitu
eksperimen menggunakan voltan tinggi and arus tinggi ke atas talian penghataran telah
dijalankan di makmal voltan dan arus tinggi, Institut Voltan dan Arus Tinggi, FKE,
UTM ke atas talian penghantaran. Bagi merealisasikan implementasi yang tersebut,
kajian yang bertajuk “Bit Error Rate for Private Mobile Radio (PMR) Due to Lightning
Electromagnetic Field Radiation (LEMP)” telah dijalankan. Tujuan utama kajian ini
adalah untuk melihat samada kilat akan menpengaruhi atau memberi kesan ke atas
komunikasi digital dalam bentuk kadar ralat bit (bit error rate). Jika terdapat ralat, kajian
diteruskan bagi memantau sejauhmana kerosakan pada data, secara praktikalnya, kadar
ralat bit amat rendah iaitu antara 10-7 hingga 10-10 yang mungkin boleh diterima dengan
penghantaran menggunakan pemodulatan kod denyut (PCM). Walaubagaimanapun,
dalam perhubungan tanpa wayar, bahagian penerima isyarat terpaksa berhadapan
dengan kadar ralat bit yang lebih tinggi disebabkan persekitaran dan fenomena alam
semulajadi seperti hujan, kabus, ribut dan kilat.
vii
TABLE OF CONTENTS
Title Page i
Declaration ii
Dedication iii
Acknowledgement iv
Abstract v
Abstrak vi
Table of Contents vii
List of Tables xii
List of Figures xiii
List of Symbols xvi
List of Abbreviations xviii
List of Appendices xx
CHAPTER TITLE PAGE
1 INTRODUCTION 1
1.1 General 1
1.2 Objective of Research 2
1.3 Research Scopes 3
1.4 Research Methodology 4
1.4.1 Flow Chart 4
1.4.2 Methodology 4
viii
2 FREQUENCY SHIFT KEYING (FSK) SIGNAL 6
2.1 Introduction - Passband Data Transmission 6
2.2 Coherent Fsk (Frequency Shift-Keying) 6
2.2.1 Problems with Coherent Detection 8
2.3 Non Coherent FSK 9
2.4 Signal Model 10
2.5 Sampling 10
2.6 Spectrum of Sampled Signals 11
2.7 Nyquist Sampling Theorem 12
2.8 Spectrum Representation of Signals 13
2.10 Free Space Loss 16
3 BIT ERROR RATE 17
3.1 Fundamental Concepts and Measurement Issues 17
3.1.1 Noise and BER 18
3.1.2 Quantization Errors 19
3.1.3 Q Function 19
3.1.4 Probability of Error (POE) 21
3.1.4.1 Probability of Error-Single Observation 21
3.1.4.2 Probability of Error – Multiple Observations 23
3.1.5 Factors Affecting BER 24
3.1.6 BER Measurement 24
3.1.7 How to Use BER Data? 25
3.2 Previous Research of BER 26
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4 LIGHTNING ELECTROMAGNETIC FIELD 28
4.1 Lightning Process 28
4.1.1 Type of Lightning Strike 30
4.1.2 Electromagnetic Pulse (EMP) 31
4.2 Modelling of Electromagnetic Fields 34
4.3 Previous Study of Lightning 40
5 MEASUREMENT AND EFFECT OF HIGH VOLTAGE AND
HIGH CURRENT OVER DATA TRANSMISSION 41
5.1 General 41
5.2 Experimental Set up 42
5.2.1 Introduction 42
5.2.2 Walkie Talkie as the Transmitter and Receiver 44
5.2.2.1 Frequency Channel Allocation 45
5.2.2.2 Transmitter 46
5.2.2.3 Receiver 48
5.3 First Experiment – Impulse Voltage Generator (IGV) 49
5.3.1 Impulse Voltage Generator (IVG) 50
5.3.3.1 Function 51
5.3.3.2 Experiment and Measurement 53
5.4 Second Experiment – Recloser Test Set (RTS) 54
5.4.1 Experiment and Measurement 56
x
6 RESULTS AND ANALYSIS 58
6.1 Generation of fsk signal 58
6.2 Result of Received Signal 62
6.2.1 Without Lightning (No High Voltage and High Current
Induced) 62
6.2.2 High Voltage – Using IVG 63
a) 170kV 63
b) 400kV 63
6.2.3 High Current – Using RTS RCL19 64
a) 200A 64
b) 440A 64
c) 650A 65
d) 720A 65
e) 850A 66
f) 1500A 66
g) 2000A 67
6.3 Analysis of Received Signal 67
6.3.1 No Lightning Condition 67
6.3.2 High Voltage – Using IVG 68
6.3.3 High Current – Using RTS RCL19 69
7 DISCUSSIONS AND CONCLUSIONS 70
7.1 Discussion 70
7.1.1 High Voltage Experiment 70
7.1.2 High Current Experiment 71
7.1.3 Overall Experiments 72
7.2 Conclusion 74
xi
8 REFERENCES 75
APPENDICES 78
APPENDIX A – IMPULSE VOLTAGE GENERATOR 78
APPENDIX B – OPERATING SPECIFICATION RECLOSER
TEST SET 95
xii
LIST OF TABLES
TABLE TITLE PAGE
Table 4-1 Lightning Return Stroke Data 33
Table 5-1 Frequency allocation or channel information of
the radios 46
Table 7-1 Total delay of every packet received at the
receiver 73
xiii
LIST OF FIGURES
FIGURE NO. TITLE PAGE
2-1 Frequency shift keying (fsk) signal with input
11100110011001100 7
2-2 Receiver structure of FSK signal 8
2-3 Coherent detection for X1(t) 8
2-4 Non coherent receiver structure 9
2-5 Sampling process 11
2-6 Amplitude spectra of a signal before and after sampling 12
2-7 Time domain representation of signal 14
2-8 Signal is represent in frequency domain 15
2-9 Frequency domain representation as T approaches infinity. 16
3-1 Probability of error under the graph 22
3-2 Schematic diagram of equipment for propagation measurements 26
3-3 Schematic Diagram of equipment for BER measurement using
phase-locked oscillator 27
4-1 Charge Separation 29
4-2 Stroke Channel Electromagnetic Pulse (EMP) 32
4-3 Geometry of straight vertical lightning channel of height H used to
calculate the EM field at a point above a perfectly conducting
ground 36
5-1 Overall view of research 41
5-2 Overall view of the experiment 44
xiv
5-3 Walkie-talkie Motorola Talkabout T5420 45
5-4 (a) Modification of handsfree into transmission line cable
connecting with the stereo jack 47
(b) Cable connected to the microphone of the radio 47
(c) Cable connected to the output port (speaker port) 47
(d) Actual connection of transmitter and base station 47
5-5 (a) Modification of handsfree into transmission line cable
connecting with the mono jack 48
(b) Cable connected to the speaker of the radio 48
(c) Cable connected to the input port of the computer
(microphone port) 48
(d) Actual connection of the receiver and the base station 48
5-6 (a) The plan view of the high voltage experiment layout 49
(b) The side view of the high voltage experiment layout 50
5-7 Impulse Voltage Generator (IVG) 50
5-8 (a) Basic diagram 52
(b) Basic diagram with parallel spark gaps 52
(c) Trigger range 53
5-9 Recloser Test Set (RTS) – RCL 19 54
5-10 (a) The plan view of the high current experiment layout 55
(b) The front view of the high current experiment layout 56
6-1 Sequence of 10 binary bits that has been transform to fsk signal 59
6-2 Sequence of 1000 bits binary data 60
6-3 Sequence of 1000 bit of binary data in the form of fsk signal 60
6-4 Frequency domain representation that used to differentiate two
different frequencies in figure 6-3 above 61
6-5 Time and frequency domain of received signal when no lightning
condition 62
6-6 Received signal when 170kV is induced to the transmitted signal 63
6-7 Received signal when 400kV is induced to the transmitted signal 63
6-8 Received signal when 200A is induced to the transmitted signal 64
xv
6-9 Received signal when 440A is induced to the transmitted signal 64
6-10 Received signal when 650A is induced to the transmitted signal 65
6-11 Received signal when 720A is induced to the transmitted signal 65
6-12 Received signal when 850A is induced to the transmitted signal 66
6-13 Received signal when 1500A is induced to the transmitted signal 66
6-14 Received signal when 2000A is induced to the transmitted signal 67
xvi
LIST OF SYMBOLS
x (t) - Frequency shift keying (FSK) signal
x0 (t) - FSK signal when bit is 0
x1 (t) - FSK signal when bit is 1
t - Time domain representation
A - Amplitude of cosine signal
f1 - Upper frequency
f0 - Lower frequency
Tb - Time interval
S, s - Sequence of binary bit
y (t) - Original signal including noise
n (t) - Noise signal
rb - Bit rate
n0 - Noise at time n (t0)
N0 - Noise power at t0
x(n) - Discrete-time signal
n - Number of discrete signal
x (t) - Set of impulse of the continuous-time signal
Ts - Discrete time interval
fs - Sampling frequency
fmax - Maximum frequency
X(f) - Aperiodic continuous-frequency
Ls - Free space loss
d - Distance in km
xvii
Q - Q function
Pe - Probability of error
Erf - Error function
Eb - Energy in one bit
C - Coulomb
kA - kiloampere
V - Volts
kJ - Kilojoules
s - Microsecond
Ms - Milisecond
E - Electric field intensity
B - Magnetic field intensity
J - Current density
c - Velocity of light
- Electric charge density
0 - Permeability of free space
0 - Permittivity of free space
A - Vector magnetic potential
- Scalar electric potential
H - Lightning channel height
z’ - Observation point height of EM field
fc - Carrier frequency
m - Meter
cm - Centimeter
Hz - Hertz
kHz - kilo Hertz
MHz - Mega Hertz
GHz - Giga Hertz
Cos - Cosine
xviii
LIST OF ABBREVIATIONS
A/D - Analog to Digital
ASK - Amplitude Shift Keying
BER - Bit error rate
BW - Bandwidth
CPFSK - Continuous Phase FSK
DPSK - Differential PSK
EM - Electromagnetic
EMP - Electromagnetic Pulse
FM - Frequency Modulation
FRS - Family Radio Service
FSK - Frequency Shift Keying
FS - Fourier Series
FT - Fourier Transform
HC - High Current
HEF - Horizontal Electric Field
HV - High Voltage
IF - Intermediate Frequency
IVG - Impulse Voltage Generator
LEMP - Lightning Electromagnetic Pulse
LEMR - Lightning Electromagnetic Radiation
LOS - Line of Sight
pdf - Probability Density Function
PMR - Private Mobile Radio
xix
POE - Probability of Error
PRBS - Pseudo random Binary Sequence
PSK - Phase Shift-Keying
PSTN - Public Switch Telephone Network
PTT - Push to Talk
QPSK - Quadrature PSK
QAM - Quadrature Amplitude
RTS - Recloser Test Set
UHF - Ultra High Frequency
xx
LIST OF APPENDICES
APPENDIX TITLE PAGE
A Impulse Voltage Generator 78
B Operating Specification Recloser
Test Set 95
CHAPTER 1
INTRODUCTION
1.1 General
Wireless communication technology has developed and more reliable in order to
communicate with other people around the world. In transferring the data from one end
to the other end, especially in wireless and mobile data transmission, the expected data
at the receiver should be the same as from the transmitter. Otherwise, the data will not
be classified as a reliable data.
However, the development of this technology is still unable to preserve their
reliability from several natural phenomena such as rain drops, storm and lightning
effects. In telecommunication, the sequence of rain on the microwave system at a
particular frequency is more critical especially for the countries located in tropical and
equatorial region (Din J. et. al, 2003) and so as lightning.
Lightning is a natural prodigy that is of great attention to human being because it
annihilating deformities to the equipment and installations. It integrated the formation of
high flashing of light and thunder sounds. In the early year, some primitive people
2
lightning were assigned to myths and superstitious. The first person endeavoured that
lightning is an electrical phenomenon was Sir Benjamin Franklin (Golam Sorwar,
1997).
Lightning plays a role as a major natural force of electromagnetic radiation and
the ability of transmitting data to the receiver become unreliable. A lot of amendments,
improvements, adjustments and alterations are to be made over the affected data in order
to make it become reliable and as the same as has been transmitted. A lot of research
and experiment has been done to conserve the data during the transmission after it being
influenced by this kind of natural prodigy. Therefore, a reliable and dependable data can
be accumulated at the receiver.
1.2 Objectives of Research
The objectives of this research are as follows;
1. To ascertain and prove whether lightning can contribute to BER in digital
communication.
2. To determine which of the lightning electromagnetic field components cause
maximum data corruption and deterioration.
3. To model the lightning interaction model with the data transmission using
electromagnetic theory.
3
1.3 Research Scopes
In order to ensure an accurate and reliable transmitted data, persistency and
consistency of data detector or receiver need to be clearly studied. The measurement of
bit error rate (BER) is a step towards the development of a reliable and error-free data
receiver. This research is to study the interaction between the electromagnetic field
produced by the lightning and the electromagnet field existed when transmitting signal
to the other end. Therefore, it is important to know which type of lightning is extremely
hazardous to the signal or data during the transmission. For that reason, it is required to
develop an electromagnetic modelling regarding the lightning interaction with the data
transmission. Besides, bit error rate (BER) during lightning strike activities for private
mobile radio will be measured. Two experiments has been conducted which involved
the use of a high voltage low current equipment and a high current low voltage
equipment. The first experiment, using impulse voltage generator (IVG) and the second
experiment using recloser test set. A pair of walkie-talkie at frequency from
925.130MHz to 935.430MHz Motorola T5420 was used in this experiment.
4
1.4 Research Methodology
1.4.1 Flow chart
Literature Review
Cable Input/output modification
1.4.2 Methodology
From the chart above, it can be described in detail as below:
1. Literature study related to this topic. The topic is divided into two diverse topics
which are bit error rate and lightning electromagnetic field fundamentals.
Data transmission & Collecting
Walkie-talkie
BER calculation and comparison(Matlab programming)
Analysis
Walkie-talkieset-up for set-up for
measurement inH.C. Lab
measurement inH.V. Lab
5
2. A sequence of binary data is generated using Matlab software and been
transform into frequency shift keying (fsk) signal before it can be transmitted
into the air interface.
3. A pair of walkie-talkie will be used in order to transmit and receive data;
therefore a pair of cable is going to be utilized in the experiment. The cable is
modified from the walkie-talkie handsfree that it possible to be connected into
the input and output port of the computer.
4. Experimental Setup - Two types of experiment will be conducted that are using
two main different equipments:
a. High voltage equipment – Impulse Voltage Generator (IVG) in High
Voltage Laboratory
b. High current equipment – Recloser Test Set (RTS) RCL19 in High
Current Laboratory
5. Signal is ready to be transmitted. Layout of both experiments can be referred in
chapter 5. The position of radios must be in line of sight (LOS) in order to ensure
there is no obstacle along the transmission path. Data is collected at the end of
the transmission path, receiver.
6. Several data starting with no lightning condition, high voltage values and high
current values. Received data or signal than be stored in the base station
(computer) and analysis will be done at the end of measurement.
7. All signals in the base station will actuate several simulation processes in order
to identify bit error rate. Bit error of the received signal will be calculated using
Matlab software. Other analysis will also be executed to determine the effect of
lightning strike to the transmitted signal through air interface.
74
unavailability of insulator to insulate the IVG. The results have found that no error or
loss of bit has been identified and not much of delay been exposed. Maximum delay of
received signal compared to no lightning data transmission is 2.0ms.
For the second experiment, it can be concluded that 8 has been analyzed started
with 200A, 440A, 650A, 720A, 850A, 1100A, 1500A and 2000A. From the results, loss
of bit has been identified at the current value of 440A, 850A and 2000A. Total bit loss
for those three current values is 25 bits or 0.025% loss out of 1000 bits of binary data.
Furthermore, delay of received signal in high current experiment has also been exposed
compared to no lightning condition. Minimum delay of received signal (for no lightning
condition) is 18.0ms. Maximum delay of received signal compared to original
10seconds data is 29.2ms. Maximum delay of received signal compared to no lightning
condition is 11.2ms
As the final conclusion, in telecommunication nowadays, an accurate data
transmission is the most expected in developing countries. In this proposal, literature
reviews of the effect of lightning electromagnetic field radiation to the mobile data
transmission have been presented. The results of the research can be used as the basis
for improving the performance of mobile transmission system especially in environment
where there are high lightning activities. This is can be executed by proper placing of
microwave repeater towers on hilly area which are less prone to lightning strikes.
REFERENCES
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Point-to-Point Microwave Link”, 4 th National Conference on
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Data Transmission”.
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Signals and Systems”.
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76
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