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PSEUDO RANDOM NOISE BASED SPREAD
SPECTRUM MODULATION SCHEME FOR SECURE
UWB WIRELESS COMMUNICATION
BY
SITI HAZWANI YAACOB
A dissertation submitted in fulfilment of the requirement
for the degree of Masters of Science in Communication
Engineering
Kulliyyah of Engineering
International Islamic University Malaysia
DECEMBER 2014
ii
ABSTRACT
A Pseudo Random Noise Generator (PRNG) using 24 bits Linear Feedback Shift
Registers (LFSR) have been proposed to generate a sufficiently long period of key
sequence for a secure UWB communication application. The Direct Sequence Spread
Spectrum (DSSS) principle is employed in the system as a data modulation and
transmission technique due to its low Power Spectral Density (PSD).The investigation
is carried out to analyze the performance of UWB pulse generator by using Avalanche
transistor which able to generate nanosecond pulses that contained data embedded
with the key to be transmitted. The designed UWB transmitter circuit has been
simulated using NI Multisim 11.0. The circuit successfully generated a kind of
inverted Gaussian pulses with the best pulse width achieved is 1.91 ns and pulse
amplitude is 5.72V. The Power Spectral Density (PSD) of the pulses satisfies the
specification of FCC mask defined with the magnitude of -81.5 dBm at 3.1GHz
frequency. In fact, the PRNG pass the NIST Test Suite randomness tests. With the
features such as simple structure, high speed and low power as low cost this circuit
system is applicable to UWB wireless communication system.
iii
لبحثا صملخ
تغذية راجعة خطية و سعة قترح استخدام مولد ضجيج شبه عشوائي يستخدم مسجل ذو ا
خانة، لانتاج متسلسلة مفتاح طويلة بما فيه الكفاية لتأمين تطبيقات الاتصال على 42ظف في النظام و النطاقات فائقة السعة.مبدأ تمديد الطيف بالاستخدام المباشر للمتسلسلات
حقيق تم كمعدل للبيانات و كتقنية للارسال نسبة لانخفاض كثافة طيف القدرة لديه. التلتحليل اداء مولد نبضات لنطاقات فائقة الاتساع، و ذلك باستخدام ترانزستور افلانش الذي له قدرة على توليد نبضات بطول في حدود جزء من الالف مليون جزء من الثانية و التي احتوت على بيانات مضمنة مع المفتاح ليتم ارسالها.دائرة النطاقات فائقة السعة المصممة
(. الدائرة انتجت بنجاح شكل من NI Multisim 11.0اكاهاا باستخدام برنامج تمت محجزء من الالف مليون 19.1نبضات جاوسالمعكوسة، و كان افضل طول للنبضة تحقق هو
فولت.كثافة طيف القدرة للنبضات وافق المواصفات 29.4جزء من الثانية و مقدار النبضة صالات الاتحادية بالولايات المتحدة الامريكية، و الذي الموصى عليها بواسطة مفوضية الات
قيقا هيرتز. اجتاز مولد الضجيج شبه 191مل ديسبل عند تردد 5192-يبلغ مقداره العشوائيمجموعة اختبارات العشوائية المصممة بواسطة المعهد الوطني للمعايير و التقنية
البنية البسيطة و السرعة العالية و القدرة بالولايات المتحدة الامريكية.بخصائصه المتمثلة في المستهلكة المنخفضة بالاضافة لتكلفة الانتاج المنخفضة، هذه الدائرة تعتبر مناسبة للتطبيق
على انظمة الاتصالات اللاسلكية التي تعمل على النطاقات فائقة السعة.
iv
APPROVAL PAGE
I certify that I have supervised and read this study and that in my opinion; it conforms
to acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Master of Science in Communication
Engineering.
…………………………………..
Sheroz Khan
Supervisor
I certify that I have supervised and read this study and that in my opinion; it conforms
to acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Master of Science in Communication
Engineering.
…….……………………………..
Mohammad Umar Siddiqi
Co Supervisor
I certify that I have read this study and that in my opinion it conforms to acceptable
standards of scholarly presentation and is fully adequate, in scope and quality, as a
dissertation for the degree of Master of Science in Communication Engineering.
…………………………………..
Mohamed HadiHabaebi
Internal Examiner
This dissertation was submitted to the Department of Electrical and Computer
Engineering and is accepted as a fulfilment of the requirement for the degree of
Master of Science in Communication Engineering.
…………………………………..
Othman O- Khalifa
Head, Department of Electrical
and Computer Engineering
This dissertation was submitted to the Kulliyyah Engineering and is accepted as a
fulfilment of the requirement for the degree of Master of Science in Communication
Engineering.
…………………………………..
Md. Noor Hj. Salleh
Dean, Kulliyyah of Engineering
v
DECLARATION
I hereby declare that this dissertation is the result of my own investigation, except
where otherwise stated. I also declare that it has not been previously or concurrently
submitted as a whole for any other degrees at IIUM or other institutions.
SitiHazwaniBintiYaacob
Signature…………………. Date …..................
vi
INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA
DECLARATION OF COPYRIGHT AND AFFIRMATION
OF FAIR USE OF UNPUBLISHED RESEARCH
Copyright ©2014 by International Islamic University Malaysia. All rights reserved.
PSEUDO RANDOM NOISE BASED SPREAD SPECTRUM MODULATION
SCHEME FOR SECURE UWB WIRELESS COMMUNICATION
No part of this unpublished research may be reproduced, stored in a retrieval system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying,
recording or otherwise without prior written permission of the copyright holder except
as provided below.
1. Any material contained in or derived from this unpublished research may
be used by others in their writing with due acknowledgement.
2. IIUM or its library will have the right to make and transmit copies (print
or electronic) for institutional and academic purposes.
3. The IIUM library will have the right to make, store in a retrieval system
and supply copies of this unpublished research if requested by other
universities and research libraries.
Affirmed by SitiHazwaniBintiYaacob
……..……..…………… …………………..
Signature Date
vii
ACKNOWLEDGEMENTS
It has been a long awaited journey to complete this thesis. Alhamdulillah. Praise to
Allah s.w.t. Without His blessing, all my hard work would not come to an impressive
result. One other important factor in completing this thesis is the guidance of my
supervisor Assoc. Prof. Dr. Sheroz Khan and my co-supervisor Prof. Dr. Mohammad
Umar Siddiqi. Their guidance is the key to my success. Thank you very much, I really
appreciate their support. Last but not least, my most heartfelt gratitude is reserved to
my husband and mother for their patience, trust, and belief in my endeavor.
viii
TABLE OF CONTENTS
Abstract .......................................................................................................................... ii Abstract(Arabic)............................................................................................................ iii Approval page ............................................................................................................... iv Declaration ..................................................................................................................... v
Copyright Page .............................................................................................................. vi Acknowledgement ....................................................................................................... vii List of Tables ................................................................................................................. x List of Figures ............................................................................................................... xi
List of Abbreviations .................................................................................................. xiii List of Symbols ........................................................................................................... xiv
CHAPTER 1: INTRODUCTION ............................................................................... 1 1.1 Background ................................................................................................... 1
1.2 Problem Statement ........................................................................................ 4
1.3 Research Scope ............................................................................................. 5
1.4 Research Methodology ................................................................................. 6
1.5 Research Objectives...................................................................................... 7
1.6 Thesis Outlines ............................................................................................. 7
CHAPTER 2: LITERATURE REVIEW ................................................................... 9 2.1 Background of Secure UWB Communication ............................................. 9
2.2 Contemporary Techniques .......................................................................... 13
2.3 Summary ..................................................................................................... 16
CHAPTER 3: METHODOLOGY ............................................................................ 17 3.1 Introduction................................................................................................. 17
3.2 Experimental Tools ..................................................................................... 17
3.2.1 Simulation Tools ................................................................................................. 18
3.2.2 NIST Test Suites Tools ....................................................................................... 19
3.3 Specification of Proposed Circuit ............................................................... 19
3.4 Circuit Level Mechanism ........................................................................... 22
3.5 Methodology Procedures ............................................................................ 27
3.6 Randomness Tests ...................................................................................... 29
3.7 Summary ..................................................................................................... 38
CHAPTER 4: RESULTS, ANALYSIS AND DISCUSSION ................................ 39
4.1 Introduction................................................................................................. 39
4.2 Simulation Results ...................................................................................... 39
4.2.1 Effect of Changing Component Values .............................................................. 44
4.2.2 PSD Validation ................................................................................................... 47
4.3 Randomness Test Evaluation ...................................................................... 54
ix
4.4 Summary ..................................................................................................... 56
CHAPTER 5: CONCLUSION .................................................................................. 57
5.1 Conclusion .................................................................................................. 57
5.2 Recommendation ........................................................................................ 58
REFERENCES ........................................................................................................... 60
x
LIST OF TABLES
Table No.
Page No.
2.1 Comparison of techniques used in a few related works 15
3.1 The simulation components list 18
3.2 The circuit components specification 20
3.3 The subblock and maximum run 32
3.4 The subblock and the longest run 32
3.5 The L-bit blocks and the content 34
3.6 The possible L-bit value and the location 35
3.7 The computed Li, Ti values and its determination 37
4.1 The output pulse parameters changes with Avalanche
capacitor C3
46
4.2 Performance comparision of UWB pulse generator using
Avalanche Transistor with previous designs
46
4.3 Power Spectral Density (PSD) magnitude of UWB pulses
changes with Avalanche capacitor at frequency ≥ 3.1GHz
53
4.4 NIST randomness test results 54
4.5 The comparison of NIST randomness tests with previous
PRNG
55
xi
LIST OF FIGURES
Figure No.
Page No.
1.1 Figure 1.1 UWB spectral mask for indoor
communication systems
2
1.2 Flow chart of research methodology 6
2.1 Comparison of the spectrum allocation for different
wireless radio systems
11
2.2 A secure UWB transceiver block diagram 12
3.1 Interface of NI Multisim 11.0 showing the transient
simulation tools
18
3.2 The schematic diagram of designed circuits: PRNG
using LFSR, DSSS modulator and UWB Avalanche
pulse generator
21
3.3 The whole system block diagram 22
3.4 24 bit of LFSR circuit 23
3.5 An example of simulation output of PRN code c(t), data
stream d(t anddata modulated by PRN v(t) running in
50us/Div time base and 10V/Div amplitude
24
3.6 Avalanche transistor output characteristics chart
25
3.7 Schematic circuit of UWB Avalanche pulse generator
using 2N5551 transistor
26
4.1 Pseudo Random Noise (PRN) sequence generated by 24
–bit LFSR (underside) and clock pulses (upside)
40
4.2 Simulation results of keying process: PRN code
(upside), data stream (middle) and PRN code modulated
by data signal (underside)
41
4.3 Time period measurement of PRNK and data signal 42
4.4 The UWB pulse train generated by using 30pF
Avalanche capacitor
43
xii
4.5 A single inverted Gaussian monocycle pulse of UWB
pulse generated by using 30pF Avalanche capacitor
43
4.6 The waveforms of input trigger signal (underside) and
collector output signal (upside)
44
4.7 A single inverted Gaussian monocycle pulse generated
by using 1.5pF Avalanche capacitor
45
4.8 A single inverted Gaussian monocycle pulse generated
by using 15pF Avalanche capacitor
45
4.9 The transition from narrowband to UWB in the
frequency domain
48
4.10 The power spectrum density of narrowband, spread
spectrum and UWB signal
49
4.11 Power spectral density of data signal with dBm
magnitude
50
4.12 Power spectral density of data signal with voltage
magnitude
50
4.13 Power spectral density of PRN sequence 51
4.14 Power spectral density of DSSS modulated signal 51
4.15 Power spectral density of UWB signal using 30pF
Avalanche Capacitor
52
4.16 Power spectral density of UWB signal using 15pF
Avalanche Capacitor
53
4.17 Power spectral density of UWB signal using 1.5pF
Avalanche capacitor
53
xiii
LIST OF ABBREVIATIONS
BJT Bipolar Junction Transistor
BPSK Binary Phase Shift Keying
CMOS Complementary Metal Oxide Semiconductor
Div. Division
DPSK- DSSS Differential Phase Shift Keying –Direct Sequence Spread
Spectrum
DS-CDMA Direct Sequence - Code Division Multiple Access
DSSS Direct Sequence Spread Spectrum
dB Decibel
dBm Mili-decibel
EDA Electronic Design Automation
erfc complementary error function
FCC Federal Communications Commission
FHSS Frequency Hopping Spread Spectrum
GPS Satellite Positioning System
IEEE Institute of Electrical and Electronics Engineers
igmc incomplete gamma function
LFSR Linear Feedback Shift Register
MANET Mobile ad hoc Network
NI National Institute
NIST National Institute of Standards and Technology
PAM Pulse Amplitude Modulation
PN Pseudo Number
PPM Pulse Position Modulation
PRNK Pseudo Random Noise Key
PRNG Pseudo Random Noise Generator
PSD Power Spectral Density
PSK Phase Shift Keying
RFID Radio Frequency IDentification
RNG Random Number Generator
SRD Step Recovery Diodes
THSS Time Hopping Spread Spectrum
UWB Ultra Wideband
WiMax Worldwide Interoperability for Microwave Access
WSA Weighted Switching Activity
XOR Exclusive OR gate
xiv
LIST OF SYMBOLS
α Common base current gain
σ Standard deviation
µ Mean
π 3.14159…unless defined otherwise for a specific test
Ω Resistance unit (Ohm)
𝛴 The summation symbol
Σ2
Variance
χ2 The chi-square distribution
χ2
(obs) The chi-square statistics computed on the observed value.
ε The original input string of zero and one bits to be tested
εi ith
bit in the original sequence
BVCBO Collector-base breakdown voltage
C Capacitor
F Capacitance unit (Farad)
fn The sum of the log2 distances between matching L-bit template
i Current
iB Base current
iC Collector current
K The number of degrees of freedom
L The length of each block
Li Length of the shortest Linear Feedback Shift Register sequence that
generate all bits in the block i
log(x) The natural logarithm of x: log(x) = loge(x) = ln x
xv
M Miller Avalanche multiplication coefficient
M The number of bits in a substring (block) to be tested.
m Semiconductor constant
N The number of M-bit blocks to be tested
n Length of the length testing bit string
Q The number of blocks in the initialization sequence
R Resistor
RL Load resistor
rb Data rate
rc Chip rate
Sn The nth
partial sum for values Xi = (-1,+1)
Sobs Absolute value of the sum of the Xi
Tj Table entry corresponding to the decimal representation of the content
of the ith
L-bit block
V Voltage (volt)
VCC IC power supply pin
Vc Collector output signal
Vcc Common collector voltage
VCE Voltage between collector and emitter
Vi Input signal
Vi The frequencies of the pattern
Vn The expected number of runs that would occur in sequence of length n
Vn(obs) The observed number of runs that would occur in sequence of length n
Xi The elements of the string consisting of ±1 that is to be tested
1
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND
Ultra Wideband (UWB) is a technology for use in short-distance communication of
data with an element of reliability. It consists of streaming of short pulses embedded
with data and produced by step or pulse excited-antennas or filters for a carrier free
communication. The UWB style of communication offers the advantages of high
speed data transmission with a very low power operation. Transmitting a large amount
of digital data over a wide spectrum of UWB in a secure fashion can be accomplished
by using some data embedding features (modulation) coupled with encryption
techniques. The methods such as spread spectrum, time and frequency modulation
schemes as well as multiplexing are reported and being discussed in recent reports
(Bobby, 2012; Long and Peng, 2011; Leon et al., 2004). While making sure a perfect
match between data items and the bits used for encryption, the use of cryptography
techniques based on generating high performance of random numbers increases the
reliability of the UWB systems.
UWB signals are used for commercial operation in the unlicensed frequency
band of 7500 MHz (3.1 – 10.6 GHz) with maximum emission power of -41 dBm per
MHz as per the specification released by the Federal Communications Commission
(FCC) on February 2002. (Roberto and Gerald, 2003).The illustration of the UWB
spectral mask for indoor communication systems as shown as in figure 1.1
below.(Roberto and Gerald, 2003). The announcement has opened many opportunities
for UWB potential applications in such short range and high speed wireless
communication including Radio Frequency IDentification (RFID), vehicular
2
monitoring and tracking systems, short range positioning system and handheld
outdoor applications in peer to peer mode operation without location restriction.
Figure 1.1 UWB spectral mask for indoor communication systems
The researchers in UWB area are actively reporting on issues such
improvement of system on signal generation, security enhancement, power
consumption, transmission speed, and enhancement of transceiver designs. Those
issues are necessary and could be chained together in order to make sure the resulting
system is able to meet the specifications of UWB regulation. In an article by Roberto
and Gerald (2003) stated that the emerging trends of UWB is a solution for the IEEE
802.15.3a (TG3a) standard which provides specification for a low complexity, low
power consumption and high data rate wireless connectivity. As for a security purpose
variety of modulation schemes should be properly selected to meet the different
design parameters for different applications. For instance, in a recent reported work by
Bobby (2012) Differential Phase Shift Keying –Direct Sequence Spread Spectrum,
called DPSK- DSSS for short, is being used for UWB transceiver modulation and
3
demodulation technique with Bi-phase modulation for recovering original input.
Another related work by Leon et al. (2004) is using Direct Sequence - Code Division
Multiple Access (DS-CDMA) technique for providing enhanced multiple access
capacity in mobile communication system. Both papers have proven that spread
spectrum technique is the most favorable choice and option for indoor wireless
communication applications.
Another aspect that should be the focus in security issues is the Pseudo
Random Noise Sequence generation or what is known as the spreading code sequence
(key) in spread spectrum applications. Linear Feedback Shift Register (LFSR) is the
most reliable method for generating pseudo random number in cryptographic key
generation algorithms. Having good statistical properties, low implementation cost,
low complexity and high speed rates are the reasons of wider acceptance of its usage
(Faheem et al., 2012). However, the enhancement of mathematical algorithms could
improve the performance of Pseudo Random Number Generator (PRNG). As reported
by Rahimov et al. (2011) proposes a combination chaotic equation for LFSR operation
that can produce a longer period of random sequence and improve the linear property
of LFSR.
The recent works by Long and Peng. (2011) and Bobby (2012) are most
preferable approaches when applied correctly to this research methodology. In another
published work by Long and Peng (2011) they proposed another technique of spread
spectrum which is Time Hopping Spread Spectrum (THSS) to be employed in UWB
communication system to improve the PSD performance of UWB Binary Phase Shift
Keying (BPSK) modulation schemes. The analysis of transceiver circuit design and its
performance is verified using spread spectrum modulation technique for UWB
wireless local area network using simulink model of DPSK DSSS transceiver. With
4
proper chosen of PN sequence generator and matching filters the circuit is
successfully used for transmitting and recovering of data messages with acceptable
accuracy.
This research is inclined towards on security area by choosing Direct Sequence
Spread Spectrum (DSSS) technique to be used in secure UWB wireless
communication systems with its own architecture of circuitry components such as 24
bits of PRNG and Avalanche UWB pulse generator. The system is managed to
maintain the operation in desirable low power. The theoretical explanation of how the
system works is provided and then matched by the simulation results of our sample
data transmission in UWB mode. At the end of work, we expect to show that the
spectral density validation has satisfied the UWB regulation specification
requirements better than other reported related works. We also emphasize the strength
of our transmitter is satisfied by evaluating the NIST randomness tests results. The
techniques of secure data transmission in the Ultra Wideband (UWB) wireless
communication application are increasingly discussed and reported. Most authors
agree that pseudo random key generation technique and data encoding technique are
most important considerations. Similar to the narrowband technology, UWB allows a
modulation scheme for data encoding technique applied in the system including
spread spectrum modulation.
1.2 PROBLEM STATEMENT
For a secured UWB communication system, the need for high quality of randomness
of key sequence generated by Pseudo Random Noise Generator (PRNG) is a challenge
for researchers as the sequence is only said to be random only if it is passes a number
5
of statistical tests. 24- bits of LFSR that used in this research work can provide a
sufficiently long period of key sequence and passes all the randomness tests.
Meanwhile, for a UWB system which adopts Direct Sequence Spread
Spectrum technique (DSSS) for data encoding purpose, it is important to clarify a
fundamental different between UWB communication and spread spectrum such their
bandwidth allocation. Therefore, the need of proper component operation in the
transceivers is essential to allocate the appropriate bandwidth for data signal during
transmission. As a solution, Avalanche UWB pulse generator has been proposed to
generate the nanosecond pulses of UWB signals in the Gigahertz bandwidth spectrum.
The shorter pulse duration and lower pulse amplitude is desirable for high speed and
low power communication. As the result, its Power Spectral Density (PSD) would
satisfy the UWB FCC mask spectrum. The lower magnitude of PSD would promise
the covert communication. Meanwhile, at the same time our system is making use of
the potentials of spread spectrum technique and UWB technology advantages such
high strength of security, low power, low cost and high speed of UWB wireless
communication application.
1.3 RESEARCH SCOPE
This research is based on the idea of using Direct Sequence Spread Spectrum (DSSS)
principle into a secure UWB communication system with its own architecture of
circuitry components such as 24 bits of PRNG and Avalanche UWB pulse generator.
Theoretical explanation of how the system is working is provided which is validated
by the simulation results of sample data transmission in UWB mode at the transmitter
side. Our work covers the evaluation using the NIST randomness tests results only.
However, immunity of our system against possible attacks (such as jamming, hacking
6
and blocking) of our data transmission is out of the scope of this thesis and are left for
future work.
1.4 RESEARCH METHODOLOGY
Figure 1.2 Flow chart of research methodology
E
ERRORS & JUSTIFICATION
RESULTS & ANALYSIS
1) Simulation Results
2) Randomness test evaluation
3) Effect of component values
4) Spectral Density validation
5) Benchmarking
TEST
Randomness test by NIST test suites
TECHNIQUES (SIMULATION)
1) PRN sequence generation by 24 bit LFSR
2) Data modulation by DSSS technique
3) UWB data signal generation by Avalanche transistor circuit
MODEL (SIMULATION)
1) Pseudo Random Number Generator (PRNG) of 24 bit LFSR
2) Direct Sequence Spread Spectrum (DSSS ) modulator
3) AvalancheUWB pulse generator circuit
PROBLEMS IDENTIFICATION
Literature survey and critical review of papers for identifying problem to be address
7
1.5 RESEARCH OBJECTIVES
The research work is aimed at investigating and developing aspects of proposed data
transmission technique with application in secure UWB communication. The main
objectives of the research work are as follow;
1. To design the Pseudo Random Noise Key Generator (PRNG) for a secure
UWB communication system.
2. To employ the Direct Sequence Spread Spectrum (DSSS) technique for a low
power UWB communication system.
3. To analyze the performance of Avalanche UWB pulse generator.
4. To test the randomness of proposed PRNG
1.6 THESIS OUTLINES
Chapter one has given the knowledge for the reader on what are the research all about,
the problem issues that we want to improve and the rationale of performing this
project.
Chapter two is very informative sources to review the researcher’s ideas and
approaches on solving the problems issues such security, power consumption and so
on. It is starting from general discussion on the work, narrowing it to the focus of
work in this research while passing through less and less general contemporary work,
ultimately zooming in more and much related research work for bench-marking
purpose.
Chapter three is provided with the information of the experimental tools
involved in this research work including circuit simulation, pseudo randomness test
and the specification of the components used for future reference. The UWB
transmitter design is thoroughly detailed by explaining the mechanism of the proposed
8
system. The experimental work is done by following the procedure and the results are
collected according to the flow of experiment. Last but not least, the algorithm and
computation for randomness tests of Pseudo Random Noise (PRN) sequence are
performed and justified.
Chapter four is about analysis of the simulation results of the designed circuits.
The result signals discussed step by step according to the system flow. The effect of
tunable values parameter such of Avalanche UWB pulse generator is observed. Lastly,
we validated the PSD of each signal going through in the design system to be in the
proper specification. The UWB pulse generated, Power Spectral Density (PSD) and
NIST statistical test result are compared with other related work.
Chapter five is a conclusion of the whole thesis and results obtained. Some
recommendation for future work is also stated in this last chapter.
9
CHAPTER TWO
LITERATURE REVIEW
This chapter provides the summary of the secure UWB communication background
including the key generation and its function, the encryption and decryption
technique, and the UWB pulse generation technique. Several contemporary works are
discussed on their general description, technique used, the result obtained and the
comparison of obtained result to other related work. The further discussion continued
by reviewing the much related work and ending with benchmarking.
2.1 BACKGROUND OF SECURE UWB COMMUNICATION
A communication between two authorized parties is said to be secure only if the
information transmitted is protected against any attempts by unauthorized parties to
capture, modify or block the transmitted information. (Denning, 1983; Scheneir, 1996;
Menezes, Oorschots and Stone, 1997). They state that securing wireless
communication requires a secret key generation and the same key (symmetric
encryption) or associated key (asymmetric or public-key encryption) is being used by
transmitter and receiver for encryption and decryption purpose. Basically, random
noise is used as a source signal for devices in a system to build up those keys to secure
the information data. Pseudo Random Number Generator (PRNG) is a common key
generator used in data communication that generates sequence of random binary
numbers. The sequence is said as pseudo random only if it passes a number of
statistical tests.
Linear Feedback Shift Register (LFSR) is the most preferable method for
generating pseudo random noise in cryptographic algorithm. Faheem, Shadab and