vii
TABLE OF CONTENTS
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
x
LIST OF FIGURES
xi
LIST OF ABBREVIATIONS
xvi
LIST OF SYMBOLS
xviii
LIST OF APPENDICES
xx
INTRODUCTION
1
1.1
Introduction
1
1.2
Background
2
1.3
Problem Statement
3
1.4
Research Objectives
4
1.5
Scope of Work
4
1.6
Significance of Research Work
5
1.7
Thesis Contributions
6
1.8
Thesis Organization
6
LITERATURE REVIEW
8
2.1
Introduction
8
2.2
OFDM
8
2.2.1
OFDM Principles
9
viii
2.3
2.4
2.5
3
4
ICI Analysis for OFDM
16
2.2.3
OFDM Performance
26
Mobile Radio Channel
31
2.3.1
Modeling Multipath Fading Channels
31
2.3.2
Mobile Channel Parameters
32
2.3.3
Fading Channel Classification
36
ICI Mitigations Techniques
41
2.4.1
Channel Estimation Techniques
42
2.4.2
Pulse-Shaping Techniques
47
2.4.3
Recent Related Works
54
Summary
62
RESEARCH METHODOLOGY
63
3.1
Introduction
63
3.2
Chart Description
63
3.3
Distortion Scheme
65
3.4
Generalized Scheme
66
3.5
Proposed Pulse-Shape
66
3.6
OFDM Parameters
66
3.7
Summary
69
ICI MITIGATION TECHNIQUES
70
4.1
Introduction
70
4.2
Channel Estimation Schemes
70
4.2.1
Data-Distorted Scheme
70
4.2.2
Generalized Scheme
78
4.3
4.4
5
2.2.2
Pulse-Shaping
82
1.3.4
Derivation of the Pulse-Shape
83
4.3.2
System Model
87
Summary
89
RESULTS AND DISCUSSIONS
90
5.1
Introduction
90
5.2
Preliminary Results
90
5.3
Channel Estimation Results
95
ix
5.4
5.5
6
5.3.1
Data-Distortion Scheme
95
5.3.2
Generalized Scheme
106
Pulse-Shaping Results
110
5.4.1
ICI Power and SIR Numerical Results
111
5.4.2
OFDM over AWGN Channel with CFO Results
114
5.4.3
OFDM over Time-Varying Channel Results
119
Summary
123
CONCLUSION
124
6.1
Introduction
124
6.2
Contributions
124
6.3
Conclusions
126
6.4
Further Work
127
6.5
Summary
128
REFERENCES
Appendices A-D
129
143-163
x
LIST OF TABLES
TABLE NO.
TITLE
‎2.1
Summary of recent related ICI mitigation techniques
‎3.1
OFDM Parameters Used in Mobile WiMAX (Ramler et
PAGE
59
al., 2008)
68
‎3.2
Velocity and Normalized Doppler frequency offsets
69
‎5.1
OFDM simulation parameters
95
‎5.2
OFDM simulation parameters
107
‎5.3
OFDM simulation parameters
111
xi
LIST OF FIGURES
FIGURE NO.
‎2.1
TITLE
Impact of a frequency-selective channel on single
wideband carrier and OFDM (Dahlman et al., 2008)
‎2.2
10
Effect of multipath on the ICI with guard period (Jha and
Prasad, 2007)
‎2.4
9
OFDM system implemented by DFT/FFT (Fazel and
Kaiser, 2008)
‎2.3
PAGE
15
OFDM symbol with cyclic extension (Jha and Prasad,
2007)
16
‎2.5
ICI in OFDM System
16
‎2.6
The scheme of the OFDM system with frequency offset
18
‎2.7
The OFDM system, described as a set of parallel
Gaussian channel (Edfors et al., 1996b)
26
‎2.8
Multipath mobile propagation model (Pätzold, 2012)
31
‎2.9
Doppler effect (Rappaport, 2002)
33
‎2.10
Characteristics of time-varying channel with different
speeds (Tao et al., 2010)
34
‎2.11
Propagation loss (Figueiras and Frattasi, 2010)
37
‎2.12
Types of small-scale fading based on Doppler spread
(Rappaport, 2002)
‎2.13
Relationship between coherence time, and Doppler
spread (Ergen, 2009)
‎2.14
39
41
Pilot arrangement: (a) block-type (b) comb-type and (c)
lattice-type (Cho et al., 2010)
44
‎2.15
Pilot positioning in time and frequency (Ergen, 2009)
45
‎2.16
Time domain of different windows for
48
xii
‎2.17
Spectra of different windows for
‎2.18
OFDM symbol sequence with cyclic extension and
49
windowing (Prasad, 2004)
‎2.19
50
Nyquist windowing: an OFDM symbol is cyclically
extended and shaped by a Nyquist window (Song, 2010)
51
‎2.20
Overlap and add the weighted samples in the receiver
52
‎2.21
Time and frequency of shortened Nyquist windows and
rectangular window for
and
(Peiker et
al., 2009)
58
‎3.1
Research methodology chart
64
‎3.2
Proposed ICI mitigation methods flow chart
65
‎4.1
A base band-model of an OFDM system with the
distortion scheme
‎4.2
71
Channel approximation. Solid line: real or imaginary
part
of
a
channel
path,
Dashed
lines:
PLM
approximation of the channel path
‎4.3
75
Channel approximation. Solid line: real or imaginary
part of a channel path, Dashed line: LM approximation
of the channel path
77
‎4.4
Baseband OFDM system (Bahai et al., 2004)
79
‎4.5
Generalized estimation scheme. Solid line: real or
imaginary part of a channel path, Dashed lines: multiple
linear approximations within OFDM data periods
‎4.6
Time domain comparison of the new pulse with different
values of the parameter
‎4.7
85
Time domain comparison of various Nyquist pulses
.
‎4.9
85
Frequency domain comparison of the new pulse with
different values of the parameter
‎4.8
81
86
Frequency domain comparison of various Nyquist pulses
.
86
‎4.10
OFDM with Nyquist window at the transmitter
87
‎4.11
OFDM with Nyquist window at the receiver
89
xiii
‎5.1
ICI coefficient between -th and
-th subcarriers for
,
‎5.2
91
CIR for different number of subcarriers (
2, 8, and
256)
92
‎5.3
CIR versus
‎5.4
OFDM performance over AWGN channel
93
‎5.5
OFDM performance over flat Rayleigh fading channel
94
‎5.6
The power spectral density of one subcarrier of an
for OFDM system
93
OFDM signal with RC pulse-shaping for different
choices of roll-off parameter
(Farhang-Boroujeny and
Kempter, 2008)
‎5.7
Performance of 64-subcarrier 16QAM-OFDM with the
proposed scheme (channel #2,
‎5.8
97
)
97
Performance of 64-subcarrier 16QAM-OFDM with the
proposed scheme (channel #2,
‎5.10
)
Performance of 64-subcarrier 64QAM-OFDM with the
proposed scheme (channel #2,
‎5.9
94
, Ng
7)
98
The BER performance comparisons as a function of the
normalized Doppler frequency of 64-subcarrier 16QAMOFDM system (channel# 2, Eb /N0
‎5.11
)
102
)
102
)
103
Performance of 128-subcarrier 256PSK-OFDM with the
proposed scheme (channel #2,
‎5.16
101
Performance of 128-subcarrier 128PSK-OFDM with the
proposed scheme (channel #2,
‎5.15
)
Performance of 128-subcarrier 64PSK-OFDM with the
proposed scheme (channel #2,
‎5.14
99
Performance of 128-subcarrier 16PSK-OFDM with the
proposed scheme (channel #2,
‎5.13
)
Performance of 128-subcarrier 16PSK-OFDM with the
proposed scheme (channel #1,
‎5.12
40 dB,
)
103
Performance of 128-subcarrier 16PSK-OFDM with the
proposed scheme (channel #2,
)
104
xiv
‎5.17
The BER performance comparisons of 128-subcarrier
16PSK-OFDM system (channel #1, Eb N0 = 40 dB,
)
‎5.18
105
The BER performance comparisons of 128-subcarrier
16PSK-OFDM system (channel #2, Eb/N0
40 dB,
)
106
‎5.19
OFDM simulated model
‎5.20
Performance of 256-subcarrier BPSK-OFDM with
107
Mostofi scheme and the proposed scheme (
1,
“Vehicular A” channel model)
‎5.21
108
Performance of 256-subcarrier QPSK-OFDM with
Mostofi scheme and the proposed scheme (
1,
“Vehicular A” channel model)
‎5.22
108
Performance of 256-subcarrier QPSK-OFDM with
Mostofi scheme and the proposed scheme (
1, COST
207 channel model)
‎5.23
109
Performance of 256-subcarrier QPSK-OFDM with the
proposed estimator for different values of Q (“Vehicular
A” channel model)
‎5.24
110
Frequency domain of various Nyquist pulses with
0.25
‎5.25
112
The ICI power comparison of the pulse-shaped OFDM
.
system
‎5.26
The ICI power comparison of the pulse-shaped OFDM
.
system
‎5.27
112
113
The SIR comparison of the pulse-shaped OFDM system
.
‎5.28
113
The SIR comparison of the pulse-shaped OFDM system
.
‎5.29
114
The average BER versus roll-off factor α for a pulseshaped 64-subcarrier BPSK-OFDM system over AWGN
channel (
0.1 and Eb /N0
10 dB)
115
xv
‎5.30
The average BER versus roll-off factor α for a pulseshaped 64-subcarrier QPSK-OFDM system over AWGN
0.12 and Eb /N0
channel (
‎5.31
20 dB)
116
Performance of pulse-shaped 64-subcarrier BPSKOFDM system over AWGN channel in case of
and α
‎5.32
0.80
116
Performance of pulse-shaped 64-subcarrier QPSKOFDM system over AWGN channel in case of
and
‎5.33
0.1
0.80)
117
Performance of pulse-shaped 64-subcarrier BPSKOFDM system over AWGN channel in case of
and
‎5.34
0.2
0.25
0.25
118
Performance of pulse-shaped 64-subcarrier 16QAMOFDM system over AWGN channel in case of
‎5.35
0.043 and
0.25
Performance
of
118
64-subcarrier
BPSK-OFDM
with
transmitter pulse-shaping and receiver windowing over
AWGN channel in case of
‎5.36
0.25 and
0.5
119
Performance of 128-subcarrier 16QAM-OFDM with
transmitter pulse-shaping and receiver windowing in
case of
0.05 and
0.6 (COST 207 TU channel
model)
‎5.37
Performance of pulse-shaped 128-subcarrier 16QAMOFDM system (COST 207 TU channel model,
‎5.38
121
0.05)
121
Performance of pulse-shaped 128-subcarrier 16QAMOFDM system (COST 207 TU channel model,
‎5.40
0.05)
Performance of pulse-shaped 128-subcarrier 16QAMOFDM system (COST 207 TU channel model,
‎5.39
120
0.1)
122
Performance of pulse-shaped 128-subcarrier 16QAMOFDM system (COST 207 TU channel model,
0.2)
122
xvi
LIST OF ABBREVIATIONS
3G
-
Third Generation
3GPP
-
3rd Generation Partnership Project
4G
-
Fourth Generation
AWGN
-
Additive White Gaussian Noise
BER
-
Bit Error Rate
BEM
-
Basis Expansion Modeling
BPSK
-
Binary Phase Shift Keying
BTRC
-
“better than” Raised-Cosine Pulse
CFO
-
Carrier Frequency Offset
CIR
-
Carrier Interference Ratio
CIR
-
Channel Impulse Response
CM
-
Cyclic Mean
CSI
-
Channel State Information
dB
-
Decibel
D/A
-
Digital-to-Analog (Converter)
DAB
-
Digital Audio Broadcasting
DFT
-
Discrete Fourier Transform
DVB
-
Digital Video Broadcasting
FDM
-
Frequency Division Multiplexing
FEQ
-
Frequency-Domain Equalizer
FFT
-
Fast Fourier Transform
ICI
-
Intercarrier Interference
IDFT
-
Inverse Discrete Fourier Transform
IFFT
-
Inverse Fast Fourier Transform
IMT
-
International Mobile Telecommunication
ISI
-
Inter Symbol Interference
xvii
ISP
-
Improved Sinc Power
ITU-R
-
International Telecommunications Union – Radio
LM
-
Linear model
LMMSE
-
Linear Minimum Mean Square Estimation
LPF
-
Low-Pass Filter
LS
-
Least Squares
LTE
-
Long-Term Evolution
MMSE
-
Minimum Mean Square Error
MSE
-
Mean-Square Error
OFDM
-
Orthogonal Frequency Division Multiplexing
OFDMA
-
Orthogonal Frequency Division Multiple Access
PAPR
-
Peak-to-Average Power Ratio
P-BEM
-
Polynomial BEM
PDP
-
Power Delay Profile
PLM
-
Piecewise Linear Model
PSD
-
Power Spectral Density
PSK
-
Phase-Shift Keying
QAM
-
Quadrature Amplitude Modulation
QPSK
-
Quadrature Phase Shift Keying
RC
-
Raised-Cosine Pulse
Rect
-
Rectangular Pulse
RF
-
Radio Frequency
Rx
-
Receiver Side
SER
-
Symbol Error Rate
SCM
-
Single-Carrier Modulation
SC
-
Self-Cancellation
SIR
-
Signal to Interference Ratio
SNR
-
Signal to Noise Ratio
SOCW
-
Second Order Continuity Window
SP
-
Sinc Power Pulse
TFT-OFDM -
Time-Frequency Training OFDM
Tx
-
Transmitter Side
WiMAX
-
Worldwide Interoperability for Microwave Access
WSSUS
-
Wide-Sense Stationary Uncorrelated Scattering Process
xviii
LIST OF SYMBOLS
0
-
All-Zero Matrix
1
-
All-One Matrix
Eb
-
Energy per Transmitted Bit
ES
-
Energy per Transmitted Symbol
-
The Exponential Operation
-
The complementary error function
fd
-
Maximum Doppler frequency
fDoppler
-
Doppler Shift
BD
-
Doppler Spread of the Channel
BS
-
Bandwidth of the Baseband Signal
-
Expectation of a Random Variable
fc
-
Carrier frequency
fk
-
Subcarrier Frequency Associated with the k-th Subcarrier
FH
-
N-point IFFT matrix
J0
-
Modified Bessel Function with Zero Order
hl,n
-
The l-th Time-Domain Channel Path at n-th Sample
Hk,m
-
The Frequency-Domain Channel Coefficient
hvar
-
Time-Domain Channel Matrix
Hvar
-
Frequency-Domain Channel Matrix
-
Identity Matrix
-
Length of Channel Impulse Response
-
FFT Size
-
Periods of Pilot Symbols in Frequency Domain
-
Length of Added Cyclic-Prefix
-
Periods of Pilot Symbols in Time Domain
-
Coherence Time
{.}
xix
-
Guard Interval
-
Duration of the Transmitted Baseband Signal
-
Sampling Interval
-
OFDM Symbol Duration without Cyclic Prefix
-
Windowing Interval
-
Multipath Maximum Delay Spread
-
Maximum Channel Delay in samples
var{.}
-
Variance of a Random Variable
wn
-
The n-th Sample of Additive Gaussian Noise
W
-
Frequency Domain Gaussian Noise Vector
X
-
Frequency Domain Transmitted Signal Vector
Y
-
Frequency Domain Recieved Signal Vector
Xk
-
Data Symbol Transmitted on the k-th Subcarrier
Yk
-
Data Symbol Received on the k-th Subcarrier
-
Normalized Doppler Frequency
-
Roll-off Factor
-
Gaussian Noise Variance
-
Subcarrier Spacing
-
Frequency Offset
(·)H
-
Hermitian (Conjugate) Transpose of a matrix
T
(·)
-
The Transposition Operation
(·)#
-
Pseudo-Invers of a Matrix, defined by [(.)H(.)]-1(.)
(·)∗
-
Complex Conjugate
(·)-1
-
Matrix Inverse
⌊⌋
-
The largest Integer That Is Not Greater than Its Argument
⨂
-
The Kronecher Product Operator of Two Matrices
τmax
α
δf
xx
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A
Pulse-Shaping Functions
143
B
Jakes’ Simulator and Power Delay Profiles
145
C
Matlab Source Code
147
D
List of Publication
163