See discussions, stats, and author profiles for this publication at: https://www.researchgate.
net/publication/313531337
Orthogonal Frequency Division Multiplexing (OFDM) Implementation by
MATLAB
Thesis · May 2016
DOI: 10.13140/RG.2.2.34931.73763
CITATIONS READS
0 890
4 authors, including:
Ali Jasim Ramadhan
University of Alkafeel
14 PUBLICATIONS 15 CITATIONS
SEE PROFILE
Some of the authors of this publication are also working on these related projects:
5G Technologies View project
Wireless Sensor Networks WSNs View project
All content following this page was uploaded by Ali Jasim Ramadhan on 10 February 2017.
The user has requested enhancement of the downloaded file.
Orthogonal Frequency Division Multiplexing
(OFDM) Implementation by MATLAB
A Thesis
Submitted to the Department of Computer Engineering Technologies /
The University College of Humanity Studies / An Najaf / Iraq
in Partial Fulfilment of the Requirements for the Degree of
Bachelor of Science in Computer Engineering Technologies
By
Zain Al-abdeen Deah Al-deen Salim
Ahmed Murtadh Kareem
Yousif Gassan Baqer
Supervised by
Mr. Ali Jasim Ramadhan Al-Aameri
2015-2016
Scanned by CamScanner
Scanned by CamScanner
Specially dedicated to
My dear Father and my Mother compassionate
III
اﻹﻫﺪاء
اﺷﻜﺮ ﷲ رب اﻟﻌﺎﻟﻤﻴﻦ اﻟﺬي اﻧﻌﻢ ﻋﻠﻴﻨﺎ ﺑﻨﻌﻤﺔ اﻟﻌﻘـﻞ واﻟﺪﻳﻦ
اﻟﻰ اﻟﺬي ﻣﻨﺤﻨﺎ ﻛﻞ ﻣﺎ ﻳﻤﻠﻚ ......وﻟﻮ ﻳﺄﺧﺬ ﺟﻬﺪا ﻓﻲ ﺗﻘﺪﻳﻢ اﻟﺪﻋﻢ اﻟﻴﻨﺎ ....ﻣﺎدﻳﺎ
وﻣﻌﻨﻮﻳﺎ وﻧﻔﺴﻴﺎ ﺣﺘﻰ ﻛﻨﺎ ﻧﺒﺎﺗﺎ اﺳﺘﻮى ﻋﻠﻰ ﺳﻮﻗﻪ ﺑﺄذن ﷲ ....وﻛﻨﺎ اﻟﺰرع
اﻟﺬي ﻳﻌﺠﺐ اﻟﺰراع ﻧﺒﺎﺗﻪ
وﺳﺮ ﻧﺠﺎﺣﻨﺎ وﻧﻮر درﺑﻨﺎ .........واﻟﺪي اﻟﻌﺰﻳﺰ
إﻟﻰ ﻧﺒﻊ اﻟﻤﺤﺒﺔ واﻟﺤﻨﺎن واﻟﻮﻓـﺎء ........واﻟﺪﺗﻲ اﻟﺤﺒﻴﺒﺔ
اﻟﺘﻲ ﻟﻢ ﺗﺄل ﺟﻬﺪا ﻓﻲ ﺗﺮﺑﻴﺘﻲ وﺗﻮﺟﻴﻬﻲ
اﻟﻰ أﺑﻨﺎء اﻟﺤﺸﺪ اﻟﺸﻌﺒﻲ اﻟﻤﻘﺪس وأﺑﻨﺎء ﻗﻮاﺗﻨﺎ اﻷﻣﻨﻴﺔ اﻟﺒﺎﺳﻠﺔ
اﻻﺑﻄﺎل اﻟﺬﻳﻦ ﻓﻨﻮا ارواﺣﻬﻢ ﻣﻦ اﺟﻠﻨﺎ
اﻟﻰ ﻣﻦ اﺿﺎء ﺑﻌﻠﻤﻪ ﻋﻘـﻞ ﻏﻴﺮﻩ
او ﻫﺪى ﺑﺎﻟﺠﻮاب اﻟﺼﺤﻴﺢ ﺣﻴﺮة ﺳﺎﺋﻠﻴﻪ
ﻓـﺄﻇﻬﺮ ﺑﺴﻤﺎﺣﺘﻪ ﺗﻮاﺿﻊ اﻟﻌﻠﻤﺎء
وﺑﺮﺣﺎﺑﺘﻪ ﺳﻤﺎﺣﺔ اﻟﻌﺎرﻓﻴﻦ ....أﺳﺘﺎذﻧﺎ اﻟﻤﺤﺘﺮم
اﻟﻤُﺨﺘَﺮِع )ﻋﻠﻲ ﺟﺎﺳﻢ رﻣﻀﺎن اﻟﻌﺎﻣﺮي(
اﻟﻰ ﻛﻞ ﻣﻦ ﻋﻠﻤﻨﻲ ﺣﺮﻓـﺎ
اﻫﺪي ﻫﺬا اﻟﻌﻤﻞ اﻟﻤﺘﻮاﺿﻊ راﺟﻴﺔ ﻣﻦ
اﻟﻤﻮﻟﻰ ﻋﺰوﺟﻞ ان ﻳﺠﺪ اﻟﻘﺒﻮل واﻟﻨﺠﺎح
IV
Abstract
The next generation wireless communications systems need to be of a
higher standard in order to provide the customers with the multitude of
high quality services they demand.
In recent years, Orthogonal Frequency Division Multiplexing (OFDM)
has been successfully used in terrestrial digital video broadcasting and
showed it is a strong candidate for the modulation technique of future
wireless systems.
This project is concerned with how well OFDM performs when
transmitted over an Additive White Gaussian Noise (AWGN) channel
only. In order to investigate this, a simulation model was created and
implemented using MATLAB program.
The OFDM (.bmp image) signal was transmitted over the AWGN
channel for various Phase Shift Keying (PSK) technique cases and
various Signal to Noise Ratio (SNR) values. To evaluate the
performance, for each SNR level, the received image was demodulated
and compared to the original image.
V
Table of Contents
Declaration I
Approval for Submission II
Special dedicate III
Acknowledgements IV
Abstract V
Table of Contents VI
List of Abbreviations VIII
Chapter
1 Introduction
1.1 Introduction 1
1.2 Problem 3
1.3 Objective 4
2 Orthogonal Frequancy Divison Multiplexin
2.1 Introduction 5
2.2 Historical Background 6
2.3 Principle OFDM 8
2.4 Basic OFDM System 12
2.5 OFDM Parameters and Characteristics 13
2.6 Orthogonality 14
2.7 Advantages of OFDM 14
2.8 Disadvantages of OFDM 16
2.9 Limitation of OFDM 17
2.10 OFDM Application 18
VI
3 Design and Implementation
3.1 Overview 19
3.2 System Configurations and Parameters 20
3.3 Input And Output 22
3.4 OFDM transmitter 25
3.4.1 Frame Guards 25
3.4.2 OFDM Modulator 27
3.5 Communication Channel 30
3.6 OFDM receiver 31
3.6.1 Frame detector 31
3.6.2 Demodulation Status Indicator 32
3.6.3 OFDM Demodulator 33
3.7 Error Calculations 36
3.8 Plotting 37
4 Results And Discussion
4.1 Results 40
4.2 Discussion 41
5 Conclusion and Future Work
5.1 Conclusion 43
5.2. Future Work 44
References 45
Appendix 47
VII
List of Abbreviations
OFDM Orthogonal Frequency Division Multiplexing
ISI Inter Symbol Interference
FDM Frequency Division Multiplexing
FFT Fast Fourier Transform
HDTV High Definition Television
DAB Digital Audio Broadcasting
WLANs Wireless Local Area Networks
MBWA Mobile Broadband Wireless Access
LAN Local Area Networks
IDFT Inverse Discrete Fourier Transform
IFFT Inverse Fast Fourier Transform
RF Radio Frequency
ICI Inter Carrier Interference
AWGN Additive White Gaussian Noise
DPSK Differential Phase Shift Keying
BER Bit Error Rate
SNR Signal to Noise Ratio
VIII
Chapter Four
Results and Discussion
Chapter Four Results and Discussion
Chapter Four
Results and Discussion
4.1. Results:
Figures 4.1 to 4.4 show the original image and received images for
different PSK techniques.
Fig 4.1 BPSK ; SNR=5
Fig 4.2 QPSK ; SNR=10
40
Chapter Four Results and Discussion
Fig 4.3 16PSK ; SNR=15
Fig 4.4 256PSK ; SNR=20
4.2. Discussion:
Even some low SNR received images, especially 256-DPSK
modulated images, have rather high BER; most of the information in
the received images is still observable. In fact, when toggling
41
Chapter Four Results and Discussion
between the original and received image in this case, it’s obvious that
the gray level on most of the pixels did change, but the relatively
contents are still somewhat intact. A balanced trade-off between
BER-tolerance and desire of data rate needs to be found for the type of
data to be transmitted using OFDM.
42
Chapter Five
Conclusion and Future Work
Chapter Five Conclusion and Future Work
5.1. Conclusion:
An OFDM system is successfully simulated using MATLAB in this
project. All major components of an OFDM system are covered. This
has demonstrated the basic concept and feasibility of OFDM, which
was thoroughly described and explained in Chapter 3 of this report.
Some of the challenges in developing this OFDM simulation program
were carefully matching steps in modulator and demodulator, keeping
track of data format and data size throughout all the processes of the
whole simulation, designing an appropriate frame detector for the
receiver, and debugging the MATLAB codes. Chapter 4 showed and
explained some analyses of the performance and characteristics of this
simulated OFDM system. It was noted that for some combinations of
OFDM parameters, the simulation may fail for some trials but may
succeed for repeated trails with the same parameters. It is because the
random noise generated on every trial differs, and trouble may have
been caused for the frame detector in the OFDM receiver due to
certain random noise. Future work is required to debug this issue and
make the frame detector free of error.
43
Chapter Five Conclusion and Future Work
5.2. Future work:
Other possible future works to enhance this simulation program
include adding ability to accept input source data in a word size other
than 8-bit, adding an option to use QAM (Quadrature amplitude
modulation) instead of M-DPSK as the modulation method.
44
References
References
References
1. Ramadhan, Ali Jasim. Space-Time Coding STC. Diss. University
of Kufa, 2011.
2. A. Jasim, "A Novel MIMO-OFDM Technique for Improving
Wireless Communications System Performance based on SF--
BC," International Journal of Computer Applications, vol. 131,
pp. 28-31, 2015.
3. Schulze, Henrik and Christian Luders. Theory and Applications
of OFDM and CDMA John Wiley & Sons, Ltd. 2005.
4. Theory of Frequency Division Multiplexing:
http://zone.ni.com/devzone/cda/ph/p/id/269.
5. Acosta, Guillermo. “OFDM Simulation Using MATLAB” 2000.
6. A Brief History of OFDM
http://www.wimax.com/commentary/wimax_weekly/sidebar-1-1-
a-brief-history-of-ofdm.
7. Lui, Hui and Li, Guoqing. OFDM-Based Broadband Wireless
Networks Design and Optimization Wiley-Interscience 2005.
8. Litwin, Louis and Pugel, Michael. “The Principles of OFDM”
2001.
45
References
9. Heiskala, Juha and Terry, John. OFDM Wireless LANs: A
Theoretical and Practical Guide SAMS 2001.
10. Lawrey, Eric “Adaptive Techniques for Multiuser OFDM” Ph.D.
Thesis, James Cook University 2001.
11. BBC Research Department, Engineering Division, “An
Introduction to Digital Modulation and OFDM Techniques”
1993.
12. Tran, L.C. and Mertins, A. “Quasi-Orthogonal Space-Time-
Frequency Codes in MB- OFDM UWB” 2007.
13. Understanding an OFDM transmission:
http://www.dsplog.com/2008/02/03/understanding-an-ofdm-
transmission/.
14.Minimum frequency spacing for having orthogonal sinusoidals
http://www.dsplog.com/2007/12/31/minimum-frequency-spacing-
for-having-orthogonal-sinusoidals/.
46
View publication stats
