UNIVERSITI PUTRA MALAYSIA

HYBRID SUBCARRIER - OPTICAL SPECTRUM CODE DIVISION MULTIPLEXING SYSTEM WITH SPECTRAL DIRECT DECODING

DETECTION TECHNIQUE

RATNA KALOS ZAKIAH BT SAHBUDIN

FK 2010 110

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HYBRID SUBCARRIER - OPTICAL SPECTRUM CODE DIVISION MULTIPLEXING SYSTEM WITH SPECTRAL

DIRECT DECODING DETECTION TECHNIQUE

RATNA KALOS ZAKIAH BT SAHBUDIN

DOCTOR OF PHILOSOPHY

UNIVERSITI PUTRA MALAYSIA

2010

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HYBRID SUBCARRIER - OPTICAL SPECTRUM CODE DIVISION

MULTIPLEXING SYSTEM WITH SPECTRAL DIRECT DECODING

DETECTION TECHNIQUE

By

RATNA KALOS ZAKIAH BT SAHBUDIN

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,

in Fulfilment of the Requirements for the Degree of Doctor of Philosophy

January 2010

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DEDICATION

To the memory of my father Sahbudin b. Ja‟adil.

5th July 1941-13th Oct 1974

To my mother Ramlah bt. Midun, who had the arduous task of raising four children

by herself after the untimely death of my father.

To my husband Ishak b. Aris, who has supported me in all my endeavors

and all my children

Sarah Irdina, Muhammad Irfan, Muhammad Irham, Muhammad Ridwan

and Safea Irdina.

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Abstract of the thesis presented to the Senate of Universiti Putra Malaysia in

fulfilment of the requirement for the degree of Doctor of Philosophy

HYBRID SUBCARRIER - OPTICAL SPECTRUM CODE DIVISION

MULTIPLEXING SYSTEM WITH SPECTRAL DIRECT DECODING

DETECTION TECHNIQUE

By

RATNA KALOS ZAKIAH BT SAHBUDIN

January 2010

Chairman: Professor Mohamad Khazani Abdullah, PhD

Faculty: Engineering

Today‟s telecommunication systems are expected to provide a reliable, affordable,

flexible, scalable services and possess substantial information carrying capacity in

order to meet the increasingly high user‟s expectation. There has been tremendous

interest in applying hybrid multiplexing technique to fiber optic communication

systems to enhance network flexibility and scalability. Optical spectrum code

division multiplexing (OSCDM) is one of the multiplexing techniques that is

becoming popular because of the flexibility in the allocation of channels, ability to

operate asynchronously, enhanced privacy and increased capacity in bursty nature

networks. On the other hand, subcarrier multiplexing (SCM) technique is able to

enhance the channel data rate of OSCDM systems. The attractive feature of the

current SCM technology is cost-effective as it provides a way to take advantage of

the multi-gigahertz bandwidth of the fiber optics, using well-established microwave

techniques for which components are commercially available. Hence, this thesis

proposes a hybrid SCM and OSCDM (SCM-OSCDM) system for the purpose of

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combining the advantages of both techniques. This hybrid technique can increase the

number of simultaneous users by increasing the SCM and/or the OSCDM codeword.

The performance of the hybrid system strongly depends on the codes properties and

the detection technique. The system utilizes a new unified code construction named

Khazani-Syed (KS) code based on the Double Weight (DW) and Modified Double

Weight (MDW) codes. KS code possesses an ideal in-phase cross correlation

property, which led to the elimination of multiple access interference (MAI). The

effect of MAI will degrade the system performance. Conventionally, MAI is reduced

by using subtraction detection techniques. In this thesis, a new detection technique

called Spectral Direct Decoding (SDD) is introduced. SDD technique requires less

number of filters for the decoders as compared to the subtraction detection

techniques and only filters out the non-overlapping spectral. Thus, eliminate the

phase induced intensity noise (PIIN). The effectiveness of the new hybrid system

with the proposed SDD technique has been verified and demonstrated through

theoretical analysis, simulation and experimental work. The results show that the

new hybrid system with the proposed SDD technique improves the performance than

that using the conventional subtraction detection techniques. For example in

theoretical analysis, at bit error rate (BER) of 10-9, the SDD technique provides an

improvement in the total number of users over the AND subtraction by a factor of 4.

The system capacity also shows an improvement of 17.734 Gbps for 20 users.

Furthermore, the computer simulation results show that the transmission distance and

bit rate per channel improve by 27% and 100%, respectively.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk ijazah Doktor Falsafah

SISTEM HIBRID SUBPEMBAWA - PEMULTIPLEKSAN PEMBAHAGIAN

KOD SPEKTRUM OPTIK DENGAN TEKNIK PENGESANAN

PENYAHKODAN TERUS SPEKTRUM

Oleh

RATNA KALOS ZAKIAH BT SAHBUDIN

Januari 2010

Pengerusi: Profesor Mohamad Khazani Abdullah, PhD

Fakulti: Kejuruteraan

Sistem telekomunikasi pada masa kini dijangka dapat memberi perkhidmatan yang

boleh dipercayai, mampu dimiliki, fleksibel, dapat berkembang dan memiliki

keupayaan untuk membawa maklumat dengan kapasiti yang besar bagi memenuhi

keperluan pelanggan yang semakin meningkat. Penggunaan teknik pemultipleksan

hibrid untuk sistem komunikasi gentian optik telah mendapat perhatian untuk

menambah fleksibiliti dan keupayaan rangkaian untuk berkembang. Salah satu

daripada teknik pemultipleksan yang semakin popular adalah pemultipleksan

pembahagian kod spektrum optik (OSCDM) kerana kesesuaian dalam pembahagian

saluran, keupayaan untuk beroperasi secara tak segerak, peningkatan dari segi

keselamatan dan juga kapasiti dalam rangkaian yang bersifat merebak. Bagi teknik

pemultipleksan subpembawa (SCM), ia berupaya untuk menambah kadar data

saluran untuk sistem OSCDM. Antara ciri-ciri yang menarik bagi teknologi SCM

pada masa kini ialah penggunaan teknik gelombang mikro yang terbukti baik serta

komponen-komponen yang terdapat di pasaran dengan harga yang berpatutan. Ia

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juga memberi jalan untuk menggunakan kelebihan lebar jalur gentian optik yang

berbilang-gigahertz. Oleh itu, tesis ini mencadangkan satu sistem hibrid

pemultipleksan subpembawa dan pemultipleksan pembahagian kod spektrum optik

(SCM-OSCDM) dengan tujuan menggabungkan kelebihan kedua-dua teknik

tersebut. Teknik hibrid ini dapat menambahkan lagi bilangan pengguna serentak

dengan cara menambahkan SCM dan/atau kata kod OSCDM.

Prestasi sistem hibrid bergantung kuat kepada ciri-ciri kod dan teknik pengesanan.

Sistem ini menggunakan pembinaan kod penggabungan baru yang diberi nama kod

Khazani-Syed (KS) berasaskan kepada kod-kod Dwi Pemberat (DW) dan Dwi

Pemberat Terubahsuai (MDW). Kod KS mempunyai ciri-ciri sekaitan silang yang

unggul, yang dapat menghapuskan gangguan akses pelbagai (MAI). Gangguan ini

akan menyebabkan prestasi sistem tersebut menurun. Pada kebiasaannya MAI dapat

dikurangkan dengan menggunakan teknik pengesanan penolakan. Di dalam tesis ini,

satu pendekatan baru yang diberi nama teknik pengesanan penyahkodan terus

spektrum (SDD) diperkenalkan. Teknik SDD memerlukan jumlah penapis untuk

penyahkodan yang kurang berbanding dengan jumlah penapis yang diperlukan oleh

teknik pengesanan penolakan dan hanya menapis spektrum yang tidak bertindih.

Oleh itu, hingar keamatan teraruh fasa (PIIN) dapat dihapuskan. Keberkesanan

sistem hibrid dengan menggunakan teknik pengesanan SDD ini telah diuji dan

dibuktikan dengan menggunakan analisa teori, simulasi dan eksperimen. Hasil

keputusan menunjukkan prestasi sistem hibrid dengan menggunakan teknik

pengesanan SDD lebih baik berbanding dengan menggunakan teknik pengesanan

penolakan. Sebagai contoh, pada kadar ralat bit (BER) 10-9, teknik SDD dapat

memperbaiki jumlah bilangan pengguna sebanyak 4 kali ganda berbanding teknik

penolakan AND. Kapasiti sistem juga menunjukkan peningkatan sebanyak 17.734

Gbps untuk 20 pengguna. Tambahan pula, keputusan simulasi komputer

menunjukkan jarak penghantaran dan kadar bit setiap saluran meningkat sebanyak

27% dan 100%, masing-masing.

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ACKNOWLEDGEMENTS

First of all, I would like to express my greatest gratitude to ALLAH Almighty, for

giving me the utmost strength, patience and guidance to have this work completed.

Alhamdulillah.

I would like to express my appreciation and sincere gratitude to my supervisor,

Professor Dr Mohamad Khazani Abdullah for his invaluable contribution, continuous

support, encouragement and endless patience towards completing the research. These

special thanks also dedicated to my supervisory committee member, Professor Dr

Mohd Adzir Mahdi and Professor Dr Mahamod Ismail for their invaluable guidance

and constructive suggestions throughout the success of this project.

My special thanks to Mohd. Dzahiril Abdul Samad, Zuraidah Zan and Dr

Makhfudzah Mokhtar for their comments, help and discussions. I would also like to

thank all my colleagues and friends for their support and encouragement.

Special acknowledgement to Head of Basic Research Division, head and staffs of

Photonic Technology Laboratory, Telekom R&D Sdn Bhd, UPM-MTDC for their

generous loan of equipment and space for the experiment.

Last but not least, I would like to thank UPM for providing the scholarship during

my study at UPM.

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I certify that a Thesis Examination Committee has met on 26 January 2010 toconduct the final examination

of Ratna Kalos Zakiah bt Sahbudin on her thesis entitled “Hybrid Subcarrier-Optical Spectrum Code Division

Multiplexing System with Spectral Direct Decoding Detection Technique” in accordance with the

Universities and University Colleges Act 1971 and the Constitution of the Universiti Putra Malaysia [P. U. (A)

106] 15 March 1998. The Committee recommends that the student be awarded the Doctor of Philosophy.

Members of the Thesis Examination Committee were as follows:

Adznan Jantan, PhD

Associate Professor

Faculty of Engineering

Universiti Putra Malaysia

(Chairman)

Sabira Khatun, PhD

Associate Professor

Faculty of Engineering

Universiti Putra Malaysia

(Internal Examiner)

Mohamed Othman, PhD

Professor

Faculty of Computer Science and Information Technology

Universiti Putra Malaysia

(Internal Examiner)

Faidz Abdul Rahman, PhD

Professor

Department of Electrical and Electronic Engineering

Faculty of Engineering and Science

Universiti Tunku Abdul Rahman

Malaysia

(External Examiner)

_ _______________________________

BUJANG KIM HUAT, PhD

Professor and Deputy Dean

School of Graduate Studies

Universiti Putra Malaysia

Date : 12 April 2010

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This thesis submitted to the Senate of Universiti Putra Malaysia and has been

accepted as fulfilment of the requirement for the degree of Doctor of Philosophy.

The members of the Supervisory Committee were as follows:

Mohamad Khazani Abdullah, PhD

Professor

Department of Computer and Communication Systems Engineering

Faculty of Engineering

Universiti Putra Malaysia

(Chairman)

Mohd Adzir Mahdi, PhD

Professor

Department of Computer and Communication Systems Engineering

Faculty of Engineering

Universiti Putra Malaysia

(Member)

Mahamod Ismail, PhD

Professor

Faculty of Engineering

Department of Electric and Electronic and Systems Engineering

Universiti Kebangsaan Malaysia

(Member)

__________________

HASANAH MOHD GHAZALI, PhD

Professor and Dean

School of Graduate Studies

Universiti Putra Malaysia

Date: 13 May 2010

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DECLARATION

I declare that the thesis is my original work except for the quotations and citations

which have been duly acknowledged. I also declare that it has not been previously,

and is not concurrently, submitted for any other degree at Universiti Putra Malaysia

or at any other institution.

______________________________________

RATNA KALOS ZAKIAH BT SAHBUDIN

Date: 1 May 2010

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TABLE OF CONTENTS

DEDICATION ii

ABSTRACT iii

ABSTRAK v

ACKNOWLEDGEMENTS viii

APPROVAL ix

DECLARATION xi

LIST OF TABLESx vi

LIST OF FIGURES xvii

LIST OF ABBREVIATIONS xxii

LIST OF NOTATIONS xxv

CHAPTER

1 INTRODUCTION 1

1.1 Background 1

1.2 Problem Statement 6

1.3 Motivation of Study 7

1.4 Objectives 8

1.5 Scope of Study 9

1.6Thesis Organization 12

2 MULTIPLEXING AND MULTIPLE ACCESS

TECHNOLOGIES 14

2.1 Introduction 14

2.2 Multiplexing and Multiple Access Techniques 14

2.3 Multiplexing Techniques 18

2.3.1 Time Division Multiplexing (TDM) 18

2.3.2 Frequency Division Multiplexing (FDM) 19

2.3.3 Wavelength Division Multiplexing (WDM) 20

2.3.4 Subcarrier Multiplexing (SCM) 21

2.3.5 Optical Code Division Multiplexing

(OCDM) 22

2.4 Subcarrier Multiplexing (SCM) System 24

2.4.1 Transmitters 25

2.4.2 Receivers 26

2.4.3 SCM Applications 28

2.5 Optical Code Division Multiple Access (OCDMA) 28

2.5.1 OCDMA System Using Continuous-Wave 30

(CW) Laser Source

2.5.2 OCDMA System Using Narrow Pulse Laser 31

Source

2.5.3 OCDMA System Using Broadband Source 33

2.5.4 OCDMA Codes 35

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2.5.5 OCDMA Applications 44

2.5.6 Multiple Access Interference (MAI) 45

2.6 Hybrid SCM-CDMA System 47

2.7 Noise Sources Consideration for Theoretical 47

Analysis

2.7.1 Shot Noise 49

2.7.2 Phase Induced Intensity Noise (PIIN) 50

2.7.3 Thermal Noise 51

2.7.4 Inter-modulation Distortion Noise 52

2.7.5 Fiber Nonlinearities 53

2.8 Detection Techniques for OSCDM of the Hybrid 57

System

2.8.1 Complementary Subtraction Detection 58

Technique

2.8.2 AND Subtraction Detection Technique 61

2.9 Summary 63

3 METHODOLOGY 64

3.1 Introduction 64

3.2 The System Model 66

3.3Methodology of the Hybrid SCM-OSCDM System 68

3.3.1 Theoretical Analysis 70

3.3.2 Simulation 72

3.3.3 Experiment 75

3.3.4 Design Parameters 78

3.3.5 Performance Parameter 83

3.4 Summary 85

4 THEORETICAL PERFORMANCE OF HYBRID

SCM-OSCDM SYSTEMS 86

4.1 Introduction 86

4.2 Spectral Direct Decoding Detection Technique 86

4.3 Analysis of Hybrid SCM-OSCDM System 88

4.3.1 Hybrid System Based Complementary 89

Subtraction Technique

4.3.2 Hybrid System Based AND Subtraction

Technique 101

4.3.3 Hybrid System Based SDD Technique 105

4.4 Comparison between Hybrid SCM-OCDM using KS

Code and Other Codes 109

4.5 Comparison between Complementary and AND

Subtraction Detection Techniques 111

4.6 Performance Comparison Between the Hybrid 116

System Using AND Subtraction and Spectral Direct

Decoding Detection Techniques

4.6.1 Effect of Nonlinear Effects on the System 116

4.6.2 Effect of Psr on Shot Noise 117

4.6.3 Effect of Psr on System Performance by

Considering only Shot Noise 118

4.6.4 Effect of Psr on System Performance

Considering All Noises 120

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4.6.5 Effect of the Number of Subcarriers on

System Performance Considering All Noises 123

4.6.6 Effect of the Number of Codes on System

Performance Considering All Noises 124

4.6.7 Effect of the Total Number of Users on

System Performance Considering All Noises 126

4.6.8 Effect of the Modulation Index on System

Performance Considering All Noises 128

4.6.9 Effect of the Total Number of Users on

System Capacity Considering All Noises 130

4.7 Summary 131

5 SIMULATION PERFORMANCE OF HYBRID SCMOSCDM

SYSTEM 133

5.1 Introduction 133

5.2 Simulation Results for the Hybrid System Using the

Laser Light Source 134

5.2.1 Effect of SCM Channel Spacing on System

Performance 134

5.2.2 The Effect of Distance on System

Performance 136

5.2.3 Effect of Distance on Noise Power and

Output Power 139

5.2.4 Effect of Total Number of Users on System

Performance 141

5.2.5 Effect of Input Power on System

Performance 144

5.2.6 Effect of Input Power on Noise Power and

Output Power 146

5.2.7 Effect of Bit Rate on System Performance 147

5.2.8 Effect of Received Optical Power on System

Performance 150

5.3 Simulation Results for the Hybrid System Using the

LED Light Source 152

5.3.1 The Effect of Distance on System

Performance Using LEDs 153

5.3.2 The Effect of Input Power on System 156

Performance Using LEDs 157

Experimental Analysis

5.4.1 Experimental Setup 158

5.4.2 Experimental Results 160

Summary 165

6 CONCLUSION AND FUTURE WORK 167

6.1 Conclusion 167

6.2 Contribution to Research Field 170

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6.3 Future Work 171

6.3.1 Higher Layers Studies 171

6.3.2 Application to Free Space and Wireless 170

Infrared Transmission

6.3.3 Implementation in Fiber-to-the-Home

(FTTH) 172

REFERENCES 173

APPENDIX A 186

BIODATA OF STUDENT 189

LIST OF PUBLICATIONS 190