ACKNOWLEDGEMENT I m deeply grateful to my supervisor, P.M. Dr. Syed Alwee Aljunid B. Syed Junid, for his guidance, patience and support. I consider myself very fortunate for being able to work with a very considerate and encouraging professor like him. Without his offering to accomplish this research, I would not be able to finish my study at UniMAP. I m much obliged to my group members Nursyazwani and Farah Hayati. Their enlightening suggestions and encouragements made me feel I was not isolated in my research. I also want to show my sincere gratitude to my other two committee members, Liyana Dhamirah and Norizan, for taking their precious time to consider my work. I m indebted to Mr. Ir. Anuar B. Mat Safar, for his help during accomplish my project. He always gives a support for the in-depth discussions about various research problems. His insights in developing the ZCC code, especially from the perspective of an experimentalist, clarified a lot of my questions. I owe many thanks to my classmate and all of my friends, especially Khairul Nizam that always support and give full attention for me to solve my problem. They always help me in exchanging any ideas and give the enjoyable studying environment. They made my life at UniMAP a truly memorable experience and their friendships are invaluable to me. I am most grateful to my parents, mom and especially to my father, Osman B. Salim that had passed away last year. They have always loved me and supported my every choice. As I know, they are the happiest and the most proud when seeing their daughter gets this degree, I dedicate this project to them. I m also thankful for the great joys and happiness brought to me by my other sister s and brother s. i
APPROVAL AND DECLARATION SHEET This project report titled Development of New OCDMA Code was prepared and submitted by Nor Ilyana Bt Osman (Matrix Number : 031080714) and has been found satisfactory in terms of scope, quality and presentation as partial fulfillment of the requirement for the Bachelor of Engineering (Communication Engineering) in Universiti Malaysia Perlis (UniMAP). Checked and Approved by (P.M. Dr. Syed Alwee Aljunid B. Syed Junid) Project Supervisor School of Computer and Communication Engineering Universiti Malaysia Perlis May 2007 ii
PEMBENTUKAN KOD OCDMA BARU ABSTRAK Komunikasi merupakan perkara yang penting pada masa sekarang tidak kira masa, tempat dan situasi. Medium penghantaran isyarat boleh dikelaskan kepada tanpa wayar dan berwayar (terutamanya gentian optik di mana ianya mempunyai kelebihan dari segi penghantaran jarak jauh berbanding dengan medium penghantaran yang lain). Tambahan pula terdapat tiga jenis akses pelbagai bahagian yang digunakan di dalam sistem komunikasi iaitu Akses Pelbagai Bahagian Masa (TDMA), Akses Pelbagai Bahagian Jarak Gelombang (WDMA) dan Akses Pelbagai Bahagian Kod (CDMA). CDMA diakui dapat menyediakan tahap kecekapan, keselamatan dan kelebihan pelbagai akses di dalam dunia komunikasi tanpa wayar. Akses Pelbagai Bahagian Kod Optik (OCDMA) merupakan topik menarik untuk dibuat kajian kerana ianya berpotensi untuk menyokong ledakan komunikasi tanpa segerak. Perlaksanaan mana-mana sistem OCDMA adalah bergantung kepada ciri-ciri kod. Pembangunan aplikasi kod ini perlu dipertingkatkan untuk mendapatkan tahap penghantaran isyarat yang optimum di dalam sistem OCDMA. iii
ABSTRACT Nowadays, communication is very important at any place, time and situation. The transmission of signal can be in wireless or cable (especially fiber optic that has more advantages than others cable for a long distance). Furthermore, there are three type of division multiple accesses that use in communication systems which are Time Division Multiple Access (TDMA), Wavelength Division Multiple Access (WDMA) and Code Division Multiple Access (CDMA). But, CDMA has been recognized to provide efficiency, security, and multi-access benefits in wireless communications. This has triggered interest in providing similar advantages for optical communication systems. Optical code division multiple access (OCDMA) is an interesting subject of research because of its potential to support asynchronous, burst communications. The performance of any OCDMA system strongly depends on the codes properties. The application of codes had been develop need to be improved to get the good transmission performance in OCDMA system. iv
TABLE OF CONTENTS ACKNOWLEDGMENT APPROVAL AND DECLARATION SHEET ABSTRAK ABSTRACT TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS AND ABBREVIATIONS Page i ii iii iv v viii ix xi CHAPTER 1 INTRODUCTION 1.1 Background 1 1.2 Multiple Access Scheme 2 1.3 Problem Statement 4 1.4 Objectives 4 1.5 Scope of Work 5 CHAPTER 2 LITERATURE REVIEW 2.1 Introduction 6 2.2 Optical Code Division Multiple Access (OCDMA) 8 2.2.1 Spread Spectrum 8 2.3 OCDMA Codes 10 2.3.1 Hadamart Code 11 v
Page 2.3.2 Double Weight (DW) 13 2.3.3 Modified Double Weight (MDW) 14 CHAPTER 3 METHODOLOGY 3.1 Theoretical Studies 19 3.2 Simulation 20 3.2.1 Simulation Analysis 20 3.2.2 Design Parameter 21 3.2.2.1 Chip Spacing 21 3.2.2.2 Distance 22 3.2.2.3 Bit Rate 23 3.2.2.4 Transmission Power (Input Power) 23 3.2.3 Performance Parameter 24 3.2.3.1 Bit Error Rate (BER) 24 3.2.3.2 Received Power 24 3.2.3.3 Eye Pattern 25 CHAPTER 4 RESULTS AND DISCUSSION 4.1 Introduction 26 4.1.1 Code Development 27 4.1.2 Performance Analysis 29 4.1.3 Code Comparison 31 4.2 Simulation 35 CHAPTER 5 CONCLUSION 5.1 Summary 43 5.2 Recommendation for Future Project 44 vi
Page 5.3 Commercialization Potential 44 REFERENCES 46 APPENDICES Appendix A (i) : MATLAB programme for insertrow 48 Appendix A (ii) : MATLAB programme for ZCC 51 Appendix B : Layout Design 53 Appendix C : Optisystem 5.0 Advertisement 54 vii
LIST OF TABLES Tables No. 2.0 Hadamard Code Sequences for 6 Users. 12 Page 2.1 Example of MDW ( W = 4 ) Code Sequences. 18 4.0 Symbol and description for the formula. 30 4.1 Comparison between OOC, Hadamard, MDW code, MFH 31 and ZCC code. viii
LIST OF FIGURES Figures No. 1.0 Fiber optic communications system using optical codec. 3 Page 1.1 A General Study Model of the Research Work. 5 2.0 Time-frequency space usage in (a) TDMA, (b) WDMA, 7 (c) CDMA. 2.1 Spreading process by data signal, spreading signal and 9 message signal. 2.2 Signal for transmission system. 9 3.0 Chip Spacing. 22 3.1 Ideal Rectangular Shaped Weights. 22 4.0 Performance comparison between Hadamard, MDW, MFH 32 and ZCC codes. 4.1 Output for w = 1 and the number of user = 2. 33 4.2 Output for w = 2 and the number of user = 3. 33 ix
Page 4.3 (a) For w = 3 and the number of user = 4. 34 4.3 (b) Continue page from Figure 4.2 (s) for w = 3 and the number 34 of user = 4. 4.4 The system architecture of Optical CDMA network under 36 study using OptiSys 5.0. 4.5 Sample eye diagram at Channel 1 output for distance 50km. 37 4.6 Sample eye diagram at Channel 1 output for distance 100km. 37 4.7 Sample signal occurred at BER Analyzer for 38 Channel 1 output (distance=50km). 4.8 Sample Optical Power Meter Visualizer as an input measured. 38 4.9 Sample Electrical Power Meter Visualizer as an input measured 38 at Channel 1. 4.10 BER versus Chip Width for Channel 1. 39 4.11 BER versus Distance for Channel 1. 40 4.12 BER versus Bit Rate for Channel 1. 41 4.13 BER versus Input Power (dbm) for Channel 1. 42 4.14 BER versus Output Power (dbm) for Channel 1. 42 x
LIST OF SYMBOLS AND ABBREVIATIONS Δ F chip width Δ v B e k k B N,C P sr R R L total spectral width electrical equivalent noise band-width of the receiver electron charge number of user Boltzmann s constant code length effective power at receiver photodiode responsivity load resistance T r w BER DW MAI MDW OCDMA PIIN SNR TDMA WDMA ZCC temperature of receiver noise code weight Bit Error Rate Double Weight Multiple Access Interference Modified Double Weight Optical Code Division Multiple Access Phase Intensity Induced Noise Signal-to-Noise Ratio Time Division Multiple Access Wavelength Division Multiple Access Zero Cross Correlation xi