Title of thesis
Multi-User Detection for the Optical Code Division Multiple Access (OCDMA): Optical Parallel Interference Cancellation
(OPIC)
I, NAG! ELFADEL MASAD MOHAMED
hereby allow my thesis to be placed at the Information Resource Center (IRC) of Universiti Teknologi PETRONAS (UTP) with the following conditions:
1. The thesis becomes the property ofUTP.
2. The IRC ofUTP may make copies of the thesis for academic purposes only.
3. This thesis is classified as
D
Confidential0
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The contents of the thesis will remain confidential for _ _ _ _ _ years.
Remarks on disclosure:
Signature of Author
Permanent: Faculty of engineering and technology Address Gezira University
Wad Madani, Sudan Date: - - - -
Jdhy
Signature of Supervisor Name of Supervisor Dr.Mohamad Naufal Mohamad Saad
Date: - - - -
UNJVERSITI TEKNOLOGJ PETRONAS Approval by Supervisor
The undersigned certify that they have read, and recommend to The Postgraduate Studies Programme for acceptance, a thesis entitled
Multi-User Detection for the Optical Code Division Multiple Access (OCDMA):
Optical Parallel Interference Cancellation (OPIC) submitted by
Nagi Elfadel Masad Mohamed
for the fulfilment of the requirements for the degree of Masters of Science in Electrical and Electronic Engineering
Date
Signature
Main Supervisor Dr.Mohamad Naufal Mohamad Saad _ _ _ _ _ Date
Co-Supervisor
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UNIVERSITI TEKNOLOGI PETRONAS
Multi-User Detection for the Optical Code Division Multiple Access (OCDMA):
Optical Parallel Interference Cancellation (OPIC)
By
Nagi Elfadel Masad Mohamed
A THESIS
SUBMITTED TO THE POSTGRADUATE STUDIES PROGRAMME AS A REQUIREMENT FOR THE
DEGREE OF MASTERS OF SCIENCE IN ELECTRICAL AND ELECTRONIC ENGINEERING
Electrical and Electronic Engineering
BANDAR SERI ISKANDAR, PERAK
September, 2007
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DEC LARA TJON
l hereby declare that the thesis is based on my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UTP or other institutions.
Signature:
Name : Nagi El(adel Masad Mohamed
Date
IV
ACKNOWLEDGEMENT
First of all, thanks God for giving me the ability to complete this work. I would like to express my gratitude to my family for their tireless efforts and their support, without their love and sacrifice, I never could have come this far.
I am sincerely grateful to Dr. M. Naufal M. Saad for being my advisor and providing guidance for this thesis work. His insight and motivation were invaluable. I would also like to express my appreciation to Mr. Azizuddin for his valuable help that significantly improves both the technical content and the presentation of this dissertation.
I am grateful to all the members of the Electrical and Electronic Engineering Department who assisted me through my thesis. I would especially like to thank Dr. M.
Asif for his encouragement and support.
I am deeply indebted to the following individuals from the Post Graduate Office, without whom this study would not have been possible: Mrs. Norma, Mrs. Kamalia, Mrs.
Haslina and Mr. Fadil Ariff.
My stay at UTP would not have been as enjoyable and rewarding without the wonderful friends who made it a great place to do research; especial thanks given to them.
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ABSTRACT
Optical Code Division Multiple Access (OCDMA) has recently been proposed as an alternative to frequency and time based multiple access methods for the next generation high-speed optical fiber networks. This is because such system offers a large bandwidth.
Based on the vast amount of bandwidth available in optical line, OCDMA system has received much attention in fiber optic Local Area Network (LAN) where the traffic is typically bursty. However, Multiple Access Interference (MAl), which is originated from other simultaneous users, severely limits the capacity of the system. In addition, the need for dynamic threshold in the Conventional Correlation Receiver (CCR) is a very demanding requirement particularly in the high speed LANs.
To overcome the stated problems, Optical Parallel Interference Cancellation is used throughout this thesis. Optical Hard Limiter (OHL) has been placed at the front of the OPIC receiver to reduce the effect of MAl and fixed threshold is used to overcome the problem of dynamic threshold. The study carried out using theoretical and simulation.
The results reveal that, OPJC system is attractive technology for next generation optical networks. The drawback of OPIC is the increases in the demand for hardware in each receiver. As a result, it requires more complex hardware, higher processing time and cost.
To overcome these difficulties, an efficient method is proposed called, One Stage Optical Parallel Interference Cancellation (OS-OPIC) which is based mainly on the OPIC.
Performance analysis of the proposed design is done using Optical Orthogonal Code (OOC) as a signature sequence and a new expression for error probability is demonstrated. It is shown that, the proposed method is effective to reduce the hardware complexity, processing time and cost while maintaining the same BER at the cost of increasing threshold value.
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ABSTRAK
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