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WAVELENGTH TIME OPTICAL ORTHOGONAL
CODES AND PHASE ENCODING SEQUENCES
FOR OPTICAL CDMA
by
Reza Omrani
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Ful¯llment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(ELECTRICAL ENGINEERING)
December 2006
Copyright 2006 Reza Omrani
Object Description
| Title | Wavelength time optical orthogonal codes and phase encoding sequences for optical CDMA |
| Author | Omrani, Reza |
| Author email | rezaomrani@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Electrical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2006 |
| Date submitted | 2006 |
| Restricted until | Unrestricted |
| Date published | 2006-12-01 |
| Advisor (committee chair) | Kumar, P. Vijay |
| Advisor (committee member) |
Golomb, Solomon W. Guralnick, Robert M. |
| Abstract | There has been recent upsurge of interest in applying code division multiple access (CDMA) techniques to optical networks due to their enhanced data privacy, and simplicity of network control. There are two main approaches to code design for OCDMA systems. The first approach uses direct sequence encoding in which data sequence modulates the code sequence simply by switching it on or off. These codes, considered as 1-D optical orthogonal codes (OOC), employ {0,1} sequences with good correlation properties. In order to bring down the required chip rate within practical limits, 2-D {0,1} codes are used in which the code sequences consist of 2-D patterns with the second dimension corresponding to wavelength.; The second approach is via phase encoding in which the code sequences are collections of complex numbers of unit magnitude with each entry associated to a carrier of different wavelength. The phase of an element in the [lambda]th entry corresponds to the phase of the [lambda]th carrier. The focus of this thesis is on efficient code design for both approaches.; We begin by introducing some new bounds on the size of 1-D and 2-D OOCs. Subsequently, the focus is on explicit constructions for 2-D wavelength-time OOCs. We introduce four major constructions for wavelength-time OOCs, i.e., a method to map 1-D OOCs to 2-D OOCs, a method based on Reed-Solomon Codes, a method which concatenates a constant weight code with a Reed-Solomon based 2-D OOC and finally a function-plot method in which the values of an appropriately-chosen function are used to derive the 2-D codes. The functions used in the function plot construction include polynomial functions and rational functions.; Next, we consider phase-encoded OCDMA. We first derive a mathematical model for the output of this system and based on that introduce a metric to design codes for asynchronous transmission. Then, a connection between phase-encoding sequence design and PMEPR (peak to mean envelope power ratio) problem of OFDM systems is established. We construct a family of phase sequences based on generalized bent functions with desirable properties for asynchronous transmission. |
| Keyword | sequences; optical orthogonal code; OOC; 2-D OOC; constant weight code; two-dimensional codes; bound; Johnson bound; OCDMA; pptical CDMA; wavelength-time OOC; multiple-wavelength OOC; MWOOC; wavelength-time hopping codes; frequency-hopping Codes; phase encoding; rational function; difference set; difference family; Affine geometry; M-ary modulation; CCM; code cycle modulation |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m208 |
| Rights | Omrani, Reza |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Omrani-20061201 |
| Archival file | uscthesesreloadpub_Volume48/etd-Omrani-20061201.pdf |
Description
| Title | Page 1 |
| Full text | WAVELENGTH TIME OPTICAL ORTHOGONAL CODES AND PHASE ENCODING SEQUENCES FOR OPTICAL CDMA by Reza Omrani A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Ful¯llment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (ELECTRICAL ENGINEERING) December 2006 Copyright 2006 Reza Omrani |
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