Study of multi-wavelength optical code division multiple access system

Dissertant

Fakhri, Zaynab Hasan

University

University of Technology

Faculty

-

Department

Department of Electrical Engineering

University Country

Iraq

Degree

Master

Degree Date

2006

English Abstract

Many technologies are proposed to get use of the huge bandwidth of the optical fibers and to improve the network connection such as time division multiple access (TDMA) and wavelength division multiple access (WDMA) but the optical code division multiple access (OCDMA) is a technique that achieving asynchronous ,high speed, more flexible simpler protocol local area (LAN) connection.

In this work a new OCDMA technology that used unit-polar incoherent multi-wavelength optical CDMA system and the associated multi wavelength optical orthogonal codes (MWOOC's) are examined and discussed.

Three types of one dimensional (1-D) and two types of two dimensional (2-D) are analyzed and their cardinality and correlation properties are studied.

These 1-D codes are prime sequence, modified prime sequence and quadratic congruence codes while the 2-D codes are prime sequence and generalized multi-wavelength prim code (CjMWPC).

All these are based on prime sequence permutation algorithm.

The performance of multi wavelength code division multiple access (MWCDMA) communication system network is investigated, the transmitted signal is coupled into dispersion shifted fiber (DSF) which in turn is coupled to PIN+OA or an avalanche photo diode (AI-'D) receiver.

The probability of error for the above receiver's configurations is computed taking into consideration various sources of receiver noise, multiple user interference and four wave mixing (FWM) effects.

To examine the improvement gained by using MWCDMA, a comparison is made between MWCDMA and hybrid CDMA &WDM (WaCDMA) systems.

It is found that for the same parameter MWCDMA network with PIN+OA gives improved.

Performance air compared to the latter with the level of improvement depending upon users for which the network is to be designed.

This is done for ail values (if link loss.

However at high values of link loss FWM become dominant since the transmitted power is high and leads to a smaller range of input transmitted power levels for a given number of users and performance requirement.

It is also found that MWCDMA system have better performance than WaCDMA system at high speed network and comparable performance for medium traffic load and comparable performance to conventional CDMA, Since MWOOC's support large number of subscribers and simultaneous users and have improved auto and cross correlation constraints it has improved performance upon the 1-D codes.

The modeling and calculations of this work is done using MATLAB 7 software running on Pentium 4 computer.

Main Subjects

Electronic engineering

Topics

• Telecommunications
• Optical communications

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305815