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Title:	Time hopping odd double weight code for spectral amplitude coding optical code division multiple access (OCDMA) systems
Authors:	Ali Z. Ghazi Zahid (P52465)
Supervisor:	Sahbudin Shaari, Prof. Dr.
Keywords:	Optical code division multiple access Spectral amplitude coding Weight code Bandwidth Dissertations, Academic -- Malaysia Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	3-Mar-2015
Description:	The superiority of Optical Code Division Multiple Access (OCDMA) technology especially in Local Area Networks (LANs) construction compared to other access network multiplexing techniques have interested researchers to explore and investigate more in OCDMA. With increasing demand on bandwidth and multiple accesses, the spectral bandwidth has become crowded. Therefore, many techniques developed to reduce the bandwidth consumption. One of the techniques used is two-dimensional OCDMA codes. Many two-dimensional codes have been proposed and some of these codes improve the bandwidth consumption, yet there codes suffer from other issues such as complexity. This work presents, a new two-dimensional code based on time and spectral amplitude coding of odd numbers of the Double Weight (DW) code structure in optical code division multiple access, known as Time Hopping Odd Double Weight (THODW) code. THODW aims to reduce bandwidth consumption in addition to the design reliability and simplicity. Time Hopping Odd Double Weight (THODW) code has improved properties such as zero cross correlation, the eliminate multiple access interference (MAI) and simple design, which reduces the total bandwidth conumption. The theoretical and experimental simulation analysis have shown that THODW code performs considerably better compared with other two dimensional codes such as two dimensional Modified Double Weight (2D-MDW). In this thesis, two OCDMA detection techniques were used: Modified AND subtract technique and irect technique. Moreover, several measurement parameters used to study the system such as effect of distance, bit rate, bandwidth, system design complexity, and input power. Theoretical analysis, as well as experimental simulation, shows that the performance of THODW system using direct detection technique is better and easier to design, and implement compared to Modified AND subtract detection technique. The simulated eye pattern shows that direct technique had better performance with a larger eye opening: for a 1.25 Gbps, the BER is 10-12 at 50 km. Furthermore, THODW reserves 50% of the bandwith. Various applications and systems were designed using THODW code such as point-to-point (P2P) network, data control system, and cryptography. The new code shows superiority in many aspects such as performance, simplicity, and bandwith economy.,Ph.D.
Pages:	165
Publisher:	UKM, Bangi
Appears in Collections:	Institute of Microengineering and Nanoelectronics / Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN)

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