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Digital Design and Implementation of a Multilevel OCDMA System

Rafiei, Mehran | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: English
  3. Document No: 40262 (55)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Salehi, Javad
  7. Abstract:
  8. Optical Wireless Communication is believed to have a great potential in establishing point to point connection and have attracted an unexpected growth in research , applications and market. Furthermore, Optical wireless systems have recently emerged as a new means of communication, especially in places where electromagnetic interferences is of utmost concern such as in passenger planes and hospitals and in other communications applications where cost could is of concern. In this thesis we build upon previously introduced wireless optical code-division multiple –access communication. In the context of an OCDMA system we begin our study by considering synchronization circuit via a particular acquisition algorithm, namely matched filtering followed by a trucking circuit that ultimately locks on the incoming sequence. Furthermore, we elevate the digital design of the required transmitter and receiver structures in such application using optical orthogonal codes (OOCs). The overall digital systems in CDMA including encoders, transmitter, decoders, receivers, acquisition and tracking indicate a great potential of such optical wireless systems for many important application. Finally we introduce and study a new and novel signaling technique namely, multilevel signaling , in OCDMA in order to increase the throughput of such systems. In multilevel signaling technique we take advantage of different power levels to design various class of OOC with different power. Each power level corresponds to a class of users and the performance of all class can be independent of other classes is a shared optical channel. We close this thesis by discussing the digital implementation of the above aforementioned multilevel signaling technique in an OCDMA communication system.
  9. Keywords:
  10. Optical Code Division Multiple Access (OCDMA) ; Field Programmable Gate Array (FPGA) ; Very Highspeed Integrated Circuits Hardware Description Language (VHDL) ; Multilevel Optical Signal

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