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العنوان
PERFORMANCE ENHANCEMENT FOR A DIMMABLE VISIBLE LIGHT COMMUNICATION SYSTEM BASED ON PPM /
المؤلف
Ghandour,Christena Ghandour Zak.
هيئة الاعداد
باحث / Christena Ghandour Zaki Ghandour
مشرف / Abdelhalim Zekry
مشرف / EL-Sayed M. EL-Rabaie
مشرف / Nazmy Azzam
تاريخ النشر
2018
عدد الصفحات
132p.:
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
الهندسة الكهربائية والالكترونية
تاريخ الإجازة
1/1/2018
مكان الإجازة
جامعة عين شمس - كلية الهندسة - هندسة الالكترونيات والاتصالات الكهربية
الفهرس
Only 14 pages are availabe for public view

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Abstract

Nowadays, the need for alternative communication technologies is a result of
increased wireless data traffic from the quickly growing wireless mobile devices,
which is inspiring compression on the dwindling radio frequency (RF) spectrum.
This interest about spectrum led to the formularization of a new technology called
visible light communication (VLC).
One of the interesting research area regarding VLC is the reduction of the receiver
sensitivity requirement while stretching the range of reliable constant rate
transmission while satisfying lighting and communication requirements. Two of the
main objectives of LED based system are the achievement of dimming and
communication support. Although these two objectives are relevant to each other,
they are generally treated separately. Dimming and communication support are
achieved using different modulation techniques.
In this thesis, we explore the bit rate characteristics, receiver sensitivity and power
requirements of multicarrier modulation schemes (MCM) for visible light
communication (VLC). Before exploring the performance, this study develops the
mathematical formulation for merging pulse position modulation (PPM) and
overlapping pulse position modulation (OPPM) all with M-ary quadrature
amplitude modulation DC-Biased optical orthogonal frequency division
multiplexing (MQAM-DCO-OFDM). These schemes are then compared with the
conventional merging (i.e MQAM-DCO-OFDM with pulse width modulation
(PWM)). To relate with the recent advances in the field, additional comparative
study is established with the latest merging platform (i.e M-QAM DCO OFDM with
multiple pulse position modulation (MPPM)). Then make the same previous study
when replacing PWM and MPPM pulses with variable pulse position modulation
(VPPM), color shift keying (CSK) as key schemes of IEEE 802.15. 7 and PPM as
key scheme of IrDA protocol Alternatives for the conventional merging scheme are
explored. A trade-off issues between the addressed merging schemes are presented.
Finally, we design circuits to transmit (using LED) and receive (using photodetector
(PD)) the data after merging techniques.
The thesis is divided into six chapters, as listed below:
• Chapter One: This chapter is an introduction to the thesis that clarifies the
history of visible light communication and the aims of this thesis.
• Chapter Two: This chapter presents literature review of the topics relevant
to the thesis, discussing VLC concept, components, and applications.
• Chapter Three: This chapter introduces an elaborated modeling and
simulation of the compensating effect of the different pulse position
modulation techniques on the conventional M-QAM DCO OFDM PWM
modulation dimming techniques. This is done by replacing PWM by MPPM
pulses, or PPM or OPPM pulses with the same duty cycle, then assessing the
performance of these techniques. The main performance parameter is the bit
error rate for energy per bit to noise density ratio. Then for a given bit rate
and bit error rate one, the achievable bit rate, receiver sensitivity and required
LED power are determined.
• Chapter Four: explores the performance of multicarrier VLC modulation
schemes results from merging selected schemes from IEEE 802.15. 7 and
IrDA with MQAM-DCO-OFDM.
• Chapter Five: This chapter discusses the implementation of VLC system. A
comparison between the simulated results and measured results is
introduced.
• Chapter Six: This chapter is devoted to main conclusion and future work for
this research point.
• Last Part: it includes references for this thesis.