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Article
Design and Implementation of Optical Wireless Communication System

Author: Saba A. Shukry
Journal: Al-Fatih journal مجلة الفتح ISSN: 87521996 Year: 2005 Volume: 1 Issue: 23 Pages: 100-110
Publisher: Diyala University جامعة ديالى

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Abstract

In this paper, we have designed and constructed an optical communication system to transmit two-voice channel full duplex technique with line of sight, which uses a laser beam as a carrier wave in free space. The constructed system consists of a tranciever (transmitter and receiver ) for both sides. The transmitter part includes a laser source and other transmitter accessories as well as a receiver component. Pulse code modulation (PCM) technique has been used to transmit voice signal. High quality sound communication link for a distance reaching about 1300m is achieved with signal to noise ratio (S/N) equal to 21.1 d

تم في هذا البحث تصميم وبناء منظومة اتصالات ضوئية رقمية لنقل قناتين صوتية بأتجاهين متعاكسين بوقت واحد بتقنية الإرسال الآني مع تأمين خط النظر تعمل باستخدام أشعة الليزر كوسط ناقل للمعلومات في الفضاء الحر.ان بناء منظومة الاتصالات الضوئية تضمنت بوردين الكترونيين يحتوي كل بورد على وحدة ارسال واستقبال ، وباستخدام تقنية التضمين النبضي المشفر PCM لنقل قناة صوتية يتراوح ترددها بين 0.3 – 4 kHz ومعدل نقل البيانات الرقمية لهذه المنظومة 100kbps باستخدام تقنية توشير اللاعودة الى الصفر لقد تم تحقيق حلقة اتصال صوتية بوقت واحد وبوضوح عالي الدقة وعلى مديات وصلت الى مسافة 1300 m وتم حساب نسبة الإشارة إلى الضوضاء S/N فوجد انها تساوي (21.1dB) .


Article
Design and Implementation of Infrared (IR) Communication System

Authors: Suha I. Al-nassar --- Haraa Raheem Hatem --- Jinan N. Shehab
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2018 Volume: 11 Issue: 3 Pages: 29-33
Publisher: Diyala University جامعة ديالى

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Abstract

Wireless Infrared (IR) communications system is meant to use free-space propagation of light waves as a transmission medium in near infrared band. In this paper, voice communication system is simulated and implemented by protues software using IR as a source that is established an audio communication (link to transmit and receive voices and music via infrared light). The outcome of this proposed work is to design and implementation an optical wireless system to transmit voice over a certain distance in laboratory. This system has many advantages such as is a common, inexpensive, and the transmitter or receiver can be showed to another location with least distraction.


Article
New Modulation Method in FSO Communication Using Different Wavelengths (650,532,405) nm in the Iraqi Weather
أسلوب التضمين الجديد في الأتصالات FSO بأستخدام أطوال موجية مختلفة (650،532،405) نانومتر في الطقس العراقي

Authors: Abdullah.A.Abdullah عبدالله احمد عبدالله --- Jassim.M.Najim جاسم محمد نجم --- Akram.N.Mohameed اكرم نوري محمد
Journal: Iraqi Journal of Science المجلة العراقية للعلوم ISSN: 00672904/23121637 Year: 2018 Volume: 59 Issue: 1A Pages: 233-239
Publisher: Baghdad University جامعة بغداد

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Abstract

The FSO technique depends on the compatibility of the optical path between the transmitter and the receiver (line-of-sight) to transmit data between two points. FSO system uses the light to provide optical Contact to send and receive various data. This study shows the design of a new optical system for the transmission of voice through free space at wavelengths (650,532,405) nm within point-point technology for specified distances. What distinguishes this work is the quality of the reflection-based modulation based on the Doppler phenomenon. Also, it is interested in studying the different attenuation conditions of the atmosphere at the wavelengths used, in addition to the attenuation caused by the large laser beam divergence for distant distances. This study shows the quality of modulation used under different weather conditions and is characterized by very low cost and high efficiency for power sent.

أن تقنية نظام FSO تعتمد على التوافق البصري للمسار بين الأرسال والأستقبال (خط البصر) لنقل البيانات بين نقطتين. يستخدم نظام FSO الضوء لتوفير أتصال بصري لأرسال وأستقبال البيانات المختلفة. وتبين هذه الدراسة تصميم نظام بصري جديد لنقل الصوت عبر الفضاء الحر عند أطوال موجية (650،532،405) نانومتر ضمن تكنولوجيا نقطة نقطة لمسافات محددة. ما يميز هذا العمل هو نوعية التضمين المبنية على الأنعكاس أستنادا إلى ظاهرة دوبلر. كذلك تهتم بدراسة ظروف التوهين المختلفة للغلاف الجوي للأطوال الموجية المستخدمة، بالإضافة إلى التوهين الناجم عن تباعد شعاع الليزر الكبير للمسافات البعيدة. وتبين هذه الدراسة جودة التضمين المستخدم في ظل ظروف الطقس المختلفة، ويتميز بتكلفة منخفضة جداً وكفاءة عالية للطاقة المرسلة.


Article
Study the effect of Iraqi weather parameter in FSO communication using different wavelength (650, 532) nm
دراسة تأثير معلمات الطقس العراقي في الأتصالات البصرية عبر الفضاء الحر بأستخدام أطوال موجية مختلفة (650, 532) نانومتر

Authors: Abdullah A. Abdullah عبد الله احمد عبد الله --- Akram N. Mohameed اكرم نوري محمد --- Jassim M. Najim جاسم محمد نجم
Journal: Iraqi Journal of Physics المجلة العراقية للفيزياء ISSN: 20704003 Year: 2018 Volume: 16 Issue: 36 Pages: 104-112
Publisher: Baghdad University جامعة بغداد

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Abstract

Light has already becomes a popular means of communication, and the high-bandwidth data into free space without the use of wires. A great idea took us to design a new system for transmitting sound through free space at (650, 532) nm wavelengths using reflective mirrors under different atmospheric conditions. The study showed us the effect of various weather factors (temperature, wind speed and humidity) on these wavelengths for different distances. As well as studying the attenuation caused by long-distance laser and beam divergence, A reflective dish was used to focus the spot of the laser beam on the photocell. Results were discussed under the effect of these factors and the attenuation resulting from the beam divergence. Thus, the system performance can be improved for range and the quantity transfer data by increasing transmitted power and reducing the divergence of the laser beam.

أصبح الضوء بالفعل وسيلة شعبية للأتصال، وللبيانات ذات النطاق الترددي العالي في الفضاء الحر دون استخدام الأسلاك. وقد أخذنا فكرة عظية لتصميم نظام جديد لنقل الصوت عبر الفضاء الحر عند أطوال موجية في منطقة المرئية من الطيف (650 ،532) نانومتر بأستخدام مرايا عاكسة في ظل ظروف جوية مختلفة. وأظهرت الدراسة لنا تأثير عوامل الطقس المختلفة (درجة الحرارة وسرعة الرياح والرطوبة) على هذه الأطوال الموجية لمسافات مختلفة. فضلاً عن دراسة التوهين الناجم عن أنفراجية شعاع الليزر لمسافات طويلة، حيث تم أستخدام صحن عاكس لتركيز بقعة شعاع الليزر على الخلية الضوئية. ونوقشت النتائج تحت تأثير هذه العوامل والتوهين الناجم عن أنفراجية الحزمة. وبالتالي، يمكن تحسين أداء النظام للمدى وسرعة نقل البيانات عن طريق زيادة القدرة المرسلة والحد من زاوية أنفراجية شعاع الليزر.


Article
Position Control of Solar Panel Receiver by Joint Generated Power and Received Signal Power Maximization

Author: Bassam Fadel Mohammed
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2018 Volume: 25 Issue: 3 Pages: 24-29
Publisher: Tikrit University جامعة تكريت

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Abstract

The use of solar cells as photodetectors in Optical Wireless Communications (OWC) systems, is acquiring an increasing attention. This is due to the fact that a solar cell can detect an incident optical signal without the need to be biased by an external dc source, unlike traditional photodetectors. Basically, solar cells are designed to be used in solar energy harvesting systems. However, the solar cells are used during the day time and they remain idle at night. Then, they can be used in other applications, such as optical signal detection during night hours. Moreover, the efficiency of solar systems and solar receivers can be maximized by using dual axis light source tracking, to keep the cell orientation at the direction that results in the maximum electrical output. Therefore, in this paper, a solar cell positioning algorithm is proposed to track the maximum power point of both of the sun at day time and the optical communication signal at night. The proposed system can automatically distinguish between its two operation modes and then provides the necessary control. The proposed system is implemented and tested under realistic outdoor environment. It showed an accurate detection of the operation situation and also an accurate and smooth positioning during the specific operation mode. The measurement of the generated and consumed power by the designed system has emphasized it feasibility.


Article
Light Fidelity TechnologyTechnique andParameters: A Review Paper

Authors: Ibrahim A. Murdas --- Ahmed NajahJabbar
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2018 Volume: 26 Issue: 9 Pages: 35-41
Publisher: Babylon University جامعة بابل

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Abstract

The process of increasing the speed of the internet in the present time is of great interest to researchers. In this paper we reviewed the Light Fidelity (Li-Fi) technology, which is the future of communications that will provide solutions to the problems of bottlenecks.This technology has the ability to transfer data rate at very high speed of up to 100 times faster than Wi-Fi technology The focus of this paper is on the definition of Li-Fi and the applications,benefits, disadvantages of Li-Fi technology and the future uses of this technology as compared to the existing ones such as Wi-Fi technology, where the abundance of technology for Wi-Fi offers a larger package ,a better work efficiency and a greater security of data transfer technologies Currently exist.

في وقتنا الحاضر عمليات زيادة سرعة نقل البيانات لاقت اهتمام كبيرا من قبل الباحثين لتلبية الزياده الكبيرة بعدد المستخدمين وكثرة تبادل البيانات. في ورقه المراجعة هذه قمنا بمراجعة تقنية نقل البيانات عبر الضوء المرئي والتي تعتبر تكنولوجيا المستقبل والتي ستوفر الحل لجميع الاختناقات بسبب امكانيتها العاليه لنقل البيانات بسرع عالية جدا تصل الى 100 مرة أسرع من تقنية Wi-Fi. تم التركيز بهذه الورقه على تعريف هذه التقنية وتطبيقاتها ومنافعها وكذلك معوقاتها لكي يتم تجاوزها والتي تعتبر البديل لتقنية Wi-Fiالموجوده.


Article
Performance Evaluation of DHT Based Optical OFDM for IM/DD Transmission Over Diffused Multipath Optical Wireless Channel

Author: Hussein A. Leftah
Journal: Iraqi Journal for Electrical And Electronic Engineering المجلة العراقية للهندسة الكهربائية والالكترونية ISSN: 18145892 Year: 2019 Volume: 15 Issue: 1 Pages: 72-75
Publisher: Basrah University جامعة البصرة

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Abstract

Optical OFDM based on discrete Hartley transform(DHT-O-OFDM) has been proposed for large-size data mappingintensity modulation direct detection (IM/DD) scheme as an alternativeto the conventional optical OFDM. This paper presents aperformance analysis and evaluation of IM/DD optical DC-biasedDHT-O-OFDM over diffused multipath optical wireless channels.Zero-padding guard interval along with minimum mean-squareerror (MMSE) equalizer are used in electrical domain after thedirect detection to remove the inter-symbol interference (ISI)and eliminate the deleterious effects of the multi-path channels.Simulation results show that the ZP-MMSE can effectively reducethe effects of multi-path channels. The results also show that theeffects of optical wireless multi-path channel become more seriousas the data signaling order increases.

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