Investigation of Free Space Optical Link Performance with Wavelength Diversity under Different Turbulence Conditions (Record no. 112296)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 04543ngm a22001457a 4500 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION | |
| fixed length control field | 180508b xxu||||| |||| 00| 0 eng d |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | TT000055 |
| Item number | SHA |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Shah, Dhaval Gopalchandra |
| 245 ## - TITLE STATEMENT | |
| Title | Investigation of Free Space Optical Link Performance with Wavelength Diversity under Different Turbulence Conditions |
| Statement of responsibility, etc | by Dhaval Gopalchandra Shah |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc | Ahmedabad |
| Name of publisher, distributor, etc | Nirma Institute of Technology |
| Date of publication, distribution, etc | 2017 |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 147p Ph. D. Thesis with Synopsis and CD |
| 500 ## - GENERAL NOTE | |
| General note | Guided by: Dr. D. K. Kothari With Synopsis and CD 11EXTPHDE72<br/><br/>ABSTRACT:<br/>Free Space Optical (FSO) communication is rapidly growing technology in the field<br/>of wireless communication. Higher bandwidth, licence free spectrum, high security<br/>and quick deployment are the key advantages of this technology. However, the<br/>atmospheric losses due to bad weather and atmospheric turbulence are still the<br/>challenges which prevent the growth of FSO communication at a higher rate.<br/>Wavelength diversity technique has shown the capability to overcome these<br/>challenges. In this technique, the information signal is transmitted simultaneously on<br/>a different wavelength which increases the availability of FSO link and overcomes the<br/>problem of link blockage. Apart from this, each wavelength is immune against certain<br/>atmospheric elements so the use of multiple wavelengths for transmission helps to<br/>combat the atmospheric losses. Further, different wavelengths are affected differently<br/>by same atmospheric condition which makes FSO communication robust under<br/>different atmospheric turbulence conditions.<br/>In this thesis, wavelength diversity technique is applied to enhance the performance of<br/>FSO system under different turbulence conditions. Three different wavelengths of<br/>1550, 1310 and 850 nm are chosen for this technique. Different turbulence conditions<br/>are realized by adopting well-defined channel model for a particular turbulence<br/>condition. K channel model has been considered to categorize strong turbulence<br/>condition and Exponentiated Weibull channel has been used to represent all turbulence<br/>scenarios. Outage probability and average Bit Error Rate (BER) are considered as a<br/>performance metrics. Simulations results are obtained using Matlab software.<br/>The performance of FSO system under strong turbulence with wavelength diversity<br/>technique is investigated with three different combining methods: optimal combining,<br/>equal gain combining and selection combining. Mathematical expressions are derived<br/>to evaluate average BER and outage probability. The results exhibit that wavelength<br/>diversity with optimal combining method achieves better improvement compared to<br/>equal gain combining and selection combining methods. The obtained BER results are<br/>also compared with the published article in which spatial diversity technique is used<br/>to mitigate the effect of strong turbulence using same channel model. It is observed<br/>that wavelength diversity archives 2–3 dB higher improvement. An effort has been made to identify an appropriate diversity order to improve the BER<br/>and outage probability of the system under all turbulence conditions. The effect of<br/>receiver aperture size on the results is also analyzed. 10 mm and 60 mm aperture size<br/>is considered to represent an ideal and practical FSO implementation. Different<br/>turbulence condition is characterized using Exponentiated Weibull channel and<br/>optimal combining method is considered at receiver. Numerical results achieved from<br/>the derived expression of average BER and outage probability show that increasing<br/>diversity order improves the results with both aperture size. It is observed that<br/>increasing receiver aperture size decreases the performance improvement. But, the<br/>BER requirement for modern communication is easily fulfilled with the diversity order<br/>of 3 even at 60 mm receiver aperture under all turbulence conditions.<br/>A comparative analysis of BER results of FSO system with wavelength diversity using<br/>under different turbulence conditions is carried out. The results obtained considering<br/>Exponentiated Weibull channel for all turbulence conditions are compared with the<br/>published articles in the literature in which different turbulence conditions are<br/>represented by appropriate classical channel models. It is found that deployment of<br/>wavelength diversity archives a maximum gain when different turbulence conditions<br/>are characterized with Exponentiated Weibull channel. |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | http://repository.nirmauni.ac.in/jspui/handle/123456789/7980 |
| Public note | Institute Repository (Campus Access) |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | https://shodhganga.inflibnet.ac.in/jspui/handle/10603/208200 |
| Public note | Shodhganga |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | Dewey Decimal Classification |
| Koha item type | Thesis |
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