Free space optical link perfomance analysis under Malaysian weather conditions and its impact on quantum key distribution /

Free Space Optical (FSO) communication links constitute an alternative way to radio links and optical cables. They provide high bandwidth, excellent security, and fast installation, and reach places where cables are very difficult to reach. FSO links however are greatly affected by weather condition...

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Bibliographic Details
Main Author: Alma, Husagic
Format: Thesis
Language:English
Published: Gombak, Selangor : Kulliyyah of Engineering, International Islamic University Malaysia, 2009
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Online Access:http://studentrepo.iium.edu.my/handle/123456789/4830
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Summary:Free Space Optical (FSO) communication links constitute an alternative way to radio links and optical cables. They provide high bandwidth, excellent security, and fast installation, and reach places where cables are very difficult to reach. FSO links however are greatly affected by weather conditions and link distance. It is therefore very important to examine weather conditions of certain transmission site, in order to determine probable atmospheric losses, so that the performance of the channel and its availability can be properly predicted. Since there is no analysis for weather conditions found in Malaysia, this work provides analysis of the effects of typical local weather conditions, ranging from heavy to light rain, heavy to light haze and clear weather, on the FSO links. The performance analysis of the links is done in terms of BER, attenuation, link margin and availability. The analysis showed that it is possible to reach availability of 0.999 for FSO links over the distance of 700 m. Besides the performance analysis of FSO, this research work also focuses on security applications of this kind of optical channel, namely Quantum Key Distribution (QKD). QKD is part of Quantum Cryptography that was invented as an alternative for classical public-key exchange, due to the advancements in the field of quantum computing and possible compromise of existing key-exchange algorithm. Thus it is an important task in the world of computer communication networks to properly investigate QKD and determine its performance over fiber and FSO. In this research work, simulation-based evaluation of FSO QKD is done. The simulation is done for Malaysian weather conditions previously analyzed. The results show the size of the final encryption key after it is being transmitted over FSO channel influenced by various weather conditions, which implies that it is possible to use FSO based QKD in Malaysia successfully.
Item Description:"A dissertation submitted in partial fulfilment of the requirements for the degree of Master Science in Computer and Information Engineering" --On t.p.
Physical Description:xvii, 135 leaves : ill. ; 30 cm.
Bibliography:Includes bibliographical references (leaves 125 - 128).