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dc.contributor.advisor Velempini, M. Mapunya, Sekgoari Semaka 2020-09-24T08:54:37Z 2020-09-24T08:54:37Z 2019
dc.description Thesis ( M.Sc. (Computer Science)) -- University of Limpopo, 2019 en_US
dc.description.abstract Cognitive radio network, which enables dynamic spectrum access, addresses the shortage of radio spectrum caused by ever-increasing wireless technology. This allows efficient utilisation of underutilised licenced spectrum by allowing cognitive radios to opportunistically make use of available licenced spectrum. Cognitive radios (CR), also known as secondary users, must constantly sense the spectrum band to avoid interfering with the transmission of the licenced users, known as primary users. Cognitive radios must cooperate in sensing the spectrum environment to avoid environmental issues that can affect the spectrum sensing. However, cooperative spectrum sensing is vulnerable to Byzantine attacks where selfish CR falsify the spectrum reports. Hence, there is a need to design and implement a defence mechanism that will thwart the Byzantine attacks and guarantee correct available spectrum access decisions. The use of extreme studentized deviate (ESD) test together with consensus algorithms are proposed in this study to combat the results of the availability of Byzantine attack in a cognitive radio network. The ESD test was used to detect and isolate falsified reports from selfish cognitive radios during the information sharing phase. The consensus algorithm was used to combine sensing reports at each time k to arrive at a consensus value which will be used to decide the spectrum availability. The proposed scheme, known extreme studentized cooperative consensus spectrum sensing (ESCCSS), was implemented in an ad hoc cognitive radio networks environment where the use of a data fusion centre (DFC) is not required. Cognitive radios make their own data fusion and make the final decision about the availability of the spectrum on their sensed reports and reports from their neighbouring nodes without any assistance from the fusion centre. MATLAB was used to implement and simulate the proposed scheme. We compared our scheme with Attack-Proof Cooperative Spectrum Sensing to check its effectiveness in combating the effect of byzantine attack. en_US
dc.format.extent viii, 58 leaves en_US
dc.language.iso en en_US
dc.relation.requires Adobe Acrobat Reader en_US
dc.subject Cognitive radio network en_US
dc.subject Byzantine attacks en_US
dc.subject Wireless communications en_US
dc.subject.lcsh Cognitive radio networks en_US
dc.subject.lcsh Radio resource management (Wireless communications) en_US
dc.subject.lcsh Radio -- Packet transmission en_US
dc.title The design and the implementation of the byzantine attack mitigation scheme in cognitive radio ad hoc networks en_US
dc.type Thesis en_US

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