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Malicious user attacks in decentralised cognitive radio networks
Dissertation (MEng)--University of Pretoria, 2020.
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| Format: | Thesis |
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University of Pretoria
2021
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| _version_ | 1867613719311155200 |
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| access_status_str | Open Access |
| author2 | Maharaj, Bodhaswar Tikanath Jugpershad |
| author_browse | Maharaj, Bodhaswar Tikanath Jugpershad |
| author_facet | Maharaj, Bodhaswar Tikanath Jugpershad |
| collection | Thesis |
| dc_rights_str_mv | © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng)--University of Pretoria, 2020. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/79657 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:36.899Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/79657 Malicious user attacks in decentralised cognitive radio networks Maharaj, Bodhaswar Tikanath Jugpershad u13108698@tuks.co.za Alfa, Attahiru S. Sivakumaran, Arun UCTD Decentralised cognitive radio networks malicious user detection cooperative spectrum sensing data fusion Dissertation (MEng)--University of Pretoria, 2020. Cognitive radio networks (CRNs) have emerged as a solution for the looming spectrum crunch caused by the rapid adoption of wireless devices over the previous decade. This technology enables efficient spectrum utility by dynamically reusing existing spectral bands. A CRN achieves this by requiring its users – called secondary users (SUs) – to measure and opportunistically utilise the band of a legacy broadcaster – called a primary user (PU) – in a process called spectrum sensing. Sensing requires the distribution and fusion of measurements from all SUs, which is facilitated by a variety of architectures and topologies. CRNs possessing a central computation node are called centralised networks, while CRNs composed of multiple computation nodes are called decentralised networks. While simpler to implement, centralised networks are reliant on the central node – the entire network fails if this node is compromised. In contrast, decentralised networks require more sophisticated protocols to implement, while offering greater robustness to node failure. Relay-based networks, a subset of decentralised networks, distribute the computation over a number of specialised relay nodes – little research exists on spectrum sensing using these networks. CRNs are vulnerable to unique physical layer attacks targeted at their spectrum sensing functionality. One such attack is the Byzantine attack; these attacks occur when malicious SUs (MUs) alter their sensing reports to achieve some goal (e.g. exploitation of the CRN’s resources, reduction of the CRN’s sensing performance, etc.). Mitigation strategies for Byzantine attacks vary based on the CRN’s network architecture, requiring defence algorithms to be explored for all architectures. Because of the sparse literature regarding relay-based networks, a novel algorithm – suitable for relay-based networks – is proposed in this work. The proposed algorithm performs joint MU detection and secure sensing by large-scale probabilistic inference of a statistical model. The proposed algorithm’s development is separated into the following two parts. • The first part involves the construction of a probabilistic graphical model representing the likelihood of all possible outcomes in the sensing process of a relay-based network. This is done by discovering the conditional dependencies present between the variables of the model. Various candidate graphical models are explored, and the mathematical description of the chosen graphical model is determined. • The second part involves the extraction of information from the graphical model to provide utility for sensing. Marginal inference is used to enable this information extraction. Belief propagation is used to infer the developed graphical model efficiently. Sensing is performed by exchanging the intermediate belief propagation computations between the relays of the CRN. Through a performance evaluation, the proposed algorithm was found to be resistant to probabilistic MU attacks of all frequencies and proportions. The sensing performance was highly sensitive to the placement of the relays and honest SUs, with the performance improving when the number of relays was increased. The transient behaviour of the proposed algorithm was evaluated in terms of its dynamics and computational complexity, with the algorithm’s results deemed satisfactory in this regard. Finally, an analysis of the effectiveness of the graphical model’s components was conducted, with a few model components accounting for most of the performance, implying that further simplifications to the proposed algorithm are possible. Electrical, Electronic and Computer Engineering MEng Unrestricted 2021-04-22T10:33:28Z 2021-04-22T10:33:28Z 2020/09/29 2020 Dissertation Sivakumaran, A 2020, Malicious user attacks in decentralised cognitive radio networks, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/79657> S2020 http://hdl.handle.net/2263/79657 DOI: 10.25403/UPresearchdata.13022435 en © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Decentralised cognitive radio networks malicious user detection cooperative spectrum sensing data fusion Malicious user attacks in decentralised cognitive radio networks |
| title | Malicious user attacks in decentralised cognitive radio networks |
| title_full | Malicious user attacks in decentralised cognitive radio networks |
| title_fullStr | Malicious user attacks in decentralised cognitive radio networks |
| title_full_unstemmed | Malicious user attacks in decentralised cognitive radio networks |
| title_short | Malicious user attacks in decentralised cognitive radio networks |
| title_sort | malicious user attacks in decentralised cognitive radio networks |
| topic | UCTD Decentralised cognitive radio networks malicious user detection cooperative spectrum sensing data fusion |
| url | http://hdl.handle.net/2263/79657 |