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Reliable communication in cognitive radio networks Shirshekar, Hossna

Abstract

The emergence of new wireless applications has driven increased demand for radio spectrum and therefore, the fixed spectrum assignment approach cannot efficiently utilize the radio spectrum. On the other side, several researches show that there are many parts of the licensed spectrum bands that are left unused most of the time. To address the problem of limited spectrum resources and underutilization of the radio spectrum resource, cognitive radio was used to make it possible for secondary users to opportunistically access the underutilized radio spectrum bands. However, in comparison with the general wireless network, cognitive radio technology gives invaders more possibilities to influence the wireless networks. This makes it more challenging to guarantee reliable communication in cognitive radio networks. In this thesis, first we describe the cognitive radio, cognitive radio networks, and security threats in these networks. Then the concepts of spectrum sensing as well as cooperative spectrum sensing are presented. There are two important kinds of security threats in the cognitive radio networks, which have attracted considerable attention in the literature. The first kind of threat which is called primary user mimicry invasion includes the cognitive radios or some outsiders that try to emulate the primary user’s signal characteristics in order to interrupt the spectrum sensing process. In the second kind of invasion, known as spectrum sensing data distortion invasion, the disruption of the spectrum sensing process is caused by those cognitive radios that send false data to the fusion center. Primary user mimicry invasion and spectrum sensing data distortion invasion have been majorly focused on in the past researches. Considering the significance of these two kinds of security threats in the ways in which they have disturbing effects on the overall performance of the cognitive radio networks, I focus my research work on these two kinds of threats. Then I provide a survey of the state of the art detection and mitigation techniques against them. The shortcomings associated with some of these detection and mitigation techniques are also investigated, which can be used as starting points for future researches.

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Attribution-NonCommercial-NoDerivatives 4.0 International