Abstract
Abstract Cognitive radio (CR) is a promising technology that brings about remarkable improvement in spectrum utilization. To tackle the hidden terminal problem, cooperative spectrum sensing (CSS) which benefits from the spatial diversity has been studied extensively. Since CSS is vulnerable to the attacks initiated by malicious secondary users (SUs), several secure CSS schemes based on Dempster-Shafer theory have been proposed. However, the existing works only utilize the current difference of SUs, such as the difference in SNR or similarity degree, to evaluate the trustworthiness of each SU. As the current difference is only one-sided and sometimes inaccurate, the statistical information contained in each SU's historical behavior should not be overlooked. In this article, we propose a robust CSS scheme based on Dempster-Shafer theory and trustworthiness degree calculation. It is carried out in four successive steps, which are basic probability assignment (BPA), trustworthiness degree calculation, selection and adjustment of BPA, and combination by Dempster-Shafer rule, respectively. Our proposed scheme evaluates the trustworthiness degree of SUs from both current difference aspect and historical behavior aspect and exploits Dempster-Shafer theory's potential to establish a ‘soft update’ approach for the reputation value maintenance. It can not only differentiate malicious SUs from honest ones based on their historical behaviors but also reserve the current difference for each SU to achieve a better real-time performance. Abundant simulation results have validated that the proposed scheme outperforms the existing ones under the impact of different attack patterns and different number of malicious SUs.
Highlights
Due to the static licensing and allocation strategies, current spectrum regulation has resulted in extreme scarcity of available spectrum, while plenty of radio frequencies are unused temporally/geographically [1]
System model we describe the scenario of cooperative spectrum sensing (CSS) in cognitive radio network (CRN) and introduce two attack patterns considered in this article
Robust cooperative spectrum sensing scheme based on Dempster-Shafer theory and trustworthiness degree calculation we propose a robust CSS scheme based on Dempster-Shafer theory and trustworthiness degree calculation in CRNs
Summary
Due to the static licensing and allocation strategies, current spectrum regulation has resulted in extreme scarcity of available spectrum, while plenty of radio frequencies are unused temporally/geographically [1]. Quan et al [13] have proposed an optimal linear CSS scheme, which makes the global decision over a linear combination of the local measurements It has reduced the computational complexity and can reach performance comparable to LRT-based optimal fusion rules. In this article, we propose a robust CSS scheme based on Dempster-Shafer theory and trustworthiness degree calculation. To perform CSS, SUs will send their reports of the local spectrum sensing to FC for further processing These reports can either be the received energy xEi or a function of it (such as 1-bit hard decision), depending on the specific fusion rule adopted by FC. This attack pattern will increase the false alarm probability and result in the underutilization of available spectrum or the exclusive usage of it by FA attackers
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