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UBC Theses and Dissertations

Trust-based spectrum and energy efficient collaborative spectrum sensing in cognitive radio networks Mousavifar, Seyed Ali


Cognitive radio (CR) is a promising technology designed to improve the utilization of lightly used portions of the licensed spectrum while ensuring no undue interference with incumbent users (IUs). CR networks (CRNs) employ collaborative spectrum sensing (CSS) methods to discover spectrum opportunities. Spectrum and energy overhead costs play important roles in the efficiency of CSS in CRNs. A trust-based energy efficient CSS (EE-CSS) protocol is proposed. The protocol achieves energy efficiency by reducing the total number of sensing reports exchanged between the secondary users (SUs) and the fusion center (FC) in the presence of misbehaving SUs (MSUs). The steady-state and transient behavior of the average number of sensing reports and trust values of SUs in EE-CSS are analyzed and compared to those in traditional CSS (T-CSS). The impact of link outages on the global false alarm (FA) probabilities, ℚf, and the global miss detection (MD) probabilities, ℚmd, in EE-CSS and T-CSS is also analyzed. A centralized trust-based collusion attack strategy, in conjunction with integer linear programming, is proposed to compromise the decision of the FC in EE-CSS. The proposed strategy aims to attack only when it is likely to alter the decision of the FC. A mitigating scheme, based on the cross-correlation of sensing reports, is proposed to identify SUs with abnormal behaviors and to eliminate them from the decision making process at the FC. We also propose a trust-based spectrum and energy efficient CSS (SEE-CSS) scheme for the IEEE 802.22 standard wireless regional area network (WRAN). The proposed scheme aims to reduce the number of urgent coexistence situation (UCS) notifications transmitted from customer premise equipment (CPE) nodes to the WRAN base station (BS). The UCS messages inform the BS of the presence of active IUs on the licensed spectrum. We adapt the collusion attack strategy for SEE-CSS and apply the cross-correlation method at the BS to mitigate against the collusion attack. The results show that while ℚf and ℚmd are kept the same in T-CSS and SEE-CSS, the SEE-CSS protocol is more energy and spectrum efficient.

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Attribution 2.5 Canada