| In cognitive radio (CR) mobile ad hoc networks (MANETs), secondary users can cooperatively sense the spectrum to detect the presence of primary users. In this thesis, we propose a fully distributed and scalable cooperative spectrum sensing scheme based on recent advances in consensus algorithms. In the proposed scheme, the secondary users can maintain coordination based on only local information exchange without a centralized common receiver. We use the consensus of secondary users to make the final decision. The proposed scheme is essentially based on recent advances in consensus algorithms that have taken inspiration from complex natural phenomena including flocking of birds, schooling of fish, swarming of ants and honeybees. In addition, we consider the security issues such as spectrum sensing data falsification (SSDF) attacks in CR MANETs. In SSDF attacks, intruders send false local spectrum sensing results in cooperative spectrum sensing, which will cause wrong spectrum sensing decisions by cognitive radios. To counter SSDF attacks in cognitive radio MANETs, we further make little modification on the proposed consensus-based scheme. Simulation results show that the proposed consensus scheme can have significant lower missing detection probabilities and false alarm probabilities in cognitive radio MANETs. It is also demonstrated that the proposed scheme not only has proven sensitivity in detecting the primary user's presence, but also has robustness in choosing a desirable decision threshold. |
