Robust Distributed Cooperative Spectrum Sensing for Cognitive Radio Ad Hoc Networks

摘要

Dynamic spectrum access paradigm, enabled by cognitive radios, presents an adaptive approach for spectrum sharing by allowing secondary users to use licensed spectrum bands on an opportunistic non-interference basis. Cooperation among cognitive radios for spectrum sensing is deemed essential for environments with deep shadows. However, the existing cooperative spectrum sensing schemes for mobile ad hoc networks are high-overhead and vulnerable to spectrum sensing data falsification attacks. In this thesis, we propose a novel trust-aware consensus-inspired cooperative sensing scheme based on iterative broadcast and linear updates that is fully distributed, low-cost and resilient to malicious behavior in the cooperative network. Unlike the existing schemes, our method does not require any network discovery by the nodes for cooperation; therefore, it offers significantly lower overhead with no degradation in the sensing performance.;We study Insistent Spectrum Sensing Data Falsification (ISSDF) attack aimed at iterative cooperative sensing schemes and show its destructive effect on the cooperation performance which accordingly results in reduced spectrum efficiency and increased interference with primary users. We design a novel distributed trust management scheme that is integrated into cooperation to mitigate different types of ISSDF attacks in practical scenarios where the primary user and secondary users of the spectrum and the malicious users behave dynamically. The characteristics of the proposed trust scheme is thoroughly analyzed by theory and experiments.;We evaluate our proposed trust-aware distributed cooperative sensing scheme by extensive Monte Carlo simulations modeling realistic scenarios of mobile cognitive radio ad hoc networks in TV white space. We show that the proposed scheme reduces the harm of a set of collusive ISSDF attackers up to two orders of magnitude in terms of missed-detection and false alarm error rates. In addition, in a hostile environment, integration of trust management into distributed cooperative sensing considerably relaxes the sensitivity requirements on the cognitive radio devices. Furthermore, in order to evaluate the scalability, we analyze the impact of various parameters of the cognitive radio network, the cooperation scheme and the trust management scheme on the sensing performance in the presence of malicious behavior.