Survey on Collaborative Spectrum Sensing and Belief Propagation Based Defense in Cognitive Radio Networks

that can alleviate the spectrum shortage problem by enabling unlicensed users equipped with CRs to coexist with incumbent users in licensed spectrum bands without inducing interference to incumbent communications. Spectrum sensing is one of the essential mechanisms of CRs. Although the operational aspects of spectrum sensing are being investigated actively, its security aspects have gained little attention. Collaborative spectrum sensing among the cognitive radio nodes is expected to improve the ability of checking complete spectrum usage. But this spectrum access mechanism of CR network has lead to the discovery of new vulnerabilities. The objective of this paper is to study some of the collaborative spectrum sensing techniques and belief propagation based defense in CR networks. An attack proof collaborative spectrum sensing technique which calculates the suspicious level of secondary users and then utilizes th