Performance of CSS cognitive radio networks under primary user emulation attack

Cognitive radio (CR) is a promising technology for improving spectrum utilization by means of opportunistic spectrum sharing. As more number of smart wireless devices are increasing in cognitive radio networks (CRNs), CR systems becomes more vulnerable to many security threats that influence the overall performance. To alleviate the spectrum shortage problem, CR sense the spectrum for availability of white spaces in it and use it without harmful interference with primary user (PU), thereby improves the spectrum utilization. Cooperative spectrum sensing (CSS) is more accurate than individual spectrum sensing as it exploits the cooperation among multiple secondary users (SUs) or CRs. However, CSS is more vulnerable to different attacks which degrades the network performance. In this paper, we consider the primary user emulation attack (PUEA) in CSS and propose the protocol to identify and eliminate the attacker or malicious user (MU) to improve the network performance. In PUEA attack, many malicious users (MUs) in network generate the signals identical to primary user's signals and generate enough power at good SUs locations to confuse them with PU transmission. The good SU then evacuates the channel by believing these signals as PU signals. The good SUs then will vacate the spectrum which will be utilized by MUs thereby prohibiting the authorized SUs to utilize the spectrum.