Ads: An Adaptive Spectrum Sensing Technique For Survivability Under Jamming Attack In Cognitive Radio Networks

IEEE 802.22 Cognitive Radio Network (CRN) allows sharing of geographically unused spectrum allocated to the television broadcast service, on a non-interfering basis. CRNs make use of Dynamic Spectrum Access (DSA) which is a two-stage mechanism comprising fast sensing, which is mandatory and fine sensing which is optional. However, the two-stage spectrum sensing mechanism suits malicious nodes in the CRN which intend to deny the use of vacant spectrum to the CRN by jamming its communication while at the same time, minimizing the amount of power expended on jamming. Such Minimal Denial of Service (MDoS) jamming attack can be launched by the malicious nodes by transmitting a very short jamming signal during the mandatory fast sensing stage which will in turn force the CRN to carry out the otherwise optional, fine sensing. MDoS jamming attack results in wastage of spectrum opportunities for the rest of the CRN to the extent which can jeopardize its survivability. In this paper we present AdS: an Intelligent Adaptive spectrum Sensing technique which, not only minimizes the effects of MDoS jamming attack but can also reduce the effects of noise during the spectrum sensing stages of DSA. The adaptive nature of AdS improves spectrum utilization by CRNs by up to 90% through adaptive tuning of the fine sensing threshold which is based on an estimate of PU's activity and the severity of MDoS jamming attack.