NOVEL MITIGATION METHODS AGAINST REACTIVE JAMMING ATTACK: THEORETICAL AND PRACTICAL SOLUTIONS By INCHEOL SHIN A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY

of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy NOVEL MITIGATION METHODS AGAINST REACTIVE JAMMING ATTACK: THEORETICAL AND PRACTICAL SOLUTIONS By Incheol Shin August 2010 Chair: My Tra Thai Major: Computer Engineering Wireless Sensor Networks (WSNs) consist of many spatially deployed sensor devices to cooperatively monitor selected target locations and communicate with base stations. WSNs have potential applications in various complex environments such as military surveillance, health-care systems, disaster area monitoring and etc. Due to the requirement of large-scale and real-time data processing in WSNs, security is critical in many sensor network applications. The wireless communication of sensor devices in resource-constrained WSNs leads to many challenging and intriguing security-sensitive problems that cannot be handled using conventional security solutions. Especially, since jammers attack the broadcast nature of the transmission medium by injecting interference signals, they are considered the most critical and fatally adversarial threats to subvert or disrupt the networks. Jamming attacks do not have to modify communication packets or compromise any sensors in order to launch, which makes them difficult to detect and defend against. Existing countermeasures against such attacks either consider sensor nodes equipped with sophisticated hardware, which is infeasible for low cost resource constraint WSNs, or have high overhead in term of time and message complexity and energy consumption. However, to overcome the problems in existing methods against reactive jamming attack, this dissertation introduces a novel approach by identifying the