Detection of reactive jamming in sensor networks

An integral part of most security- and safety-critical applications is a dependable and timely alarm notification. However, owing to the resource constraints of wireless sensor nodes (i.e., their limited power and spectral diversity), ensuring a timely and jamming-resistant delivery of alarm messages in applications that rely on wireless sensor networks is a challenging task. With current alarm forwarding schemes, blocking of an alarm by jamming is straightforward and jamming is very likely to remain unnoticed. In this work, we propose a novel jamming detection scheme as a solution to this problem. Our scheme is able to identify the cause of bit errors for individual packets by looking at the received signal strength during the reception of these bits and is well-suited for the protection of reactive alarm systems with very low network traffic. We present three different techniques for the identification of bit errors based on: predetermined knowledge, error correcting codes, and limited node wiring. We perform a detailed evaluation of the proposed solution and validate our findings experimentally with Chipcon CC1000 radios. The results show that our solution effectively detects sophisticated jamming attacks that cannot be detected with existing techniques and enables the formation of robust sensor networks for dependable delivery of alarm notifications. Our scheme also meets the high demands on the energy efficiency of reactive surveillance applications as it can operate without introducing additional wireless network traffic.