Reactive jammers have been shown to be a serious threat for wireless communication. Despite this, it is difficult to detect their presence reliably. We propose a novel method to detect such sophisticated jammers in direct sequence spread spectrum (DSSS) wireless communication systems. The key idea is to extract statistics from the jamming-free symbols of the DSSS synchronizer to discern jammed packets from those lost due to bad channel conditions. Our contribution is twofold. First, we experimentally evaluate new empirical models utilizing the preamble symbols of IEEE 802.15.4 packets, thus enabling the accurate prediction of the packet delivery ratio (PDR). We show that the chip error rate-based metric is superior to metrics used in the literature, offering an accurate and reactive indicator of the true PDR. Our second contribution is the design and evaluation of a detection technique relying on this metric to detect reactive jammers. We build a software-defined radio testbed and show that our technique enables the error-free detection of reactive jammers that jam all packets on links with a PDR above 0.3. To the best of our knowledge, our detector is the first to detect reactive jamming attacks targeting the physical layer header of DSSS packets, and does not require any modifications of the wireless communication system.
['Michael Spuhler', 'Domenico Giustiniano', 'Vincent Lenders', 'Matthias Wilhelm', 'Jens B. Schmitt']
Detection of Reactive Jamming in DSSS-based Wireless Communications