Detection of reactive jamming in DSSS-based wireless networks

We propose a novel approach to detect reactive jammers in direct sequence spread spectrum (DSSS) wireless networks. The key idea is to use the chip error rate of the first few jamming-free symbols at the DSSS demodulator during the signal synchronization phase of regular packet reception to estimate the probability of successful packet delivery. If the estimated probability is significantly higher than the actual packet delivery ratio, we declare jamming. As a proof of concept, we implement a prototype in a network of three USRP software-defined radios (transmitter, receiver, and jammer) and evaluate the feasibility, responsiveness, and accuracy of our approach in a controlled lab environment. Our experiments with IEEE 802.15.4 DSSS-based communication show that for links with a jamming-free packet delivery probability above 0.5, the false positive and negative detection rates remain below 5%.