Detecting MAC layer collision abnormalities in CSMA/CA wireless networks

We present a robust non-parametric detection mechanism for CSMA/CA MAC layer denial-of-service attacks that does not require any modification to the existing protocols. This technique, based on the M-truncated sequential Kolmogorov-Smirnov statistics, monitors the successful transmissions and the collisions of the terminals in the network, and determines how 'explainable' the collisions are given such observations. We show that the distribution of explainability of the collisions is very sensitive to abnormal changes in the network, even with a changing number competing terminals. NS-2 simulation results show that the proposed method has a very short detection latency and high detection accuracy.