Detecting and mitigating the impact of wideband jammers in IEEE 802.11 WLANs

Abstract

IEEE 802.11 Wireless LANs (WLANs) are highly sensitive to Denial of Service (DoS) attacks carried out with jamming devices. In this paper we focus on 2.4GHz wideband constant jammers. The interest in the wideband jammer lies in the fact that it beats all possible channels at the same time, leaving no possible escape following traditional channel-switching defenses. After studying and developing an effective detection mechanism, we propose the implementation of a load balancing technique based on cell breathing for mitigating the harmful effects of the jammer over an IEEE 802.11 WLAN. Cell breathing is achieved by dynamically tuning the transmission power to adjust the size of a WLAN cell.

MPH-M, AODV-M and DSR-M Performance Evaluation under Jamming Attacks

“…Burbank et al in [ 20 ] studied path statistics and spectrum availability for the jammer detector. In [ 21 ], the authors assume a jammer that constantly emits signals, which can also attack several channels at the same time. The jammer detector is based on load balancing.…”

A novel cheater and jammer detection scheme for IEEE 802.11-based wireless LANs

“…Previous experiments with IEEE 802.11b equipment [7] concluded that, for robust modulations, it is more effective to target the transmitter's CCA; on the contrary, a faster modulation is more sensitive to packet errors produced at the receiver. However, according to our observations in the testbed depicted in Figure 1, attacking an OFDM-based IEEE 802.11 transmitter is clearly more effective than attacking a receiver regardless of whether a robust or a fast 1 Agilent ESG-D 2 A sine waveform whose frequency varies to sweep the whole 2.4GHz band 3 TCP is not being used in order to avoid the influence of TCP congestion control and retransmission mechanisms in the jammer evaluation.…”

“…But the CST value does not only increase in the presence of a jammer, it can also rise with high number of transmitters. The authors in [7] define a jammer detection method based on the inspection of the number of transmission attempts per frame and use it to correspond to CST. The authors define a ratio T f that is based on the total number of frames that have been sent to the channel and the total number of transmissions that were deferred to avoid collision.…”

“…In [7], the authors propose to use CCA channel busy indication for detection process. But this method has an apparent drawback that the channel busy time can increase in the presence of a jammer as well as with increased number of active users.…”

“…Assuming that BAT is a random variable uniformly distributed between 19µs and 2138µs 7 , s = 120 guarantees, with a confidence of 95%, that the estimated BAT has an error smaller than 10%. Using the default Beacon Interval of 100ms, 120 samples require 12s.…”