Issue No.07 - July (2012 vol.11)
Guanhua Yan , Los Alamos National Laboratories, Los Alamos
Stephan Eidenbenz , Los Alamos National Laboratories, Los Alamos
Konstantinos Pelechrinis , University of Pittsburgh, Pittsburgh
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/TMC.2011.131
Recently, tuning the clear channel assessment (CCA) threshold in conjunction with power control has been considered for improving the performance of WLANs. However, we show that, CCA tuning can be exploited by selfish nodes to obtain an unfair share of the available bandwidth. Specifically, a selfish entity can manipulate the CCA threshold to ignore ongoing transmissions; this increases the probability of accessing the medium and provides the entity a higher, unfair share of the bandwidth. We experiment on our 802.11 testbed to characterize the effects of CCA tuning on both isolated links and in 802.11 WLAN configurations. We focus on AP-client(s) configurations, proposing a novel approach to detect this misbehavior. A misbehaving client is unlikely to recognize low power receptions as legitimate packets; by intelligently sending low power probe messages, an AP can efficiently detect a misbehaving node. Our key contributions are: 1) We are the first to quantify the impact of selfish CCA tuning via extensive experimentation on various 802.11 configurations. 2) We propose a lightweight scheme for detecting selfish nodes that inappropriately increase their CCAs. 3) We extensively evaluate our system on our testbed; its accuracy is 95 percent while the false positive rate is less than 5 percent.
Wireless networks, carrier sensing, clear channel assessment threshold, denial of service, selfish behavior, experimentation, analysis.
Guanhua Yan, Stephan Eidenbenz, Konstantinos Pelechrinis, "Detection of Selfish Manipulation of Carrier Sensing in 802.11 Networks", IEEE Transactions on Mobile Computing, vol.11, no. 7, pp. 1086-1101, July 2012, doi:10.1109/TMC.2011.131