SimpleMAC: A Simple Wireless MAC-Layer Countermeasure to Intelligent and Insider Jammers

In wireless networks, users share a transmission medium. For efficient channel use, wireless systems often use a Medium Access Control (MAC) protocol to perform channel coordination by having each node announce its usage intentions and other nodes avoid making conflicting transmissions. Traditionally, such announcements are made on a common control channel. However, this control channel is vulnerable to jamming because its location is pre-assigned and known to attackers. Furthermore, the announcements themselves provide information useful for jamming. We focus on a situation where transmitters share spectrum in the presence of intelligent and insider jammers capable of adaptively changing their jamming patterns. Despite the complex threat model, we propose a simple MAC scheme, called SimpleMAC, that effectively counters network compromise and MAC-aware jamming attacks. We then study the optimal adversarial behavior and analyze the performance of the proposed scheme theoretically, through Monte Carlo simulations, and by implementation on the WARP software-defined radio platform. In comparison to the Nash equilibrium alternative of disabling the MAC protocol, SimpleMAC quickly attains vastly improved performance and converges to the optimal solution (over six-fold improvement in SINR and 50% gains in channel capacity in a realistic mobile scenario).