SimpleMAC: a jamming-resilient MAC-layer protocol for wireless channel coordination

Abstract

In wireless networks, users share a transmission medium. To increase the efficiency of channel usage, wireless systems often use a Medium Access Control (MAC) protocol to perform channel coordination by having each node announce its usage intentions; other nodes avoid making conflicting transmissions minimizing interference both to the node that has announced its intentions and to a node that cooperates by avoiding transmissions during the reserved slot. Traditionally, in a multi-channel environment, 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. In this paper, we focus on a situation where multiple wireless transmitters share spectrum in the presence of intelligent and possibly insider jammers capable of dynamically and adaptively changing their jamming patterns. We develop a framework for effectively countering MAC-aware jamming attacks and then propose SimpleMAC, a protocol resilient to these attacks. SimpleMAC consists of two schemes (the Simple Transmitter Strategy and the Simple Signaling Scheme) that are easily analyzed using game theory, and show the optimal adversarial behavior under these protocols. We evaluate our schemes mathematically, through Monte Carlo simulations, and by implementation on the WARP software-defined radio platform. SimpleMAC provides very rapid improvement over the alternative of not using any MAC protocol, and eventually converges to optimal performance (over six-fold improvement in SINR, 50% gains in Shannon capacity in a realistic mobile scenario).