Rational behaviors in hotspots and in ad hoc networks

ABSTRACT

In this talk, we address the problem of modelling, analyzing, and simulating rational behaviors in wireless networks. We illustrate this problem with two examples. The first is a recently discovered vulnerability of WiFi hotspots: a selfish user can easily alter the behavior of the IEEE 802.11 MAC layer of his adaptor in order to capture most of the bandwidth for his own benefit, at the expense of the other users of the same access point. We show how to quantify the benefits of this cheating technique, and how to protect access points against this kind of misbehaviors. The second example refers to packet forwarding in wireless ad hoc networks in which each node is its own authority: here a selfish user could drop the packets he is expect to forward, in order to save his own battery. We show how to model this problem in a game theory setting, and we identify the conditions under which cooperation can exist without incentives. The slides of this talk are available at http://lcawww.epfl.ch/hubaux.