Encouraging Cooperation in Multi-Hop Wireless Networks

We present Catch, a protocol that encourages cooperation in multi-hop wireless networks comprised of autonomous nodes. While these nodes depend on each other to relay packets, scarce bandwidth and energy resources may motivate some nodes to cheat and avoid packet forwarding. Catch employs a novel technique based on anonymous messages to significantly increase the difficulty of cheating with impunity. Existing routing protocols simply assume that nodes will act cooperatively and have no mechanisms to encourage this behavior or punish cheaters. Catch imposes minimal requirements and overheads on the system, and so is broadly applicable across routing protocols and system workloads. We show that Catch makes cheating counter-productive, thus encouraging the cooperative behavior on which multi-hop wireless networks are predicated. We evaluate Catch on an 802.11 wireless testbed, as well as through simulation.