Towards cooperation fairness in mobile ad hoc networks

For the sustainable operation of ad hoc networks, incentive mechanisms are required to encourage cooperation. More importantly, we must enforce available bandwidth fairness among nodes in ad hoc networks. While such fair sharing of bandwidth in traditional networks is carried out by the dedicated routers with a variety of algorithms, in mobile ad-hoc networks, it must be performed by each node because nodes can act as routers as well as end hosts. Here, we say that bandwidth sharing is fair if a node's available bandwidth is proportional to its forwarding contribution. In this paper we achieve fair bandwidth sharing through a new packet scheduling algorithm, called cooperative queueing, on each node. In cooperative queueing, which is analogous to fair queueing, packet scheduling is based on a new abstraction that we call cooperation coefficient. The cooperation coefficient quantifies how much a given node contributes to and consumes from the ad-hoc network; the larger the cooperation coefficient, the more bandwidth a node can obtain. We exploit the widely used dynamic source routing information to obtain the cooperation coefficient. We evaluate the effectiveness of cooperative queueing with different parameters and network configurations. We demonstrate that our algorithm is able to encourage cooperation and ensure fair sharing of bandwidth between nodes. We show that cooperative queueing is simple and has little overhead.