Evaluation of path dependent scheduling in Ad Hoc networks: A suitable fairness mechanism?

In this paper we investigate whether scheduling packets based on path information can improve the fairness in an ad hoc network. The users may have a need for a predictable service over time and common to the whole ad hoc network. However, the performance depends on the path between sender and receiver, and it will therefore vary over time. Two schemes are analyzed; the first scheme differentiates local traffic from transfer traffic, while the second scheme differentiates packets on their last hop to the destination from other packets. Fairness will come at a price, and there will always have to be a trade-off between the degree of equal service and the utilization or effectiveness of the ad-hoc network. In simulations we illustrate the trade-off between fairness and total good put. The simulations are done for a simple topology to illustrate the trade-offs, and for a full QoS architecture with mobility and random topologies.