QoS Architecture in Ad Hoc Networks

We propose and discuss an augmented DiffServ architecture for ad hoc networks. It utilizes the concept of shadow classes and monitoring for admission control. Each DiffServ class has an associated shadow class with a higher drop probability, but the same scheduling properties. A new flow must reside in its shadow class before it is admitted. The resulting QoS is monitored, and the new flow is not admitted if the received QoS is not satisfactory. This ensures that new flows chiefly affect lower priority flows. Through simulations with three classes, EF, AF and BE, we find the QoS architecture´s performance in terms of loss and delay. The real-time traffic in the EF class shows good and stable performance independent of the load. The AF class gets a constant throughput, while the BE class utilizes the available resources and maximizes its throughput.