QoS compliance through cross-layer assisted resource allocation

This article adresses the QoS compliant delivery of packet data flows through the MAC and PHY layers of a wirless communication system. The available degrees of freedom in the call admission control, the scheduling unit, the MAC protocol as well as in the signal processing units of the PHY layer are employed to maximize the resource efficiency or equivalently minimize the amount of resources required for a quality compliant service. In order to solve the resulting cross-layer problem we make three contributions: First, a generic approach derives an optimum solution to the problem of jointly optimizing the radio parameters in a system that is constrained by upper layer requirements. Second, QoS aware scheduling algorithms are proposed that access the cross-layer information provided by the above scheme. Based upon these scheduling techniques a third part targets the problem of call admission control. Basing its decision on cross-layer knowledge gathered in the above schemes the admission control can be designed to maximize the number of flows that can be served QoS compliantly. The proposed compound of cross-layer techniques is evaluated numerically.