Call admission control in wireless communications networks

Abstract

This thesis is concerned with call admission control (CAC) in wireless communication networks. A salient feature of mobile wireless communications is the support of roaming. However, user mobility has a profound effect on QoS provisioning. A study of the effect of user mobility on QoS provisioning is first studied. It provides a fundamental understanding of the effect of user roaming on utilization performance and capacity requirement. For a CDMA environment, a linkage between the link layer specification and network layer QoS performance is established. Second, a proposed joint-levels resource allocation (RA) scheme is studied. This scheme is based on simultaneous satisfaction of the packet-level and call -level QoS constraints. It is shown that the utilization is greatly increased. Third, a proposed movable boundary (MB) channel allocation scheme for two traffic classes, real-time and non-real-time, is discussed. By allowing non-real-time traffic to borrow idle real-time channels, utilization is enhanced. Fourth, a combined scheme, by integrating the joint-levels RA scheme and MB channel allocation scheme, is presented. Results have shown that the combined scheme improves the utilization performance drastically. Lastly, a CAC mechanism based on the combined scheme is structured.