A Utility-based Optimal Joint Call Admission Control Scheme with Vertical Handoff in Heterogeneous Wireless Networks

This paper comes up with a mechanism of optimal joint call admission control based on different service types. Considering practical wireless transmission environment, it divides the heterogeneous wireless network into several areas and also defines the peak rates that its users could get in each area. The process of call admission control is modeled into a semi-Markov process for the two typical services of streaming media service and elastic traffic which need high band width demand. In accordance with the features of different services, it also defines corresponding admission utility function. The optimal admission strategy with highest admission utility in the whole process of call admission control is obtained on the basis of guaranteeing successful session admission and vertical handoff. Simulation results show that the defined admission utility function could effectively reflect the influence of the change of network status to admission control. The suggested optimal joint call admission control excels the both schemes of non-combined call admission control and non-supporting users' mobility in terms of average admission utility and call blocking rate, and is capable of ensuring lower blocking probability and handoff success ratio.