A Channel Preemption and Time-Threshold Based Channel Allocation Scheme for Vertical Handoff in Heterogeneous Networks

In this paper, a channel preemption and time-threshold based channel allocation scheme is presented. The main idea of the new scheme is based on the priority of the call and the channel preemption. Depending on whether it is a new call and the elapsed time of the ongoing call, the call is divided into different types. When a high-priority call proposed channel preemption request, other calls of low priority which meet preemption conditions may be forced to vertical handoff or dropped. The network performance in terms of the blocking and dropping probability of the call, the Grade of Service cost function of the system and the channel utilization of the system are calculated, The results indicates that our scheme can effectively reduce the dropping probability of high-priority calls and the value of Grade of Service cost function.