A Time-Threshold-Based Upward Priority Scheme for Vertical Handoff in Cellular/WLAN Interworking

This paper proposes a novel Time-threshold-based Upward Priority Scheme (TUPS) for vertical handoff in a cellular/WLAN interworking networks. In order to improve the newly blocking probability of cellular calls while guaranteeing system performance and utilization of the cellular bandwidth, the proposed scheme defines priorities for Upward Vertical Handoff (UVH) calls by using time-threshold values and designs newly bandwidth allocation scheme and priority preemption rule to modify the Upward Priority channel Preemption Scheme (UPPS) scheme. Simulation results show that the proposed scheme enormously improves performance of the newly cellular call blocking probability at the cost of some increasing non-prioritized UVH call dropping probability that may tolerate uncritical while keeping high cellular bandwidth utilization and low prioritized UVH call dropping probability compared with UPPS. The proposed scheme has much significance in providing good QoS guarantees in cellular /WLAN interworking networks.