Smooth Handoff Based on Virtual Interface in Wireless Network

The IEEE 802.11 based network is the most popular wireless network, but its packet latency and loss rate in mobility support disable a lot of interactive real-time network applications to run on wireless mobile station. The existing handoff schemes can only resolve the problems of inner ESS domain handoff, but cannot effectively resolve that of inter ESS domains handoff because the handoff between two ESS domains involves network layer operations. In this paper, a smooth handoff scheme based on virtual interface in wireless network is proposed. This scheme applies a time-sharing policy on physical wireless interface, which enables mobile station to establish new wireless link with the right new access point at the same time to keep normal communication in present wireless link with the previous access point, so it can resolve the problems of packet latency and loss ratio not only for inner ESS domain handoff but also for inter ESS domain handoff perfectly. And the simulation results on NS2 confirms that it could satisfy the demand of interactive real-time applications in wireless mobile network.