Enhanced SIP based method for vertical handoff between WiFi and WiMax networks

One of the most important issues in wireless and mobile communication technologies is the mobility management when a mobile node moves between different access networks. Many alternative ways to realize mobility management have been proposed on different layers. In this paper we discuss the vertical handoff behavior when a mobile node moves from IEEE 802.11 network to IEEE 802.16 network and vice versa using Session Initiation Protocol (SIP) in order to support real-time communication in a more efficient way in application layer. A new approach named Enhanced Mid-call Mobility SIP(EMSIP)which provides better billing procedures during handoff for real-time operator environment is proposed. Bandwidth and received signal strength (RSS)are used as metrics. Real-time application (streaming video) is taken into consideration. We are using NS2 to measure handoff latency and packet loss in two cases. Varying the speed of Mobile Node(MN) keeping other parameters viz., video packet size constant. Varying the size of video packet keeping the speed of MN constant and the performance characteristics of EMSIP are studied.