Seamless handover scheme based on SIP in Wireless LAN

In this paper, we propose L3 handover scheme using SIP messages to minimize handover latency and packet loss in a MN with single interface. Packet loss and handover latency arise from L2/L3 association delay and IP configuration delay when the MN transfers internet connectivity from the serving access router to the target access router using legacy terminal mobility mechanisms. Therefore, seamless handover is not provided by these problems such as long latency time and packet loss. In the Proposed scheme, the MN restricts that the CNs transmit packets to MN during handover procedures. Also, P-CSCF configures IP address previously for the MN in target WLAN by using CARD mechanism, and then performs registration procedures to IMS server instead of MN. And changed information about ongoing session is notified to both MN and CNs by P-CSCF. Finally, the MN communicates with CNs after transferring internet connectivity from the serving access router to the target access router. The proposed scheme reduces handover latency, particularly delay of IP address configuration. And packet loss is minimized by restriction of sending packets during handover procedures. We numerically analysed handover latency and signalling cost of the proposed scheme to show the improved performance.