Reducing handover latency in future IP-based wireless networks: Proxy Mobile IPv6 with simultaneous bindings

Handover in future wireless communication systems must be seamless. Current IP-level mobility protocols have difficulties meeting the stringent handover delay requirements. At the same time they do not give sufficient control to the network to optimize the handover process and they do not deal well with slow connection setups of some wireless technologies. In this paper we propose an enhancement of Proxy MIPv6 (PMIPv6) with Simultaneous bindings. The result, called SPMIPv6, is a proactive network-controlled handover solution that allows some handover processes to be carried proactively while the mobile node is connected to the serving network. We analyze SPMIPv6 performance and show that the handover latency can be limited to one RTT between the mobile node and the target access router, which is typically below 10ms, and that the packet loss due to handover can be decreased and eliminated by appropriately buffering packets at the target access router. Moreover, our performance evaluation based on a SPMIPv6 implementation shows no TCP and UDP performance degradation during handovers. Two important characteristics of SPMIPv6 are its robustness to incorrect handover predictions and its built-in features to accommodate large network attachment latencies.