Efficient Mobility Management for Seamless Roaming between WWAN and WLAN

As we are moving toward the next generation all-IP wireless networks, we are facing the integration of non-homogeneous networks, such as wireless wide area networks (WWAN) and wireless local area networks (WLAN). In vertical handoff between WWAN and WLAN, the mobile hosts are required to be able to move freely across different networks while satisfying the quality of service requirements for a variety of applications. In order to maintain continuity of connection and seamless roaming with particular emphasis on the data applications, in this paper, we propose novel mobility management system which integrates a connection manager (CM) that can intelligently detect the network conditions change and a virtual connectivity manager (VC) that uses end-to-end principle to maintain the session connectivity. In our solution, handoff rate and ping-pong effect can be significantly reduced using CM. Meanwhile, mobility can be made transparent to application without network infrastructure support using VC, which can also handle mobility under Network Address Translation (NAT) and simultaneous movements scenarios. Experiment results demonstrate the effectiveness of our proposed schemes. Our prototyping system shows that seamless roaming between WLAN and WWAN can be achieved while much better performance can be obtained comparing with the one using traditional scheme.