User-Centric Seamless Handover Scheme for Realtime Applications

We bring a new perspective on a vertical handover scheme, a user-centric seamless handover, toward a next generation network where heterogeneous network systems converge. The proposed scheme allows us to provide users with the optimal service quality for real-time applications in respective network systems, as well as sustaining on-going sessions. Firstly we propose SIP-based bi-casting technology using a Handover Assistant Server to provide optimal service quality in respective network systems and avoid packet loss during handover. The delay difference absorption method is also proposed to adjust the service quality smoothly to the newly connected network. Evaluation results show that the scheme works well for the handover between cellular and high speed wireless access via the implementation of a prototype system.