On IMS-based Fast Session Handover Based on Available Network Resources of Access Networks

Mobile users´ demand for using the best available network connection encourages mobile network operators (MNOs) to construct multi-access networks managed by all-IP based mobile networks. For such an MNO, the IP Multimedia Subsystem (IMS) is a promising service control infrastructure to provide IP-based multimedia services with QoS guarantee in the multi-access network. The service centralization and continuity application server (SCC AS), which is a dedicated application server cooperating with the IMS, enables user equipments (UEs) to continuously use IMS-based services (e.g., VoIP) even when the UEs make handovers between different access networks. In the case where the UE cannot simultaneously use multiple wireless devices, there is the possibility of occurring a long media disruption time during handovers. This is caused by several consecutive handovers as a result of attempting to ensure the QoS-guaranteed communications. In this paper, we propose a method for reducing the media disruption time when the UE makes handovers between different access networks. In the proposal, the UE proactively performs the service continuity procedure, and selects the access network that can provide the required network resources to the UE. We implement and evaluate the proposed method, and show how the media disruption time can be reduced.