Abstract
The rapid growth of the access technologies provides an opportunity for appropriately equipped user terminals to access the rich communication suite services. And the IP Multimedia Subsystem (IMS) could very well be the best solution for most operators. The more recent releases have included interfaces to non-IP Capable Access Network (IP-CAN) as well as IP-CAN. In addition to, a Mobile VoIP (mVoIP) is one of the most issues according to introducing WLAN or WIMAX networks. In order to provide complete convergence service such as mVoIP based on IMS over both legacy CS networks and IPCANs, it is important to define the new architecture over heterogeneous networks. One of the research challenges for this interworking between various networks is the design of service continuity and consistency to support seamless session mobility based on IMS. In this work, first we review the concept of session continuity as well as the VoIP architecture in 3GPP standardization. Then, we propose the IMS Centralized Network (ICN) Architecture towards convergence services containing Call flows and new services.