Handover Delay Estimation Method for IMS-Based Systems with Heterogeneous Access Networks

IP multimedia subsystem (IMS) is an architectural framework designed to merge the Internet and cellular networks, as such users can have access to the current and future services available over the Internet with their mobile devices anytime and virtually everywhere at affordable charges and faster rates, but heterogeneity of access networks in IMS-based systems makes handover process to be a critical issue, especially when moving from one access network to another access network with different technology, hence there is a need to devise a simple approach to estimate handover delay when moving to any access network. This paper proposes a simple method to estimate handover delay for IMS-based systems with heterogeneous access networks. The proposed method can be used to estimate handover delay for current and future access networks, but for illustration purpose, in the paper two access networks were considered, i.e. UMTS and WLAN. Numerical analysis conducted in the paper has shown that handover process to UMTS access network tends to be much longer than that of WLAN access network.