Improved IP Multimedia Subsystem Authentication mechanism for 3G-WLAN networks

The provision of IP Multimedia Subsystem (IMS) introduces important advantages for users of 3G WLAN networks. However, a multi pass authentication procedure needs to be performed before accessing the IMS, resulting in added overhead and quality of service (QoS) degradation, which deters service providers from adopting the IMS model. The problem is further compounded when the user moves from one Wireless Local Area Network (WLAN) domain into another, requiring that the authentication procedure be constantly repeated. To mitigate this problem, we present a lightweight, robust, and architecture-compatible IMS authentication protocol that implements a one-pass IMS procedure by promoting efficient key re-use for a mobile user. We derive an analytical model of our proposed scheme, and conduct numerical analysis that reveal a user authentication delay decrease of more than 50 percent.