Cross-domain authentication for multi-protocol phones

The last decade has seen a surge in demand for cellular and WLAN networks. With the introduction of Voice Over IP, cellular companies are looking at WLAN-Cellular integrated networks that shall provide users with economical voice and data services. These networks shall be complimentary to the existing cellular networks. A lot of money is spent in registering and authenticating new users, since they are separately authenticated and registered on the WLAN and Cellular domains. This leads to extra costs for the company. Thus for the integrated networks to have an impact on the market some issues such as simpler authentication and registration must be resolved. Therefore we propose a new inter-working model that shall addresses the authentication and registration problem for an integrated network for voice and data. The Single authentication system of the new inter-working model, shall authenticate the user in an integrated network using the SIM credentials, this authentication shall be valid for both voice and data. Also registration costs will be saved by preventing separate registration of users in the WLAN and Cellular domain.