Secure interworking & roaming of WiMAX with 3G and Wi-Fi

The roaming between different WiMAX (Worldwide Interoperability for Microwave Access) networks as well as the interworking between WiMAX and other access technologies will be a key enabler for global WiMAX deployment. To provide secure and seamless roaming capability for mobile users across different access network domains, belonging to the same or different operators, we propose a roaming & interworking solution using intermediary entities, called Roaming Interworking Intermediary (RII). A generic RII-based interworking and roaming architecture between WiMAX, 3GPP (third Generation Partnership Project) and WLAN networks is presented. A test-bed has been setup, using real pre-WiMAX and Wi-Fi equipments and real operational cellular network, to demonstrate and evaluate the proposed solutions. The robustness, feasibility and efficiency of the proposed architecture are proven through different user scenarios.