R-CSCF USIM Authentication for IMS Roaming
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Solution Overview
Problem
User devices without an Integrated Services Identity Module (ISIM) cannot perform IMS authentication when roaming on IMS-enabled wireless networks, limiting their ability to use IMS services.
Innovation Solution
Implementing a Roaming Call Session Control Function (R-CSCF) that uses Universal Subscriber Identity Module (USIM) credentials for IMS authentication by generating an EPC authentication challenge and response, allowing user devices without an ISIM to authenticate with IMS core networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional IMS authentication using ISIM is implemented, then IMS authentication functionality is provided for roaming users, but user devices without an ISIM cannot access IMS services
Solution Approach 1:
The patent applies universality by enabling the USIM (originally designed for EPC authentication) to perform dual functionality - both EPC authentication and IMS authentication. The R-CSCF is configured to accept EPC authentication credentials from the USIM and convert them into IMS authentication responses, allowing a single authentication mechanism to serve multiple purposes and eliminate the need for separate ISIM functionality.
2Adaptability or versatility
If EPC authentication credentials are used for IMS authentication, then user devices without ISIM can access IMS services, but additional authentication coordination infrastructure is required
Solution Approach 1:
The R-CSCF acts as an intermediary between the USIM and the IMS core network. It receives EPC authentication credentials from the USIM, processes them through the authentication challenge-response mechanism, and generates appropriate IMS authentication responses. This intermediary function bridges the gap between different authentication systems without requiring changes to the user device or home network infrastructure.
3Productivity
If roaming agreements include IMS service access, then service providers can monetize IMS services through usage charges, but non-IMS service providers cannot provide IMS-capable roaming devices
Solution Approach 1:
The patent enables service providers to monetize IMS services by making IMS authentication capability universal across all roaming devices, regardless of whether the home network provides IMS services. The R-CSCF configuration allows any roaming device with USIM credentials to access IMS services on the visited network, creating new revenue opportunities while maintaining service provider flexibility in choosing whether to deploy IMS infrastructure.
Data Source
AI summary
A call session control function (“CSCF”), of an Internet Protocol Multimedia Subsystem (“IMS”) core network, may receive a set of authentication credentials that do not include IMS authentication credentials; and may use the set of authentication credentials, which do not include IMS authentication credentials, to authenticate a user device for the IMS core network.