Interworking Function for Inbound Roaming Authentication
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Solution Overview
Problem
Visited networks without CS components or IMS support struggle to offer inbound roaming services to subscribers from non-IMS or non-ICS capable home networks without a service level agreement, as they lack the necessary infrastructure for authentication and subscription management.
Innovation Solution
The implementation of a communication apparatus and method that uses a transceiver and controller to retrieve authentication information from the home network's HSS/HLR via an ICS IWF, enabling CS authentication and subscription profile conversion for IMS-enabled visited networks, allowing registration and service provision without requiring VLR functionality in the visited network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If visited networks remove CS components and IMS support to simplify network architecture, then device complexity is reduced, but inbound roaming services for non-IMS capable subscribers cannot be provided
Solution Approach 1:
The patent introduces an Interworking Function (IWF) as an intermediary component that enables communication between the IMS network and legacy non-IMS networks. The IWF translates and adapts signaling protocols, allowing the visited network to provide roaming services to subscribers from non-IMS capable home networks without requiring CS components or IMS support in the visited network itself. This mediator handles authentication information retrieval and subscription profile conversion between different network architectures.
2Adaptability or versatility
If visited networks retain CS components and VLR functionality to support inbound roaming, then service coverage is improved, but network complexity and operational requirements increase
Solution Approach 1:
The patent extracts the essential authentication and subscription management functions from the traditional VLR and CS components, concentrating these capabilities in the IWF. This allows the visited network to eliminate redundant CS components and VLR functionality while maintaining inbound roaming support. The IWF retrieves authentication information directly from the home network's HSS/HLR, removing the need for local VLR storage and processing of subscriber data.
3Reliability
If visited networks require service level agreements with home networks for roaming support, then authentication reliability is improved, but service accessibility is reduced
Solution Approach 1:
The patent implements a universal authentication mechanism through the IWF that can handle multiple types of home networks (IMS-capable and non-IMS capable) using a common approach. The IWF retrieves authentication information from the home network's HSS/HLR regardless of whether the home network supports IMS or not, and converts subscription profiles into a unified format suitable for the visited IMS network. This multi-functional capability eliminates the need for separate service level agreements for different network types.
Data Source
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AI summary
A communication system is disclosed in which an interworking function (or similar communication apparatus) supports a registration procedure for an inbound roamer user equipment (UE) in a visited public land mobile network (VPLMN), by receiving, from a communication entity of the VPLMN, a request for authentication information; retrieving the authentication information from a communication entity of a home public land mobile network (HPLMN); and transmitting the authentication information to the communication entity of the VPLMN for use in the registration procedure.