IMS Service Policy Control for Roaming Devices

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Solution Overview

Problem

Mobile devices roaming in foreign networks face challenges in registering for IMS services due to potential technical conflicts and network optimization needs, requiring operators to manage service policies across multiple servers and reduce signaling, while ensuring access to whitelisted services based on visited networks and Radio Access Technology (RAT) types.

Innovation Solution

Implementing a registration manager component within the IMS network that utilizes a policy table to determine whitelisted services, allowing mobile devices to register only for authorized services by querying the policy table based on visited network and RAT type, thereby streamlining the registration process and reducing signaling requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If operators maintain service policies in multiple application servers, then service restriction and selection control can be implemented, but system complexity and signaling overhead increase

Engineering Contradiction:
Improveservice restriction and selection controlVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent consolidates service policy management into a single centralized application server rather than distributing policies across multiple servers. This merging approach maintains the ability to restrict and control IMS services while reducing system complexity and signaling overhead by eliminating redundant policy copies and synchronization requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The centralized application server is designed to handle multiple service restriction scenarios and policy types universally. It can manage different RAT types, visited networks, and service combinations through a single policy evaluation mechanism, replacing the need for specialized policy handling in multiple servers.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If operators maintain service policies in multiple application servers, then service restriction and selection control can be implemented, but signaling overhead increases

Engineering Contradiction:
Improveservice restriction and selection controlVSAvoidsignaling overhead
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

By merging policy management into a single application server, the patent eliminates redundant signaling messages that would occur when multiple servers need to synchronize and evaluate the same service policies. The centralized approach processes service registration requests in one location, reducing overall network signaling load.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If mobile devices register for multiple IMS services while roaming, then service functionality increases, but technical conflicts and network optimization issues arise

Engineering Contradiction:
Improveservice functionalityVSAvoidtechnical conflicts
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The application server performs preliminary evaluation of service registration requests against stored service policies before allowing device registration. By pre-defining which service combinations are permitted for specific RAT types and visited networks, the system prevents technical conflicts before they occur, maintaining reliability while allowing functional versatility within policy boundaries.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The service policy evaluation mechanism provides feedback to device registration requests by accepting or rejecting them based on predefined policies. This feedback loop ensures that only compatible service combinations are registered, preventing technical conflicts while maintaining the ability to offer multiple services when policies permit.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3170327B1Enhanced IMS services restriction and selection control for mobile devices roaming in foreign networks
Publication Date: 2020.09.23 T MOBILE US INC
  • EP3170327B1 patent drawingFigure 1A
  • EP3170327B1 patent drawingFigure 1B
  • EP3170327B1 patent drawingFigure 2A

AI summary

A system and method that allows a mobile device to register for IMS services while the mobile device is roaming in a visited telecommunications network is disclosed. The system receives a request for multiple IMS services from a mobile device while the mobile device is roaming in a foreign network. The system uses an identifier of the foreign network and an associated RAT type to query a policy table containing a list of whitelisted IMS services for the foreign network and associated RAT type. The system processes the requested IMS registrations for services that are whitelisted and does not process requested IMS registrations for services that are not on the whitelist.