IMS-CS Message Mapping for Multi-Device Routing

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Solution Overview

Problem

Existing communication systems face challenges in delivering messages between IMS and CS domains, particularly when a user has multiple user equipment under the same subscription, as terminating SIP messages are not clearly directed to the intended device, and GRUU is not applicable in the CS world, leading to issues with message forwarding and authentication.

Innovation Solution

A method and apparatus that create and store a mapping between Equipment Identifier, IMPI, and C-MSISDN during registration, enabling translation and message forwarding between IMS and CS domains, ensuring messages reach the correct user equipment even when registered or not in IMS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If SIP messages are used for message delivery in IMS domain, then message delivery capability is improved, but message routing precision to specific user equipment deteriorates

Engineering Contradiction:
Improvemessage delivery capabilityVSAvoidmessage routing precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces a mapping mechanism that acts as an intermediary between SIP messages and CS domain messages. The mapping stores correlations between user identities (IMPI, IMPU) and equipment identifiers (IMEI, GRUU), enabling precise routing to specific user equipment while maintaining SIP-based message delivery in the IMS domain.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If GRUU is used for directing messages to specific user equipment, then message routing precision is improved, but domain compatibility deteriorates

Engineering Contradiction:
Improvemessage routing precisionVSAvoiddomain compatibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal mapping mechanism that works across both IMS and CS domains. The mapping stores multiple types of identifiers (IMPI, IMPU, IMEI, GRUU, MSISDN) and can translate between them, making the system universally applicable to both domains without requiring GRUU to be natively supported in CS domain.

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

Solution Approach 2:

The mapping serves as an intermediary that translates GRUU (IMS-specific) to MSISDN (CS domain-compatible). This allows messages routed using GRUU in IMS to be successfully delivered to CS domain user equipment that only understands MSISDN addressing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If message forwarding is enabled for users with multiple user equipment, then message delivery coverage is improved, but message delivery security deteriorates

Engineering Contradiction:
Improvemessage delivery coverageVSAvoidmessage delivery security
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system uses registration feedback to dynamically control message forwarding. When a user equipment registers with the network, it provides feedback about its current status and location. The network uses this feedback to update the mapping and control whether messages should be forwarded to this specific equipment, ensuring secure delivery based on current registration state.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2489210B1Delivery of a message between an IMS domain and a CS domain
Publication Date: 2017.06.21 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2489210B1 patent drawingFigure 1
  • EP2489210B1 patent drawingFigure 2
  • EP2489210B1 patent drawingFigure 3

AI summary

A method and apparatus for enabling delivery of a message in a communication system comprising an IMS domain and a circuit switched domain. Upon receiving a registration message in the IMS domain from a user equipment operated by a user, wherein the message comprises an Equipment Identifier valid for the user equipment and an IMPI valid for the user, the Equipment Identifier and the IMPI are extracted from the received message. Then a creation or an update of a mapping of the Equipment Identifier to the IMPI and a C-MSISDN is initiated. Upon receiving a message, relating to the user, which is to be communicate between the IMS and circuit switched domains in the communication system, a use of the mapping for translating between the Equipment Identifier, IMPI and the C-MSISDN is initiated.