IMS Session Setup for Unregistered User Equipment

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Solution Overview

Problem

In 3G mobile communication, establishing a seamless Internet Multimedia Sub-system (IMS) session between user equipment (UE) in a Circuit Switched (CS) domain call is hindered when one or both UEs have not registered with the IMS, leading to communication failures due to lack of IP address information.

Innovation Solution

The user equipment (UE) initiates an IMS registration request when detecting an unregistered UE, facilitating IMS registration and subsequent session establishment by exchanging necessary messages through the CS and IMS cores, ensuring compatibility and service continuity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an IMS session is established during a CS domain call, then service versatility is improved, but communication reliability deteriorates when UEs are not registered with IMS

Engineering Contradiction:

Improveservice versatilityVSAvoidcommunication reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary IMS registration detection before establishing an IMS session during a CS call. The calling UE or called UE checks whether both parties are registered with IMS before proceeding with session establishment, preventing communication failures by ensuring prerequisites are met in advance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The CS core network acts as an intermediary to facilitate IMS registration detection and notification. When a CS call is established, the CS core sends registration status requests to both UEs and relays the information back to determine whether an IMS session can be successfully established

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If IMS session establishment is attempted without registration detection, then communication speed is improved, but information completeness deteriorates due to missing IP address information

Engineering Contradiction:

Improvecommunication speedVSAvoidIP address information

Core Design Contradiction:

SpeedVSLoss of information

Solution Approach 1:

The system performs preliminary registration status detection before attempting IMS session establishment. By checking whether UEs are registered with IMS before initiating the session, the system ensures that necessary IP address information will be available, preventing communication failures while maintaining efficient session setup

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP2487840B1User equipment and method for performing an IMS session

Publication Date: 2020.10.21 SAMSUNG ELECTRONICS CO LTD

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AI summary

The invention provides a system for requesting an unregistered User Equipment, UE to perform an Internet Multimedia Sub-system, IMS session in an IMS, the system comprising: - a calling UE for initiating a Circuit Switching, CS domain call to a called UE to request the called UE to conduct an IMS registration using a control message; - the called UE for receiving the control message and informing the calling UE that whether the called UE has been registered in the IMS or not, or whether the called UE prefers to perform the IMS registration or not; and - a network entity for processing the IMS registration of the called UE between an IMS core entity in the IMS and the called UE which receives the IMS registration request from the calling UE.