Dual IMS Registration via Single PDN Connection

Solution Overview

Problem

Current methods for user equipment (UE) to register with two IMS networks require separate Packet Data Network (PDN) connections when roaming, which is cumbersome and inefficient.

Innovation Solution

A method and apparatus that enable dual registration of UE with two IMS networks using a single PDN connection by sending network addresses of respective Proxy Call Session Control Functions (P-CSCF) to the UE, allowing registration with both IMS networks via a gateway node, even in a visited network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If preconfigured IP address is used for second P-CSCF, then dual registration is enabled in home network, but separate PDN connection is required when roaming

Engineering Contradiction:

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The gateway node provides multiple P-CSCF IP addresses through a single PDN connection, enabling the same connection to serve both home network and visited network registration requirements. This multi-functional approach eliminates the need for separate PDN connections when roaming.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The gateway node acts as an intermediary that translates the UE's single PDN connection into access to multiple P-CSCF addresses. It receives the connection request, provides both first and second P-CSCF IP addresses, and enables dual registration without requiring separate connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If separate PDN connections are used for second P-CSCF when roaming, then dual registration is enabled, but connection establishment becomes cumbersome

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The gateway node pre-provides both first and second P-CSCF IP addresses in the initial connection response, so the UE has both addresses available before roaming begins. This eliminates the need to establish separate connections later when roaming.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The gateway node combines the provision of multiple P-CSCF addresses into a single PDN connection response, merging what would traditionally require separate connection establishment steps into one unified process.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If local IP address is used for P-CSCF, then network access is enabled within home network, but address becomes invalid outside home network

Engineering Contradiction:

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The gateway node provides P-CSCF IP addresses that function universally across both home network and visited network contexts. The same mechanism serves dual purposes: enabling efficient registration at home and maintaining compatibility when roaming abroad.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10257801B2Enabling dual registration of user equipment with IP multimedia subsystems

Publication Date: 2019.04.09

AI summary

A method of enabling dual registration of a User Equipment, UE, with first and second Internet Protocol Multimedia Subsystem, IMS, networks, the method comprising, in response to a connection request made to a gateway node by the UE, sending to the UE, network addresses of respective first and second Proxy Call Session Control Functions, P-CSCF, the first and second P-CSCFs being configured to enable IMS registrations to the first and second IMS networks respectively.