IMS PDN Connection Recovery via Secondary IP Call Notifications

Solution Overview

Problem

Inefficient usage of Internet Protocol (IP) Multimedia Subsystem (IMS) Packet Data Network (PDN) connections in communication systems, where most communications occur over internet PDN connections, leading to resource wastage in shorter-lived sessions like voice calls and video calls.

Innovation Solution

Establishing both an IMS PDN connection and an internet PDN connection with allocated primary and secondary IP addresses, sharing the secondary IP address over the internet PDN connection, and re-establishing the IMS PDN connection upon receiving a mobile terminated call notification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the communication network disconnects the IMS PDN connection after a short-lived session to optimize resource usage, then resource efficiency is improved, but the ability to receive mobile terminated calls is worsened

Engineering Contradiction:

Improveresource efficiencyVSAvoidcall reception capability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The UE performs preliminary registration with the IMS over the internet PDN connection before the IMS PDN connection is disconnected. This preliminary action ensures that the UE maintains registration status and can receive mobile terminated calls even after the dedicated IMS PDN connection is released by the network for resource optimization.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The internet PDN connection serves as an intermediary mechanism to maintain IMS registration and call reception capability. Instead of requiring the dedicated IMS PDN connection to remain active, the system uses the internet PDN connection as a substitute pathway for IMS signaling, allowing resource optimization while preserving service functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the UE maintains both IMS PDN connection and internet PDN connection simultaneously, then call reception capability is improved, but resource usage efficiency is worsened

Engineering Contradiction:

Improvecall reception capabilityVSAvoidresource usage efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The UE performs preliminary registration with the IMS over the internet PDN connection before the IMS PDN connection is disconnected. This preliminary action ensures that the UE maintains registration status and can receive mobile terminated calls even after the dedicated IMS PDN connection is released by the network for resource optimization.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system discards the dedicated IMS PDN connection after short-lived sessions to optimize resources, while recovering the essential functionality through preliminary registration over the internet PDN connection. This allows the network to release resources while the UE retains the ability to receive calls through the alternative pathway.

Inventive Principle:

Principle #34Discarding and recovering

3Device complexity

If the UE uses only internet PDN connection for all communications including IMS services, then resource allocation is simplified, but service quality for IMS-specific communications is worsened

Engineering Contradiction:

Improveconnection management complexityVSAvoidIMS service quality

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The UE performs preliminary registration with the IMS over the internet PDN connection before the IMS PDN connection is disconnected. This preliminary action ensures that the UE maintains registration status and can receive mobile terminated calls even after the dedicated IMS PDN connection is released by the network for resource optimization.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12426120B2Method and system for optimizing IMS PDN connection in communication system

Publication Date: 2025.09.23 SAMSUNG ELECTRONICS CO LTD

AI summary

A method for optimizing an internet protocol (IP) multimedia subsystem (IMS) packet data network (PDN) connection, includes: establishing, by a user equipment (UE), an IMS PDN connection and an internet PDN connection with at least one data network element of a communication network, wherein a primary IP address corresponding to the IMS PDN connection and a secondary IP address corresponding to the internet PDN connection are allocated to the UE by the at least one data network element; sharing, by the UE with an IMS, the secondary IP address over the internet PDN connection, before disconnecting the IMS PDN connection by the communication network; receiving, by the UE from the IMS, a mobile terminated (MT) call notification using the secondary IP address over the internet PDN connection; and based on the received MT call notification, re-establishing, by the UE, the IMS PDN connection.