P-CSCF Restoration for Multi-IMS PDU Sessions
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Solution Overview
Problem
In 5G mobile communication systems, the Proxy-Call Session Control Function (P-CSCF) restoration for User Equipment (UE) served by multiple IMS networks is challenging due to the inability to differentiate between multiple PDU sessions, leading to difficulties in identifying the correct session for restoration when a failure occurs.
Innovation Solution
A method and system that involves a network node receiving a PDU session establishment request from the UE, subscribing with a Unified Data Manager (UDM) for P-CSCF restoration notifications, and performing restoration based on identifiers such as Data Network Name (DNN), IMS home network domain name, and P-CSCF address, allowing for accurate identification and restoration of the affected PDU session.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a UE is served by multiple IMS networks, then service versatility and network coverage are improved, but the ability to differentiate and identify correct PDU sessions during failure restoration deteriorates
Solution Approach 1:
The patent segments the identification process by introducing unique identifiers (such as PDU session ID, AMF set ID, or combined identifiers) for each PDU session. This segmentation allows the network to distinguish between multiple sessions belonging to the same UE across different IMS networks, resolving the ambiguity in session identification while maintaining service versatility.
Solution Approach 2:
The patent introduces an intermediary identification mechanism involving the AMF (Access and Mobility Management Function) and UDM (Unified Data Management) that mediates between the UE and the P-CSCF restoration process. This intermediary layer provides structured identification information that enables accurate session differentiation without requiring direct complex interactions between all network functions.
2Reliability
If multiple PDU sessions are established for multiple IMS networks, then network coverage and service availability are improved, but the complexity of managing and restoring sessions during failure deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-configuring identification parameters and establishing clear session differentiation mechanisms before failures occur. The network pre-establishes identifier mappings and restoration policies, so when a failure is detected, the restoration process can immediately identify the correct session without complex real-time analysis, reducing operational complexity.
Solution Approach 2:
The patent implements feedback mechanisms where the network monitors PDU session status and provides feedback information about session identifiers and restoration requirements. This feedback loop enables automated session management and restoration, reducing the manual complexity of managing multiple sessions across different IMS networks while maintaining broad coverage.
Data Source
AI summary
The disclosure relates to a 5th generation (5G) or 6th generation (6G) communication system for supporting a higher data transmission rate. A method performed by a session management function (SMF) node in a wireless communication system is provided. The method includes receiving, from the user equipment (UE), a protocol data unit (PDU) session establishment request for establishing at least one PDU session between the UE and multiple internet protocol (IP) multimedia subsystem (IMS) networks, subscribing, with a unified data manager (UDM) node to receive a first notification for a proxy-call session control function (P-CSCF) restoration, by providing an identifier for each PDU session, receiving, from the UDM node, the first notification for the P-CSCF restoration based on a subscription with a UDM, and performing, the P-CSCF restoration for the PDU session of the UE based on the received first notification for the P-CSCF restoration.