MA PDU Session Reactivation Across 3GPP and Non-3GPP Access
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Solution Overview
Problem
The existing 5G wireless communication systems lack clarity on how a user equipment (UE) should reinitiate a UE-requested PDU session establishment procedure after receiving a network-requested PDU session modification command with 'reactivation requested' for a Multi-Access (MA) PDU session, particularly in Session and Service Continuity (SSC) mode 3, which can lead to connectivity issues.
Innovation Solution
The UE determines the appropriate access type(s) for reinitiating the PDU session establishment based on its registration status and user plane resources, sending PDU session establishment requests over one or more access types to maintain service continuity, including scenarios where resources are established over both 3GPP and non-3GPP networks or a single network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE reinitiates PDU session establishment procedure after receiving reactivation requested for an MA PDU session, then service continuity is maintained, but the procedure becomes complex and undefined for MA PDU sessions
Solution Approach 1:
The patent segments the MA PDU session reactivation procedure into distinct cases based on access type (3GPP vs non-3GPP) and SSC mode. Each case has a defined reinitiation procedure, transforming the undefined complex procedure into structured, manageable segments with clear handling rules for each scenario.
Solution Approach 2:
Instead of defining a single generic reinitiation procedure, the patent inverts the approach by defining specific procedures for specific cases (3GPP access, non-3GPP access, SSC mode 3), then combines them to cover all MA PDU session scenarios. This case-based definition simplifies the overall complexity by avoiding a single complex undefined procedure.
2Reliability
If the UE establishes new PDU Session Anchor point before terminating previous connection, then service continuity is improved, but IP address is not preserved and requires new PDU session ID
Solution Approach 1:
The patent implements preliminary action by establishing the new PDU Session Anchor point and new PDU session resources before terminating the previous connection. This ensures that service continuity is maintained without interruption, as the new anchor is ready to immediately take over traffic flow when the old anchor is disconnected.
3Productivity
If the network balances data traffic between mobile networks and non-3GPP access, then network congestion is reduced, but the UE must simultaneously manage multiple access networks
Solution Approach 1:
The patent applies universality by designing the MA PDU session mechanism to work across both 3GPP and non-3GPP access networks using a unified procedure framework. The same PDU session establishment and modification procedures are used regardless of access type, allowing the UE to manage multiple access networks without learning entirely different protocols for each access type.
Data Source
AI summary
A method for handling a reactivation request from the network for an MA PDU session with session and service continuity (SSC) mode 3 is proposed. When UE receives a PDU SESSION MODIFICATION COMMAND message which includes 5GSM cause #39 “reactivation requested” for an existing MA PDU session, UE handles the network-requested PDU session modification procedure, and UE re-initiates the UE-requested PDU session establishment procedure with a new MA PDU session ID. UE determines how to proceed with a PDU session reestablishment procedure for the new MA PDU session based on different scenarios of UE registration and user plane resources of the existing MA PDU session, and/or also based on whether the PDU SESSION MODIFICATION COMMAND message is sent over 3GPP access type or non-3GPP access type.