PDU Session Status IE Signaling for UE-Network Synchronization

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in managing PDU session synchronization between user equipment (UE) and the network, leading to resource-intensive message transmissions and desynchronization issues due to radio link failures, which can be exacerbated by frequent service request and registration messages.

Innovation Solution

Optimizing the use of PDU session status information elements (IEs) by selectively including them in messages based on specific conditions, such as pending data or mode changes at the UE, to reduce unnecessary transmissions and ensure synchronization without excessive resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PDU session status IEs are included in all registration request messages, then PDU session synchronization between UE and network is maintained, but resource consumption increases unnecessarily

Engineering Contradiction:

ImprovePDU session synchronizationVSAvoidresource consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the PDU session status IE from routine inclusion in all registration request messages, and instead includes it only in specific scenarios where synchronization is needed (e.g., after radio link failures, when session status changes). This selective extraction maintains synchronization reliability while reducing unnecessary resource consumption during normal operations.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by including PDU session status IEs only when necessary rather than in every message. The system determines partial inclusion based on specific conditions such as detected session status changes or recovery from failures, avoiding excessive resource usage while maintaining adequate synchronization.

Inventive Principle:

Principle #16Partial or excessive action

2Reliability

If PDU session status IEs are transmitted frequently to ensure synchronization, then desynchronization issues are reduced, but resource consumption and message overhead increase

Engineering Contradiction:

Improvesynchronization accuracyVSAvoidmessage overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements periodic action by transmitting PDU session status IEs at specific intervals or triggers rather than continuously. Status updates are sent periodically when specific events occur (e.g., session establishment, release, or failure recovery), maintaining synchronization accuracy while minimizing message overhead compared to continuous transmission.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system uses feedback mechanisms where the UE monitors its own PDU session status and provides status information to the network only when changes are detected. This feedback-based approach ensures synchronization accuracy by transmitting status information when needed, while reducing message overhead by avoiding unnecessary transmissions when status remains unchanged.

Inventive Principle:

Principle #23Feedback

3Use of energy by moving object

If service request messages are used instead of registration request messages, then resource efficiency improves, but PDU session status update capability may be reduced

Engineering Contradiction:

Improveresource efficiencyVSAvoidstatus update capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by enabling service request messages to perform multiple functions: both resource allocation requests and PDU session status updates. The service request message structure is enhanced to include PDU session status information elements, allowing a single message type to serve dual purposes and maintain adaptability while improving resource efficiency.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent inverts the conventional approach by using service request messages (typically for resource allocation) to also carry PDU session status update information. Instead of relying on registration request messages for status updates, the system reverses the expected message flow, allowing service requests to fulfill both resource and status update functions.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12621893B2Optimizing use of PDU session status IE

Publication Date: 2026.05.05 APPLE INC

AI summary

Systems and methods for managing synchronization of protocol data unit (PDU) sessions between a user equipment (UE) and a network are disclosed herein. In some embodiments, a determination of whether a message comprising a PDU session status information element (IE) should be sent is based on previous messaging between peer entities of the network. In some embodiments, a determination that the peer entity is informed of a relevant PDU session status is made after expected reply messaging is received in response to prior messaging. In some cases, a reply message without a PDU session status IE is sent from one entity to a peer entity when it is determined that each entity has a matching PDU session status. Cases involving failures detected at the network, and cases where an entity activates a data radio bearer (DRB) of a PDU session that is inactive at its peer are also discussed.