SMF Node PDU Session Management in Local Area Networks

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Solution Overview

Problem

Current technologies face challenges in efficiently managing PDU sessions, particularly in local area services (LADN), leading to inefficient signaling and resource waste due to repeated session generation and release when a user moves between authorized and unauthorized areas.

Innovation Solution

A method and device for efficient PDU session management in LADN, where the network node determines whether to transmit LADN information based on user preferences and service policies, and implements schemes such as forced PDU session generation, version-based information exchange, and suspension/deactivation of sessions to optimize resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the network transmits LADN information to the UE every time the UE moves between authorized and unauthorized areas, then the UE can maintain proper session state, but unnecessary signaling is generated and network resources are wasted

Engineering Contradiction:
Improvesession state accuracyVSAvoidnetwork signaling overhead
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The network applies partial action by selectively transmitting LADN information only when necessary (when UE moves between authorized and unauthorized areas), rather than continuously or excessively. This is achieved through movement detection and conditional information transmission, reducing signaling overhead while maintaining session state accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system implements feedback mechanisms where the network monitors UE movement status and session state, then transmits LADN information based on detected conditions. The UE also provides feedback through session establishment requests and state information, enabling the network to adjust information transmission timing and reduce unnecessary signaling.

Inventive Principle:
Principle #23Feedback

2Reliability

If the network forces PDU session generation for LADN, then service delivery is ensured in authorized areas, but additional signaling and resource consumption occur

Engineering Contradiction:
Improveservice delivery assuranceVSAvoidnetwork resource efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The network performs preliminary actions by proactively forcing PDU session generation when the UE enters authorized LADN areas, ensuring service availability before the UE actually needs it. This preliminary session establishment prevents service interruptions and ensures reliable delivery, while the network can later release sessions when unauthorized to optimize resources.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts PDU session states based on UE location and authorization status. Sessions are forced/generated when in authorized areas and suspended or released when in unauthorized areas, allowing the network to optimize resource usage while ensuring service delivery when needed.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the network suspends PDU sessions when UE moves to unauthorized areas, then network resources are optimized, but service interruption may occur when UE returns to authorized areas

Engineering Contradiction:
Improvenetwork resource optimizationVSAvoidservice continuity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The network applies the discarding and recovering principle by suspending or releasing PDU sessions when UE moves to unauthorized areas (discarding resources), then rapidly re-establishing or resuming sessions when UE returns to authorized areas (recovering service). This optimizes resource usage during unauthorized periods while ensuring service continuity when authorized.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The network maintains session context and configuration information even when sessions are suspended, preparing for rapid re-establishment when UE returns to authorized areas. This preliminary preservation of session state enables quick service recovery without full re-establishment overhead.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If the network manages PDU sessions with detailed location tracking and conditional logic, then session management accuracy is improved, but device and network complexity increases

Engineering Contradiction:
Improvesession management accuracyVSAvoidnetwork node complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments session management into distinct states (active, suspended, released) and separate location tracking from session control logic. The network node divides responsibilities between movement detection, authorization checking, and session state management, reducing overall complexity while maintaining accurate session management through structured state transitions.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3599785B1Session management method and SMF node
Publication Date: 2022.10.05 LG ELECTRONICS INC
  • EP3599785B1 patent drawingFigure 1
  • EP3599785B1 patent drawingFigure 2
  • EP3599785B1 patent drawingFigure 3a~3b

AI summary

The one disclosure of the present specification proposes a method for managing session. The method may be performed by a session management function, SMF, node and comprise: generating a packet data unit, PDU, session for a user equipment, UE; receiving, from an access and mobility management function, AMF, node, information about the UE; and determining, based on the information, whether to transmit an indication for notifying a user plane function, UPF, node to discard a downlink data for the PDU session of the UE. The determination may be dependent on whether the PDU session corresponds to a first service provided to the UE.