SDAP End Marker Handling During QoS-Flow Remapping Handover

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current handover systems in NG-RAN networks face challenges when QoS-flow to DRB mapping is changed during the handover procedure, leading to issues with data forwarding and duplication avoidance, particularly due to ongoing remapping processes at the source NG-RAN node.

Innovation Solution

The proposed solution involves informing the target NG-RAN node about ongoing QoS-flow to DRB remapping at the source node, providing both old and new QoS-flow mappings, and using the SN Status Transfer message to manage PDCP SN and HFN status transfer during handovers, ensuring correct data forwarding and duplication handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If QoS-flow to DRB remapping is performed during handover at the source NG-RAN node, then the network can adapt to changing QoS requirements and optimize data routing, but the target NG-RAN node may misinterpret data packets and cause data forwarding errors

Engineering Contradiction:

ImproveQoS-flow remapping capabilityVSAvoiddata packet interpretation accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The source NG-RAN node informs the target NG-RAN node about the ongoing QoS-flow to DRB remapping before the handover is completed, by including remapping indication information in the handover request message. This preliminary notification allows the target node to prepare for receiving packets with both old and new QoS-flow mappings, preventing misinterpretation and data forwarding errors.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the source NG-RAN node changes QoS-flow to DRB mapping during handover preparation, then network flexibility and QoS optimization are improved, but data forwarding and duplication avoidance become problematic

Engineering Contradiction:

ImproveQoS-flow mapping flexibilityVSAvoiddata forwarding integrity

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The source NG-RAN node provides feedback to the target NG-RAN node about the QoS-flow to DRB mapping status by including remapping indication information in the handover request. This feedback mechanism enables the target node to understand whether packets may arrive with old or new mappings, allowing it to properly handle data forwarding and avoid duplication by knowing the expected packet format.

Inventive Principle:

Principle #23Feedback

3Speed

If handover proceeds without notifying the target node about ongoing remapping, then handover speed is maintained, but the target node experiences errors in packet reception and processing

Engineering Contradiction:

Improvehandover execution speedVSAvoidpacket reception accuracy

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The handover request message serves as an intermediary carrier that conveys remapping indication information from the source NG-RAN node to the target NG-RAN node. This intermediary communication mechanism allows the target node to receive critical information about ongoing remapping without delaying the handover execution, thereby maintaining speed while ensuring packet reception accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20240314623A1HANDLING SERVICE DATA APPLICATION PROTOCOL (SDApP) END MARKERS AT HANDOVER

Publication Date: 2024.09.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

According to certain embodiments, a method performed by the wireless device comprises sending data packets using a first QoS-flow to DRB mapping; receiving a new mapping; and sending an SDAP end marker indicating that the wireless device is applying the new mapping. Also disclosed is a wireless device configured to perform the method.