AMF-Mediated Data Forwarding in Multi-Hop 5G Mobility

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Solution Overview

Problem

The inefficiency of data forwarding and context release procedures in multi-hop mobility scenarios within 5G networks due to the lack of direct Xn connectivity between network nodes leads to significant signaling overhead, making existing methods suboptimal for UE context retrieval and data transfer.

Innovation Solution

A mechanism where the access and mobility management function (AMF) initiates context release and data forwarding by including specific flags or TEIDs in messages, allowing direct communication between the new and last serving nodes to minimize multi-hop signaling overhead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-hop mobility is used to enable UE connection when direct Xn connectivity is unavailable, then network coverage and mobility are improved, but signaling overhead increases significantly

Engineering Contradiction:
Improvenetwork coverageVSAvoidsignaling overhead
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent introduces the AMF as an intermediary entity to mediate between the new gNB and the last serving gNB. Instead of direct multi-hop signaling between gNBs, the AMF receives context release requests from the new gNB and forwards them to the last serving gNB, thereby reducing signaling overhead while maintaining multi-hop mobility capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the context release and data forwarding functions from the multi-hop gNB signaling path and centralizes them at the AMF. This separation allows the gNBs to communicate more efficiently through the core network entity, reducing the signaling burden on the access network

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If existing context release procedures are used in multi-hop scenarios, then basic functionality is maintained, but data forwarding efficiency deteriorates

Engineering Contradiction:
ImprovefunctionalityVSAvoiddata forwarding efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements preliminary action by having the new gNB send a context release request message to the AMF that includes data forwarding information (such as tunnel endpoint identifiers) before actual data forwarding occurs. This allows the AMF to prepare the context release command with appropriate forwarding parameters, enabling efficient data transfer from the last serving gNB to the new gNB

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes a feedback mechanism where the new gNB provides data forwarding requirements to the AMF through the context release request, and the AMF incorporates this feedback into the context release command sent to the last serving gNB, ensuring that data forwarding is optimized based on actual network conditions

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3968696B1NG based context release and data forwarding for multi-hop mobility
Publication Date: 2026.02.18 NOKIA TECHNOLOGIES OY
  • EP3968696B1 patent drawingFigure 1
  • EP3968696B1 patent drawingFigure 2
  • EP3968696B1 patent drawingFigure 3

AI summary

A method, apparatus, and a computer-readable storage medium are provided for NG based context release and data forwarding for multi-hop mobility. In an example implementation, the method may include a core network entity receiving a first message from a first network node, the first message including at least one of a user equipment context release request and a data forwarding request and detecting the at least one of the user equipment context release request and the data forwarding request from the first message. The method may further include sending a second message including at least one of a user equipment context release command and data forwarding information to a second network node based at least on the detected at least one of the user equipment context release request and the data forwarding request.