Anchor Node Data Forwarding in RRC Inactive State

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Solution Overview

Problem

In the RRC Inactive state of wireless communication systems, the context transfer procedure between anchor and serving nodes is complex, leading to high signaling overhead and long setup delays, particularly when small data transmissions are required.

Innovation Solution

The method involves the anchor node deciding not to perform context transfer when receiving a Retrieve UE Context Request message, instead using PDCP PDU data interaction through the current serving node, simplifying the procedure and reducing overhead and delay.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the anchor node performs context transfer procedure to move user terminal context information to the serving node, then the user terminal can be served by the current node, but the procedure becomes complex with large signaling overhead and long setup delay

Engineering Contradiction:
Improvecontext transfer completionVSAvoidprocedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of context transfer by allowing the anchor node to retain the user terminal context information while the serving node forwards data packets. This eliminates the need to physically transfer the entire context, keeping only the necessary forwarding capability at the serving node.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The anchor node acts as an intermediary that holds the user terminal context information and receives data packets from the network. It forwards these packets to the serving node, which then delivers them to the user terminal, avoiding direct context transfer while maintaining proper data routing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the anchor node performs context transfer procedure, then the user terminal context can be accessed by the serving node, but the signaling overhead increases

Engineering Contradiction:
Improvecontext accessibilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent extracts only the essential forwarding function from the context transfer procedure. The serving node obtains minimal forwarding information (anchor node identity and data forwarding capability) without receiving the complete user terminal context, significantly reducing signaling overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of transferring the original context information, the patent uses a simplified copy or reference mechanism where the serving node stores only the anchor node identifier and forwarding parameters, allowing it to access context through the anchor node without duplicating the entire context.

Inventive Principle:
Principle #26Copying

3Reliability

If the anchor node performs context transfer procedure, then the serving node can handle user terminal data, but the setup delay increases

Engineering Contradiction:
Improvedata forwarding capabilityVSAvoidsetup delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary setup by having the anchor node pre-configure the serving node with forwarding parameters and context references before actual data transmission begins. This preliminary configuration enables immediate data forwarding without waiting for complete context transfer during active communication.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the time-consuming context transfer step by allowing the serving node to start forwarding data using minimal pre-configured information, while the complete context remains at the anchor node. This separation enables parallel processing of data forwarding and context management.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3813428B1Method and apparatus for data transmission in RRC inactive state, and terminal and device
Publication Date: 2023.01.18 DATANG MOBILE COMM EQUIP CO LTD
  • EP3813428B1 patent drawingFigure 1~2
  • EP3813428B1 patent drawingFigure 3~4
  • EP3813428B1 patent drawingFigure 5~6

AI summary

A data transmission method in the RRC Inactive state, a data transmission device in the RRC Inactive state, a user terminal and a device are provided. The method includes: if a Retrieve UE Context Request message is received from a second node device, in respond to the Retrieve UE Context Request message, sending an interface message including at least one Packet Data Convergence Protocol Protocol Data Unit to the second node device; wherein the second node device is a current serving node of a user terminal in an RRC Inactive state, and the first node device is an anchor node of the user terminal.