Layer 2 Relay UE Connection Setup With Coordinated RRC State Handling

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Solution Overview

Problem

Existing methods fail to specify a connection establishment process for a UE to a network device based on a layer 2 relay, which is not specified in the network device based on a layer 2 relay, which is not specified in related technologies.

Innovation Solution

A method for establishing a relay connection between a UE and a network device using a layer 2 relay, involving a relay UE sending a connection establishment request message with a cause value, and the network device determining the connection based on this value, with the relay UE and remote UE communicating through a sidelink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the relay UE sends its own RRC establishment request before entering connected state, then the connection establishment can be initiated, but the relay UE cannot relay the remote UE's request before entering connected state, resulting in the remote UE being in connected state while the relay UE is in non-connected state, which is not acceptable

Engineering Contradiction:
Improveconnection establishment initiationVSAvoidconnection state consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The relay UE performs preliminary actions by sending its own RRC establishment request before entering connected state, and also prepares to relay the remote UE's request. The patent resolves the contradiction by allowing the relay UE to send both requests in advance, with the network device coordinating the connection establishment to ensure both UEs are in connected state simultaneously, thus maintaining state consistency while enabling early initiation.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If two parallel RRC establishment or resume procedures are ongoing, then both relay UE and remote UE can initiate connections, but it is impossible to include both requests in one MAC PDU and the relay UE cannot send remote UE's request before entering connected state

Engineering Contradiction:
Improveconnection establishment efficiencyVSAvoidMAC PDU handling complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the connection establishment process into distinct phases: the relay UE first sends its own RRC establishment request, enters connected state, and then relays the remote UE's request. This segmentation avoids the complexity of handling multiple parallel requests in a single MAC PDU while maintaining efficient connection establishment for both UEs through sequential but coordinated operations.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the relay UE waits until entering connected state to send requests, then the connection state consistency is maintained, but the connection establishment is delayed

Engineering Contradiction:
Improveconnection state consistencyVSAvoidconnection establishment delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The relay UE performs preliminary actions by sending its own RRC establishment request before entering connected state. The patent resolves the time loss contradiction by allowing this preliminary initiation while maintaining state consistency through coordinated network device handling that ensures both UEs transition to connected state appropriately, thus reducing overall establishment delay without sacrificing reliability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4266819B1Relay connection establishment method, and device
Publication Date: 2025.12.17 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4266819B1 patent drawingFigure 1~2
  • EP4266819B1 patent drawingFigure 3~6
  • EP4266819B1 patent drawingFigure 7~8

AI summary

Disclosed in the present application is a relay connection establishment method. The method comprises: a relay terminal device sending a first connection establishment request message to a network device, wherein the first connection establishment request message carries a connection establishment cause value; and the first connection establishment request message is used for requesting the establishment of a connection between the relay terminal device and the network device. Further disclosed in the present application are another relay connection establishment method, an electronic device and a storage medium.