CU-DU Tunnel Duplication for Reliable Radio Bearer Paths

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Solution Overview

Problem

The implementation of a duplication mode for a radio bearer in a CU-DU architecture is a pressing issue in radio communications systems, particularly in the context of 5th generation communications technologies where one PDCP entity corresponds to at least two RLC entities, necessitating effective duplication strategies.

Innovation Solution

A method is provided to establish a CU-DU connection in a duplication mode by configuring and managing uplink and downlink tunnel endpoints and paths between the CU and DU, including the establishment of primary and secondary paths, and implementing duplication modes for both data and signaling radio bearers through explicit messaging and configuration between the CU and DU.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If duplication mode is implemented for radio bearers in CU-DU architecture, then communication reliability is improved, but system complexity increases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the radio bearer duplication function into distinct components: PDCP entities at the CU, multiple RLC entities at the DU, and separate tunnel endpoints. This segmentation allows each component to be independently configured and managed, reducing overall system complexity while maintaining reliability through duplication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The F1 interface acts as an intermediary between the CU and DU, carrying duplication configuration messages and user plane data. This intermediary mechanism enables coordinated duplication operations without requiring direct complex interactions between PDCP and RLC entities, simplifying the overall system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple tunnel endpoints are configured for duplication mode, then path diversity is improved, but configuration complexity increases

Engineering Contradiction:
Improvepath diversityVSAvoidconfiguration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent establishes multiple tunnel endpoints and associates them with different paths before actual data transmission begins. The CU configures uplink tunnel endpoints and the DU configures downlink tunnel endpoints in advance, creating a ready-to-use duplicated path structure that simplifies real-time operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The CU and DU exchange configuration messages through the F1 interface to confirm tunnel endpoint associations and path configurations. This feedback mechanism ensures both sides have consistent understanding of the duplication setup, reducing configuration errors and simplifying management.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4221443B1Duplication mode communication processing methods in CU-du architecture, corresponding devices, system and computer readable storage medium
Publication Date: 2026.03.11 HUAWEI TECH CO LTD
  • EP4221443B1 patent drawingFigure 1
  • EP4221443B1 patent drawingFigure 2A~2B
  • EP4221443B1 patent drawingFigure 2C~3A

AI summary

Embodiments of this application provide a duplication (duplication) mode communication processing method in a central unit-distributed unit (CU-DU) architecture. In a possible implementation, in a process of establishing a user plane tunnel between a CU and a DU by exchanging information about uplink tunnel endpoints and information about downlink tunnel endpoints, the DU provides an identity of a primary path to the CU, thereby implementing a duplication mode of a data radio bearer.