Dual Connectivity Data Usage Reporting with Secondary-Node PDCP Counting

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Solution Overview

Problem

The method for implementing the Secondary RAT Data Usage Report function, specifically how the en-gNB as a secondary node (SN) counts the data volume in EN-DC, has not been defined, particularly for data transmitted between the SN and the UE through MN Terminated and SN Terminated bearers.

Innovation Solution

The data volume is counted in the PDCP layer or between the PDCP and RLC layer by a central unit (CU) of the first base station operating as a secondary node (SN) in dual connectivity, enabling the CU to report this data volume to the master node (MN).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If data volume counting is implemented in the secondary node (SN) for EN-DC, then data usage reporting capability is improved, but system complexity increases due to undefined counting methods

Engineering Contradiction:
Improvedata usage reporting capabilityVSAvoidsystem complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary mechanism where the secondary node (SN) counts data volume in the PDCP layer and reports it to the master node (MN) through the X2 interface. This intermediary approach enables data usage reporting without requiring complex redistribution of counting functions, thus improving information completeness while maintaining system complexity at acceptable levels.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the data volume counting function specifically to the PDCP layer in the secondary node, separating it from other protocol layers. This segmentation allows for focused implementation of the counting function without affecting the complexity of other system components, enabling improved reporting capability with minimal complexity increase.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If data volume is counted at the PDCP layer in the secondary node, then reporting accuracy is improved, but implementation difficulty increases due to undefined methods

Engineering Contradiction:
Improvedata volume measurement accuracyVSAvoidimplementation ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent leverages the existing PDCP layer structure and its universal data handling functions to implement volume counting. By using the already-established PDCP layer for multiple purposes (data transmission, error handling, and now volume counting), the patent improves measurement accuracy without significantly increasing implementation difficulty, as the PDCP layer infrastructure is already in place.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The secondary node's PDCP layer performs data volume counting as a self-service function, utilizing its own data processing capabilities to generate accuracy reports. This self-service approach allows the system to achieve improved measurement precision without requiring external assistance or complex additional mechanisms, thereby maintaining reasonable implementation ease.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3755035B1Methods and devices to report data usage in dual connectivity
Publication Date: 2025.08.27 NEC CORP
  • EP3755035B1 patent drawingFigure 1
  • EP3755035B1 patent drawingFigure 2
  • EP3755035B1 patent drawingFigure 3

AI summary

In order to enable reporting of data volume from a secondary node (SN) to a master node (MN) in dual connectivity, a communication apparatus according to the present invention includes: an information obtaining unit configured to obtain data volume information indicating volume of data transmitted between a first base station and a terminal apparatus, the first base station operating for the terminal apparatus as a secondary node of dual connectivity using at least New Radio (NR); and a communication processing unit configured to transmit the data volume information to a second base station operating for the terminal apparatus as a master node of the dual connectivity. The volume of the data is data volume counted in a Packet Data Convergence Protocol (PDCP) layer or between the PDCP layer and a Radio Link Control (RLC) layer.