PDCP Cell-Group Indication for MR-DC Integrity Failures

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Solution Overview

Problem

Existing 5G New Radio (NR) systems face issues with integrity protection and verification operations, particularly in Multi-RAT Dual Connectivity (MR-DC) scenarios, where split bearers and different network nodes lack effective mechanisms to identify and communicate integrity verification failures between Master Cell Group (MCG) and Secondary Cell Group (SCG), leading to unnecessary RRC connection re-establishments and inadequate failure reporting.

Innovation Solution

Implementing improved integrity verification procedures at the PDCP layer to indicate failure to the RRC with specific cell group information, and using XnAP and E1AP protocols to communicate failures between network nodes, allowing differentiated responses for MCG and SCG failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If integrity verification failure indication is sent without cell group information, then the indication can be sent to upper layers, but the upper layers cannot differentiate between MCG and SCG failures leading to unnecessary RRC connection re-establishments

Engineering Contradiction:

Improvecell group identification informationVSAvoidintegrity verification procedure

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The integrity verification failure indication is segmented to include separate cell group identification information, allowing the upper layers to distinguish between MCG and SCG failures. This segmentation enables differentiated handling of failures without triggering unnecessary RRC connection re-establishments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The integrity verification procedure implements feedback by sending detailed failure indications including cell group information back to upper layers. This feedback mechanism enables the upper layers to make informed decisions about whether to initiate RRC connection re-establishment or handle the failure differently based on the cell group affected.

Inventive Principle:

Principle #23Feedback

2Reliability

If differentiated responses are implemented for MCG and SCG failures, then unnecessary RRC connection re-establishments are reduced, but the complexity of integrity verification procedures increases

Engineering Contradiction:

Improvefailure response accuracyVSAvoidintegrity verification procedure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The failure response mechanism is segmented to provide different handling procedures for MCG and SCG failures. By including cell group identification in the integrity verification failure indication, the system can apply specific response strategies for each cell group type, improving reliability while managing complexity through structured differentiation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different quality of response is applied locally based on the cell group affected. MCG failures trigger RRC connection re-establishment while SCG failures may be handled differently without requiring full re-establishment. This local quality approach optimizes reliability by matching the response severity to the actual failure impact.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If split bearers are used in MR-DC scenarios, then network flexibility and data routing options are improved, but integrity verification failure communication between network nodes becomes inadequate

Engineering Contradiction:

Improvedata routing flexibilityVSAvoidintegrity verification failure information

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The integrity verification procedure implements comprehensive feedback mechanisms that communicate failure information between network nodes for split bearers. The failure indications include cell group information that enables proper routing of failure notifications to the appropriate network nodes (MN or SN) based on which cell group experienced the failure.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The PDCP layer acts as an intermediary that receives integrity verification failure indications from lower layers and forwards appropriate information to upper layers and network nodes. This intermediary function ensures that failure information is properly communicated and routed in complex MR-DC scenarios with split bearers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3824662B1Cell-group indication from PDCP upon integrity-verification failure

Publication Date: 2025.08.06 NOKIA TECHNOLOGIES OY

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AI summary

The example embodiments of the invention provide at least a method and apparatus to perform identifying, by a network device of a communication network, an integrity verification failure of at least one protocol data unit received by the network device over a cell group configured to a user equipment; and based on identifying the integrity verification failure, sending to a control protocol entity associated with the network device information comprising an indication of the integrity verification failure and an indication of the cell group.