Dual Connectivity SCG Failure Reporting Through MCG Uplink

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Solution Overview

Problem

In dual connectivity scenarios, user equipment (UE) detects secondary cell group (SCG) failures but is unable to report these failures to the master node (MN) due to suspended SCG transmissions, leading to unaddressed issues and potential data loss.

Innovation Solution

The UE overrides the SCG suspension to transmit an indication of SCG failure or measurement report to the MN using existing SRBs, even when SCG transmissions are suspended, allowing the MN to take remedial actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE suspends SCG transmission upon detecting SCG failure, then the UE avoids transmitting on a failed radio link, but the UE cannot report the SCG failure to the MN

Engineering Contradiction:

Improveradio link reliabilityVSAvoidSCG failure information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent uses the MCG (Master Cell Group) as an intermediary to transmit SCG failure information. When SCG transmission is suspended due to failure, the UE embeds the SCG failure indication within MCG uplink transmissions, allowing the failure information to reach the MN through the reliable MCG path rather than attempting to send it through the failed SCG link.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent separates the control plane functions by using MCG for failure reporting while suspending SCG data transmission. This segmentation allows the UE to maintain reliable control signaling through MCG for failure reporting while isolating the failed SCG link to prevent further transmission errors.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the UE suspends SCG transmission to avoid using failed resources, then data transmission on SCG stops, but the MN remains unaware of the failure and cannot take remedial action

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidnetwork recovery speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where the UE actively reports SCG failure status to the MN by embedding failure indications in MCG uplink transmissions. This feedback loop enables the MN to detect the SCG failure condition and initiate appropriate remedial actions such as releasing the SCG configuration or reconfiguring the dual connectivity, thereby improving network recovery speed.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If the UE uses SCG resources for measurement reporting, then measurement accuracy improves, but the UE cannot deliver measurements when SCG transmission is suspended

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidmeasurement report

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent uses MCG uplink transmission as an intermediary channel to deliver measurement reports when SCG transmission is suspended. The UE embeds measurement information within MCG transmissions, allowing measurements taken on SCG resources to be reported to the MN through the reliable MCG path, preventing loss of measurement data.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12418952B2Secondary cell group failure in dual connectivity

Publication Date: 2025.09.16 GOOGLE LLC

AI summary

A user device operating in dual-mode connectivity with a master node and a secondary node detects a failure of a secondary cell group associated with the secondary node (1004). In response, the user device suspends an secondary cell group transmission (1006). The user device generates a message related to a status of the SCG for transmission to the MN (1008) and transmitting the message to the MN when the SCG transmission is suspended (1010).