SCG Deactivation Timing Synchronization with Signal-Based TA Reuse

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Solution Overview

Problem

Existing wireless communication systems face challenges in maintaining reliable uplink timing synchronization during secondary cell group (SCG) activation and deactivation, leading to inefficiencies and potential communication disruptions.

Innovation Solution

A wireless device and cellular network system that maintains timing advance (TA) parameters for uplink communication, allowing the device to determine whether to reuse these parameters based on signal quality measurements and network configurations during SCG activation and deactivation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wireless device maintains TA parameters during SCG deactivation, then uplink timing synchronization is preserved, but device complexity increases

Engineering Contradiction:
Improveuplink timing synchronizationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wireless device performs signal quality measurements during the SCG deactivation period before full deactivation occurs. This preliminary action allows the device to assess whether TA parameters remain valid, enabling informed decisions about parameter reuse and avoiding unnecessary synchronization procedures when reactivating the SCG

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The wireless device autonomously determines whether to reuse stored TA parameters by comparing signal quality measurements against thresholds, without requiring network intervention. This self-service approach maintains timing synchronization reliability while reducing signaling overhead and network device complexity

Inventive Principle:
Principle #25Self-service

2Reliability

If the wireless device performs signal quality measurements during SCG deactivation, then timing synchronization reliability is improved, but use of energy increases

Engineering Contradiction:
Improvetiming synchronization reliabilityVSAvoiduse of energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The wireless device compares signal quality measurements against configurable thresholds to dynamically determine TA parameter validity. By using parameter-based decision-making rather than continuous monitoring, the device achieves reliable timing synchronization while minimizing energy consumption during SCG deactivation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The device performs a limited set of signal quality measurements during deactivation rather than continuous monitoring. This partial action approach provides sufficient information to make informed decisions about TA parameter reuse while significantly reducing energy consumption compared to full continuous monitoring

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the wireless device determines TA parameter reuse based on signal quality thresholds, then communication reliability is improved, but device complexity increases

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

Solution Approach 1:

The wireless device uses signal quality measurements as feedback to determine whether stored TA parameters remain valid. This feedback mechanism enables reliable communication by automatically detecting when parameters need updating while keeping device complexity manageable through rule-based decision logic

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Signal quality thresholds act as an intermediary criterion between the raw measurement data and the decision to reuse or update TA parameters. This intermediary layer simplifies the decision-making process by providing clear pass/fail criteria, reducing device complexity while maintaining communication reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4315927B1Uplink timing synchronization maintenance in secondary cell group
Publication Date: 2025.09.24 APPLE INC
  • EP4315927B1 patent drawingFigure 1~2
  • EP4315927B1 patent drawingFigure 3
  • EP4315927B1 patent drawingFigure 4

AI summary

Aspects are presented herein of apparatuses, systems, and methods for secondary cell group (SCG) addition. A wireless device may establish communication with a first base station that is comprised in a master cell group (MCG) and a second base station that is comprised in the SCG. The wireless device may maintain timing advance (TA) parameters for performing uplink communication with the second base station. The wireless device may perform a plurality of signal quality measurements after receiving an indication to deactivate the SCG. The wireless device may determine whether to reuse the TA parameters for communicating with the second base station after receiving an indication. The determination may be based on comparing one or more signal quality measurements of the second base station to one or more signal quality thresholds.