Secondary Cell Random Access Control for SCG Failure Detection

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Solution Overview

Problem

Existing LTE mobile communications systems face reduced success rates in random access processes initiated by user equipment (UE) to secondary cells due to the use of a uniform maximum quantity of random access scrambling codes, and lack of specified conditions for radio link monitoring, affecting data transmission efficiency.

Innovation Solution

User equipment is equipped with modules to receive and send random access scrambling codes within specified time periods and quantities, with timers and notifications for secondary cell group failures, differentiated for initial and subsequent access attempts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a same maximum quantity of times is used for both initial and subsequent random access processes, then the device complexity is reduced, but the success rate of initial random access deteriorates

Engineering Contradiction:
Improveaccess control complexityVSAvoidinitial access success rate
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating access control parameters for different access scenarios. Specifically, the maximum quantity of times for sending random access scrambling code is set to a first value for initial access and a second value for subsequent access, allowing optimized control for each scenario rather than using a uniform parameter across all cases.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If no time limit is imposed on initial random access, then the ease of operation is improved, but the loss of time increases

Engineering Contradiction:
Improveaccess flexibilityVSAvoidaccess time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent applies parameter changes by introducing a time limit parameter (time length) for the initial random access process. The terminal device is configured with a maximum time duration within which the initial random access must be completed, transforming the access control from purely attempt-based to time-constrained, thereby balancing flexibility with time efficiency.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3780855B1User equipment, base station, base station access method, and radio link monitoring method
Publication Date: 2026.05.20 HUAWEI TECH CO LTD
  • EP3780855B1 patent drawingFigure 1~2
  • EP3780855B1 patent drawingFigure 3~4
  • EP3780855B1 patent drawingFigure 5~6

AI summary

User equipment, a base station, a base station access method, and a radio link monitoring method are provided, where the user equipment includes: a first receiving module, configured to receive first indication information sent by a first base station, where the first indication information includes a time period required by the user equipment to initially request to access a second base station, or includes a preset first maximum quantity of times the user equipment sends random access scrambling code to a second base station when the user equipment initially requests to access the second base station; a first sending module, configured to send the random access scrambling code to the second base station; and a first notification module, configured to: if the user equipment fails to access the second base station within the time period, or if a quantity of times the user equipment sends the random access scrambling code to the second base station when the user equipment initially requests to access the second base station is greater than the first maximum quantity of times, notify the first base station that a secondary cell group failure occurs. In this application, efficiency of accessing the second base station by the user equipment is improved by limiting a time in which the user equipment requests to access the second base station or a quantity of times of sending the random access scrambling code in initial and subsequent access.