Conditional PSCell Change Using Preconfigured RRC Triggers

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Solution Overview

Problem

In 5G communication systems, the continuous conditional primary secondary cell change (CPC) process is prone to secondary cell group radio link failures (SCG RLFs) due to inaccurate evaluation of execution trigger conditions, leading to inefficiencies and energy wastage in evaluating invalid neighboring cells.

Innovation Solution

A method where user equipment (UE) receives a first RRC reconfiguration message containing information for multiple candidate PSCells, allowing timely application of execution trigger conditions and measurement configurations, thereby improving the accuracy and timeliness of CPC and reducing unnecessary evaluations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If the UE continues to use the execution trigger condition determined by the trigger node based on the source PSCell 0 after changing to PSCell 1, then the CPC configuration can be maintained without re-delivery, but the accuracy of CPC evaluation deteriorates leading to SCG RLF

Engineering Contradiction:

ImproveCPC configuration validity durationVSAvoidCPC evaluation accuracy

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The network device pre-prepares execution trigger conditions for multiple candidate PSCells (PSCell 0, PSCell 1, PSCell 2, etc.) and delivers them to the UE in advance through the first RRC reconfiguration message. When the UE changes from PSCell 0 to PSCell 1, it can immediately apply the pre-prepared execution trigger condition corresponding to PSCell 1, avoiding the use of outdated conditions and preventing SCG RLF.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The execution trigger condition is made dynamic by associating different conditions with different candidate PSCells. The UE dynamically selects and applies the appropriate execution trigger condition based on the current serving PSCell, ensuring that the evaluation criteria are always current and accurate rather than static and outdated.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the UE evaluates all M candidate PSCells continuously, then the CPC function can be maintained, but energy consumption increases due to evaluation of invalid neighboring cells

Engineering Contradiction:

ImproveCPC continuous evaluation capabilityVSAvoidUE energy consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The network device performs preliminary filtering and preparation of execution trigger conditions for multiple candidate PSCells before delivering them to the UE. This pre-processing allows the UE to efficiently evaluate only relevant candidates without wasting energy on invalid neighboring cells, as the network has already identified which cells are legitimate candidates for CPC.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If the network device delivers CPC configuration to the UE again for continuous CPC, then the accuracy of CPC evaluation is improved, but the signaling overhead and complexity increase

Engineering Contradiction:

ImproveCPC evaluation precisionVSAvoidRRC reconfiguration signaling complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The network device merges the delivery of execution trigger conditions for multiple candidate PSCells into a single first RRC reconfiguration message. Instead of sending separate reconfiguration messages when the UE changes from PSCell 0 to PSCell 1 or to PSCell 2, all necessary conditions are delivered upfront in one message, reducing signaling overhead and network device complexity while maintaining high evaluation precision.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250374156A1Conditional primary secondary cell change method and apparatus

Publication Date: 2025.12.04 HUAWEI TECH CO LTD

AI summary

The present disclosure relates to conditional primary secondary cell change methods and apparatuses. In one example method, a UE receives a first RRC reconfiguration message from a network device, where the first RRC reconfiguration message includes first information and second RRC messages that correspond to M candidate PSCells, the second RRC messages include second information corresponding to N candidate PSCells in the M candidate PSCells, and the first information and the second information include at least one of an execution trigger condition and measurement configuration information. The UE evaluates, based on the first information, whether execution trigger conditions of the M candidate PSCells are met. When the UE determines, through evaluation, that an execution trigger condition of a first candidate PSCell meets the execution trigger condition, the UE applies a second RRC message corresponding to the first candidate PSCell.