PSCell Random Access During SCG Deactivation

Solution Overview

Problem

Current 3GPP standards for SCG deactivation and activation in multi-connectivity scenarios lead to inconsistencies and delays due to requirements for random access procedures and configuration management, particularly regarding AS security keys and radio resource handling, which can result in failed SCG activation and increased latency.

Innovation Solution

A UE and RAN node configuration that allows immediate random access to a PSCell during SCG deactivation and mobility events, and maintains relevant radio resource configurations to avoid reconfiguration delays upon SCG activation, with explicit indications for random access and resource management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE performs random access to the PSCell upon PSCell addition or PSCell mobility while the SCG is deactivated, then consistency with 3GPP standards is ensured, but SCG activation latency increases

Engineering Contradiction:

Improveconsistency with 3GPP standardsVSAvoidSCG activation latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The UE performs random access to the PSCell in advance during PSCell addition or PSCell mobility procedures, even though the SCG is deactivated. This preliminary action ensures that the random access is completed before the SCG activation is triggered, avoiding delays during actual activation and ensuring consistency with 3GPP standards that require random access when AS security keys are configured or updated.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If the UE does not perform random access to the PSCell upon PSCell addition or PSCell mobility while the SCG is deactivated, then SCG activation latency is reduced, but the success rate of random access operations decreases

Engineering Contradiction:

ImproveSCG activation latencyVSAvoidsuccess rate of random access operations

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The UE performs random access to the PSCell in advance during PSCell addition or PSCell mobility procedures, even though the SCG is deactivated. This preliminary action ensures that the random access is completed before the SCG activation is triggered, avoiding delays during actual activation and ensuring consistency with 3GPP standards that require random access when AS security keys are configured or updated.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the UE releases the SCG configuration when the SCG is deactivated, then device complexity is reduced, but reconfiguration delays occur upon SCG activation

Engineering Contradiction:

ImproveSCG configuration managementVSAvoidreconfiguration delays

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The SCG configuration is maintained in advance during SCG deactivation rather than being released. This preliminary preservation of configuration ensures that when the SCG is activated, the UE can quickly resume operations without undergoing time-consuming reconfiguration procedures, thus reducing activation latency while managing device complexity efficiently.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20230254901A1User equipment, radio access network node, and methods therefor

Publication Date: 2023.08.10 NEC CORP

AI summary

When a Secondary Cell Group (SCG) containing a Primary SCG Cell (PSCell) is deactivated upon a PSCell addition or a PSCell mobility, a User Equipment (3) performs random access to the PSCell in response to the PSCell addition or the PSCell mobility without waiting until a future SCG activation. This can contribute, for example, to proper random access when the SCG is deactivated.