Conditional PSCell Addition via Master Node Forwarded Reconfiguration

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Solution Overview

Problem

Existing solutions for conditional PSCell addition in Multi-Radio Dual Connectivity (MR-DC) are inadequate, particularly when involving inter-node messages, as they do not account for scenarios where a target Secondary Node (SN) is not yet established, leading to potential resource misallocation and unclear message handling during preparation and execution.

Innovation Solution

A method where the Master Node (MN) initiates the conditional PSCell addition procedure by sending an indication for CPA, allowing the target SN to generate the RRC Reconfiguration with execution conditions, enabling the SN to prepare resources without requiring the MN to understand the specific configurations, applicable across different Radio Access Technologies (RATs).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the MN generates the RRC Reconfiguration message for conditional PSCell addition, then the MN can control the handover process, but the MN must understand and process complex target SN configurations which increases processing complexity

Engineering Contradiction:

Improvehandover controlVSAvoidMN processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The target SN acts as an intermediary by generating the RRC Reconfiguration message directly, eliminating the need for MN to process complex target SN configurations. The MN simply forwards the message from target SN to UE, reducing MN processing complexity while maintaining handover control capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of generating the RRC Reconfiguration message itself, the MN copies and forwards the message generated by the target SN. This approach allows the MN to maintain handover control without the complexity of understanding and processing detailed target SN configurations.

Inventive Principle:

Principle #26Copying

2Device complexity

If the MN forwards the RRC Reconfiguration message from target SN, then the MN reduces processing complexity, but the MN must handle message routing when target SN is not yet established

Engineering Contradiction:

ImproveMN processing complexityVSAvoidmessage handling procedure

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The MN performs preliminary actions by establishing the conditional PSCell addition procedure before the target SN is fully established. The MN receives the RRC Reconfiguration message from target SN and prepares to forward it to the UE, handling the message routing in advance to avoid operational complexities.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The MN serves as an intermediary in the message routing process, receiving the RRC Reconfiguration message from the target SN and forwarding it to the UE. This intermediary role simplifies the message handling procedure by centralizing the routing function at the MN.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the target SN generates the RRC Reconfiguration message, then resource allocation becomes efficient and RAT compatibility improves, but the target SN must prepare configurations before being fully established

Engineering Contradiction:

ImproveRAT compatibilityVSAvoidconfiguration preparation time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The target SN performs preliminary configuration preparation before being fully established, generating the RRC Reconfiguration message in advance. This allows the configuration to be ready when needed, reducing the time loss while maintaining the ability to adapt to different RATs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The target SN generates the RRC Reconfiguration message with parameters optimized for its specific RAT configuration. By preparing the message with the correct parameters in advance, the system achieves efficient resource allocation and RAT compatibility without significant time loss.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4193792B1Systems and methods for master node-initiated conditional primary secondary cell addition

Publication Date: 2026.01.28 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

A method by a network node operating as a Master Node (MN) for conditional Primary Secondary Cell Addition (CPA) includes sending, to a target secondary node (SN) a Request message. The network node receives, from the target SN, an Acknowledge message comprising an RRC Reconfiguration message (RRCReconfiguration**), including a Secondary Cell Group (SCG) configuration for a target candidate cell. The network node sends, to a wireless device, another RRC Reconfiguration message (RRCReconfiguration), which includes at least one conditional reconfiguration. The conditional reconfiguration includes: another RRC Reconfiguration message (RRCReconfiguration*) in MN format and a Master Cell Group (MCG) configuration; at least one execution condition for the CPA; and a conditional reconfiguration identity associated with the CPA for the target candidate cell. The RRCReconfiguration* includes the RRCReconfiguration**. The network node receives, from the wireless device, a first reconfiguration complete message.