Conditional PSCell Addition via Master Node for Dual Connectivity
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Solution Overview
Problem
Existing methods for conditional PSCell addition in multi-radio dual connectivity scenarios are inadequate, particularly when the secondary node is not yet established, leading to potential resource misallocation and unclear message handling during the preparation and execution phases.
Innovation Solution
A method where the master node initiates conditional PSCell addition by sending an S-Node Addition Request message to a target candidate secondary node, including a conditional reconfiguration with execution conditions, allowing the secondary node to prepare resources without requiring the master node to understand the secondary node's configurations, facilitating inter-RAT scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the master node sends RRC reconfiguration message immediately upon receiving measurement report, then the handover preparation is fast, but the radio link may already be unstable when the message reaches the UE
Solution Approach 1:
The master node performs preliminary actions by receiving measurement reports early and preparing RRC reconfiguration messages in advance. The conditional handover configuration is prepared and stored before the actual handover execution, allowing the network to respond quickly when conditions are met without compromising radio link stability.
Solution Approach 2:
The system dynamically adjusts the handover execution timing based on real-time radio conditions. The UE evaluates execution conditions continuously and executes handover only when both the condition is met and the radio link is stable, creating a dynamic response mechanism that adapts to changing network conditions.
2Reliability
If the master node waits for measurement report threshold to be met before sending handover command, then the radio link stability is maintained, but the handover execution is delayed
Solution Approach 1:
The master node performs preliminary configuration of conditional handover by receiving measurement reports and preparing RRC reconfiguration messages in advance. This allows the network to be ready for immediate execution when the execution condition is met, minimizing the delay between condition fulfillment and handover execution.
Solution Approach 2:
The system implements feedback mechanisms where the UE continuously reports measurement results to the master node. The master node uses this feedback to evaluate execution conditions and trigger handover commands at the optimal moment, ensuring both stability and timely execution.
3Productivity
If the master node configures conditional PSCell addition for a target candidate secondary node, then the resource allocation is efficient, but the message handling becomes complex when the secondary node is not yet established
Solution Approach 1:
The master node segments the configuration process by separating the PSCell addition configuration from the full secondary node establishment. The RRC reconfiguration message contains only the necessary PSCell configuration parameters, allowing conditional addition without requiring complete secondary node setup, thus simplifying message handling.
Solution Approach 2:
The master node acts as an intermediary that bridges the UE and the target candidate secondary node. It receives measurement reports from the UE, evaluates execution conditions, and sends conditional PSCell addition configurations to the UE without needing direct communication with the target secondary node, simplifying the overall message handling process.
4Ease of operation
If the master node uses standard RRC reconfiguration message format, then the message handling is simple, but the secondary node's specific configuration requirements cannot be met
Solution Approach 1:
The master node uses a nested message structure where the RRC reconfiguration message contains embedded configuration parameters for the target candidate secondary node. The PSCell configuration is nested within the standard RRC message framework, allowing the master node to maintain simple message handling while incorporating secondary node-specific configuration requirements through structured data containers.
Data Source
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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.