Conditional PSCell Change Handling for Reliable Dual Connectivity Handover
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Solution Overview
Problem
Existing wireless communication systems face challenges in ensuring robust handover operations, particularly when radio conditions deteriorate, leading to potential failures in delivering handover commands to user equipment (UE), and there is a need for improved methods to handle conditional PSCell addition or change in dual connectivity scenarios.
Innovation Solution
Implementing conditional PSCell addition or change (CPAC) procedures, where a master node (MN) configures UE with multiple candidate target cells based on specific conditions, monitors UE configurations, and responds to condition fulfillment with appropriate reconfigurations, involving both MN and secondary node (SN) interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If handover command is sent when radio conditions are already bad, then handover execution is timely, but message delivery reliability deteriorates
Solution Approach 1:
The patent applies preliminary action by sending the handover command in advance when radio conditions are still good, rather than waiting until conditions deteriorate. The UE stores the handover command and executes it later when the execution condition is met, ensuring both timely execution and reliable message delivery.
2Reliability
If conditional handover configuration is provided early, then handover execution reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the handover process into two independent parts: (1) receiving and storing the handover command with associated execution conditions, and (2) evaluating conditions and executing handover when conditions are met. This segmentation reduces UE complexity by allowing deferred execution rather than immediate processing.
Solution Approach 2:
The patent applies copying by having the UE store a copy of the handover command in memory for later execution. The stored command includes all necessary parameters and configurations, allowing the UE to execute the handover without needing to maintain active connection to the source cell or process the command immediately.
3Adaptability or versatility
If multiple conditional handover commands are provided for different candidate cells, then handover adaptability is improved, but message delivery complexity increases
Solution Approach 1:
The patent applies dynamics by making the handover execution conditional and dynamic. The UE evaluates execution conditions (e.g., radio condition thresholds, event triggers) and automatically selects which handover command to execute based on current conditions. This dynamic approach allows multiple candidate configurations while keeping UE complexity manageable through automated condition evaluation.
Data Source
AI summary
A method of operating a master node includes determining to configure conditional PSCell addition or change (CPAC). A request is transmitted to a SN to prepare a conditional SN addition, a response therefrom confirms that a UE may be accepted unless a canceling message is later received. A RRC message is transmitted to the UE containing CPAC configurations for candidate target cell(s), where the RRC message contains condition(s) which the UE should monitor and message to be applied when condition fulfilled. Multiple MN or MCG related configurations are monitored for reception of messages from the UE. A message is received from the UE on one of the multiple MN or MCG related configurations monitored. The method detects which one of the multiple MN or MCG related configurations the UE has applied and responsively reconfigures the MN based on the detected one of the multiple MN or MCG related configurations.