RRC Reconfiguration Handling During Conditional Handover
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Solution Overview
Problem
Conditional handover in wireless communication networks faces challenges with RRC reconfiguration inconsistencies between the source and target cells, leading to potential call drops and increased signaling complexity, particularly when multiple target cells are involved.
Innovation Solution
The solution categorizes RRC reconfigurations into different groups based on their impact on the target cell, allowing the source cell to perform reconfigurations without notification for certain categories, while ensuring consistency by agreeing with the target cell for others, and inhibiting reconfigurations unless specific sequences of operations are followed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the source cell performs RRC reconfiguration of the terminal during conditional handover preparation, then the RRC configuration can be updated to meet changing network conditions, but inconsistencies arise between the UE configuration and the target cell's expected configuration
Solution Approach 1:
The patent segments RRC reconfigurations into different categories (first category requiring target cell agreement, second category allowing source cell autonomy) based on their impact on handover consistency. This segmentation enables differentiated handling of configuration changes, maintaining reliability for critical parameters while preserving adaptability for non-critical ones.
Solution Approach 2:
The patent applies local quality by treating different RRC configuration parameters differently - some parameters require target cell coordination while others can be changed autonomously by the source cell. This allows the system to maintain configuration consistency for handover-critical parameters while remaining flexible for other parameters.
2Reliability
If the source cell agrees with the target cell before performing RRC reconfiguration, then configuration consistency is maintained, but signaling overhead increases
Solution Approach 1:
The patent divides RRC reconfigurations into two categories: those requiring target cell agreement (first category) and those that can be performed autonomously (second category). This segmentation reduces signaling overhead by eliminating unnecessary agreement procedures for non-critical parameters while maintaining consistency for handover-critical parameters.
Solution Approach 2:
The patent applies partial action by requiring target cell agreement only for specific categories of RRC reconfigurations that impact handover consistency, rather than requiring agreement for all reconfigurations. This reduces signaling overhead while maintaining necessary consistency.
3Reliability
If the source cell cancels and re-initiates CHO upon RRC reconfiguration, then configuration consistency is ensured, but handover execution is delayed
Solution Approach 1:
The patent performs preliminary action by categorizing RRC reconfigurations in advance into those requiring target cell agreement and those that can be performed autonomously. This pre-categorization allows the source cell to proceed with autonomous reconfigurations immediately without cancellation and re-initiation of CHO, reducing handover execution time while maintaining consistency for critical parameters.
Solution Approach 2:
The patent segments RRC reconfigurations into categories based on their impact on handover consistency. For the second category (autonomous reconfigurations), the source cell can perform changes without canceling CHO, avoiding the time loss associated with cancellation and re-initiation while maintaining necessary consistency.
4Reliability
If full configuration is used for CHO to avoid inconsistencies, then configuration consistency is maintained, but signaling overhead increases significantly
Solution Approach 1:
The patent segments RRC configuration parameters into two groups: those that require target cell agreement (affecting handover consistency) and those that can be changed autonomously. This segmentation allows the system to maintain consistency for critical parameters without requiring full configuration retransmission, significantly reducing signaling overhead compared to the full configuration approach.
Solution Approach 2:
The patent extracts only the essential parameters that require target cell agreement from the full RRC configuration. By identifying and separately handling only these critical parameters, the system maintains configuration consistency without the excessive signaling overhead of transmitting and reconfiguring the entire RRC configuration.
Data Source
AI summary
It is provided a method comprising monitoring if a source cell intends performing a radio reconfiguration of a terminal configured with a conditional handover from the source cell to a target cell; determining a determined category among plural predetermined categories; wherein the radio reconfiguration is associated to the determined category; for each category a respective predetermined sequence of one or more operations is defined; the respective predetermined of one of the categories is different from the respective predetermined sequence of another one of the categories; and the method further comprises inhibiting the performing of the radio reconfiguration of the terminal unless the predetermined sequence of one or more operations of the determined category is performed along with the performing of the radio reconfiguration if the source cell intends performing the radio reconfiguration of the terminal.