MUSIM Cell Prioritization for Conditional Handover Reliability
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Solution Overview
Problem
Existing UE devices with Multi-Universal Subscriber Identity Module (MUSIM) support face challenges in maintaining connectivity and reducing radio link failures during conditional handovers and secondary cell additions/changes due to the lack of prioritization based on MUSIM assistance configurations, leading to potential data loss and service disruptions.
Innovation Solution
The UE prioritizes secondary cells based on MUSIM assistance configurations, such as musim-LeaveAssistanceConfig-r17 and musim-GapAssistanceConfig-r17, during conditional handovers and secondary cell additions/changes, ensuring seamless connectivity and reducing radio link failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE selects secondary cells based on conventional criteria without prioritizing MUSIM assistance configuration, then the cell selection process is simpler and faster, but the reliability of maintaining connectivity between two networks deteriorates
Solution Approach 1:
The network pre-configures MUSIM assistance information in RRC reconfiguration messages for candidate secondary cells before the UE performs cell selection. This allows the UE to identify and prioritize suitable cells in advance, ensuring reliable connectivity maintenance without adding complex real-time decision-making processes during handover execution.
Solution Approach 2:
The patent applies different selection criteria to different candidate cells based on their individual characteristics. Cells with MUSIM assistance configuration receive priority treatment, while other cells follow conventional selection rules. This localized differentiation ensures reliable connectivity where needed without universally increasing complexity.
2Reliability
If the UE prioritizes secondary cells with MUSIM assistance configuration during conditional handover, then the reliability of service continuity improves, but the complexity of cell evaluation and selection increases
Solution Approach 1:
The MUSIM assistance configuration is provided in advance through RRC reconfiguration messages, allowing the UE to evaluate candidate cells with clear prioritization criteria before making handover decisions. This preliminary provision of information simplifies the evaluation process compared to real-time complex analysis.
Solution Approach 2:
The UE evaluates candidate cells based on received MUSIM assistance information and provides feedback by selecting cells that meet the prioritization criteria. This structured feedback mechanism ensures service continuity while maintaining manageable evaluation complexity through clear decision rules.
3Reliability
If the UE does not prioritize MUSIM assistance configuration, then the handover execution is faster and simpler, but the likelihood of radio link failure increases
Solution Approach 1:
The MUSIM assistance configuration and cell prioritization are established before handover execution through RRC reconfiguration. This preliminary setup ensures that when handover is triggered, the UE can quickly execute the decision without complex real-time analysis, reducing both radio link failures and execution time.
Solution Approach 2:
The network prepares the RRC reconfiguration message with prioritized candidate cell information in advance, so the UE has pre-validated options ready for immediate execution. This eliminates the need for time-consuming evaluation during critical handover moments while ensuring reliable cell selection.
Data Source
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AI summary
An example method performed by a User Equipment (UE) supporting a Multi-Universal Subscriber Identity Module (MUSIM), the method comprises connecting a first SIM of the UE with a primary cell. The method comprises receiving a radio resource control (RRC) reconfiguration message of the primary cell including information on candidate cells for a conditional handover, a conditional Primary Secondary (PS) cell addition, or a conditional PS cell change. The method comprises identifying that a RRC reconfiguration message of each of the candidate cells comprises at least one of leave assistance information or gap assistance information. The method comprises performing prioritizing at least one candidate cell of the candidate cells that supports MUSIM assistance information, in response to identifying that the RRC reconfiguration message comprises at least one of the leave assistance information or the gap assistance information.