Conditional Handover Failure Reporting in MR-DC SN Change
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Solution Overview
Problem
The existing 3GPP 5G NR technology lacks detailed mechanisms for handling failures in conditional handover (CHO) procedures, particularly in Multi-Radio Dual Connectivity (MR-DC) scenarios, leading to inefficiencies and potential network disruptions.
Innovation Solution
Implement methods for UE and network nodes to manage CHO configurations, including re-establishment procedures, cell selection, and failure reporting mechanisms to handle CHO-based SN changes and PCell handovers, with specific conditions for releasing or storing configurations and using timers to optimize handover processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a CHO procedure is implemented in 3GPP 5G NR, then handover efficiency is improved, but failure handling mechanisms are insufficient leading to network disruptions
Solution Approach 1:
The patent applies preliminary action by configuring the UE with multiple CHO candidate cells and their associated execution conditions before a handover is needed. When a failure occurs, the UE can immediately switch to a pre-configured backup cell or execute the re-establishment procedure without waiting for network instructions, thus improving reliability while maintaining handover efficiency.
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports CHO execution status and failure information to the network node. This feedback loop enables the network to optimize future handover decisions and configure more appropriate CHO candidates, resolving the contradiction between efficient handover and reliable failure handling.
2Reliability
If re-establishment procedure is initiated upon CHO failure, then network reliability is improved, but handover time is increased
Solution Approach 1:
The patent applies preliminary action by pre-configuring backup cells and re-establishment parameters before CHO failure occurs. When failure is detected, the UE can immediately initiate the re-establishment procedure using pre-prepared configuration data, significantly reducing the time required compared to reactive approaches where the network would need to generate and transmit new configuration messages.
Solution Approach 2:
The patent extracts the critical re-establishment configuration information from the CHO configuration itself, allowing the UE to retain essential parameters (such as cell identities, frequency information, and security context) even after CHO failure. This extraction enables rapid re-establishment without requiring complete reconfiguration, thus reducing handover time while maintaining reliability.
3Speed
If CHO configuration is stored for future use, then handover speed is improved, but configuration management complexity increases
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different configuration parameters. Instead of uniformly storing all CHO configuration data, the UE selectively stores only the essential parameters needed for rapid re-establishment (such as cell identifiers, frequency information, and security context) while discarding or updating less critical configuration details. This selective storage approach maintains high handover speed while reducing configuration management complexity.
Solution Approach 2:
The patent implements dynamics by making the CHO configuration management adaptive and flexible. The UE dynamically updates and prunes the stored configuration based on current network conditions, failure history, and configuration validity. This dynamic approach allows the system to maintain handover speed by retaining useful configurations while automatically managing complexity through adaptive updates and selective retention.
Data Source
AI summary
The present application is related to failure handling in conditional handover (CHO). A user equipment (UE) may receive a CHO configuration for secondary node (SN) change. The UE may initiate a procedure to report information indicating a CHO failure from a source SN to a target SN if at least one condition includes a CHO based SN change failure or a CHO based SN addition failure. The UE may report the information indicating the CHO failure to a master node (MN).