Conditional Handover Cancellation Signaling for CHO Modification
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Solution Overview
Problem
Current RAN3 solutions for target-initiated conditional handover (CHO) cancellation fail to differentiate between genuine and modification-driven cancellations, leading to race conditions and inefficient resource management due to unclear purpose of CHO cancellation.
Innovation Solution
Incorporate an indication in the CHO cancel message from the target node to the source node, specifying the purpose of the cancellation as either genuine or modification-related, allowing the source node to decide on sending a new CHO request and manage UE context accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the target node sends a CHO cancel message without indicating the purpose, then the cancellation procedure is simple, but the source node cannot differentiate between genuine and modification-driven cancellations, leading to race conditions
Solution Approach 1:
The patent segments the CHO cancellation procedure by introducing a cause value field that divides cancellations into distinct categories (genuine cancellation vs. modification-driven cancellation). This segmentation allows the source node to differentiate between different cancellation purposes and respond appropriately, resolving the race condition issue while maintaining procedural clarity.
Solution Approach 2:
The cause value field acts as an intermediary element in the CHO cancel message. It carries the purpose information from the target node to the source node without complicating the overall message structure. This intermediary mechanism enables accurate differentiation of cancellation types while keeping the signaling procedure straightforward.
2Productivity
If the source node sends a new CHO request immediately upon receiving CHO cancel, then resource management is proactive, but it may create race conditions when the cancellation was for modification purposes
Solution Approach 1:
The patent implements a feedback mechanism where the source node uses the cause value information to determine its next action. When the cause indicates modification-driven cancellation, the source node waits for further instructions rather than sending a new CHO request immediately. This feedback-based decision-making ensures resource management actions are consistent with the actual cancellation purpose, preventing race conditions while maintaining proactive resource management.
3Device complexity
If no indication is provided in CHO cancel message, then message structure is simple, but resource management becomes inefficient due to unclear cancellation purpose
Solution Approach 1:
The patent extracts the cause value information from the overall message flow and embeds it as a specific field within the CHO cancel message. This extraction approach provides the necessary indication information without significantly increasing message structure complexity. The cause value field is a discrete element that can be easily parsed and processed, maintaining message simplicity while enabling efficient resource management decisions.
Data Source
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AI summary
A method may include receiving a request for conditional handover from a source node. The method may also include sending a conditional handover request acknowledgment message in response to the request. The method may further include sending a conditional handover cancellation message to a source node. The conditional cancellation message may include a genuine cancellation or a modification-related cancellation. Further, the method may include receiving a response message from the source node in response to the conditional handover cancellation message. In addition, the method may include deciding to keep or release user equipment context based on the response message.