Selected Cell Status in Handover Failure Reports
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Solution Overview
Problem
In cellular communications systems, when a User Equipment (UE) experiences a handover failure during voice fallback from New Radio (NR) to Long Term Evolution (LTE), the UE currently does not log information about the selected cell, preventing the network from understanding whether the selected cell was suitable or acceptable, which hinders network optimization.
Innovation Solution
The UE is configured to include information in a failure report indicating whether the selected cell was suitable or acceptable, along with additional details such as PLMN identity and emergency service availability, aiding the network in optimizing future handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the UE does not log information about the selected cell, then the failure report structure remains simple, but the network cannot understand whether the selected cell was suitable or acceptable, hindering network optimization
Solution Approach 1:
The failure report is segmented into existing fields and new optional fields. The report structure is divided into mandatory components (failure type, timing information) and optional components (cell selection information, PLMN identity, emergency service status). This allows the report to maintain simplicity for basic cases while enabling enhanced information collection when needed, resolving the contradiction between information completeness and structural simplicity.
Solution Approach 2:
The patent changes the parameter state of the failure report from a fixed simple structure to a flexible structure that can adapt its complexity based on the failure scenario. By introducing optional fields that can be conditionally included, the report structure dynamically adjusts its information capacity, allowing detailed cell selection information to be captured when relevant while maintaining simplicity for other failure types.
2Reliability
If the UE includes detailed information about the selected cell in the failure report, then the network can optimize future handovers, but the report size and processing complexity increase
Solution Approach 1:
The patent extracts only the essential cell selection information needed for network optimization and includes it in the failure report. Rather than transmitting complete cell configuration data, the report extracts specific fields such as cell identity, PLMN identity, and emergency service availability. This selective extraction maintains the reliability improvement while minimizing the overhead and processing complexity increase.
Solution Approach 2:
The patent applies partial action by including only the necessary subset of cell information in the failure report. The optional fields are selectively populated based on the failure scenario and network configuration, providing sufficient information for optimization without excessive detail that would unnecessarily increase processing complexity. This balanced approach achieves the reliability benefit while controlling the complexity cost.
Data Source
AI summary
Systems and methods are disclosed for including information concerning a selected cell in a failure report. In one embodiment, a method performed by a wireless terminal comprises receiving a configuration from a first cell to perform handover to a second cell, the configuration comprising an indication indicating voice fallback purpose. The method further comprises attempting to connect to the second cell using a mobility procedure, determining that a failure has occurred, and storing information associated to the failure in a first report. The method further comprises attempting to perform cell selection in a same radio access technology as the second cell and, as a result, selecting a cell in the same radio access technology as the second cell. The method further comprises storing, in the first report, at least one piece of information that indicates whether the selected cell was a suitable cell or an acceptable cell.