Emergency Call Access in Barred Cells for RedCap UEs
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Solution Overview
Problem
User equipment (UEs) with reduced capabilities, such as RedCap and eRedCap UEs, are unable to make emergency calls when located in cells that do not support their capabilities, leading to a failure in providing essential services.
Innovation Solution
UEs are allowed to treat cells as 'acceptable' for emergency calls by modifying the cell barring logic in the UE, either by assuming compliance with reception chain or HD-FDD requirements or through explicit network signaling to enable emergency call support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UEs treat cells as barred when they do not support reduced capabilities, then network resource optimization is improved, but emergency call availability deteriorates
Solution Approach 1:
The patent segments the cell access control by distinguishing between normal calls and emergency calls. The UE capability evaluation is performed separately for normal calls (where barred cells are avoided) and emergency calls (where barred cells are accessed). This segmentation allows the system to optimize network resources for normal traffic while ensuring emergency call availability through a separate access path.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of emergency call indicator handling. When a UE detects an emergency call indicator, the system temporarily overrides the normal cell barring logic. This intermediary mechanism allows emergency calls to bypass the usual capability mismatch restrictions, enabling access to barred cells while maintaining normal resource optimization for other traffic types.
2Reliability
If UEs avoid barred cells for normal calls, then call setup failure rate is reduced, but emergency call capability is lost
Solution Approach 1:
The patent applies dynamic behavior change based on call type. The UE dynamically adjusts its cell selection criteria based on whether the call is normal or emergency. For normal calls, the UE sticks to non-barred cells to ensure success. For emergency calls, the UE dynamically switches to accepting barred cells, thereby adapting its behavior to the specific operational context and maintaining emergency call capability.
Solution Approach 2:
The patent changes the cell acceptance parameter based on call type. The UE modifies its cell selection parameter from 'only accept non-barred cells' for normal calls to 'accept both barred and non-barred cells' for emergency calls. This parameter change enables the UE to maintain high call setup success rates for normal traffic while gaining emergency call capability when needed.
3Reliability
If network provides emergency call support in barred cells, then emergency service coverage is improved, but network complexity increases
Solution Approach 1:
The patent enables self-service behavior where the UE autonomously determines when to access barred cells for emergency calls. The UE independently evaluates emergency call indicators and automatically adjusts its cell access behavior without requiring complex network-side reconfiguration. This self-service approach improves emergency service coverage while minimizing network complexity by leveraging UE autonomy.
Data Source
AI summary
The present application relates to devices and components including apparatus, systems, and methods to provide emergency calls for user equipments with reduced capabilities via barred cells in wireless communication systems.