Emergency Service Indicators in System Information Block Type 1
Solution Overview
Problem
User Equipment (UE) faces ambiguity in determining whether a cell supports emergency services, eCall, and eDRX capabilities through EPC or 5G CN, as current system information broadcast by E-UTRAN does not clearly indicate the specific core network providing these services, leading to potential misconnection and service failures.
Innovation Solution
The UE receives and decodes System Information Block Type 1 messages broadcast by E-UTRAN, which include separate indicators for EPC and 5G CN support of IMS emergency services, eCall, and eDRX, allowing it to initiate services through the appropriate core network, ensuring correct service routing and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a single broadcast indicator is used to indicate emergency service support, then the system information is concise and easy to broadcast, but the UE cannot determine which core network (EPC or 5GC) supports emergency services
Solution Approach 1:
The patent segments the single emergency service support indicator into separate indicators for EPC and 5GC core networks. The system information now includes distinct fields (e.g., ims-EmergencySupport for EPC and ims-EmergencySupport5GC for 5GC) that independently indicate whether each core network supports IMS emergency services. This segmentation allows the UE to clearly determine which core network provides emergency services while maintaining a structured and manageable information format.
2Measurement precision
If separate indicators are added for EPC and 5GC support, then the UE can accurately determine service availability, but the system information becomes more complex and larger in size
Solution Approach 1:
The patent applies local quality by making the system information structure adaptive based on network configuration. Each cell can selectively include only the indicator fields relevant to its configured core networks. For example, a cell connected only to EPC will include only the EPC emergency support indicator, while a cell connected to both EPC and 5GC will include both indicators. This approach provides precise service capability information without uniformly increasing complexity across all cells.
Solution Approach 2:
The patent implements partial action by conditionally including indicator fields based on actual network capabilities. The system information block includes emergency service indicators only for the core networks that are actually connected and configured. This avoids the overhead of including all possible indicators in every cell, reducing the average system information size while still providing complete information where needed.
3Reliability
If the UE attaches to the wrong core network based on ambiguous system information, then service initiation may fail, but additional indicators increase broadcast overhead
Solution Approach 1:
The patent applies preliminary action by providing the UE with complete and unambiguous emergency service capability information through system information broadcast before the UE attempts to initiate emergency services. The separate indicators for EPC and 5GC support enable the UE to make informed decisions about which core network to attach to, preventing attachment failures and ensuring successful service initiation from the outset.
Solution Approach 2:
The system enables self-service by allowing the UE to autonomously determine the appropriate core network for emergency services based on the broadcast indicators. The UE reads the system information, interprets the separate EPC and 5GC support indicators, and independently decides which core network to attach to without requiring additional network coordination or intervention, thereby improving reliability while minimizing overhead.
Data Source
AI summary
This disclosure is related to a procedure to provide emergency services support for a UE which does not have a valid subscription for the serving PLMN. This disclosure more specifically provides procedure to support IMS emergency call or eCall support for a UE which is in limited state on a E-UTRA cell is connected to both EPC and 5GCN.