F1 Interface Core Status Signaling for DU Activation Failures
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Solution Overview
Problem
Current 3GPP standards do not provide a method for a base station to indicate to its distributed unit (DU) if it lacks connectivity with the 5G core network (5GC), leading to the DU being unable to provide service to UEs trying to access standalone (SA) mode, resulting in underutilization.
Innovation Solution
Setting up an F1 interface between the centralized unit (CU) and the DU, with core connectivity status information transmission to enable the DU to provide service to both Non-Standalone (NSA) and Standalone (SA) UEs even in the absence of core network connectivity, allowing the DU to transition to an active state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station waits for core network connectivity before activating the DU, then service reliability is improved, but device utilization deteriorates
Solution Approach 1:
The F1 interface is set up in advance between the CU and DU before core network connectivity is confirmed. This preliminary configuration allows the DU to be activated and ready to serve UEs immediately when connectivity is restored, rather than waiting passively. The system performs the interface setup action beforehand to enable faster service resumption.
2Reliability
If the DU remains inactive without core network connectivity, then service quality is maintained, but loss of time increases
Solution Approach 1:
The F1 interface configuration is established in advance during periods when core network connectivity is unavailable. This preliminary setup eliminates the need for time-consuming reconfiguration when connectivity is restored, reducing service restoration time while maintaining quality standards.
Solution Approach 2:
The system dynamically adjusts the DU's operational state based on core network connectivity status. The DU can be configured in different modes (inactive, active with limitations, fully active) depending on connectivity conditions, allowing flexible response to changing network states rather than a static inactive/active binary state.
Data Source
AI summary
In general, the current subject matter relates to handling core network connection failure. In some implementations, an F1 interface can be set up between a centralized unit (CU) of a base station and a distributed unit (DU) of the base station. Setting up the F1 interface can include transmitting core connectivity status information from the CU to the DU, and the core connectivity status information can indicate to the DU whether or not the CU has connectivity with a core network.