gNodeB F1 Interface Activation During 5G Core Failure

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Solution Overview

Problem

In 5G wireless communication systems, a base station without connectivity to the 5G core network cannot provide service to Standalone (SA) user equipments (UEs), leading to underutilization of the distributed unit (DU), while Non-Standalone (NSA) devices are unable to communicate effectively due to core network connection failure.

Innovation Solution

Establishing an F1 interface between the centralized unit (CU) and the distributed unit (DU) of a base station, even in the absence of core network connectivity, allows the DU to transition to an active state, supporting NSA UEs and preparing for SA UEs once connectivity is restored.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the base station maintains strict core network connectivity requirements, then service quality for SA UEs is ensured, but the DU remains underutilized and NSA UEs cannot communicate effectively during core network failures

Engineering Contradiction:

Improveservice quality for SA UEsVSAvoidDU utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The base station dynamically adjusts its operational state based on core network connectivity status. When connected, it provides full service to both SA and NSA UEs. When disconnected, it transitions to a restricted mode that maintains service for NSA UEs while preserving the ability to quickly resume SA UE service upon reconnection, thus optimizing DU utilization across varying network conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the base station based on connectivity state. In connected state, parameters allow full SA and NSA service. In disconnected state, parameters are adjusted to enable NSA service only, allowing the DU to remain productive while maintaining the capability to restore full functionality when connectivity returns

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the base station allows DU to operate without core network connectivity, then NSA UEs can communicate effectively, but service to SA UEs cannot be provided

Engineering Contradiction:

ImproveNSA UE communication capabilityVSAvoidservice support for both NSA and SA UEs

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The service capability is segmented into two distinct modes: a full-service mode supporting both SA and NSA UEs when core network connectivity is available, and a restricted mode supporting only NSA UEs when connectivity is lost. This segmentation allows the system to optimize for current network conditions while maintaining adaptability to different operational scenarios

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base station dynamically switches between service modes based on core network connectivity status. The transition between modes is seamless and automatic, allowing the system to maintain optimal performance for the currently supported UE types while preserving the ability to adapt when network conditions change

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12543237B2Handling core network connection failure

Publication Date: 2026.02.03 RAKUTEN SYMPHONY INC

AI summary

In general, the current subject matter relates to handling core network connection failure. In some implementations, with a connection down between a gNodeB and a 5G core network, the gNodeB can be caused to be in an active state such that the gNodeB can provide support to Non-Standalone (NSA) user equipments (UEs) with the connection down between the gNodeB and the 5G core network.