5G Core Network EBI Allocation Management for 4G Handover

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Solution Overview

Problem

In mobile radio communication networks, the limited number of Evolved Packet System (EPS) Bearer Identifiers (EBIs) in 4G networks poses a challenge when handover occurs from 5G to 4G, as the 5G network must manage EBI allocation efficiently to prevent exceeding the 4G EBI connection limit, without mechanisms for availability notification or prioritization.

Innovation Solution

The method involves determining the availability of EBIs in the 5G network during communication service establishment, requesting identifiers from the 5G core network, and implementing a back-off timer or prioritization based on Quality of Service (QoS) flows and Domain Network Names (DNNs) to manage EBI allocation, ensuring seamless handover without exceeding the 4G EBI limit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the 5G network allows multiple communication sessions to be established, then the communication service capacity is improved, but the number of available EBIs is exceeded and handover to 4G network fails

Engineering Contradiction:
Improvecommunication service capacityVSAvoidhandover reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by establishing a subscription mechanism before EBI exhaustion occurs. The SMF subscribes to EBI availability notifications in advance, allowing the system to proactively respond when EBIs become available rather than reactively handling connection failures. This enables the network to maintain multiple communication sessions while ensuring handover reliability by acting before the resource limit is reached.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the network limits the number of communication sessions to match available EBIs, then handover reliability is improved, but the communication service capacity is reduced

Engineering Contradiction:
Improvehandover reliabilityVSAvoidcommunication service capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements feedback through an availability notification mechanism where the AMF informs the SMF when EBIs become available. This feedback loop allows the network to dynamically adjust communication session allocation based on actual EBI availability, maintaining handover reliability while maximizing communication service capacity by utilizing all available EBIs as they become free.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If the network releases EBIs without UE involvement, then the complexity of UE operations is reduced, but the control complexity in the network increases

Engineering Contradiction:
ImproveUE operation simplicityVSAvoidnetwork control complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the SMF to autonomously manage EBI release without UE involvement. The SMF receives availability notifications from the AMF and automatically releases appropriate EBIs based on current communication session requirements. This self-service mechanism simplifies UE operations while the network handles the complexity internally through automated resource management.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3487217B1Core network of a mobile radio communication network
Publication Date: 2019.12.04 NTT DOCOMO INC
  • EP3487217B1 patent drawingFigure 1
  • EP3487217B1 patent drawingFigure 2
  • EP3487217B1 patent drawingFigure 3

AI summary

A method of establishing a communication service is provided. The method may include receiving a message by a first network function in the first communication network to establish a PDU session which may include one or more Quality of Service Flow(s); the first network function in the first communication network determining that the communication service to be established requires an Identifier for service interworking with the second communication network; the first network function in the first communication network requesting an Identifier for service interworking with the second communication network from an second network function in the first communication network of the mobile radio communication network, the second network function in the first communication network determining whether the requested Identifier for service interworking with the second communication network is available for the communication service, and, in case the requested Identifier for service interworking with the second communication network is not available, providing an information to the Session Managing Function component that the request is rejected.