Bearer ID Allocation for 4G-5G Mobility Handover

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Solution Overview

Problem

Existing systems face challenges in determining allocated Evolved Packet System (EPS) bearer IDs (EBIs) during mobility events such as idle state mobility within 5G, idle state mobility from 4G to 5G, and connected state handover from 4G to 5G, leading to potential EBI collisions and compatibility issues between 4G and 5G networks.

Innovation Solution

A method and device for determining bearer IDs through a target access and mobility control function (tAMF) transmitting a session update request to a session management function (SMF) to receive bearer ID allocation information, ensuring compatibility with traditional networks without requiring modifications to the MME.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the network device determines EBI information for idle state mobility or connected state handover from 4G to 5G, then mobility between 4G and 5G networks is enabled, but the related art cannot effectively determine allocated EBI information after mobility events occur

Engineering Contradiction:
Improvemobility between 4G and 5G networksVSAvoiddetermination of allocated EBI information
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The SMF allocates EBI information in advance during PDU session establishment and stores it in the UPF. When mobility events occur (idle state mobility or connected state handover), the network device can directly retrieve the pre-allocated EBI information from the UPF without needing to perform complex determination procedures, thus enabling reliable EBI determination across 4G-5G mobility scenarios

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The UPF acts as an intermediary that stores and provides EBI information to the network device during mobility events. Instead of the network device determining EBI information from scratch during handover or mobility, it queries the UPF which has the pre-allocated information, thus resolving the reliability issue while maintaining adaptability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the network device creates a mapping relationship between 5G QoS flow identifier and EBI, then QoS management during handover is improved, but the procedure becomes more complex

Engineering Contradiction:
ImproveQoS management during handoverVSAvoidmapping relationship creation procedure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mapping relationship between 5G QoS flow identifier and EBI is pre-established and stored in the UPF during PDU session setup. During handover, the network device simply retrieves this pre-configured mapping information from the UPF rather than creating new mappings, thus maintaining reliable QoS management while avoiding the complexity of real-time mapping creation procedures

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4284083B1Methods and devices for bearer identifier determination and corresponding storage medium
Publication Date: 2026.05.06 ZTE CORP
  • EP4284083B1 patent drawingFigure 1~2
  • EP4284083B1 patent drawingFigure 3~4
  • EP4284083B1 patent drawingFigure 5~6

AI summary

Provided are a method and device for determining a bearer identifier (ID), and a storage medium. The above-mentioned method for determining the bearer ID includes that: a target access and mobility control function (tAMF) transmits a session update request to a session management function (SMF), and receives a session update response that carries bearer ID allocation information and that is fed back by the SMF. The above-mentioned technical solution may solve a problem in the related art, yet to be solved effectively, of how to determine allocated evolved packet system (EPS) bearer ID (EBI) information after mobility events such as idle state mobility within 5G, idle state mobility from 4G to 5G and a connected state handover from 4G to 5G occur.