UE Cell Access Switching for Stable 4G-to-5G NSA Handover

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Solution Overview

Problem

In the process of a user equipment (UE) accessing a 5G network through non-standalone (NSA) deployment, there is a risk of data interruption and frequent network disconnection due to poor cell signal quality, leading to inefficient communication.

Innovation Solution

The UE sends indication information to the network device before and after successfully accessing a 5G cell, allowing the network device to maintain data transmission in the 4G cell until the 5G cell is stable, ensuring seamless transition when the 5G cell is ready for use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the network device reconfigures the transmission channel to the 5G cell before the UE successfully accesses it, then the 5G network deployment is enabled, but data interruption and network disconnection occur due to poor cell signal quality

Engineering Contradiction:
Improve5G network deployment capabilityVSAvoidnetwork connection stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The network device performs preliminary reconfiguration of the transmission channel to the 5G cell and sends the reconfiguration message to the UE in advance, but delays the actual data transmission switch until the UE confirms successful access. This preliminary action enables 5G deployment while avoiding premature connection switching that would cause data interruption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The network device maintains the 4G transmission channel as a backup until the UE successfully accesses the 5G cell. This cushioning mechanism ensures that if the 5G access fails due to poor signal quality, the UE can fall back to the 4G network, preventing network disconnection and maintaining reliability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If the UE attempts to access the 5G cell with poor signal quality, then the 5G network is utilized, but multiple access failures occur causing communication interruption

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidaccess success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The UE sends feedback to the network device indicating whether it has successfully accessed the 5G cell. Based on this feedback, the network device decides whether to switch data transmission from the 4G cell to the 5G cell. This feedback mechanism ensures that data transmission only occurs on the 5G cell when access is successful, avoiding communication interruption.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The transmission channel configuration is made dynamic, allowing the network device to switch between 4G and 5G cells based on real-time access conditions. The system can adaptively adjust the data transmission path from static 4G-only to dynamic 4G-5G switching, improving both productivity and reliability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4120740B1Cell access method, device, and system
Publication Date: 2025.12.24 VIVO MOBILE COMM CO LTD
  • EP4120740B1 patent drawingFigure 1~2
  • EP4120740B1 patent drawingFigure 3
  • EP4120740B1 patent drawingFigure 4~5

AI summary

Disclosed in embodiments of the present invention are a cell access method, a device, and a system. The method includes: receiving configuration information of a second cell sent by a first network device in a case that a UE accesses a first cell; according to the configuration information of the second cell, sending first indication information to the first network device and executing a process of accessing the second cell, where the first indication information is used for indicating that the UE has not completed accessing the second cell, and the first indication information is used for the first network device to maintain data transmission in the first cell; sending second indication information to the first network device in a case that the UE has successfully accessed the second cell and the second cell satisfies a preset condition, where the second indication information is used for indicating that the UE has successfully accessed the second cell, and the second indication information is used for the first network device to switch a data transmission path from the first cell to the second cell.