Inter-RAT Address Switching for Continuous 4G-5G Handover

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Solution Overview

Problem

The challenge of ensuring seamless switching between 4G and 5G networks to maintain service continuity and reduce service interruption during inter-system transitions, particularly when the new network cannot assign the original address, is not adequately addressed by existing technologies.

Innovation Solution

A method involving the terminal sending a first message with its assigned address to a second network device, receiving a new address from the second device, and managing bearers to maintain connection continuity, thereby allowing smooth switching without immediate disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the terminal switches from the first network device to the second network device and sends the first address assigned by the first network device, then the switching process is simplified, but the service continuity cannot be guaranteed when the second network device cannot assign the original address

Engineering Contradiction:
Improveswitching process complexityVSAvoidservice continuity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The terminal performs preliminary actions by sending the first address obtained from the first network device to the second network device before the address assignment conflict becomes critical. This allows the second network device to evaluate the address compatibility in advance and prepare appropriate address assignment, ensuring service continuity while maintaining switching simplicity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The second network device provides feedback regarding the first address received from the terminal. Based on this feedback, the terminal can determine whether to keep using the first address or switch to a second address assigned by the second network device. This feedback mechanism ensures service continuity while avoiding the complexity of pre-coordinating address assignments between network devices.

Inventive Principle:
Principle #23Feedback

2Reliability

If the terminal maintains connection during inter-system switching, then service continuity is improved, but signaling complexity and abnormal occurrences increase

Engineering Contradiction:
Improveservice continuityVSAvoidsignaling complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the address assignment decision-making process from the complex inter-system switching signaling. By separating the address evaluation function into a dedicated step where the terminal assesses whether the first address can be used in the second network, the solution reduces overall signaling complexity while maintaining service continuity through structured address management.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The terminal changes the address parameter dynamically based on network conditions. When switching between network devices, the terminal evaluates the first address and either continues using it or transitions to a second address assigned by the second network device. This parameter change approach maintains service continuity without requiring complex signaling protocols.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the terminal immediately disconnects when the second network device cannot assign the original address, then signaling complexity is reduced, but service interruption latency increases

Engineering Contradiction:
Improvesignaling complexityVSAvoidservice interruption latency
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The terminal performs preliminary evaluation of the first address compatibility with the second network device before committing to disconnection. By sending the first address to the second network device in advance and evaluating the response, the terminal avoids immediate disconnection and potential service interruption latency while keeping signaling relatively simple.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a cushioning mechanism by maintaining the ability to use the first address as a fallback option during the transition to the second network device. This beforehand cushioning prevents service interruption latency by ensuring that the terminal always has a valid address to use, even while evaluating compatibility with the new network device.

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

Data Source

PatentEP4718910A1Inter-rat switching method, communication device, chip
Publication Date: 2026.04.01 BEIJING X RING TECHNOLOGY CO LTD
  • EP4718910A1 patent drawingFigure 1A~1B
  • EP4718910A1 patent drawingFigure 1C
  • EP4718910A1 patent drawingFigure 1D~2

AI summary

The invention provides a switching method, a communication device, a chip and a readable storage medium. The method includes: determining (201) that a terminal is switched from a first network device to a second network device, in which the first network device and the second network device are network devices of different systems; sending (202) a first message to the second network device, in which the first message carries a first address of the terminal, and the first address is assigned to the terminal by the first network device; and receiving (203) a second message sent by the second network device, in which the second message carries a second address of the terminal, and the second address is different from the first address. Under the condition that the terminal cannot be assigned with the original address by the network when inter-system switching occurs, a current connection will not be disconnected immediately and a new address can be assigned while maintaining the current connection, to realize smooth switching and avoid service interruption, and thus service continuity can be guaranteed, service interruption latency can be reduced, thereby effectively improving user experience.