Inter-RAT Priority List Synchronization for UE Reselection

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Solution Overview

Problem

In inter-RAT networks, the lack of coordinated reselection priorities between different radio access technologies (RATs) leads to poor load transfer efficiency and ping-pong reselection of user equipment (UE), as broadcast messages and priority adjustments are not synchronized across networks.

Innovation Solution

A communication method where a source access network device generates and sends a temporary priority list to both the target access network device and the UE, ensuring consistent broadcast messages and preventing ping-pong reselection by adjusting priorities to guide UE to the network with the highest available priority.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the source access network device unilaterally adjusts reselection priority in broadcast messages, then load transfer can be initiated, but broadcast messages among networks of different RATs become inconsistent causing ping-pong reselection

Engineering Contradiction:
Improveload transfer efficiencyVSAvoidreselection stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent merges the priority adjustment functions of the source and target access network devices by having them share and synchronize the same priority list through interface messages. This ensures both networks broadcast consistent priority information to UE, eliminating the ping-pong reselection effect while maintaining effective load transfer.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a feedback mechanism where the source access network device sends priority list information to the target access network device, which then uses this information for its broadcast messages. This feedback loop ensures both networks maintain consistent priority information, resolving the contradiction between load transfer efficiency and reselection stability.

Inventive Principle:
Principle #23Feedback

2Device complexity

If frequency reselection priorities of networks of various RATs are made consistent during initial configuration, then network coordination is simplified, but load transfer effect deteriorates when one network needs to offload UEs

Engineering Contradiction:
Improvenetwork configuration complexityVSAvoidload transfer effect
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent introduces dynamic priority adjustment where the target access network device can modify the received priority list based on its current load conditions. This allows the system to maintain simple initial configuration while achieving effective load transfer through dynamic, condition-based priority modifications at the target network.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the priority management function into two parts: the source network generates and sends the priority list, while the target network receives and applies it. This segmentation allows each network to maintain operational simplicity while achieving coordinated load transfer through the structured information exchange protocol.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the target access network device uses its own independent priority list, then it can independently control its reselection policy, but coordination with the source network deteriorates causing inconsistent broadcast messages

Engineering Contradiction:
Improveindependent policy controlVSAvoidbroadcast message consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses the interface message exchange between source and target access network devices as an intermediary mechanism. The source network's priority list serves as the baseline, and the target network adjusts it through controlled modifications, ensuring both independence and coordination through this mediating communication channel.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3065425B1Communications method, access network device, and UE in heterogeneous network
Publication Date: 2020.09.02 HUAWEI TECH CO LTD
  • EP3065425B1 patent drawingFigure 1
  • EP3065425B1 patent drawingFigure 2
  • EP3065425B1 patent drawingFigure 3~5

AI summary

A communication method in an inter-RAT network, an access network device, and UE are provided. The method includes: generating, by a source access network device, a temporary priority list, where the temporary priority list includes a frequency of a source network, a frequency of a target network, a priority of the frequency of the source network, and a priority of the frequency of the target network, and the source access network device is a device that enables UE to access the source network; sending, by the source access network device, the temporary priority list to a target access network device, where the target access network device is a device that enables the UE to access the target network; and sending, by the source access network device, the temporary priority list to the UE. The present invention can ensure that broadcast messages in networks of different RATs are consistent and prevent ping-pong reselection of the UE.