RLC Sequence Number Alignment for Reliable Network Switching

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In wireless communication, particularly in industrial scenarios requiring high reliability, existing network A/B solutions waste scarce frequency resources and cause time-consuming service switching, leading to data packet loss and reduced communication reliability.

Innovation Solution

A method for aligning serial numbers in RLC entities across network apparatuses by indicating and determining start serial numbers, ensuring accurate data packet combination and reducing latency through methods like reporting, detecting faults, and adjusting serial numbers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If network A/B solution is deployed with two access network devices, then service transmission reliability is improved, but frequency resources are wasted and service switching time increases

Engineering Contradiction:
Improveservice transmission reliabilityVSAvoidservice switching time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-synchronizing serial numbers between the first and second access network devices before fault occurrence. The second device obtains and aligns its RLC serial numbers with the first device in advance, so that when a fault occurs and switching happens, the serial number alignment is already in place, eliminating the need for time-consuming re-synchronization during the switching process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by having the second access network device copy and align its RLC serial numbers from the first device. The second device obtains the serial number information from the first device and makes it identical, creating a replica of the serial number state. This copying approach allows seamless failover without serial number conflicts.

Inventive Principle:
Principle #26Copying

2Reliability

If network A/B solution is deployed with two access network devices, then service transmission reliability is improved, but frequency resources are wasted

Engineering Contradiction:
Improveservice transmission reliabilityVSAvoidfrequency resources
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies universality by enabling the second access network device to serve dual purposes: it can function as a standby device with synchronized serial numbers for quick failover, and simultaneously maintain its own independent communication capabilities. This multi-functionality reduces the need for dedicated exclusive resources for each device.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If serial numbers are not aligned between access network devices, then device complexity is reduced, but data packet loss occurs during service switching

Engineering Contradiction:
Improveserial number management complexityVSAvoiddata packet transmission reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent uses feedback by implementing a mechanism where the second access network device receives serial number information from the first device and adjusts its own serial numbers accordingly. This feedback loop ensures that the second device's serial numbers remain aligned with the first device, preventing data packet loss during switching while maintaining manageable complexity through automated synchronization.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4187820B1Methods and devices for indicating and determining sequence number
Publication Date: 2026.01.28 HUAWEI TECH CO LTD
  • EP4187820B1 patent drawingFigure 1~2
  • EP4187820B1 patent drawingFigure 3
  • EP4187820B1 patent drawingFigure 4~5

AI summary

This application discloses a serial number indication method and determining method, and an apparatus. The indication method includes: A first network apparatus sends, to a first terminal apparatus, first indication information that indicates the first terminal apparatus to report a first serial number in an RLC entity. The first terminal apparatus sends the first serial number in the RLC entity based on the first indication information, where the first serial number is used to indicate a start serial number in an RLC entity of the first network apparatus. The first network apparatus determines the start serial number in the RLC entity of the first network apparatus based on the first serial number. The determining method includes: A network apparatus determines a first data packet; determines, based on a PDCP serial number corresponding to the first data packet, an RLC serial number corresponding to the first data packet; adds the RLC serial number to an RLC header of the first data packet; and sends the first data packet. The terminal apparatus receives the first data packet. Communication reliability is improved by using the indication solution and the determining solution.