Multicast RRC Resume Using Stored MRB Configuration

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Solution Overview

Problem

In a terminal device in RRC inactive state, frequent cell reselection leads to mismatched multicast radio bearer configurations, causing difficulties in correctly receiving multicast services after resuming the RRC connected state.

Innovation Solution

The terminal device sends an RRC resume request message to a network device, receives an RRC resume message, and enters the RRC connected state to resume a multicast service based on pre-stored configuration information, ensuring consistent MRB configuration across network devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the terminal device performs cell reselection multiple times in RRC inactive state, then the terminal device can maintain mobility and select optimal serving cells, but the multicast radio bearer configuration becomes mismatched between different serving cells, causing reception errors after RRC resume

Engineering Contradiction:
Improvecell reselection flexibilityVSAvoidmulticast reception reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by having the terminal device store the MRB configuration information from the anchor base station before cell reselection occurs. When the terminal needs to resume RRC connection, it restores the stored MRB configuration rather than acquiring a new one, ensuring consistency across different serving cells and preventing reception errors caused by configuration mismatches during mobility.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the terminal device obtains multicast configuration information from each serving cell after cell reselection, then the terminal can adapt to local network conditions, but the terminal cannot restore the original MRB configuration configured by the anchor base station, leading to reception failures

Engineering Contradiction:
Improvelocal network adaptationVSAvoidMRB configuration information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The terminal device performs preliminary action by storing the MRB configuration information from the anchor base station before cell reselection. This stored configuration is then restored during RRC resume, preserving the original network configuration intent while allowing the terminal to be physically located in different serving cells.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces the stored MRB configuration information as an intermediary element that bridges the anchor base station's original configuration and the current serving cell's multicast transmission. This intermediary ensures that the terminal uses the correct MRB configuration for receiving multicast from the anchor base station, regardless of which serving cell it is currently camped on.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the terminal device re-acquires multicast configuration information after cell reselection, then the terminal can obtain updated local configuration, but the terminal cannot correctly receive multicast from the anchor base station due to configuration mismatch

Engineering Contradiction:
Improvemulticast reception efficiencyVSAvoidmulticast reception correctness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The terminal device performs preliminary action by storing the MRB configuration information from the anchor base station before cell reselection. When the terminal needs to resume RRC connection, it restores the stored MRB configuration rather than acquiring a new one, ensuring consistency across different serving cells and preventing reception errors caused by configuration mismatches during mobility.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4701325A1Communication method, apparatus and system
Publication Date: 2026.02.25 HUAWEI TECH CO LTD
  • EP4701325A1 patent drawingFigure 1
  • EP4701325A1 patent drawingFigure 2
  • EP4701325A1 patent drawingFigure 3

AI summary

This application relates to the field of communication technologies, and provides a communication method and apparatus, and a system, to improve efficiency of receiving a multicast service. The communication method includes: sending a radio resource control RRC resume request message to a first network device; receiving an RRC resume message sent by the first network device; entering an RRC connected state from an RRC inactive state; and receiving a first multicast based on a first multicast broadcast service radio bearer MRB, where the first MRB is determined based on the RRC resume message and first multicast configuration information, the first multicast configuration information is obtained from a second network device, and the second network device is a network device in a last serving cell in an RRC connected state.