Multicast Radio Bearer Configuration in RRC Inactive State

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Solution Overview

Problem

Current cellular systems face challenges in efficiently configuring and receiving multicast services, particularly in the RRC INACTIVE state, which affects power saving, service coverage, and spectrum efficiency, especially in high-load scenarios.

Innovation Solution

User Equipment (UE) is enabled to receive multicast transmission in the RRC INACTIVE state by joining a multicast session, establishing a multicast radio bearer (MRB) based on received configuration, and updating multicast resource information under predefined conditions, including cell handovers and network updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UE receives multicast service in RRC CONNECTED state, then service coverage and reliability are improved, but power consumption increases and device complexity increases

Engineering Contradiction:
Improvemulticast service reception reliabilityVSAvoidUE power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent enables UE to dynamically switch between RRC CONNECTED and RRC INACTIVE states for multicast service reception. The network can configure UE to receive multicast in RRC INACTIVE state when traffic load is low, and switch to RRC CONNECTED state when high reliability is needed, making the system adaptive to different conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces new parameters for multicast service configuration in RRC INACTIVE state, including multicast radio bearer configuration, scheduling information, and resource allocation parameters. These parameter changes enable UE to efficiently receive multicast services without maintaining full RRC CONNECTED state

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If UE maintains RRC CONNECTED state for multicast reception, then service coverage is improved, but device complexity and network load increase

Engineering Contradiction:
Improveservice coverageVSAvoidUE and network complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent extracts the essential multicast reception functionality from the RRC CONNECTED state and enables it to operate independently in RRC INACTIVE state. UE can receive multicast data, update configuration, and manage bearers without maintaining full RRC connection, reducing both UE and network complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the multicast service reception process into independent configurable components that can operate in RRC INACTIVE state, including separate multicast radio bearer management, scheduling information reception, and resource allocation, allowing selective activation without full connection

Inventive Principle:
Principle #1Segmentation

3Reliability

If UE receives multicast in high-load scenarios with RRC CONNECTED state, then service delivery is reliable, but spectrum efficiency and network capacity deteriorate

Engineering Contradiction:
Improvemulticast service deliveryVSAvoidspectrum efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies partial action by enabling UE to receive multicast services with reduced signaling overhead in RRC INACTIVE state. The network sends essential scheduling information and resource allocation without requiring full RRC connection maintenance, achieving adequate service delivery with less spectral resource consumption

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4297524A1Methods and apparatus to set MRB configuration for UE to receive MBS multicast in RRC inactive state
Publication Date: 2023.12.27 MEDIATEK SINGAPORE PTE LTD
  • EP4297524A1 patent drawingFigure 1
  • EP4297524A1 patent drawingFigure 2A~2B
  • EP4297524A1 patent drawingFigure 3~5

AI summary

Apparatus and methods are provided for the UE to receive multicast transmission in RRC INACTIVE state. In one embodiment, the UE joins a multicast session (1001), receives a MRB configuration for a multicast service (1002), establishes an MRB for reception of the multicast service in the RRC INACTIVE state (1003), and receives data transmission of the multicast service with the established MRB in the RRC INACTIVE state (1004). In one embodiment, the UE stores the MRB configuration in the buffer when the multicast session has not started when the MRB configuration is received. In one embodiment, the UE receives a notification for the multicast session start in the RRC INACTIVE state and establishes the MRB based on the stored MRB configuration. In one embodiment, the UE, in the INACTIVE state, updates the multicast resource/MTCH information based on one or more predefined conditions.