5G Multicast Reception in RRC Inactive State

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Solution Overview

Problem

Existing 3GPP specifications only allow user equipment (UE) in an RRC connected state to receive multicast sessions, limiting the efficiency of multicast reception in 5G NR networks.

Innovation Solution

A communication method that enables UE in an RRC inactive state to receive multicast sessions by providing configuration information through dedicated signaling or MCCH scheduling, allowing efficient multicast reception even when the UE is in an inactive state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If user equipment is restricted to RRC connected state for multicast reception, then multicast reception reliability is ensured, but multicast reception flexibility and power efficiency deteriorate

Engineering Contradiction:

Improvemulticast reception reliabilityVSAvoidmulticast reception flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent enables dynamic state transitions for multicast reception by allowing UE to receive multicast data in both RRC connected and RRC inactive states. The network can flexibly configure UE to operate in different RRC states based on service requirements, transitioning from static connected-state-only reception to dynamic multi-state reception, thereby improving both reliability and flexibility

Inventive Principle:

Principle #15Dynamics

2Reliability

If user equipment maintains RRC connected state for multicast reception, then multicast reception quality is maintained, but power consumption increases

Engineering Contradiction:

Improvemulticast reception qualityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic monitoring mechanisms where UE in RRC inactive state can wake up at scheduled intervals to receive multicast data through configured grants or MCCH updates, then return to sleep state. This periodic action pattern maintains reception quality while significantly reducing power consumption compared to continuous connected state monitoring

Inventive Principle:

Principle #19Periodic action

3Manufacturing precision

If configuration information is provided through dedicated signaling, then configuration accuracy is improved, but signaling overhead increases

Engineering Contradiction:

Improveconfiguration accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent segments configuration information into different delivery mechanisms: critical UE-specific parameters are provided through dedicated RRC signaling for high accuracy, while general multicast parameters are broadcast through MCCH for efficiency. This segmentation allows the system to optimize between accuracy and overhead by matching the delivery method to the specific configuration requirements

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250358899A1Communication method

Publication Date: 2025.11.20 KYOCERA CORP

AI summary

A communication method to be used in a mobile communication system providing a Multicast/Broadcast Service (MBS) includes receiving, at a base station, a message including user equipment information and/or session identification information from a network apparatus provided in a core network. The user equipment information indicates a user equipment that has already joined a multicast session and is allowed for multicast reception in a radio resource control (RRC) inactive state. The session identification information indicates a multicast session that allows for reception in the RRC inactive state.