5G UE Multicast Configuration in RRC Release for Inactive State

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Solution Overview

Problem

Existing 3GPP specifications limit multicast reception in user equipment (UE) to the RRC connected state, which can lead to inefficient resource utilization and increased power consumption when transitioning to RRC inactive state, particularly in 5G NR networks.

Innovation Solution

A communication method and network node implementation that allows UE to transition to RRC inactive state with configuration information for multicast session reception, including PTM configuration, enabling seamless multicast session continuation and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If user equipment transitions to RRC inactive state to save power, then power consumption is reduced, but multicast reception capability is lost

Engineering Contradiction:

Improvepower consumptionVSAvoidmulticast reception capability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The network node provides configuration information for multicast reception in the RRC Release message before the UE transitions to inactive state. This preliminary provision of configuration data enables the UE to resume multicast reception quickly when transitioning back to connected state, avoiding the need to re-acquire configuration information and ensuring seamless multicast service continuity while allowing power-saving inactive state transitions

Inventive Principle:

Principle #10Preliminary action

2Reliability

If user equipment remains in RRC connected state to maintain multicast reception, then multicast reception capability is maintained, but power consumption increases

Engineering Contradiction:

Improvemulticast reception capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically manages RRC state transitions based on multicast service requirements. The network node provides configuration information that enables the UE to flexibly transition between connected and inactive states while maintaining the ability to receive multicast services. This dynamic state management allows the UE to spend more time in low-power inactive state while ensuring multicast reception capability can be rapidly restored when needed

Inventive Principle:

Principle #15Dynamics

3Reliability

If configuration information is provided in RRC Release message, then multicast session continuity is maintained, but message complexity increases

Engineering Contradiction:

Improvemulticast session continuityVSAvoidmessage complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The configuration information for multicast reception is merged into the existing RRC Release message structure. By combining multiple functions (state transition control and multicast configuration provision) into a single message, the solution avoids creating separate signaling procedures and reduces overall message exchange complexity while ensuring multicast session continuity during state transitions

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20260040401A1Communication method, user equipment, network node, non-transitory computer-readable medium, chipset and system

Publication Date: 2026.02.05 KYOCERA CORP

AI summary

A communication method performed by a user equipment in a mobile communication system that provides a multicast/broadcast service (MBS), includes receiving, from a base station, a radio resource control (RRC) Release message that causes the user equipment to transition to an RRC inactive state, the RRC Release message including configuration information used for reception of a multicast session in the RRC inactive state, checking whether the multicast session has been activated, and suspending execution of predetermined processing to start reception of the multicast session when the multicast session has not been activated.