RRC Inactive MBS Reception for Low-Power Multicast Delivery

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Solution Overview

Problem

Existing multicast and broadcast services (MBS) in the RRC connected state are not power efficient and may not meet the requirements for mission-critical services in cells with a large number of UEs, necessitating enhancements for MBS operations in the RRC inactive state to improve resource efficiency and support lower power operations.

Innovation Solution

Mechanisms for UEs to directly receive MBS data in the RRC inactive state through dedicated or broadcast signaling, including MBS session configuration and activation/deactivation notifications, enabling MBS reception while transitioning to and maintaining the RRC inactive state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If MBS is deployed for the RRC connected state, then MBS services can be delivered, but power efficiency is poor and resource efficiency is low

Engineering Contradiction:

Improvepower efficiencyVSAvoidservice delivery capability

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent enables MBS reception in both RRC connected and inactive states, allowing the UE to dynamically transition between states based on service requirements. The UE can receive MBS data in the inactive state when power efficiency is prioritized, and switch to connected state when full service functionality is needed, creating a dynamic adaptation mechanism that resolves the contradiction between power efficiency and service delivery capability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of MBS reception by enabling it in the RRC inactive state with reduced monitoring requirements. By adjusting the reception parameters (e.g., monitoring only PDCCH for MBS activation/deactivation rather than full connected-state monitoring), the system achieves better power efficiency while maintaining essential service delivery capabilities

Inventive Principle:

Principle #35Parameter changes

2Productivity

If MBS operations are enhanced for the RRC inactive state, then resource efficiency improves and lower power operations are supported, but device complexity increases

Engineering Contradiction:

Improveresource efficiencyVSAvoidMBS operation complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential MBS reception functionality needed for the inactive state, rather than implementing the full connected-state MBS protocol stack. The UE in inactive state monitors only specific downlink channels (PDCCH for activation notifications, PDSCH for MBS data) without full RRC connection maintenance, reducing complexity while preserving core resource efficiency benefits

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments MBS reception into different operational modes: full-featured reception in connected state and simplified reception in inactive state. This segmentation allows the system to apply appropriate complexity levels based on the operational context, improving resource efficiency in inactive state without requiring the entire MBS infrastructure to be simplified

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If MBS session configuration is received before or after configuring RRC inactive state, then MBS data reception is enabled, but signaling overhead increases

Engineering Contradiction:

ImproveMBS reception flexibilityVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent allows MBS session configuration to be received in advance while the UE is in RRC connected state, before transitioning to inactive state. This preliminary configuration enables the UE to immediately receive MBS data upon entering inactive state without requiring additional signaling during the transition, reducing overall signaling overhead while maintaining flexibility

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent designs the MBS session configuration mechanism to serve multiple purposes: it can be received during connected state for pre-configuration, during inactive state for activation, and works with both dedicated and broadcast signaling methods. This multi-functional approach reduces the need for separate signaling mechanisms for different scenarios, optimizing the balance between adaptability and signaling overhead

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250386289A1Multicast MBS reception in the RRC inactive state

Publication Date: 2025.12.18 APPLE INC

AI summary

Techniques discussed herein can facilitate multicast and broadcast services (MBS) in the radio resource control (RRC) inactive state. One example aspect is a baseband processor of a user equipment (UE), including one or more processors configured to receive a suspend configuration in a radio resource control (RRC) message. The one or more processors further configure the UE for a RRC inactive state based on the suspend configuration and receive a multicast and broadcast services (MBS) session configuration before or after configuring the RRC inactive state. The one or more processors further configure multicast MBS reception based on the MBS session configuration; and receive multicast MBS data based on the MBS session configuration while the UE is configured for the RRC inactive state.