Inactive-State Multicast Reception Using Dual MRB Configuration
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Solution Overview
Problem
Existing wireless communication systems face challenges in supporting multicast reception for user equipment (UE) in an inactive state, particularly for Mission Critical Services, as maintaining the RRC_CONNECTED state is not power efficient and does not fully meet the requirements for UEs with a large number of users.
Innovation Solution
A method is implemented in the radio access network (RAN) to provide different multicast configurations for UEs in connected and inactive states, including transmitting multicast configurations and data using MBS radio bearers (MRBs) to enable multicast reception in the inactive state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE maintains RRC_CONNECTED state to receive multicast services, then multicast reception capability is ensured, but power consumption increases and scalability deteriorates
Solution Approach 1:
The patent implements dynamic state transitions for the UE, allowing it to switch between RRC_CONNECTED and RRC_INACTIVE states based on multicast service requirements. The UE can be configured with specific parameters (such as monitoring occasions, frequency resources, and PDCCH configurations) that enable it to dynamically receive multicast traffic indicators and data while in the inactive state, thus adapting its reception behavior to actual service needs without maintaining continuous connection.
Solution Approach 2:
The patent extracts the essential multicast reception functionality from the full RRC_CONNECTED state by implementing a simplified reception mechanism in the inactive state. The UE receives only necessary multicast control information (MCCH, PDCCH with group RNTI) and data (PDSCH) without maintaining the complete set of connected state functions, thereby reducing power consumption while preserving core multicast reception capability.
2Reliability
If the UE maintains RRC_CONNECTED state to receive multicast services, then multicast reception capability is ensured, but system scalability deteriorates for large numbers of users
Solution Approach 1:
The patent implements dynamic state transitions for the UE, allowing it to switch between RRC_CONNECTED and RRC_INACTIVE states based on multicast service requirements. The UE can be configured with specific parameters (such as monitoring occasions, frequency resources, and PDCCH configurations) that enable it to dynamically receive multicast traffic indicators and data while in the inactive state, thus adapting its reception behavior to actual service needs without maintaining continuous connection.
Solution Approach 2:
The patent creates a universal multicast reception mechanism that works across multiple UE states (both connected and inactive). By defining standardized configurations for inactive state reception including PDCCH monitoring with group RNTI, MCCH indication handling, and PDSCH reception procedures, the system provides consistent multicast service delivery to large numbers of UEs regardless of their RRC state, thereby improving scalability.
3Use of energy by moving object
If the UE transitions to RRC_INACTIVE state to save power, then power consumption decreases, but multicast reception capability is lost
Solution Approach 1:
The patent applies preliminary action by configuring the UE with all necessary multicast reception parameters before transitioning to the inactive state. The network provides the UE with pre-configured PDCCH monitoring occasions, frequency resources, group RNTI values, and PDSCH reception parameters while the UE is still in connected state. This preliminary configuration enables the UE to immediately resume multicast reception without interruption after state transition, ensuring capability continuity while achieving power savings.
Solution Approach 2:
The patent introduces the RRC_INACTIVE state as an intermediary state between fully connected and completely idle states. In this intermediate state, the UE maintains minimal context (multicast configuration parameters) and can be paged or triggered to receive multicast data, providing a middle ground that balances power consumption and reception capability. The inactive state acts as a mediator that preserves essential multicast functionality while reducing power usage compared to continuous connected state.
Data Source
AI summary
A radio access network (RAN) participating in a multicast and broadcast services (MBS) session can implement a method for managing MBS communication. The method includes: (a) transmitting, to a UE operating in a connected state, a first multicast configuration including a first MBS radio bearer (MRB) configuration, for receiving MBS data in the connected state; (b) transmitting first MBS data to the UE operating in the connected state, according to the first multicast configuration; (c) transmitting, to the UE, a second multicast configuration including a second MRB configuration, for receiving MBS data in an inactive state; and (d) transmitting second MBS data to the UE operating in the inactive state, according to the second MRB configuration.