Multicast PTM Configuration Across RRC State Transitions
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining service continuity for multicast-broadcast services during transitions between radio resource control states, particularly when UEs switch from RRC connected mode to RRC inactive mode, due to differences in multicast radio bearer configurations and the lack of explicit MRB ID information in RRC inactive mode configurations.
Innovation Solution
The proposed solution involves maintaining separate PTM configurations for multicast reception in RRC connected and inactive modes, providing MRB ID information in RRC release messages for RRC inactive mode, and ensuring seamless service continuity by using the same or associated MRB IDs across mode transitions, along with appropriate PDCP and RLC entity configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate PTM configurations are maintained for RRC connected and inactive modes, then service continuity is improved, but device complexity increases
Solution Approach 1:
The patent segments the PTM configuration into mode-specific configurations: RRC connected mode PTM configuration and RRC inactive mode PTM configuration. Each configuration is optimized for its specific RRC state, with the inactive mode configuration containing essential parameters (MRB ID, spatial filter, N3IWF address) while the connected mode configuration has full parameters. This segmentation allows service continuity while managing complexity through context preservation across state transitions.
2Reliability
If MRB ID information is provided in RRC release messages, then service continuity is improved, but information security risks increase
Solution Approach 1:
The patent applies local quality by providing MRB ID information selectively based on the UE's RRC state. When transitioning to inactive mode, the RRC release message includes MRB ID information to enable continuous multicast reception. However, when the UE is in connected mode or idle mode, this information is not provided. This targeted approach ensures service continuity when needed while minimizing information exposure and security risks.
3Use of energy by moving object
If the same SDAP entity is used across RRC state transitions, then resource efficiency is improved, but configuration management complexity increases
Solution Approach 1:
The patent applies preliminary action by configuring the SDAP entity with mode-specific PTM configurations before the RRC state transition occurs. The RRC release message pre-configures the inactive mode PTM configuration including MRB ID, spatial filter, and N3IWF address. When the UE transitions to inactive mode, the SDAP entity can immediately use the pre-configured parameters without requiring reconfiguration, enabling seamless service continuity while managing complexity through advance preparation.
Data Source
AI summary
Systems and methods for multicast data traffic service continuity under multicast-broadcast services (MBS) operation during a radio resource control (RRC) state or mode transition are described. In some embodiments, a user equipment (UE) receives, from a network, while in an RRC connected mode, an RRC release message comprising an RRC inactive mode point to multipoint (PTM) configuration that uses an MBS session to receive multicast data traffic while the UE is in an RRC inactive mode; enters the RRC inactive mode from the RRC connected mode in response to the RRC release message; and uses the RRC inactive mode PTM configuration to receive, from the network, the multicast data traffic of the MBS session while the UE is in the RRC inactive mode. Cases where a UE instead re-uses an RRC connected mode PTM configuration after transitioning to the RRC inactive mode are also described. Analogous network behaviors are described.