Multicast Reception in RRC Inactive State for Seamless Mobility
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Solution Overview
Problem
Existing 3GPP specifications allow multicast reception only for user equipment (UE) in a radio resource control (RRC) connected state, limiting the flexibility and efficiency of multicast services, particularly in scenarios requiring seamless/lossless mobility.
Innovation Solution
The UE in an RRC inactive state receives configuration information allowing it to perform multicast sessions and measures the quality of service; transitioning to an RRC connected state when the quality of service is not satisfied, enabling handover-based cell switching to maintain seamless/lossless mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If user equipment performs cell reselection in RRC inactive state for multicast reception, then mobility flexibility is improved, but service continuity and quality of service may deteriorate
Solution Approach 1:
The system dynamically controls cell reselection behavior based on RRC state. In RRC inactive state, cell reselection is restricted to maintain service continuity, while in RRC connected state, full cell reselection flexibility is permitted. This dynamic state-dependent control resolves the contradiction by adapting mobility behavior to current connection status.
Solution Approach 2:
The patent changes the parameter of cell reselection permission based on RRC state. The network node configures whether cell reselection is permitted or restricted depending on whether the UE is in connected or inactive state. This parameter change allows the system to optimize between mobility flexibility and service continuity based on actual operational state.
2Reliability
If user equipment transitions to RRC connected state to maintain quality of service, then quality of service is improved, but system resource consumption increases
Solution Approach 1:
The user equipment autonomously monitors the quality of service of the multicast session and independently decides when to transition between RRC states. When QoS deteriorates, the UE automatically transitions to RRC connected state to restore service quality without requiring continuous network intervention, thereby optimizing resource usage while maintaining service reliability.
Solution Approach 2:
The system implements a feedback mechanism where the UE continuously monitors QoS parameters and uses this information to trigger state transitions. The feedback loop ensures that transitions to RRC connected state occur only when necessary to maintain acceptable service quality, avoiding unnecessary resource consumption during periods of satisfactory QoS.
Data Source
AI summary
A communication method used in a mobile communication system for providing a multicast/broadcast service (MBS) includes: receiving, by a user equipment in a radio resource control (RRC) connected state, configuration information from a base station; and receiving, by the user equipment having transitioned from the RRC connected state to an RRC inactive state, a multicast session in a cell of the base station. The configuration information includes an information element indicating whether to permit the user equipment receiving the multicast session in the RRC inactive state to perform cell reselection to another cell.