RRC-Inactive UE Cell Reselection with Target-Cell MBS Configuration
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining the continuity of multicast and broadcast services for User Equipment (UE) in RRC_INACTIVE state during cell reselection, particularly for MBS multicast, due to the lack of configuration information and network communication, leading to potential data loss and inefficiencies.
Innovation Solution
A method and apparatus for a UE in RRC_INACTIVE state to send a reselection request to a target base station for MBS multicast sessions, receive configuration information, and configure itself to continue receiving data without transitioning to RRC_CONNECTED state, along with a target base station method to provide context and configuration to the UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE transitions to RRC_CONNECTED state to maintain MBS service continuity during cell reselection, then service continuity is improved, but control plane footprint and power consumption increase
Solution Approach 1:
The patent applies preliminary action by having the target base station prepare and store the UE context and MBS configuration information before the UE actually needs to switch cells. The target base station receives and stores the UE context from the source base station in advance, so when cell reselection occurs, the configuration information is already ready to be transmitted to the UE without requiring full RRC connection establishment.
Solution Approach 2:
The patent introduces an intermediary mechanism where the target base station acts as a mediator to transfer UE context and configuration information during cell reselection. Instead of requiring direct UE-to-network connection establishment, the target base station facilitates the transfer of necessary information (UE context, MBS configuration) to enable seamless service continuity while keeping the UE in RRC_INACTIVE state.
2Use of energy by moving object
If UE remains in RRC_INACTIVE state during cell reselection, then power efficiency is improved, but configuration information is lost leading to service disruption
Solution Approach 1:
The target base station performs preliminary action by receiving and storing the UE context information from the source base station before the UE executes cell reselection. This ensures that when the UE switches cells while remaining in RRC_INACTIVE state, the configuration information is already prepared and can be quickly transmitted without requiring the UE to transition to RRC_CONNECTED state.
Solution Approach 2:
The patent implements feedback mechanisms where the target base station sends configuration information (including MBS configuration and UE context) back to the UE during the cell reselection process. This feedback loop ensures that the UE receives all necessary configuration information while remaining in RRC_INACTIVE state, preventing information loss and maintaining service continuity.
3Reliability
If network provides full MBS configuration information during cell reselection, then service continuity is improved, but signaling overhead and processing complexity increase
Solution Approach 1:
The patent extracts only the essential configuration information needed for MBS service continuity from the full UE context. Instead of transferring all possible configuration parameters, the system selectively extracts and transmits only the critical MBS-related configuration information (MBS session configuration, radio bearer configuration) required for service continuity, reducing signaling overhead while maintaining reliability.
Solution Approach 2:
The patent applies local quality by tailoring the configuration information transfer to the specific needs of MBS service continuity. The target base station identifies and transmits only the locally relevant configuration parameters (MBS configuration, radio bearer settings) rather than all possible UE parameters, optimizing the signaling overhead for the specific service continuity requirement.
Data Source
AI summary
A method for supporting cell reselection for a User Equipment, UE, operating in a non-connected RRC state with one or more active data sessions is described. The method at the UE comprises: sending a reselection request message for requesting cell reselection to a new serving cell for receiving the one or more active data sessions from a target base station of the new serving cell; receiving a configuration message including configuration information associated with the target base station for the one or more active data sessions; configuring the UE for receiving data of the one or more active data sessions from the target base station in the new serving cell based on the configuration information. The active data sessions may include one or more Multicast Broadcast Service, MBS, sessions.