UE SCG Failure Handling via Transaction ID Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE wireless communication networks, during Secondary Cell Group (SCG) failure handling, there are issues with determining the last valid UE configuration and coordinating SCG reconfiguration, leading to potential race conditions and unnecessary reconfigurations, especially when SCG failure occurs during ongoing reconfiguration.
Innovation Solution
The proposed solution involves mechanisms for the UE and MN to handle SCG failures by suspending actions, performing reconfigurations based on specific conditions, and using mobility flags to determine whether to resume or ignore SCG link configurations, ensuring synchronized RAN RRC context and efficient delta signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the UE and network nodes handle SCG failure independently without coordination, then each node can process failure autonomously, but race conditions occur during SCG reconfiguration leading to configuration inconsistencies
Solution Approach 1:
The UE determines the transaction ID of the last received SCG reconfiguration message before suspending SCG actions upon failure detection. This preliminary identification of the valid configuration state prevents race conditions by establishing a clear reference point for subsequent failure recovery operations, ensuring both UE and network nodes coordinate around the same configuration version.
Solution Approach 2:
The UE provides feedback to the network node by reporting the transaction ID of the last valid SCG reconfiguration in the failure indication message. This feedback mechanism enables the network node to synchronize its state with the UE, allowing the network to determine whether to resume or ignore SCG actions based on the reported configuration state, thereby preventing configuration inconsistencies.
2Speed
If the UE resumes SCG actions immediately after failure detection, then connectivity recovery is faster, but unnecessary reconfigurations occur due to race conditions with ongoing network reconfiguration
Solution Approach 1:
The UE performs preliminary determination of the last valid SCG reconfiguration transaction ID before resuming actions. By identifying the configuration state in advance and communicating it to the network, the UE enables the network to make an informed decision about whether resumption is necessary, avoiding unnecessary reconfiguration signaling while maintaining fast recovery when appropriate.
Solution Approach 2:
The network node uses the feedback transaction ID from the UE to determine whether SCG actions should be resumed or ignored. This feedback-driven decision mechanism prevents unnecessary reconfigurations by allowing the network to recognize when the UE is already operating with a valid configuration, thereby reducing signaling overhead and energy consumption.
3Adaptability or versatility
If the network node sends SCG reconfiguration messages during ongoing reconfiguration, then configuration updates can be applied, but race conditions arise when SCG failure occurs during message transmission
Solution Approach 1:
The network node determines the transaction ID of the last sent SCG reconfiguration message before processing failure indication. This preliminary identification allows the network to track which configuration it has sent and compare it with the UE's reported state, ensuring coordinated reconfiguration even when failures occur during ongoing updates.
Solution Approach 2:
The UE's feedback of its last valid configuration transaction ID enables the network node to synchronize its reconfiguration state with the UE. The network can compare the reported transaction ID with its own sent messages to determine whether to continue or abort reconfiguration, preventing race conditions while maintaining the ability to apply configuration updates when successful.
Data Source
AI summary
A method performed by a user equipment, UE, for handling communication in a wireless communication network, providing dual connectivity, DC, communication through a master node using a master cell group, MCG, over a first radio interface between the UE and the master node and through a secondary node using a secondary cell group, SCG, over a second radio interface between the UE and the secondary node. The UE detects a failure associated with the SCG and suspends actions associated with the SCG. The UE further performs a reconfiguration of the SCG in case the UE has received a MCG radio resource control, RRC, message comprising SCG configuration, wherein performing the reconfiguration of SCG comprises applying the reconfiguration; and resuming or not resuming the actions associated with the suspended SCG.