Target Base Station CSG Handover Capability Handling
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Solution Overview
Problem
During RRC connection reestablishment, User Equipment (UE) may incorrectly assume the target cell's CSG handover capability, leading to failed handovers to CSG cells, affecting subscriber service experience due to mismatched CSG handover capabilities between the original and target cells.
Innovation Solution
The target base station obtains the CSG handover capability of the serving cell before RRC connection reestablishment and processes the reestablishment accordingly, ensuring alignment by sending a RRC message to the UE with the correct CSG handover capability, allowing the UE to update its stored information and act accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the UE defaults that the CSG handover capability does not change after RRC connection reestablishment, then the UE can maintain a stable assumption about handover capability, but the UE may incorrectly assume the target cell's CSG handover capability when the target cell's capability differs from the original cell
Solution Approach 1:
The target base station obtains the CSG handover capability of the serving cell before the UE initiates RRC connection reestablishment, and prepares the correct capability information in advance. This preliminary action ensures that when the UE reestablishes connection, it receives accurate capability information immediately, preventing incorrect assumptions while maintaining procedural stability.
Solution Approach 2:
The target base station sends an RRC message to the UE containing the correct CSG handover capability of the target cell after reestablishment. This feedback mechanism allows the UE to update its stored capability information, ensuring that the UE's assumption aligns with the actual network capability, thus resolving the contradiction between stability and accuracy.
2Ease of operation
If the UE sends a message 1 to the target cell based on the original CSGinboundindication, then the UE can maintain consistent behavior with its original assumption, but the handover may fail if the target cell does not enable CSG handover
Solution Approach 1:
The target base station provides feedback to the UE through an RRC message indicating whether CSG handover is enabled at the target cell. This feedback allows the UE to adjust its behavior accordingly - sending message 1 only when appropriate - thus maintaining operational simplicity while ensuring handover success.
Solution Approach 2:
The target base station determines and communicates the CSG handover capability before the UE attempts handover. This preliminary clarification of capability status prevents the UE from making incorrect handover attempts, ensuring that message 1 is only sent when the target cell actually supports CSG handover.
3Reliability
If the target base station sends measurement configuration to the UE for CSG cell frequency, then the UE can perform proper measurements and reporting, but the network signaling overhead increases
Solution Approach 1:
The target base station sends the measurement configuration for CSG cell frequency in the initial RRC message after reestablishment, rather than waiting for subsequent interactions. This preliminary configuration ensures the UE can immediately perform accurate measurements and reporting when needed, without requiring additional signaling exchanges later.
Data Source
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AI summary
The present invention discloses a method for processing handover capability and a base station, wherein the method includes: before the Radio network Resource Control Re-establishment (RRC) is initiated in User Equipment (UE), a target base station of a target cell of the UE obtains Closed Subscriber Group (CSG) handover capability of the serving cell from the serving base station; when the RRC connection is in reestablishment, the target base station of the target cell processes the RRC connection reestablishment according to the obtained CSG handover capability. The present invention enables the behavior in UE and in the network keep in alignment after the UE finishes RRC connection reestablishment in the target cell while before it receives the first RRC connection reconfiguration message which is transmitted by the target cell.