TCI State Update for 5G Serving Cell Change Latency
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Solution Overview
Problem
Current mobility mechanisms in 5G wireless communication systems incur significant latency and interruption time during serving cell changes, which is not suitable for meeting the stringent service requirements of future mobile communication systems.
Innovation Solution
The method involves receiving an RRC reconfiguration message, transmitting a layer 1 measurement report, and applying specific TCI states to a determined cell through a MAC CE, thereby optimizing the TCI state update process during LTM procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If L3 measurements and RRC signalling triggered Reconfiguration with Sync are used for serving cell change, then mobility management is achieved, but latency and interruption time increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-configuring TCI states and performing L1 measurements before the actual cell change is needed. The UE prepares measurement reports and TCI state information in advance, so that when a cell change is triggered, the configuration is already ready to be applied immediately, eliminating the need for time-consuming RRC reconfiguration signaling during the handover process.
Solution Approach 2:
The patent segments the mobility management process into separate functions: L1 measurements for cell evaluation, pre-configured TCI states for rapid switching, and MAC CE for triggering the actual change. This segmentation allows each component to operate independently and efficiently, with the TCI state configuration prepared in advance and only the final switch trigger needed during handover, reducing overall latency.
2Reliability
If complete L2 and L1 resets are performed during serving cell change, then mobility is achieved, but overhead and interruption time increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring TCI states and performing L1 measurements before the actual cell change is needed. The UE prepares measurement reports and TCI state information in advance, so that when a cell change is triggered, the configuration is already ready to be applied immediately, eliminating the need for time-consuming RRC reconfiguration signaling during the handover process.
Solution Approach 2:
The patent extracts the essential mobility function from the complex L2/L1 reset procedure. By isolating the TCI state configuration and L1 measurement components, the system achieves mobility management without requiring complete protocol layer resets, thereby reducing overhead while maintaining the core mobility capability.
3Reliability
If RRC signalling triggered Reconfiguration with Sync is used for serving cell change, then cell change is achieved, but more interruption time is incurred compared to beam switch mobility
Solution Approach 1:
The patent applies preliminary action by pre-configuring TCI states and performing L1 measurements before the actual cell change is needed. The UE prepares measurement reports and TCI state information in advance, so that when a cell change is triggered, the configuration is already ready to be applied immediately, eliminating the need for time-consuming RRC reconfiguration signaling during the handover process.
Solution Approach 2:
The patent introduces dynamic TCI state updates through MAC CE signaling, allowing the system to adapt quickly to changing channel conditions and mobility requirements. This dynamic approach enables faster cell changes compared to static RRC reconfiguration, as the TCI states can be updated and applied rapidly without full protocol layer resets.
Data Source
AI summary
A technique for managing TCI states in conjunction with LTM operations is provided. The technique comprises first updating of activated TCI states for a cell based on a first type TCI state activation/deactivation MAC CE, final updating of TCI states for the cell based on a LTM cell switch command MAC CE and subsequent updating of TCI states for the cell based on a second type TCI state activation/deactivation MAC CE.