L1/L2 Inter-Cell Mobility Configuration from UE Measurement Reports
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently configuring Layer 1 (L1)/Layer 2 (L2) mobility during cell changes, leading to longer latency, higher overhead, and longer interruption times due to incomplete understanding of criteria for determining L1/L2 mobility candidates and unclear CU-DU interaction in RAN split architectures.
Innovation Solution
The solution involves configuring L1/L2 inter-cell mobility based on Measurement Reports received from the UE, with the CU and DU interacting to determine and set up L1/L2 mobility candidates, ensuring that the configuration does not exceed UE capabilities and includes necessary CSI measurements, using RRC Reconfiguration messages to manage cell changes efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If L3 measurements and RRC signalling are used to trigger serving cell change, then mobility reliability is improved, but latency and interruption time increase
Solution Approach 1:
The patent segments the mobility management into two parts: L1/L2 measurements and reporting for fast detection, and L3 RRC signalling for final decision-making. This segmentation allows the system to benefit from both fast measurement capabilities and reliable control signalling, reducing overall latency while maintaining mobility reliability.
Solution Approach 2:
The patent implements preliminary action by configuring multiple candidate cells in advance using RRC signalling before mobility is needed. When mobility is triggered, the UE can quickly switch to a pre-configured candidate cell without waiting for full RRC reconfiguration, thereby reducing interruption time while maintaining reliability through pre-validated candidate cells.
2Reliability
If complete L2 and L1 resets are performed during serving cell change, then mobility reliability is improved, but overhead and interruption time increase
Solution Approach 1:
The patent applies partial action by performing only necessary L1/L2 resets rather than complete resets during serving cell change. By selectively resetting only the minimal required layers and functions, the patent reduces overhead and interruption time while maintaining sufficient mobility reliability through targeted reset operations.
3Adaptability or versatility
If multiple L1/L2 mobility candidates are configured beyond UE capability, then network flexibility is improved, but UE configuration complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the UE reports its capability limitations to the network. The network uses this feedback to appropriately limit the number of L1/L2 mobility candidates configured for each UE, ensuring that network flexibility is maintained within practical constraints and UE configuration complexity is managed through capability-aware configuration.
Data Source
AI summary
A method (1300) by a user equipment, UE (402, 502, 602, 800), in a connected state is provided for configuring Layer 1/Layer 2, L1/L2, based inter-cell mobility. The method includes transmitting (1302) a Measurement Report comprising one or more measurements associated with one or more cells. The UE receives (1304) a Radio Resource Control, RRC, Reconfiguration message comprising at least one configuration of a L1/L2 based inter-cell mobility candidate cell. The UE transmits (1306) an RRC Reconfiguration Complete message.