L1/L2 Mobility Cell Switching with Pre-configured Fallback
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Solution Overview
Problem
Existing standards for L1/L2-triggered mobility (LTM) in wireless communication systems lack specific methods for recovering the RRC connection when a cell switch fails, particularly in terms of security measures.
Innovation Solution
A wireless communication system and devices that include mechanisms for switching serving cells to designated candidates or performing RRC reestablishment procedures using alternative configurations when cell change fails, ensuring efficient recovery processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If L1/L2-triggered mobility is implemented to reduce latency in cell switching, then mobility speed is improved, but the reliability of RRC connection recovery deteriorates due to lack of standardized recovery methods
Solution Approach 1:
The base station pre-configures multiple candidate cells (first cell and second cell) and their corresponding configurations (first configuration and second configuration) before mobility is needed. When cell switching is triggered, the terminal device can immediately switch to a pre-configured candidate cell without waiting for additional signaling, thus reducing latency while ensuring reliable recovery through pre-established configurations
Solution Approach 2:
The system prepares multiple fallback options (first cell with first configuration, second cell with second configuration) in advance to cushion against potential switching failures. If the primary switching target fails, the terminal device can immediately attempt switching to the alternative pre-configured cell, ensuring continuous connectivity and maintaining RRC connection reliability
2Productivity
If multiple candidate cells are configured for fast mobility switching, then mobility efficiency is improved, but the device complexity increases due to multiple configuration management requirements
Solution Approach 1:
The mobility configuration is segmented into separate, independent candidate cell configurations (first cell with first configuration, second cell with second configuration). Each candidate cell maintains its own独立的 configuration set, allowing the terminal device to manage them as discrete units. This segmentation simplifies the complexity by avoiding the need to manage a single complex unified configuration across multiple cells
Solution Approach 2:
The system uses configuration copying where the second configuration is derived from or similar to the first configuration structure. This allows the terminal device to reuse configuration templates and patterns across multiple candidate cells, reducing the cognitive load and processing complexity of managing multiple configurations while maintaining mobility efficiency
Data Source
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AI summary
A terminal device comprising: a reception unit that receives, from a base station device, a first signal including change destination information that designates first and second cells as cell change destination candidates and a second signal including information related to a cell change; and a switching unit that performs first processing of switching a serving cell from a third cell to the first cell in accordance with the information related to the cell change included in the second signal, wherein the switching unit performs second processing in a case where the first processing fails, in the second processing, when the second cell is selected as a change destination cell, a second configuration applied to the second cell is generated, and the serving cell is switched to the second cell by using the second configuration, and when a cell other than the cell change destination candidates included in the first signal is selected as the change destination cell, a first RRC connection reestablishment procedure is performed by using a third configuration applied to the third cell.