L1/L2 Triggered Mobility for Low-Interruption Cell Handover
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Solution Overview
Problem
Existing wireless communication systems face challenges in reducing mobility interruption time and improving robustness during handovers between cells, particularly in complex user equipment scenarios with increasing data demands and reliability requirements.
Innovation Solution
Implementing Layer 1 and Layer 2 signaling for triggered mobility (L1/L2 mobility) that includes configuration messages for candidate cells, measurement reports, and cell switch commands to facilitate seamless handovers with reduced latency and overhead, utilizing common and delta configurations for efficient cell transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures are used, then mobility between cells is supported, but mobility interruption time increases and robustness decreases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple candidate cells with complete cell group configurations before handover is needed. The UE receives and stores configuration messages for candidate cells in advance, so when handover is triggered, the transition can occur immediately without waiting for configuration setup, thereby reducing mobility interruption time while ensuring robustness through pre-validated configurations
Solution Approach 2:
The patent implements dynamics by enabling the UE to dynamically select among multiple pre-configured candidate cells based on real-time measurements and conditions. The handover target is not fixed but can be dynamically chosen from a set of candidates, allowing the system to adapt to changing radio conditions and optimize both interruption time and robustness based on current state
2Reliability
If detailed configurations are provided for each candidate cell, then handover robustness improves, but signaling overhead increases
Solution Approach 1:
The patent applies copying by having the network provide complete cell group configuration messages for candidate cells that can be stored and reused. Instead of re-negotiating configurations during handover, the UE copies and applies pre-configured settings from candidate cell configurations, reducing signaling overhead while maintaining robustness through comprehensive configuration details
Solution Approach 2:
The patent implements universality by designing configuration messages that can serve multiple purposes: they configure candidate cells for future handover, provide measurement criteria, and establish parameter sets that can be applied across different handover scenarios. This multi-functional configuration approach reduces overall signaling overhead while ensuring robust handover execution
Data Source
AI summary
In wireless communication, a device may change, add, or handover between cells of network access for inter-cell mobility. This may include Layer 1 and/or Layer 2 (L1/L2) signaling for a user equipment (UE) moving between cells in a network. There may be a configuration message that includes configurations for one or more Layer 1 (“L1”) or Layer 2 (“L2”) Triggered Mobility (“LTM”) candidate cells. A measurement report with L1 measurements for the LTM candidate cells is used for a cell switch command to indicate a target LTM candidate cell to trigger execution of a LTM cell switch to the target LTM candidate cell. The LTM cell switch is from a source cell to the target LTM candidate cell.