Cell Switching Commands Combining Beam and Timing Advance Signaling
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing inter-cell beam information and timing advance (TA) for Layer 1/Layer 2 mobility (LTM) operations, leading to increased signaling overhead and complexity, particularly in scenarios requiring high mobility robustness and low latency.
Innovation Solution
The proposed solution involves constructing cell switching commands using a combination of scheduling DCI and MAC-CE formats to provide beam information and TA management, including shared TCI state lists and TAG configurations, which reduce signaling overhead and enhance mobility efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional separate signaling methods are used for beam information and TA management, then complete information can be transmitted, but signaling overhead increases
Solution Approach 1:
The patent combines beam information (TCI states) and timing advance (TA) management into a single MAC CE message structure. The MAC CE includes both TCI state IDs for beam information and TA offset values for timing management, eliminating the need for separate signaling messages and reducing overall signaling overhead while maintaining complete information transmission.
Solution Approach 2:
The MAC CE message structure is designed to serve multiple functions simultaneously: it conveys beam information through TCI state IDs, provides timing advance management through TA offset values, and supports both active and dormant TCI states. This multi-functional approach replaces multiple specialized messages with a single versatile signaling structure.
2Measurement precision
If detailed beam information is provided for each candidate cell, then handover accuracy improves, but device complexity increases
Solution Approach 1:
The network pre-configures TCI state lists and associates them with candidate cells before handover execution. The MAC CE message then efficiently activates specific TCI states and provides TA offsets for the target cell, allowing the UE to perform accurate handovers with reduced processing complexity since the detailed beam information structure is already established in advance.
3Measurement precision
If separate TA management is implemented for each candidate cell, then timing accuracy improves, but signaling overhead increases
Solution Approach 1:
The patent integrates TA offset values directly into the MAC CE message that also carries beam information. This combined approach allows the network to provide precise TA management for candidate cells while avoiding the overhead of separate TA signaling messages, as the TA information is transmitted together with the beam information in a single unified message structure.
Data Source
AI summary
Systems and methods for signaling of Layer 1 (L1)/Layer 2 (L2) triggered mobility and timing management for wireless communications are described herein. In some embodiments, a user equipment (UE) receives a cell switching command as a combination of a downlink control information (DCI) and a medium access control control element (MAC-CE) that corresponds to that DCI. In some embodiments, a same set of transmission configuration indicator (TCI) state IDs is used with respect to all candidate cells of a sub-candidate cell group (CCG) of a configured CCG. In some embodiments, MAC-CEs are used to inform the UE of timing advance (TA) information using timing advance group (TAG)-specific physical cell identity (PCI) indexes for candidate cells of the TAG that correspond to full PCIs for those candidate cells.