Multi-TRP Time Alignment for Low-Latency Serving Cell Switching
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing time alignment for multi-Transmission and Reception Points (TRPs) during L1/L2 mobility procedures, leading to increased latency, overhead, and interruption time during serving cell changes.
Innovation Solution
The method involves receiving signaling for cell configuration and time alignment information, switching or adding a cell as a serving cell, and initiating a random access procedure based on provided time alignment information, specifically for multiple Timing Advance Groups (TAGs) to facilitate seamless multi-TRP communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional mobile voice communication networks are evolved into IP data packet communication networks, then communication services are enhanced, but time alignment management complexity increases
Solution Approach 1:
The patent segments time alignment management by introducing separate Timing Advance Groups (TAGs) for different TRPs. Each TAG is independently managed with its own time alignment parameters, allowing the system to handle multiple TRPs without increasing overall management complexity. This segmentation enables independent control of time alignment for each TRP while maintaining overall system coordination.
2Reliability
If multi-TRP communication is implemented, then communication reliability is improved, but latency during serving cell changes increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring time alignment parameters for multiple TRPs before serving cell changes occur. The UE maintains time alignment information for multiple TAGs in advance, so when a serving cell change is needed, the transition can occur more quickly without requiring time-consuming re-synchronization procedures.
3Adaptability or versatility
If multiple Timing Advance Groups are managed, then multi-TRP communication is enabled, but overhead increases
Solution Approach 1:
The patent implements universality by designing the TAG management mechanism to handle both single-TRP and multi-TRP scenarios through the same framework. The time alignment parameters and procedures are generalized to work for any number of TRPs, allowing the system to scale from simple to complex deployments without requiring fundamentally different mechanisms.
4Adaptability or versatility
If time alignment information is transmitted through multiple signaling methods, then flexibility is improved, but processing complexity increases
Solution Approach 1:
The patent uses the MAC layer as an intermediary to manage time alignment information between the physical layer signaling and higher layer processing. The MAC entity receives time alignment parameters from various signaling sources (RRC, DCI) and processes them through standardized procedures, simplifying the overall processing complexity while maintaining flexibility in how time alignment information can be transmitted.
Data Source
AI summary
Methods, systems, and apparatuses are provided for a User Equipment (UE) in a wireless communication system receiving, from a network, a first signaling indicative of cell configuration of a cell, receiving, from the network, a second signaling indicative of switching a Special Cell (SpCell) of the UE to the cell or adding the cell as a serving cell, receiving, from the network, a third signaling indicative of a first time alignment information associated with the first Timing Advance Group (TAG), and in response to the second signaling: (1) switching the SpCell of the UE to the cell or adding the cell as the serving cell, (2) applying the first time alignment information on the first TAG, and (3) initiating a random access procedure on the cell when no time alignment information associated with the second TAG is in the third signaling.