Multi-TRP Uplink Timing Advance via RAR TA Command Fields
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Solution Overview
Problem
In uplink transmission scenarios of intra-cell and inter-cell multiple Transmission Reception Points (TRPs), the acquisition of Timing Advance (TA) values is challenging due to conflicts between network nodes' commands and the Quality of Channel Linkage (QCL) of Random Access Responses (RARs).
Innovation Solution
A terminal device determines TA values based on multiple TA command fields in the RAR, utilizing CSI-RS indices and TCI states to optimize uplink transmission by aligning with the correct network nodes, resolving conflicts with QCL.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device uses the activated TCI state of the CORESET where the PDCCH order is located for receive beamforming to receive the PDCCH order, then the terminal device can properly receive the PDCCH order from the second network node, but the PDCCH order conflicts with the QCL of the RAR sent by the first network node
Solution Approach 1:
The patent segments the beam management process by introducing separate TCI state applications: one for receiving PDCCH orders (from second network node) and another for receiving RARs (from first network node). This segmentation allows independent optimization of each reception path, resolving the conflict between PDCCH order reception reliability and QCL compatibility.
Solution Approach 2:
The patent introduces the concept of separate CORESETs and their associated TCI states as intermediaries between the terminal device and multiple network nodes. By using different CORESETs with different QCL assumptions for different purposes (PDCCH order reception vs. RAR reception), the system mediates the conflict between different beam requirements.
2Productivity
If the terminal device sends the PRACH using the CSI-RS index or ID of downlink TCI state or ID of joint TCI state indicated in the PDCCH order, then the terminal device can optimize PRACH transmission to the second network node, but the PRACH conflicts with the QCL of the RAR sent by the first network node
Solution Approach 1:
The patent applies local quality by allowing different QCL assumptions for different uplink transmissions. Specifically, PRACH transmission uses the QCL indication from the PDCCH order (CSI-RS index or TCI state ID) when targeting the second network node, while RAR reception uses the QCL of the first network node. This localized adaptation resolves the conflict between transmission efficiency and QCL compatibility.
3Adaptability or versatility
If the RAR includes m TA command fields for m TAGs, then the terminal device can acquire TA values for multiple TRPs, but the device complexity increases
Solution Approach 1:
The patent segments the TA management by introducing multiple TAGs (Timing Advance Groups), where each TAG is associated with a specific TRP and has its own TA command field in the RAR. This segmentation allows independent TA management for each TRP, enabling multi-TRP support while maintaining organized and manageable complexity through structured grouping.
Data Source
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AI summary
Provided in the embodiments of the present application are wireless communication methods and a device. On the basis of m TA command fields in an RAR, a terminal device can determine TA values corresponding to m TAGs, so as to acquire the TA values in an intra-cell multi-TRP and inter-cell multi-TRP uplink transmission scenario, thereby optimizing uplink transmission in the multi-TRP scenario. A wireless communication method comprises: a terminal device sends a PRACH; and the terminal device receives an RAR, wherein the RAR comprises m TA command fields, the m TA command fields are respectively used for indicating TA values corresponding to m TAGs, m is a positive integer, and m=1 or m≥2.