RAR TA Field Mapping for Multi-TRP Uplink QCL Conflicts
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Solution Overview
Problem
In uplink transmission scenarios involving 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, TCI state IDs, or joint TCI state IDs to optimize uplink transmission by aligning with the appropriate Timing Advance Groups (TAGs) in multi-TRP scenarios.
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 PDCCH order can be received, but this conflicts with the QCL of the RAR sent by the first network node
Solution Approach 1:
The patent segments the beamforming configuration by introducing separate TCI state indicators for different purposes: one TCI state for receiving the PDCCH order and another TCI state for receiving the RAR. This segmentation allows the terminal device to use different receive beams for different signals, resolving the QCL conflict while maintaining reliable PDCCH order reception.
2Reliability
If the terminal device uses the activated TCI state of the CORESET associated with the type 1 CSS associated with the RAR to receive the PDCCH and PDSCH, then the RAR can be received, but this conflicts with the QCL required for optimal PRACH transmission
Solution Approach 1:
The patent introduces a PDCCH order as an intermediary mechanism that carries TCI state information specifically for PRACH transmission. This intermediary allows the network to provide beamforming and TA information tailored to the PRACH signal, enabling accurate TA value acquisition without being constrained by the RAR's QCL requirements.
3Adaptability or versatility
If multiple TA command fields are included in the RAR to support multi-TRP scenarios, then TA values for multiple TAGs can be acquired, but the complexity of the RAR structure increases
Solution Approach 1:
The patent makes the RAR structure dynamic by allowing the number and configuration of TA command fields to vary based on the specific multi-TRP scenario. The RAR can include one or multiple TA command fields depending on whether single-TRP or multi-TRP operation is required, enabling flexible adaptation without permanently increasing structural complexity.
Data Source
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 includes: 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.