Multi-TRP Timing Advance Groups for Reliable PUSCH Repetition
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately adjusting uplink timing and maintaining downlink synchronization when user equipment (UE) communicates with multiple non-co-located transmission-reception points (TRPs), leading to unreliable uplink control channels, inefficient spectrum use, and inaccurate channel state information acquisition.
Innovation Solution
Configuring separate timing advance groups (TAGs) and resource groups (RGs) for different TRPs, allowing the UE to apply distinct timing advances and maintain multiple downlink tracking loops, and utilizing inter-cell M-TRP communications to enhance radio resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single timing advance is used for communication with multiple non-co-located TRPs, then the system complexity is reduced, but the uplink timing accuracy deteriorates leading to unreliable uplink control channels
Solution Approach 1:
The patent segments the timing advance configuration by introducing separate Timing Advance Groups (TAGs), where each TAG contains one or more TRPs and is assigned a specific timing advance value. This allows different timing advances to be applied to different groups of TRPs, resolving the timing accuracy issue while maintaining manageable system complexity through structured organization.
Solution Approach 2:
The patent applies local quality by configuring timing advances locally for each TAG rather than globally for all TRPs. Each TAG can have its own timing advance value optimized for the specific geometric relationship between the UE and the TRPs in that group, improving uplink timing accuracy for each local group while avoiding the complexity of individual TRP configuration.
2Measurement precision
If separate timing advance groups are configured for different TRPs, then uplink timing accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent segments TRPs into discrete TAGs with hierarchical structure, where each TAG is a manageable unit containing one or more TRPs. This segmentation allows the UE to handle multiple TRPs through organized groups rather than individual configurations, improving timing precision while controlling complexity through the TAG abstraction layer.
Solution Approach 2:
The TAG structure serves multiple functions: it groups TRPs for timing purposes, provides a hierarchical organization level between individual TRPs and the UE, and enables flexible configuration where TRPs can be dynamically assigned to different TAGs. This multi-functionality reduces overall system complexity while maintaining timing accuracy.
3Reliability
If multiple downlink tracking loops are maintained for different TRPs, then downlink synchronization reliability is improved, but the processing complexity increases
Solution Approach 1:
The patent segments downlink tracking operations by associating each TAG with its own downlink tracking loop. This segmentation allows the UE to maintain multiple tracking loops in an organized manner, improving downlink synchronization reliability for each TRP group while managing processing complexity through the TAG hierarchical structure.
Solution Approach 2:
The patent applies local quality by configuring downlink tracking parameters locally for each TAG rather than using a global tracking configuration. Each TAG can have its own tracking loop with parameters optimized for the specific TRP group, improving synchronization reliability for each local group while avoiding the complexity of individual TRP tracking configurations.
4Productivity
If inter-cell M-TRP communications are utilized, then spectral efficiency is improved, but the difficulty of detecting and measuring channel state information increases
Solution Approach 1:
The patent segments channel state information measurement and reporting by TAG, allowing the UE to measure and report CSI separately for each TAG. This segmentation simplifies the complex task of measuring inter-cell M-TRP channels by breaking it down into manageable TAG-specific measurements, improving CSI acquisition accuracy while enabling efficient utilization of inter-cell M-TRP resources for enhanced spectral efficiency.
Data Source
AI summary
A UE may receive information indicating a layer number and a first transmit precoding matrix index (TPMI) to be used for a first physical uplink shared channel (PUSCH). The UE may also receive information indicating a second TPMI to be used for a second PUSCH. The first TPMI and the second TPMI correspond to the layer number. The UE may transmit data on the first PUSCH over a carrier according to the layer number and the first TPMI, transmit the same data on the second PUSCH over the carrier according to the layer number and the second TPMI, for PUSCH repetition transmissions.