Multi-TRP PT-RS Density by PRB Subset for Phase Tracking
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Solution Overview
Problem
Existing systems face challenges in determining the inverse frequency density for Phase Tracking Reference Signals (PT-RS) in multiple transmission points (mTRP) scenarios, particularly in Frequency Division Multiplexing (FDM) schemes 2a and 2b, leading to suboptimal performance due to phase noise.
Innovation Solution
The method involves determining the PT-RS frequency density based on the number of resource blocks (PRBs) associated with each TCI state in the FDM schemes 2a and 2b, adjusting the inverse frequency density to ensure proper phase tracking for each subset of PRBs, thereby enhancing performance in multi-TRP environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single inverse frequency density is used for all PRBs in mTRP FDM schemes, then the system complexity is reduced, but the phase tracking performance deteriorates due to phase noise in multi-TRP scenarios
Solution Approach 1:
The patent divides the frequency resources into different subsets, each associated with a specific TCI state and transmission point. Each subset has its own inverse frequency density for PT-RS, allowing independent optimization for each TRP's phase characteristics while maintaining overall system functionality
Solution Approach 2:
The patent applies different PT-RS inverse frequency density values to different PRB subsets based on their association with different TCI states. This local differentiation ensures that each transmission point's specific phase noise characteristics are compensated appropriately, improving overall phase tracking performance
2Measurement precision
If the PT-RS frequency density is adjusted for each TCI state, then the phase tracking accuracy is improved, but the signaling overhead and configuration complexity increase
Solution Approach 1:
The patent pre-configures multiple TCI states with their associated inverse frequency density values through higher layer signaling before data transmission. This preliminary configuration allows the UE to directly apply the appropriate parameters without real-time calculation, reducing processing complexity while maintaining accuracy
Solution Approach 2:
The patent introduces a new parameter relationship where the inverse frequency density is determined by the TCI state index rather than being a fixed system-wide value. This parameter change enables flexible adaptation to different transmission scenarios while maintaining a standardized configuration approach
Data Source
AI summary
A method for a UE in a multiple transmission points communication system, mTRP, scheme, is provided. The method includes receiving downlink control information, DCI, indicating at least two transmission points scheme for a scheduled data transmission on physical resource blocks, PRBs. The PRBs includes at least a first subsets of PRBs, associated with a first transmission point, and a second subset of PRBs, associated with a second transmission point. The method further includes determining a first PT-RS frequency density for the first set of PRBs based on the number of PRBs in the first set of PRBs and a second PT-RS frequency density based on the number of PRBs in the second set of PRBs. A UE, methods for a base station and a base station are also provided.