PTRS Density Adjustment for Phase Noise in 5G QCL Systems
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Solution Overview
Problem
In next-generation 5G communication systems, the mismatched frequency oscillators in millimeter wave devices lead to severe phase noise issues, affecting transmission performance due to sparse distribution of phase tracking reference signals (PTRS) across different quasi-co-location (QCL) assumptions in multipoint coordination transmission scenarios.
Innovation Solution
The method involves determining a frequency domain density K based on the quantity of scheduled frequency domain resources to denserly map PTRS across QCL assumptions, ensuring accurate channel estimation by associating PTRS with DMRS ports corresponding to specific QCL assumptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PTRS are mapped using a specific time domain density and frequency domain density based on total frequency domain resources in multipoint coordination transmission, then the system can support multiple stations transmitting the same PDSCH, but the PTRS become sparsely distributed resulting in inaccurate phase estimation
Solution Approach 1:
The patent segments the frequency domain resources by QCL assumption groups, determining PTRS frequency domain density separately for each group rather than using a unified density across all resources. This segmentation allows denser PTRS distribution within each QCL group, improving phase estimation accuracy for each transmission path while maintaining multipoint coordination capability
Solution Approach 2:
The patent applies different PTRS frequency domain densities to different QCL assumption groups based on their specific requirements. Each group receives localized optimization with density tailored to its transmission characteristics, ensuring adequate PTRS distribution for accurate phase estimation in each local context rather than using a uniform global density
2Device complexity
If PTRS frequency domain density is determined based on total scheduled frequency domain resources, then resource allocation is simplified, but PTRS distribution becomes sparse across different QCL assumptions reducing channel estimation accuracy
Solution Approach 1:
The patent divides frequency domain resources into multiple groups based on QCL assumptions and determines PTRS density for each group separately. This segmentation increases precision of channel estimation by ensuring adequate PTRS distribution in each group while managing complexity through systematic grouping and separate density determination for each segment
Data Source
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AI summary
This application provides a reference signal transmission method and an apparatus, used in a multipoint coordination transmission scenario. In the reference signal transmission method, a frequency domain resource that carries a target reference signal in a frequency domain resource or a time domain resource that is associated with each QCL assumption may be separately determined, and then the target reference signal carried on the frequency domain resource that is associated with the QCL assumption is separately received by using the corresponding QCL assumption. Therefore, each QCL assumption can be used to perform channel parameter estimation, and further, a channel parameter estimation result is used to assist a DMRS in performing channel estimation, thereby improving accuracy of channel estimation.