PT-RS Subcarrier Mapping for Interference Suppression
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Solution Overview
Problem
Existing communication systems, particularly in the context of New Radio Access Technology (New RAT), face challenges in suppressing interference between phase tracking reference signals (PT-RSs) transmitted from multiple base stations or mobile stations, which affects error rate characteristics due to common-phase error (CPE) and inter-carrier interference (ICI).
Innovation Solution
A transmitter and receiver system that maps phase tracking reference signals onto different subcarriers for each cell, group, or mobile station, and employs frequency hopping and hopping offsets determined by cell, group, or mobile station identifiers, or higher layer signaling, to minimize collisions and interference between PT-RSs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If phase tracking reference signals are transmitted from multiple base stations or mobile stations using the same subcarrier, then the system can maintain simplicity in signal mapping, but interference between PT-RSs occurs leading to deteriorated error rate characteristics
Solution Approach 1:
The patent segments the frequency resources by assigning different subcarriers to PT-RS from different base stations or mobile stations. This segmentation is achieved through frequency division multiplexing where each transmitter is allocated specific subcarrier indices, thereby preventing interference while maintaining systematic mapping procedures
Solution Approach 2:
The patent introduces frequency domain differentiation as an additional dimension for resource allocation. By varying the subcarrier index dimension for PT-RS from different transmitters, the system resolves interference issues without complicating the time or code domain mapping structures
2Reliability
If phase tracking reference signals are mapped onto different subcarriers for each cell, group, or mobile station, then interference between PT-RSs is suppressed, but the system complexity increases due to additional mapping parameters
Solution Approach 1:
The patent changes the subcarrier index parameter based on transmitter identity (cell ID, group ID, or mobile station ID). This parameter change is systematically defined through formulas that map transmitter identifiers to specific subcarrier offsets, achieving interference suppression through controlled parameter variation rather than arbitrary assignment
Solution Approach 2:
The patent creates a universal mapping mechanism that works across multiple transmitters using a standardized approach. The same subcarrier allocation formulas and offset calculations apply universally to all base stations and mobile stations in the system, reducing the need for transmitter-specific customization despite the increased parameter set
Data Source
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AI summary
In a transmitter, an assignment circuit maps a phase tracking reference signal (PT-RS) onto a subcarrier, and a transmitting circuit transmits a signal containing the phase tracking reference signal. The phase tracking reference signal is mapped onto a different subcarrier for each cell, group, or mobile station.