PT-RS Insertion Pattern for Phase Tracking Window Effect
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, particularly in 5G NR, phase tracking reference signals (PT-RS) face challenges when received in connection with Inverse Discrete Fourier Transform (IDFT), leading to errors and uncertainty due to a 'window effect' where the first and last samples in the phase error trajectory converge, causing inaccuracies in phase estimation.
Innovation Solution
The solution involves inserting PT-RS into data transmission at locations less affected by the window effect, such as avoiding the beginning and end samples, and using a pattern that minimizes the impact of the circulant structure at the receiver, thereby reducing uncertainty and errors in phase trajectory estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PT-RS samples are inserted before DFT operation at the transmitter, then phase tracking is enabled, but a window effect occurs at the receiver causing first and last samples to converge and leading to phase estimation errors
Solution Approach 1:
The patent applies local quality by differentiating the treatment of PT-RS samples based on their position in the sequence. Samples at the beginning and end (which suffer from window effect convergence) are identified and treated differently from intermediate samples. The receiver performs phase error estimation using only samples from the second to second-to-last positions, excluding the problematic first and last samples that exhibit convergence due to the circulant structure of IDFT output.
2Ease of operation
If the receiver applies IDFT to received signal, then received symbols are determined, but the circulant structure causes forced convergence of first and last samples in phase error trajectory
Solution Approach 1:
The patent applies the taking out principle by extracting and excluding the problematic first and last samples from the phase error estimation process. The receiver identifies samples subject to window effect (first and last samples) and removes them from the set of samples used for phase error estimation, using only the intermediate samples that are not affected by the circulant structure convergence.
3Quantity of substance
If PT-RS is inserted at beginning and end samples, then complete phase coverage is achieved, but uncertainty and errors increase due to window effect
Solution Approach 1:
The patent applies inversion by reversing the conventional approach of using all available samples for phase estimation. Instead of including all PT-RS samples (first to last), the method inverts the selection criterion to exclude the first and last samples, using only the intermediate samples (second to second-to-last) that are not subject to window effect convergence, thereby improving reliability despite reduced sample count.
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
At a receiver, errors may occur in estimating phase trajectory based on PT-RS due to a window effect. In order to address the problem of such errors, a transmitter determines at least one location for inserting PT-RS samples into a sequence of a plurality of samples, wherein a first set of the samples comprises a first number of samples at a beginning of the sequence and/or a second number of samples at an end of the sequence, and wherein the at least one location for the PT-RS samples is within a second set of the plurality of samples. The apparatus inserts the PT-RS samples into the sequence based on the determined at least one location and transmits a signal based on the inserted PT-RS samples. A receiver extracts the PT-RS samples and estimates phase errors for data samples in the received transmission based on the extracted PT-RS samples.