Configurable RSTD Search Window for 5G Positioning Accuracy
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately measuring reference signal time difference (RSTD) for OTDOA and multi-RTT based positioning due to issues like undersampling in the frequency domain, leading to secondary peaks that affect positioning accuracy.
Innovation Solution
Implementing configurable RSTD search windows that allow for precise measurement of RSTD between reference RF signals from multiple network nodes, enhancing positioning accuracy by adjusting the search window parameters to minimize undersampling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If every sixth or every third subcarrier is used for reference signals, then spectral efficiency is improved, but positioning accuracy deteriorates due to secondary peaks from undersampling
Solution Approach 1:
The patent changes the subcarrier spacing parameter to 30 kHz (double the conventional 15 kHz) for reference signals used in positioning measurements. This parameter change increases the frequency domain sampling rate, which eliminates the undersampling effect that causes secondary peaks in the correlation function, thereby resolving the contradiction between spectral efficiency and positioning accuracy
Solution Approach 2:
The patent segments the uplink bandwidth into multiple subcarriers with 30 kHz spacing, creating a finer granularity in frequency domain sampling. This segmentation approach allows for more accurate time delay estimation by reducing the distance between sampling points in the frequency domain, thus eliminating secondary peaks while maintaining spectral efficiency
2Measurement precision
If conventional 15 kHz subcarrier spacing is used, then positioning accuracy is maintained, but spectral efficiency and data transfer speeds are limited
Solution Approach 1:
The patent changes the subcarrier spacing parameter to 30 kHz for reference signals, which doubles the sampling rate in the frequency domain. This parameter change simultaneously improves spectral efficiency for higher data transfer speeds while maintaining positioning accuracy by eliminating the undersampling effect that causes secondary peaks
Solution Approach 2:
The patent dynamically adjusts the subcarrier spacing based on the specific function: using 30 kHz spacing for positioning reference signals to eliminate secondary peaks, while allowing flexible configuration for data channels. This dynamic adaptation enables the system to optimize both positioning accuracy and spectral efficiency for different operational requirements
Data Source
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AI summary
Disclosed are methods and apparatuses for providing configurable reference signal timing difference (RSTD) search windows for positioning. In an aspect, an RSTD search window is configured based on a positioning reference signal (PRS) configuration (1310). The RSTD search window is provided to the UE (1320). A plurality of PRS is transmitted from a network entity to a user equipment (UE), each PRS having the PRS configuration. The plurality of PRS are transmitted in a subset that is less than all sub carriers over a given bandwidth (1330).