Downlink PRS Positioning Under Slot Misalignment
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Solution Overview
Problem
In wireless communication networks, the accuracy of UE positioning is compromised due to PRS signal misalignment, leading to degraded SNR and interference from non-PRS signals, which affects TOA and RSTD measurements.
Innovation Solution
Identify non-colliding PRS symbols to determine TOA, while disregarding colliding symbols, and select the smaller TOA from multiple measurements to improve SNR and accuracy without altering hardware or signal configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PRS signals are captured without filtering colliding symbols, then more signal samples are available for TOA measurement, but measurement accuracy degrades due to interference from non-PRS signals
Solution Approach 1:
The PRS signal capture process is segmented into two distinct phases: initial capture of all potential PRS symbols including colliding ones, followed by identification and exclusion of colliding symbols. This segmentation allows the system to first maximize sample collection, then selectively remove harmful samples to improve measurement accuracy.
Solution Approach 2:
Colliding symbols are extracted and removed from the captured PRS signal set. The method identifies symbols that collide with non-PRS signals from the reference cell and excludes them from TOA measurement, thereby eliminating the source of interference while preserving valid PRS symbols.
2Adaptability or versatility
If slot misalignment is present between TRP and reference cell, then network flexibility is improved, but positioning accuracy degrades due to PRS signal collision with non-PRS signals
Solution Approach 1:
The method converts the harmful effect of slot misalignment into a beneficial filtering opportunity. By using the known slot misalignment information, the system can precisely identify which PRS symbols will collide with non-PRS signals and exclude them, thereby transforming the misalignment challenge into an enhanced measurement process.
Solution Approach 2:
The system performs preliminary identification of colliding PRS symbols before conducting TOA measurement. By anticipating which symbols will collide based on slot misalignment parameters, the method pre-filters the signal set to ensure only clean PRS symbols are used for measurement.
3Reliability
If all PRS symbols are used for TOA measurement, then measurement robustness is improved, but SNR degrades due to inclusion of colliding symbols with interference
Solution Approach 1:
The method applies local quality enhancement by treating different PRS symbols differently based on their collision status. Valid non-colliding symbols are processed with full measurement effort, while colliding symbols are identified and excluded, ensuring that each symbol contributes optimally to the overall measurement quality.
Data Source
AI summary
A method of user equipment (UE) positioning includes receiving positioning assistance data associated with a Transmission Reception Point (TRP), such as an expected Reference Signal Time difference (RSTD) between a reference cell and the TRP. The method also includes capturing, based on at least the expected RSTD, a first portion of reference signals from the TRP. The method further includes determining a first Time of Arrival (TOA) of the reference signals from the TRP based on the first portion of the reference signals.