Carrier Phase Positioning With POA Correction for ATA/AFA
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Solution Overview
Problem
In 5G positioning systems, the frequency deviation of crystal oscillators in base stations and terminals, combined with autonomous time and frequency adjustments, leads to cycle slips in carrier phase measurements, degrading positioning accuracy.
Innovation Solution
A method to correct downlink and uplink Phase of Arrivals (POAs) using adjustment information about Autonomous Time Adjustment (ATA) and Autonomous Frequency Adjustment (AFA) to eliminate their influence, thereby improving carrier phase positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal performs autonomous time adjustment and autonomous frequency adjustment to compensate for crystal oscillator frequency deviation, then the terminal can maintain synchronization, but cycle slip occurs in carrier phase measurement quantity
Solution Approach 1:
The terminal performs ATA and AFA in advance during non-PRS durations to compensate for frequency deviation before PRS measurements are taken. By proactively adjusting time and frequency offsets during periods when PRS is not being transmitted, the terminal prepares its oscillator state beforehand, ensuring that when PRS arrives, the carrier phase measurement can be taken with minimal cycle slip risk.
Solution Approach 2:
The positioning procedure is divided into distinct time segments: non-PRS durations for performing ATA and AFA adjustments, and PRS durations for taking carrier phase measurements. This segmentation allows the terminal to separate the adjustment operations from the measurement operations, preventing interference between the two functions and maintaining measurement accuracy.
2Productivity
If discontinuous downlink Positioning Reference Signal and uplink Sounding Reference Signal are used for positioning, then resource efficiency is improved, but carrier phase measurement accuracy degrades due to cycle slip
Solution Approach 1:
The system uses periodic PRS and SRS-Pos transmissions at defined intervals rather than continuous signals. The terminal performs ATA and AFA during the intervals between PRS transmissions (non-PRS durations), creating a periodic pattern where adjustment operations alternate with measurement operations. This periodic structure maintains resource efficiency while ensuring measurements are taken at optimal moments.
Solution Approach 2:
Before each PRS transmission window, the terminal performs preliminary time and frequency adjustments during the preceding non-PRS duration. This preliminary action ensures that when the PRS signal arrives, the terminal's oscillator is already synchronized, minimizing the risk of cycle slip during the actual carrier phase measurement.
Data Source
AI summary
A carrier phase positioning method, a terminal, a network side device, and an LMF are provided, which relate to the field of wireless communications technology. The terminal corrects a first downlink POA based on adjustment information about ATA and/or AFA performed by the terminal, to obtain a first downlink corrected POA; and determines a location of the terminal based on the first downlink corrected POA. The method utilizes the adjustment information about ATA and/or AFA to correct the POA, which can eliminate the influence of ATA and AFA performed by the terminal on carrier phase positioning, and thus improve the accuracy of carrier phase positioning.