5G Terminal Positioning With ATA/AFA Timing Coordination
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Solution Overview
Problem
In 5G positioning systems, frequency deviations due to crystal oscillators in base stations and terminals lead to autonomous time and frequency adjustments (ATA and AFA) that affect the accuracy of positioning methods like DL-TDOA, UL-TDOA, and Multi-RTT.
Innovation Solution
A method where terminals perform ATA and/or AFA based on notification signaling from a network-side device, transmitting time information of these adjustments to a Location Management Function (LMF) for improved positioning accuracy, with adjustments coordinated within valid adjustment windows or according to predefined rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal performs autonomous time adjustment (ATA) and autonomous frequency adjustment (AFA) operations to compensate for frequency deviations, then the frequency deviation is corrected, but the positioning accuracy deteriorates due to timing changes affecting positioning measurements
Solution Approach 1:
The network-side device performs preliminary actions by determining valid adjustment windows before the terminal executes ATA/AFA operations. These windows are calculated based on expected adjustment times and communicated to the terminal in advance, allowing the terminal to perform adjustments only during predetermined safe time intervals that minimize impact on positioning measurements
Solution Approach 2:
The solution implements periodic positioning measurements within structured time intervals. By confining measurements to specific periods between valid adjustment windows and configuring adjustment windows periodically, the system creates a rhythmic pattern where adjustments and measurements occur in separate, non-interfering time slots
2Stability of the object's composition
If the terminal adjusts receiving timing and transmitting timing based on received synchronization signals to maintain synchronization, then the synchronization is maintained, but the positioning measurement accuracy deteriorates due to timing adjustments
Solution Approach 1:
The network-side device determines valid adjustment windows in advance based on synchronization signal timing and expected adjustment durations. These pre-calculated windows are communicated to the terminal before adjustments occur, ensuring that timing adjustments are confined to predetermined intervals that do not overlap with positioning measurement opportunities
Solution Approach 2:
The time domain is segmented into distinct functional intervals: valid adjustment windows for synchronization maintenance and measurement windows for positioning observations. This segmentation separates the conflicting functions of timing adjustment and positioning measurement into non-overlapping time segments, allowing both to coexist without mutual interference
Data Source
AI summary
The present disclosure provides a method for positioning a terminal, a terminal, a base station and an LMF and relates to the technical field of wireless communications. The terminal performs ATA and/or AFA according to notification signaling transmitted by a network-side device, wherein the notification signaling includes indication information for indicating the terminal to perform the ATA and/or AFA; and transmits time information of the ATA and/or AFA performed by the terminal, wherein the time information of the ATA and/or AFA is used to determine a position of the terminal. By adopting the above method, the LMF may determine the position of the terminal according to each positioning measurement obtained within a time range between two adjacent ATA and/or AFA performed by the terminal, so the accuracy of positioning the terminal is improved.