UE Positioning via Time Offset Signals for NLoS Accuracy
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Solution Overview
Problem
Current OTDOA positioning methods in wireless telecommunications networks assume direct Line of Sight (LoS) routes for position reference signals, leading to inaccuracies when signals travel via non-line of sight (NLoS) routes, resulting in incorrect peak selection and positional errors.
Innovation Solution
The method involves user equipment transmitting a time offset signal indicating the time difference between multiple peaks in the received position reference signals to a location server, allowing the server to determine the correct time of arrival for the LoS route, thereby improving positional accuracy with reduced signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the user equipment transmits multiple RSTD measurements based on multiple peaks, then the positioning accuracy is improved, but the signaling overhead increases
Solution Approach 1:
The patent extracts only the essential information needed for positioning correction - the time offset between peaks - rather than transmitting complete multiple RSTD measurements. This selective extraction reduces signaling overhead while maintaining positioning accuracy, as the location server can use this compact time offset information to identify and correct multipath effects.
Solution Approach 2:
Instead of having the user equipment directly determine which peak corresponds to the line-of-sight path, the patent inverts the approach by having the UE measure and report time offsets between multiple peaks, then allowing the location server to perform the analysis and determination. This inversion reduces the processing burden and signaling requirements at the UE while maintaining or improving positioning accuracy.
2Device complexity
If the user equipment selects the first peak above threshold as the time of arrival, then the processing is simple, but positioning errors occur due to multipath effects
Solution Approach 1:
The patent applies preliminary action by having the user equipment measure and report time offsets between multiple peaks before the location server performs the final positioning calculation. This preliminary measurement of time offsets provides the server with corrected information that accounts for multipath effects, improving accuracy without significantly increasing UE processing complexity.
Solution Approach 2:
The time offset measurement acts as an intermediary that bridges the simple peak detection at the UE and the accurate positioning calculation at the location server. By introducing this intermediate measurement, the system maintains processing simplicity at the UE while achieving high positioning accuracy through server-side analysis of the time offset information.
Data Source
AI summary
A user equipment, user equipment method, location server, location server method and computer program are disclosed. The method performed at the user equipment comprises: monitoring for a position reference signal broadcast by a network node; measuring a time of arrival of a peak in a received signal indicative of receipt of said position reference signal and measuring a time of arrival of at least one further peak in said received signal; transmitting a time offset signal indicative of a time difference between said arrival of said at least one further peak and said peak as part of an enhanced reference time difference signal.