User Equipment Time Synchronization for TDOA Positioning
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Solution Overview
Problem
Existing network-based positioning systems face challenges in achieving accurate time synchronization between user equipment without modifying network infrastructure or communications standards.
Innovation Solution
A method for calculating time synchronization offsets between nodes using time-of-arrival estimates and time-of-flight estimates for reference signals, allowing for improved localization accuracy of target devices by correcting time differences of arrival based on these offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If network-based positioning systems use existing infrastructure without modifications, then device complexity and implementation cost are reduced, but time synchronization accuracy deteriorates
Solution Approach 1:
The patent introduces user equipment as an intermediary element that performs time synchronization calculations. Instead of requiring network infrastructure modification, the user equipment acts as a mediator to compute time synchronization offsets by measuring time of arrival and time of flight of reference signals, thereby achieving accurate synchronization without altering network complexity
Solution Approach 2:
The user equipment performs self-synchronization by autonomously calculating time synchronization offsets using locally measured time of arrival values and known time of flight values. This self-service approach eliminates the need for network-side synchronization modifications, allowing the system to maintain simplicity while achieving precision through user equipment intelligence
2Measurement precision
If time synchronization offsets are calculated using user equipment, then localization accuracy is improved, but measurement and calculation complexity increases
Solution Approach 1:
The patent performs preliminary calculations by pre-determining time of flight values for reference signals before actual positioning measurements. This preliminary action simplifies the subsequent measurement process, as the system only needs to measure time of arrival values and combine them with pre-calculated time of flight values to obtain time synchronization offsets, thereby reducing overall measurement complexity while maintaining high localization accuracy
Data Source
AI summary
A method includes: accessing a first time-of-arrival estimate for a reference signal transmitted from a reference device and received at a first node; accessing a second time-of-arrival estimate for the reference signal received at a second node; accessing a first time-of-flight estimate for the reference signal from the reference device to the first node based on a first distance between the reference device and the first node; accessing a second time-of-flight estimate for the reference signal from the reference device to the second node based on a second distance between the reference device and the second node; and calculating a time synchronization offset between the first node and the second node based on the first time-of-arrival estimate, the second time-of-arrival estimate, the first time-of-flight estimate, and the second time-of-flight estimate.