Clock-Independent Wireless Device Localization With Reference-Node TDoA
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Solution Overview
Problem
Existing device localization methods, such as Uplink Time Difference of Arrival (UL-TDoA), rely heavily on precise clock synchronization among network devices, leading to inefficiencies, interference issues, and significant localization errors due to synchronization errors, limiting scalability and performance in densely populated environments.
Innovation Solution
A system and method for device localization that estimates time difference of arrival (TDoA) independently of clock synchronization by using a reference network device to assess latency values and process notifications from peer devices, allowing localization without requiring synchronized clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent and precise clock synchronization is implemented among anchors, then localization accuracy is improved, but system complexity and airtime consumption increase significantly
Solution Approach 1:
The patent introduces a reference device as an intermediary that receives blink signals from the wireless transceiver and sends notifications to peer devices. This reference device acts as a mediator that eliminates the need for direct clock synchronization between peer devices, as each device independently calculates TDoA based on notification timestamps rather than relying on synchronized clocks. The reference device mediates the timing information distribution, allowing localization without peer-to-peer synchronization.
Solution Approach 2:
Each peer device independently determines the arrival time of notifications and calculates TDoA values using its own local clock without requiring synchronization with other devices. The system enables self-service timing where each device uses its autonomous timestamping capability to contribute to the localization calculation, eliminating the need for centralized synchronization control.
2Reliability
If frequent clock synchronization events are performed, then localization reliability is improved, but airtime availability and system efficiency deteriorate
Solution Approach 1:
The reference device serves as a mediator that distributes timing information through notifications, eliminating the need for frequent synchronization events. Each notification contains sufficient timing information for TDoA calculation, allowing the system to maintain reliability without periodic synchronization overhead, thus preserving airtime for actual localization operations.
3Measurement precision
If precise clock synchronization is maintained, then hyperbolic curve intersection accuracy is improved, but power consumption and processing overhead increase
Solution Approach 1:
Each peer device uses its own local clock to timestamp notification arrivals and independently calculates TDoA values without requiring synchronization maintenance. This self-service approach eliminates the power-consuming synchronization protocol while preserving the mathematical accuracy of hyperbolic curve intersections through proper timestamp-based differential calculation.
4Ease of manufacture
If UWB and Wi-Fi radios are co-located in anchors, then infrastructure cost is reduced, but out-of-band power leakage and interference increase
Solution Approach 1:
The patent extracts the timing reference function from the synchronized clock system and implements it through the reference device sending notifications. This extraction allows Wi-Fi and UWB radios to operate independently without requiring tight synchronization, thereby reducing the harmful power leakage and interference effects while maintaining manufacturing simplicity of co-located radios.
Data Source
AI summary
Existing device localization strategies can lead to significant localization errors due to clock synchronization discrepancies among network devices. To address this, devices, systems, methods, and processes for facilitating device localization independent of clock synchronization are described herein. A reference network device coupled to multiple peer devices receives a blink signal from a wireless transceiver and a set of notifications from the peer devices. The set of notifications indicates arrival and processing time durations of the blink signal at respective peer devices. The reference network device assesses a latency value associated with each of the set of notifications and estimates time difference of arrivals (TDoAs) for the blink signal based on a clock of the reference network device and the assessed latency values. The reference AP determines a location of the wireless transceiver based on the TDoAs estimated without clock synchronization between the reference network device and the peer devices.