UWB TDoA Anchor Clustering With DODAG Clock Synchronization

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Solution Overview

Problem

Existing UWB ranging technologies for mobile devices face challenges in large environments due to scalability issues and inefficient clock synchronization between anchors, leading to limited location accuracy and increased battery consumption.

Innovation Solution

A single cluster formation technique using a Direction-Oriented Directed Acyclic Graph (DODAG) is implemented, where a primary anchor is elected and a cluster structure is formed, allowing for dynamic clock synchronization and minimizing time drift through hop-based weighting, enabling efficient message propagation and synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If UWB ranging is used for mobile devices, then location accuracy is improved, but battery consumption increases

Engineering Contradiction:

Improvelocation accuracyVSAvoidbattery consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system segments the battery consumption burden by having anchors (fixed infrastructure) perform UWB transmissions and processing, while mobile devices only perform reception and TDoA calculation. This segmentation allows high-precision UWB ranging while the mobile device consumes minimal battery energy.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple clusters are formed in large environments, then scalability is improved, but clock synchronization between anchors deteriorates

Engineering Contradiction:

ImprovescalabilityVSAvoidclock synchronization

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges multiple clusters into a single unified cluster structure with one primary anchor that all secondary anchors synchronize to. This eliminates inter-cluster synchronization issues while maintaining scalability through the hierarchical DODAG structure that can accommodate large numbers of anchors.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The primary anchor acts as an intermediary time reference for all secondary anchors in the cluster. All clock synchronization flows through this single intermediary, ensuring consistent time references across the entire network without requiring direct synchronization between all anchor pairs.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If conventional cluster formation is used, then anchor organization is simplified, but time drift increases

Engineering Contradiction:

Improveanchor organizationVSAvoidtime drift

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The system implements dynamic clock synchronization where secondary anchors continuously adjust their clocks based on timestamped messages from the primary anchor. This dynamic adjustment compensates for time drift while maintaining the simple DODAG hierarchical structure for anchor organization.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20260082361A1Single cluster formation technique for ultra-wideband (UWB) time difference of arrival (TDOA)

Publication Date: 2026.03.19 CISCO TECHNOLOGY INC

AI summary

A single cluster formation technique for Ultra-Wideband (UWB) Time Difference of Arrival (TDoA) may be provided. A primary anchor may be elected from a plurality of anchors. Then a structure of a cluster formed by the plurality of anchors may be collected by the primary anchor. A Direction-Oriented Directed Acyclic Graph (DODAG) may be built for the cluster based on an uncontrolled time drift along the DODAG and weighted by a number of hops to the primary anchor.