Mobile Node Positioning via Time Synchronization for NLOS Coverage

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Solution Overview

Problem

Current wireless communication networks face challenges in providing precise positioning, especially in non-line-of-sight (NLOS) situations and sparse network deployments with large inter-site distances, which are exacerbated in 5G networks, and existing solutions are inadequate for meeting the accuracy requirements.

Innovation Solution

The implementation of a method using multiple mobile radio network nodes to perform time synchronization and relative positioning, employing precision time protocol (PTP) measurements and time difference of arrival (TDOA) calculations to determine the position of user equipment (UE) without requiring direct line-of-sight signals, utilizing a multi-hop route established between mobile nodes to enhance positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional fixed network nodes are used for positioning, then positioning can be performed in areas with direct line of sight, but positioning accuracy deteriorates in non-line-of-sight situations and sparse network deployments

Engineering Contradiction:
Improvepositioning accuracyVSAvoidcoverage in NLOS and sparse deployment scenarios
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces mobile radio network nodes (such as vehicles, drones, or portable base stations) that can dynamically move to positions providing line-of-sight connectivity to both the target UE and fixed network nodes. This dynamic mobility allows the system to adapt to NLOS conditions by physically repositioning measurement points, thereby maintaining positioning accuracy in environments where traditional fixed nodes would fail.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mobile radio network nodes act as intermediaries between fixed network nodes and target UEs in NLOS situations. These mobile nodes receive positioning reference signals from fixed nodes and relay them to UEs, or measure signals from UEs and forward measurements to location servers. This intermediary role enables positioning in sparse deployments and NLOS conditions by creating additional signal paths that would not exist with fixed nodes alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If mobile radio network nodes are deployed to extend coverage, then adaptability to NLOS and sparse deployment scenarios improves, but device complexity and synchronization requirements increase

Engineering Contradiction:
Improvecoverage in NLOS and sparse deployment scenariosVSAvoidsynchronization and positioning procedures
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The mobile radio network nodes are designed to perform multiple functions: they can serve as traditional base stations for data communication, act as positioning reference points for OTDOA measurements, function as moving relays to extend network coverage, and provide line-of-sight measurement points for TDOA positioning. This multi-functionality reduces the need for separate dedicated positioning infrastructure, thereby managing complexity while enhancing adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements feedback mechanisms where mobile nodes continuously report their positions, signal quality metrics, and measurement data to location servers. The location server processes this feedback to determine optimal positioning methods and adjusts positioning procedures dynamically based on current network conditions, mobile node positions, and UE locations. This feedback-driven approach automates complex synchronization and positioning decisions.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables accurate UE positioning even in challenging environments by leveraging the mobility and connectivity of mobile nodes, improving positioning precision and extending coverage where traditional methods fail, such as in rural areas or areas with sparse network deployment.

Implementation Method 1

The one or more procedures synchronize timing of the mobile radio network node relative to the two or more additional nodes

Methodology Applied
Scientific EffectTime synchronization:

Implementation Method 2

employing precision time protocol (PTP) measurements and time difference of arrival (TDOA) calculations to determine the position of user equipment (UE)

Methodology Applied
Scientific EffectTime difference of arrival: Time of Flight

Implementation Method 3

performing a measurement on a signal from a transmitting node, the measurement being a time of arrival (TOA) of the signal at the mobile radio network node

Methodology Applied
Scientific EffectTime of arrival measurement: Time of Flight

Data Source

PatentEP4022336B1Position estimation for emitters outside line of sight of fixed network nodes
Publication Date: 2024.08.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4022336B1 patent drawingFigure 1
  • EP4022336B1 patent drawingFigure 2
  • EP4022336B1 patent drawingFigure 3

AI summary

Systems and processes for position estimation for emitters outside of line of sight of fixed network nodes are disclosed. The positions of the mobile nodes are determined and the mobile nodes are time synchronized. Then, locations of one or more user equipments (UEs) are determined. The mobile radio network nodes may be air, land, or water-borne (e.g., mounted on drones, trains, boats, planes, automobiles, or the like). The UEs to be located may be a wide range of devices such as emergency transmitters, mobile phones, simple sensor nodes, and other Internet of Things (IoT) devices.