UE Localization Using ToA and Path Strength Weighting

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Solution Overview

Problem

Existing wireless communication network localization methods face challenges in accurately determining the position of user equipment (UE) in multipath channel scenarios due to errors caused by non-line-of-sight (NLoS) signal paths, which can lead to inaccurate time of arrival (ToA) estimates and position determination.

Innovation Solution

The UE estimates time of arrivals (ToAs) and path strengths of multiple path components, transmitting this information to a location server, which uses the additional data to improve position accuracy by identifying and weighting LOS and NLoS components, thereby enhancing localization precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional ToA estimation methods are used in multipath environments, then the localization process can be completed, but the position accuracy deteriorates due to NLoS path interference

Engineering Contradiction:
Improveposition accuracyVSAvoidNLoS path interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the received signal into multiple path components based on their different arrival times. By dividing the composite signal into individual multipath components, the system can separately analyze and weight each path, identifying LOS components from NLoS components through their distinct temporal characteristics, thereby resolving the contradiction between maintaining localization functionality and achieving accurate positioning in multipath environments

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of signal evaluation from considering only amplitude or single-path ToA to incorporating time-based segmentation and strength-based weighting. By introducing path strength as an additional parameter and using it to weight multiple ToA measurements, the system transforms the problematic multipath signal structure into useful information for accurate localization, overcoming the NLoS interference issue

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple path component measurements are collected and processed, then position accuracy improves through LOS/NLoS discrimination, but the computational complexity and processing requirements increase

Engineering Contradiction:
Improvelocalization precisionVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the UE measures and reports multiple path component parameters (ToA and path strength) to the network, and the network uses this feedback information to compute weighted ToA estimates. This feedback loop allows the system to iteratively refine position estimates by incorporating strength-based weighting of multiple paths, achieving high precision while distributing computational complexity between UE and network entities

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3538911B1User equipment localization in a mobile communication network based on delays and path strengths
Publication Date: 2021.07.28 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3538911B1 patent drawingFigure 1
  • EP3538911B1 patent drawingFigure 2
  • EP3538911B1 patent drawingFigure 3

AI summary

A receiver (UE) has a plurality of antennas and receives a plurality of radio signals from a plurality of transmitters of different cells of a wireless communication network. Each radio signal has a position reference signal (PRS) sequence and is transmitted to the receiver (UE) via a radio channel including a plurality of path components. The receiver (UE) processes the radio signal to estimate for a path component the time of arrival (ToA) of the PRS sequence and to determine for a path component a path strength (PS) value of the PRS sequence. A position of the receiver (UE) is estimated using the ToAs and the PS values.