Wireless Device Cell Selection for Positioning Accuracy

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Solution Overview

Problem

Current positioning methods in wireless communications networks, such as OTDOA, face challenges in selecting the optimal reference cell and neighbor cells, especially for indoor devices with severe multipath issues, leading to poor position estimation due to high TOA errors and long lists of neighbor cells that cannot be measured in time.

Innovation Solution

Implementing a systematic approach for cell selection using Selection Strategy Information (SSI) that allows wireless communications devices to choose reference and neighbor cells based on observed conditions, such as minimum TOA or signal strength, to improve positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE measures TOA of all neighbor cells provided by the location server, then the positioning accuracy may be improved, but the measurement time increases and the UE cannot complete measurements in time

Engineering Contradiction:
Improvepositioning accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the neighbor cell list into multiple groups based on TOA values. The UE is instructed to measure only cells from specific groups (e.g., groups with lower TOA values) rather than all cells. This segmentation reduces the measurement burden while maintaining positioning accuracy by focusing on the most relevant cells for RSTD calculation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by having the UE measure only a subset of neighbor cells (those in prioritized groups) rather than the complete list. The location server determines which groups to measure based on assistance data, performing enough measurements to achieve acceptable positioning accuracy without requiring exhaustive measurement of all cells.

Inventive Principle:
Principle #16Partial or excessive action

2Ease of operation

If the UE selects the serving cell as reference cell, then the cell selection process is simple, but the positioning accuracy deteriorates due to high TOA errors in indoor environments with multipath issues

Engineering Contradiction:
Improvecell selection simplicityVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent makes the reference cell selection dynamic rather than static. Instead of always using the serving cell, the UE selects the reference cell based on observed conditions such as which cell has the minimum TOA value among the measured neighbor cells. This dynamic selection adapts to the current radio environment, improving positioning accuracy in indoor scenarios while maintaining an automated selection process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent enables the UE to autonomously determine the optimal reference cell based on its own measurements of TOA values. The UE compares TOA measurements and automatically selects the cell with the minimum TOA as the reference cell, without requiring explicit network configuration. This self-service approach improves accuracy while keeping the network's involvement minimal.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3295731B1Apparatuses and methods therein for positioning measurements
Publication Date: 2020.07.08 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3295731B1 patent drawingFigure 1
  • EP3295731B1 patent drawingFigure 2
  • EP3295731B1 patent drawingFigure 3

AI summary

There is provided mechanisms for positioning of a wireless communications device in a wireless communications network, where the wireless communications network comprises a serving cell and neighbour cells. A method performed by the wireless communications device comprises obtaining information related to a cell selection process for selecting a cell to be used for computing a position of the wireless communications device. The method comprises measuring a measure of a signal associated with the cell to be selected. The method comprises selecting the cell to be used for computing the position of the wireless communications device based on the information related to the cell selection process. The method comprises computing a difference of the measures based on the selected cell.