Wireless Device Positioning via Remote Radio Head Power Signatures

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Solution Overview

Problem

In wireless communication networks, the use of remote radio heads to enhance coverage and capacity leads to insufficient positioning accuracy due to the large granularity of cell identification, which is inadequate for precise location determination, especially in indoor environments where GPS is often unavailable.

Innovation Solution

Assigning unique or shared reference power signatures to remote radio heads allows for more precise location determination of wireless devices by analyzing measurement reports from the devices, enabling positioning with finer granularity than the shared radio cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple remote radio heads share the same cell identity to provide coverage, then coverage is improved and handovers are reduced, but positioning accuracy deteriorates due to large cell identification granularity

Engineering Contradiction:
Improvecoverage areaVSAvoidpositioning accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the cell identification by introducing remote radio head-specific reference power signatures. Each remote radio head within a cell is assigned a unique signature, allowing the system to distinguish between different remote radio heads while maintaining cell-level coverage. This segmentation enables fine-grained positioning (identifying specific remote radio head locations) without requiring multiple cells, thus resolving the contradiction between coverage and positioning accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different reference power signatures to different remote radio heads based on their specific locations. Each remote radio head has a unique signature characteristic that reflects its local position within the cell. This allows the system to determine the wireless device's position by identifying which local remote radio head's signature matches the measurement, achieving high positioning accuracy while maintaining unified cell coverage.

Inventive Principle:
Principle #3Local quality

2Productivity

If many small cells are deployed to improve capacity and throughput, then capacity is improved, but coverage deteriorates and installation cost increases

Engineering Contradiction:
Improvenetwork capacityVSAvoidcoverage area
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent makes the single cell with multiple remote radio heads multi-functional. The same cell structure serves both as a coverage area and as a positioning system. By using reference power signatures, the cell simultaneously provides wide coverage and enables fine-grained positioning, eliminating the need for multiple small cells to achieve positioning accuracy. This multi-functionality allows the system to maintain coverage while improving capacity through remote radio head deployment.

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

3Area of stationary object

If remote radio heads are deployed indoors to provide coverage, then coverage is improved, but positioning accuracy deteriorates due to unavailability of GPS and large cell granularity

Engineering Contradiction:
Improveindoor coverageVSAvoidpositioning accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent introduces reference power signatures as an intermediary mechanism for indoor positioning. Since GPS is unavailable indoors, the system uses the reference power signatures of remote radio heads as intermediate reference points. The wireless device measures downlink signals from remote radio heads and compares them against stored reference power signatures to determine its position. This intermediary approach enables accurate indoor positioning without requiring GPS or multiple small cells.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3192315B1Determining a position of a wireless device
Publication Date: 2023.06.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3192315B1 patent drawingFigure 1~4
  • EP3192315B1 patent drawingFigure 5A~6B
  • EP3192315B1 patent drawingFigure 7A~10

AI summary

It is presented a method for determining a position of a wireless device within a single radio cell served by a plurality of remote radio heads. The method is performed in a position determination node and comprises the steps of: receiving a measured power signature comprising at least two, in time separated, power measurement values of a downlink signal, the measured power signature originating from the wireless device; comparing the measured power signature with a set of reference power signatures, wherein each one of the plurality of remote radio heads is associated with a reference power signature and the reference power signatures differ for at least two of the plurality of remote radio heads; and determining a position in that the wireless device is in the vicinity of one of the at least one remote radio head whose reference power signature best matches the measured power signature.