CRS Muting Signaling for Shared Cell Positioning Accuracy

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Solution Overview

Problem

In shared cell deployments, the accuracy of positioning using cellular reference signaling is negatively affected due to multiple transmission points with different locations providing comparable signaling, leading to inaccurate location determination of user equipment (UE) in wireless communication systems.

Innovation Solution

The method involves obtaining and utilizing information about CRS transmission muting by one or more transmission points in a shared cell to perform timing measurements for positioning, allowing the UE or network node to determine the correct transmission point for measurements, thereby enhancing positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple transmission points in a shared cell provide cellular reference signaling, then coverage and signal availability are improved, but positioning accuracy deteriorates due to inability to distinguish signal sources

Engineering Contradiction:
Improvesignal availabilityVSAvoidpositioning accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the shared cell into multiple transmission points by introducing unique transmission point identifiers. Each transmission point within the shared cell is distinguished by its unique identifier, allowing the UE to identify which transmission point is sending the reference signal at any given time. This segmentation resolves the contradiction by maintaining signal availability from multiple points while enabling precise identification of each signal source for accurate positioning.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces transmission point identifier information as an intermediary element between the reference signal and the UE. This identifier acts as a mediator that carries information about which transmission point is transmitting the signal, enabling the UE to distinguish between multiple transmission points without requiring separate cells. The intermediary preserves signal availability while providing the discrimination needed for positioning accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If CRS transmission is muted by certain transmission points, then interference is reduced and signal quality is improved, but positioning measurement capability deteriorates due to loss of reference signals

Engineering Contradiction:
Improvesignal qualityVSAvoidpositioning measurement capability
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent applies preliminary action by providing muting pattern information to the UE in advance before the actual muting occurs. The network node signals to the UE which transmission points will mute their CRS transmissions and when these muting patterns occur. This allows the UE to prepare appropriate measurement strategies, switching to alternative reference signals or adjusting measurement timing, thereby preventing loss of positioning capability while still allowing interference reduction through muting.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the network node provides muting pattern information to the UE, enabling the UE to adapt its measurement behavior. Based on the feedback about which transmission points will mute and when, the UE can adjust its measurement strategy to maintain positioning accuracy. This feedback loop ensures that positioning measurement capability is preserved even when CRS transmissions are muted for interference reduction.

Inventive Principle:
Principle #23Feedback

3Device complexity

If transmission points use the same cell ID for shared cell operation, then network complexity is reduced and resource utilization is improved, but the ability to distinguish signal sources for positioning deteriorates

Engineering Contradiction:
Improvenetwork complexityVSAvoidsignal source identification
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces asymmetry by adding transmission point identifier information to the otherwise symmetric shared cell structure. While all transmission points in the shared cell use the same cell ID, each transmission point is distinguished by a unique identifier that breaks the symmetry. This allows the system to maintain the simplicity of shared cell operation with common cell ID while providing the differentiation needed for signal source identification in positioning measurements.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3218737B1Signaling and using CRS muting in shared cell for positioning
Publication Date: 2019.01.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3218737B1 patent drawingFigure 1
  • EP3218737B1 patent drawingFigure 2
  • EP3218737B1 patent drawingFigure 3

AI summary

There is disclosed a method for operating a network node (100) in a shared cell with at least two transmission points. The method comprises obtaining information that at least one transmission point in the shared cell mutes cell-specific reference signal transmission, and using the obtained information for one or more of the following: transmitting the obtained information to a positioning node and/or to a user equipment and/or determining, using the obtained information, the transmission point on which a user equipment performs or has performed a timing measurement that involves measurement on CRS, and/or determining, using the obtained information, a transmission point to be considered by the network node for performing a timing measurement that involves measurement on signals transmitted by a user equipment. There are also disclosed related devices and methods.