DC Tone Signaling for 5G Positioning Accuracy

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Solution Overview

Problem

In wireless communication systems, particularly in 5G New Radio (NR) networks, there is a challenge in accurately determining the location of user equipment (UE) due to the vulnerability of direct current (DC) tones to noise, especially from local oscillator leakage. This makes it difficult for UEs to compensate for positioning signals mapped to DC tones, affecting positioning accuracy.

Innovation Solution

The proposed solution involves informing the UE of the DC tones of multiple network nodes and/or informing these network nodes of the DC tone of the UE. This is achieved through specific signaling mechanisms, such as using assistance data messages, to enable the UE to take compensating actions, such as deemphasizing measurements of signals mapped to DC tones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If DC tones are used for positioning signals, then spectral efficiency is improved, but measurement accuracy deteriorates due to noise vulnerability

Engineering Contradiction:
Improvespectral efficiencyVSAvoidpositioning accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The network node performs preliminary identification of DC tones before positioning signal transmission. The UE is informed of DC tone locations in advance through assistance data, enabling the UE to prepare compensating actions beforehand. This preliminary identification and notification mechanism allows the system to maintain spectral efficiency while preparing for accuracy preservation through compensation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention converts the harmful effect of DC tone noise into a beneficial outcome by having the network identify and notify the UE about DC tone locations. The UE then applies compensation specifically to these identified tones, transforming the previously harmful noise-affected measurements into reliable positioning data through targeted correction.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If DC tones are punctured or rate-matched, then positioning accuracy is improved, but spectral efficiency deteriorates

Engineering Contradiction:
Improvepositioning accuracyVSAvoidspectral efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Instead of applying uniform puncturing or rate-matching across all DC tones, the invention enables selective handling of individual DC tones based on their specific noise characteristics. The network identifies which DC tones are affected and notifies the UE accordingly, allowing compensation to be applied only where needed. This localized approach preserves spectral efficiency while maintaining positioning accuracy.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the UE is informed of DC tones through assistance data, then compensation capability is improved, but signaling overhead increases

Engineering Contradiction:
Improvecompensation capabilityVSAvoidsignaling overhead
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The invention extracts only the essential DC tone identification information from the complete positioning assistance data set. Rather than providing comprehensive assistance data for all signals, the system selectively includes only DC tone location information that the UE needs for compensation. This extraction approach provides necessary compensation capability while minimizing unnecessary signaling overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4243457B1Direct current (DC) tone signaling
Publication Date: 2025.01.22 QUALCOMM INC
  • EP4243457B1 patent drawingFigure 1
  • EP4243457B1 patent drawingFigure 2A
  • EP4243457B1 patent drawingFigure 2B

AI summary

Disclosed are techniques for wireless communication. In an aspect, a network entity sends, to a user equipment (UE), a notification of a plurality of direct current (DC) tones of a plurality of network nodes configured to transmit a plurality of positioning signals to the UE, and receives, from the UE, a position of the UE, a plurality of positioning related measurements of the plurality of positioning signals, or any combination thereof. In an aspect, a UE receives, from a network entity, a notification of a plurality of DC tones of a plurality of network nodes, receives, from the plurality of network nodes, a plurality of positioning signals, and determines a plurality of positioning related measurements of the plurality of positioning signals based on locations of the plurality of DC tones indicated in the notification.