Phase Tracking Reference Signal Placement Without DMRS

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Solution Overview

Problem

Existing wireless communication systems face deficiencies in feedback techniques for high throughput and low latency communications, particularly in determining the location of phase tracking reference signals in the absence of demodulation reference signals.

Innovation Solution

User equipment determines the location for transmitting phase tracking reference signals based on the absence of demodulation reference signals by using a control message to configure upcoming time intervals, allowing for enhanced phase noise compensation and improved communication reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If phase tracking reference signal location is determined based on demodulation reference signal presence, then phase noise compensation is improved, but communication reliability deteriorates when demodulation reference signals are absent

Engineering Contradiction:
Improvephase noise compensationVSAvoidcommunication reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-configuring multiple candidate locations for phase tracking reference signals and establishing predetermined rules for selection. When demodulation reference signals are present, the first candidate location is used; when absent, the second candidate location is automatically selected based on pre-established criteria. This advance preparation ensures reliable phase tracking regardless of demodulation reference signal availability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the phase tracking reference signal location adaptive rather than fixed. The system dynamically selects between multiple candidate locations based on real-time detection of demodulation reference signal presence. This dynamic adaptation allows the system to optimize phase noise compensation while maintaining communication reliability under varying channel conditions.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If phase tracking reference signals are transmitted in all time intervals, then phase noise compensation is improved, but power consumption and resource usage increase

Engineering Contradiction:
Improvephase noise compensationVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by transmitting phase tracking reference signals only when necessary rather than continuously. The system transmits these signals in the first candidate location when demodulation reference signals are present, and in the second candidate location when they are absent. This selective transmission maintains adequate phase noise compensation while reducing unnecessary power consumption and resource usage compared to continuous transmission.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent implements parameter changes by modifying the transmission parameters of phase tracking reference signals based on channel conditions. The system changes the time interval and location parameters dynamically, transmitting only when demodulation reference signals are detected or when the predetermined conditions for the second candidate location are met. This parameter adaptation reduces overall transmission power while maintaining communication quality.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If phase tracking reference signal location is fixed, then device complexity is reduced, but adaptability to different channel conditions deteriorates

Engineering Contradiction:
Improvesignal configuration complexityVSAvoidadaptability to channel conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies segmentation by dividing the phase tracking reference signal transmission into multiple candidate locations with distinct purposes. The first candidate location is used when demodulation reference signals are present, while the second candidate location is used when they are absent. This segmentation allows the system to maintain relatively simple device complexity through predetermined rules while achieving good adaptability to different channel conditions.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4320783B1Techniques for determining phase tracking reference signal location
Publication Date: 2025.11.12 QUALCOMM INC
  • EP4320783B1 patent drawingFigure 1
  • EP4320783B1 patent drawingFigure 2
  • EP4320783B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communication at a user equipment (UE) are described. A UE may receive, from a base station, a control message including an indication of a reference signal configuration associated with one or more physical channels scheduled during a set of time intervals. The UE may identify that demodulation reference signal is absent in a first time interval. In some examples, the UE may determine, based on the control message, a location for transmitting a phase tracking reference signal in the first time interval of the set of time intervals. The UE may then transmit the phase tracking reference signal in the first time interval at the determined location.