PTRS Allocation for Phase Noise Compensation

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently allocating frequency resources for phase tracking reference signals (PTRS) due to interference and frequency selective fading, which affects phase noise compensation.

Innovation Solution

The system identifies a set of frequency resources configured for PTRS transmissions and selects a subset based on channel conditions, providing control information to the user equipment (UE) to indicate the selected subset and pattern of resource elements (REs) for PTRS transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PTRS is transmitted using all configured frequency resources, then phase noise compensation coverage is maximized, but interference and frequency selective fading degrade the quality of phase tracking

Engineering Contradiction:

Improvephase noise compensation qualityVSAvoidinterference and frequency selective fading

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by transmitting PTRS only in selected frequency sub-bands with favorable channel conditions rather than uniformly across all frequency resources. The base station identifies specific sub-bands experiencing less interference and fading, and configures PTRS transmissions only in those localized regions, thereby maintaining high phase tracking quality while avoiding degraded frequency resources.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the frequency spectrum into multiple sub-bands and selectively activates PTRS transmission in only certain segments (sub-bands) based on channel conditions. This segmentation allows the system to isolate PTRS transmissions from harmful effects in other frequency segments, resolving the contradiction between comprehensive coverage and quality maintenance.

Inventive Principle:

Principle #1Segmentation

2Reliability

If PTRS is transmitted across the entire frequency spectrum, then phase tracking coverage is complete, but resource overhead increases

Engineering Contradiction:

Improvephase tracking coverageVSAvoidfrequency resource overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts PTRS transmissions from the complete frequency spectrum and relocates them to only those necessary frequency sub-bands where they are most effective. By removing PTRS from frequency resources that experience poor channel conditions or are not critical for phase tracking, the system reduces overall resource overhead while preserving essential phase tracking coverage.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements partial action by transmitting PTRS in only a subset of frequency sub-bands rather than all configured resources. This partial transmission strategy provides sufficient phase tracking coverage for reliable communication while minimizing the quantity of frequency resources consumed by PTRS overhead.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If PTRS frequency resources are dynamically selected based on channel conditions, then phase tracking accuracy improves, but system complexity increases

Engineering Contradiction:

Improvephase tracking accuracyVSAvoidfrequency resource selection complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the base station perform channel condition assessments and identify suitable frequency sub-bands for PTRS transmission in advance, before actual data transmissions occur. This pre-selection process, potentially based on uplink channel measurements or downlink reference signal feedback, establishes a mapping between channel conditions and optimal PTRS frequency resources, thereby improving phase tracking accuracy while managing system complexity through advance planning.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the base station receives channel condition information from the UE (through measurement reports or uplink transmissions) and uses this feedback to dynamically select appropriate frequency sub-bands for PTRS transmission. This closed-loop approach enables accurate phase tracking adaptation to changing channel conditions while maintaining manageable system complexity through structured feedback processing.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12294534B2Frequency selective phase tracking reference signal (PTRS) allocation

Publication Date: 2025.05.06 QUALCOMM INC

AI summary

This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer storage media, for enabling user equipment (UE) and a base station (BS) to communicate using a set of frequency resources in which a subset of frequency resources include a phase tracking reference signal (PTRS). In one aspect, the UE may measure the PTRS in the subset of frequency resources, and select a phase noise compensation that is used to demodulate a communication from the BS. The subset of frequency resources may be selected from the set frequency resources based on channel conditions of different subsets of frequency resources. The BS may provide an indication of the selected subset of frequency resources to the UE, such as in control information that schedules the communication from the BS.