PT-RS Multiplexing for Phase Noise Compensation

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Solution Overview

Problem

Next-generation wireless communication systems, such as 5G, face challenges in managing Phase Tracking Reference Signals (PT-RS) for high-frequency bands to compensate for phase noise and frequency offset, especially when dealing with multiple bandwidth parts and dynamic resource sharing scenarios.

Innovation Solution

The configuration of PT-RS involves determining dynamic presence and time/frequency densities based on Modulation and Coding Scheme (MCS), Subcarrier Spacing (SCS), and allocated bandwidth, with options for independent or joint determination across bandwidth parts, and dynamic resource sharing with control and data channels, using techniques like frequency division multiplexing and power boosting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PT-RS is configured with high density across all bandwidth parts, then phase noise compensation performance is improved, but system complexity and resource overhead increase

Engineering Contradiction:
Improvephase noise compensation performanceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by configuring PT-RS density independently for each bandwidth part based on its specific characteristics. Different bandwidth parts can have different PT-RS time densities and frequency densities, allowing optimized phase noise compensation for each part without uniformly increasing complexity across the entire system. The network can selectively apply higher PT-RS density only to bandwidth parts that require it.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamic PT-RS configuration where the presence, time density, and frequency density of PT-RS are determined based on dynamic parameters such as Modulation and Coding Scheme (MCS), Subcarrier Spacing (SCS), and allocated bandwidth. This allows the system to adapt PT-RS density to current channel conditions and service requirements, improving phase noise compensation when needed while reducing overhead when conditions permit.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If PT-RS density is increased to improve phase tracking accuracy, then compensation performance is improved, but uplink resource overhead increases

Engineering Contradiction:
Improvephase tracking accuracyVSAvoidresource overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent changes key parameters including time density (kpt-rs), frequency density (lpt-rs), and power offset (deltaPT-RS) to optimize the balance between phase tracking accuracy and resource overhead. These parameters are configured per bandwidth part and can be adjusted based on channel conditions, allowing the system to achieve required tracking precision while minimizing resource consumption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial action by configuring PT-RS only in specific bandwidth parts and specific time-frequency resources where it is most needed for phase noise compensation. Rather than uniformly distributing PT-RS across all resources, the system selectively places PT-RS in critical areas, achieving sufficient tracking accuracy with reduced overall overhead.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If dynamic resource sharing is implemented between control and data channels, then resource utilization efficiency is improved, but PT-RS configuration complexity increases

Engineering Contradiction:
Improveresource utilization efficiencyVSAvoidPT-RS configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the uplink transmission into different bandwidth parts, each with independent PT-RS configuration. This segmentation allows dynamic resource sharing between control and data channels to be managed separately in each bandwidth part, reducing the overall configuration complexity while maintaining high resource utilization efficiency through flexible allocation.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3635906B1System and method for phase tracking reference signal (PT-RS) multiplexing
Publication Date: 2024.11.06 APPLE INC
  • EP3635906B1 patent drawingFigure 1
  • EP3635906B1 patent drawingFigure 2
  • EP3635906B1 patent drawingFigure 3

AI summary

Technology for a next generation node B (gNB), operable to use phase tracking reference signals (PT-RS) is disclosed. The gNB can identify a modulation and coding 5 scheme (MCS) for the UE for a bandwidth part (BWP) with a subcarrier spacing (SCS). The gNB can select a time density of the PT-RS based on the MCS. The gNB can select a frequency density of the PT-RS based on an allocated bandwidth in the BWP. The gNB can encode the time density and the frequency density, for the PT-RS for transmission to the UE in higher layer signaling.