Dynamic Pilot and Null Tone Selection for Phase Noise

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Solution Overview

Problem

High frequency wireless communication systems, particularly those operating in millimeter wave (mmW) frequencies, face significant challenges with phase noise due to higher frequency ratios and lower quality oscillators in user equipment, leading to interference that conventional phase noise estimation and mitigation techniques inadequately address.

Innovation Solution

A method where a transmitting device identifies phase noise metrics for both itself and receiving devices, selecting pilot tones and adjacent null tones based on these metrics to provide frequent phase noise estimation, allowing receiving devices to compensate for phase noise by detecting interference in null tones during both control and data symbol transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional phase noise estimation techniques are used in high frequency systems, then the system can operate at millimeter wave frequencies, but phase noise interference significantly degrades signal quality and reception accuracy

Engineering Contradiction:
Improveoperating frequencyVSAvoidsignal reception accuracy
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The transmitting device pre-selects pilot tones and null tones based on identified phase noise metrics before transmission. This preliminary configuration allows the receiving device to have reference points already positioned optimally for capturing phase noise characteristics, enabling more accurate estimation without requiring complex real-time adjustments during reception

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Null tones serve as intermediaries between the pilot tones and the phase noise interference. By placing null tones adjacent to pilot tones, the system creates a controlled environment where phase noise can be captured and measured without the complexity of full signal processing, simplifying the estimation process while maintaining accuracy at millimeter wave frequencies

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the number of pilot tones and null tones is increased to improve phase noise estimation accuracy, then phase noise compensation improves, but transmission overhead and resource consumption increase

Engineering Contradiction:
Improvephase noise estimation accuracyVSAvoidtransmission overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts the number and positioning of pilot tones and null tones based on identified phase noise metrics. When phase noise levels are high, more null tones are allocated to capture the interference characteristics. When phase noise is low, fewer tones are used, reducing overhead. This parameter adaptation resolves the contradiction between measurement precision and resource consumption

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pilot tone and null tone configuration is made dynamic rather than static. The transmitting device adjusts the tone pattern based on real-time phase noise metric identification, allowing the system to optimize between estimation accuracy and transmission efficiency according to current channel conditions, thereby adapting resource allocation to actual needs

Inventive Principle:
Principle #15Dynamics

3Reliability

If device-specific phase noise metrics are used to customize pilot and null tone selection for each receiving device, then phase noise compensation is optimized for individual devices, but system complexity and computation requirements increase

Engineering Contradiction:
Improvedevice-specific compensation accuracyVSAvoidsystem configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each receiving device receives a customized pilot and null tone pattern tailored to its specific phase noise characteristics. The transmitting device identifies phase noise metrics for each device and configures tones locally optimized for that device's receiver quality. This local customization improves compensation accuracy without requiring complete system redesign, as each device gets its optimized pattern independently

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system segments the phase noise compensation process by device, with each receiving device having its own phase noise metric identification and tone pattern selection. This segmentation allows complex device-specific optimization to be handled independently for each device, reducing overall system complexity by breaking down the problem into manageable per-device units rather than requiring complex inter-device coordination

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3335323B1Phase noise estimation with dynamic pilot and zero tones pattern selection
Publication Date: 2021.02.24 QUALCOMM INC
  • EP3335323B1 patent drawingFigure 1
  • EP3335323B1 patent drawingFigure 2
  • EP3335323B1 patent drawingFigure 3

AI summary

Methods, systems, devices, and apparatuses are described for phase noise estimation. A transmitting device identifies a phase noise metric associated with a receiving device. The phase noise metric provides an indication of the expected phase noise for the receiving device. The transmitting device selects a plurality of pilot tones adjacent to each other and a plurality of null tones for a transmission to the receiving device based on the phase noise metric. The plurality of null tones may be adjacent to and on both sides of the pilot tones in the frequency domain. The transmitting device identifies its own phase noise metric and select the pilot tones adjacent to each other and plurality of null tones in further consideration of its own phase noise metric. The receiving device may use the pilot tones and plurality of adjacent null tones to determine a phase noise estimation for the transmission.