Single Carrier Waveform Phase Tracking Reference Signal

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Solution Overview

Problem

Current wireless communication systems face challenges in maintaining high communication quality and reliability due to integrated phase noise, particularly in OFDM waveforms, which leads to increased retransmissions and network overhead.

Innovation Solution

Implementing a phase tracking reference signal (PTRS) using a single carrier waveform encoded in the time domain instead of multiplexing across frequencies, reducing integrated phase noise and improving phase tracking for user equipment (UE).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If OFDM waveform with frequency multiplexing is used for PTRS, then frequency diversity is achieved, but integrated phase noise increases and communication quality deteriorates

Engineering Contradiction:

Improvecommunication qualityVSAvoidintegrated phase noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional approach by encoding PTRS in the time domain instead of frequency domain. Rather than multiplexing PTRS across multiple frequency subcarriers as in OFDM, the invention uses a single carrier waveform where PTRS is embedded in the time domain, fundamentally reversing the domain in which reference signals are transmitted to eliminate phase noise accumulation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts PTRS from the frequency multiplexing structure and isolates it in the time domain on a single carrier. This separation removes PTRS from the harmful frequency-domain environment where phase noise integrates across multiple subcarriers, allowing phase tracking to occur in a cleaner time-domain environment.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If single carrier waveform with time domain encoding is used for PTRS, then integrated phase noise is reduced and communication quality improves, but frequency diversity is lost

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidfrequency diversity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces time-domain encoding as an intermediary mechanism to provide the benefits of frequency diversity without actually transmitting across multiple frequencies. By encoding PTRS information in the time domain on a single carrier, the system mediates between the need for diversity and the need to avoid phase noise, achieving reliable phase tracking through temporal rather than spectral diversity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If OFDM waveform is used, then spectral efficiency is achieved, but retransmissions increase due to phase noise

Engineering Contradiction:

Improvespectral efficiencyVSAvoidretransmission delay

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent converts the harmful effect of phase noise into a benefit by using the single carrier's inherent phase stability. The single carrier waveform, which naturally experiences less phase noise, becomes the vehicle for transmitting PTRS, turning what would normally be a limitation into an advantage for achieving reliable phase tracking and reducing retransmissions.

Inventive Principle:

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

Data Source

PatentUS11909682B2Single carrier waveforms for phase tracking reference signals

Publication Date: 2024.02.20 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, a phase tracking reference signal. The phase tracking reference signal is transmitted using a single carrier waveform and encoded within a time domain. Accordingly, the UE may decode, from the base station, a message, based at least in part on the phase tracking reference signal. Numerous other aspects are provided.