Time Domain DMRS for Channel Estimation in High Doppler Scenarios

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Solution Overview

Problem

Current wireless communication systems face challenges in channel estimation, particularly in high Doppler spread scenarios, where frequency offset estimation and inter-carrier interference (ICI) impact communication performance.

Innovation Solution

The method involves obtaining a demodulation reference signal (DMRS) with a constant envelope in the time domain and multiplexing it with data resource elements (REs) to generate a communication signal for channel estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional channel estimation methods are used in high Doppler spread scenarios, then system complexity is reduced, but frequency offset estimation accuracy deteriorates and inter-carrier interference increases

Engineering Contradiction:

Improvefrequency offset estimation accuracyVSAvoidchannel estimation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-processing the received signal through cyclic prefix removal and FFT transformation before channel estimation. The DMRS is extracted and processed in advance, with frequency offset compensation applied before channel estimation, thereby improving estimation accuracy while maintaining manageable system complexity through structured signal processing steps

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the channel estimation process into distinct stages: signal reception, cyclic prefix removal, FFT transformation, DMRS extraction, frequency offset estimation, compensation, and final channel estimation. This segmentation allows each step to be optimized independently, improving overall precision without proportionally increasing complexity

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If conventional reference signals are used for channel estimation, then signal processing is simpler, but inter-carrier interference impact increases in high Doppler spread scenarios

Engineering Contradiction:

Improveinter-carrier interference impactVSAvoidsignal processing simplicity

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent uses frequency offset compensation as an intermediary step between signal reception and channel estimation. By estimating and compensating for frequency offset using the DMRS before performing channel estimation, the harmful inter-carrier interference is reduced, and the compensation acts as a mediator that protects the estimation process from Doppler-induced interference

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of frequency offset and inter-carrier interference into a benefit by using the known DMRS structure to estimate and compensate for these effects. The interference that would normally degrade performance is instead used to identify and correct the frequency offset, thereby improving channel estimation accuracy

Inventive Principle:

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

Data Source

PatentUS12301492B2Time domain demodulation reference signal for channel estimation

Publication Date: 2025.05.13 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a network node may obtain a demodulation reference signal (DMRS) having a constant envelope in a time domain. The network node may generate a communication signal based at least in part on multiplexing the DMRS with a plurality of data resource elements. Numerous other aspects are described.