NTN DMRS Bundling Synchronization for Doppler and Delay Drift

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Solution Overview

Problem

In non-terrestrial networks (NTN), the phase continuity required for demodulation reference signal (DMRS) bundling is not maintained due to changes in transmission delay and Doppler shift, leading to synchronization issues between terminal devices and network devices, which affects joint channel estimation performance.

Innovation Solution

The terminal device sends information about timing and frequency pre-compensation updates to the network device, allowing synchronization of DMRS bundling information and addressing power consistency and phase continuity failures, thereby improving joint channel estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If satellite communication is used to provide large cell radius coverage, then coverage area is improved, but transmission delay increases and phase continuity deteriorates

Engineering Contradiction:

Improvecell radiusVSAvoidtransmission delay

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The terminal device performs preliminary timing and frequency pre-compensation updates based on predicted satellite motion, proactively adjusting for future transmission delay variations before they affect DMRS bundling phase continuity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the timing and frequency pre-compensation parameters based on real-time satellite terminal relative motion, making the pre-compensation adaptive to changing transmission conditions rather than using fixed values

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If timing and frequency pre-compensation is updated frequently to maintain phase continuity, then channel estimation accuracy is improved, but signaling overhead increases

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The update information is segmented into essential components (timing pre-compensation update, frequency pre-compensation update) transmitted separately, allowing the network to receive only the necessary updates without redundant data

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the parameter update strategy from continuous full-parameter transmission to selective parameter updates based on actual phase continuity requirements, reducing signaling overhead while maintaining estimation accuracy

Inventive Principle:

Principle #35Parameter changes

3Loss of information

If DMRS bundling is performed without pre-compensation updates, then signaling overhead is reduced, but phase continuity fails and channel estimation accuracy deteriorates

Engineering Contradiction:

Improvesignaling overheadVSAvoidchannel estimation accuracy

Core Design Contradiction:

Loss of informationVSMeasurement precision

Solution Approach 1:

The terminal device provides feedback to the network device about the timing and frequency pre-compensation update requirements, enabling the network to adjust DMRS bundling parameters based on actual channel conditions while minimizing unnecessary signaling

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The terminal device autonomously determines when pre-compensation updates are needed based on local measurements of phase continuity, performing self-service updates without requiring continuous network coordination, thus reducing overall signaling overhead

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This synchronization enables accurate joint channel estimation, enhancing communication performance by aligning DMRS bundling windows between the terminal and network devices, thus improving coverage and reducing performance losses.

Implementation Method 1

due to changes in transmission delay and Doppler shift caused by relative motion between a satellite and a terminal device

Methodology Applied

Scientific EffectDoppler shift: Doppler Effect

Data Source

PatentUS20250393005A1Communication method, terminal device, and network device

Publication Date: 2025.12.25 QUECTEL WIRELESS SOLUTIONS CO LTD

AI summary

A communication method includes: a terminal device sending first information to a network device, wherein the first information indicates information of updating timing and frequency pre-compensation within a first time period. The terminal device sends the information of updating timing and frequency pre-compensation to the network device, so that the network device can directly or indirectly know DMRS bundling information of the terminal device, and thus information associated with failures of power consistency and/or phase continuity can be synchronized between the network device and the terminal device, thereby improving the performance of joint channel estimation.