Adaptive DMRS Training State Feedback for Channel Estimation

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Solution Overview

Problem

Current wireless communication systems lack efficient methods for adaptive demodulation reference signal (DMRS) transmission, particularly in varying channel conditions, which affects decoding quality and channel estimation.

Innovation Solution

A user equipment (UE) indicates its training state to a base station, requesting specific DMRS transmissions for online training, allowing for channel adaptive DMRS transmission based on feedback, enabling improved decoding quality and channel estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If DMRS transmissions are increased for better channel estimation, then channel estimation accuracy is improved, but overhead and time consumption increase

Engineering Contradiction:

Improvechannel estimation accuracyVSAvoidtime consumption

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the DMRS transmission configuration adaptive rather than fixed. The base station dynamically adjusts the number and timing of DMRS symbols based on real-time feedback about the UE's machine learning model training state, allowing the system to optimize between estimation accuracy and time consumption according to actual conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of DMRS transmission configuration based on the training state feedback. When the UE indicates it needs more training, the system increases DMRS symbols; when the UE is sufficiently trained, the system reduces DMRS symbols. This parameter adaptation resolves the contradiction by making the transmission schedule flexible rather than static

Inventive Principle:

Principle #35Parameter changes

2Reliability

If DMRS frequency is increased for better decoding quality, then decoding accuracy is improved, but overhead increases

Engineering Contradiction:

Improvedecoding accuracyVSAvoidoverhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements feedback by having the UE report its training state to the base station, which then adjusts the DMRS transmission schedule accordingly. This closed-loop feedback mechanism allows the system to allocate DMRS resources efficiently based on actual training needs, improving decoding accuracy when necessary while reducing overhead when the UE is sufficiently trained

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts DMRS frequency based on training state rather than using a fixed high overhead configuration. This dynamic adaptation allows the system to maintain high reliability during training phases while minimizing overhead during operational phases

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11456834B2Adaptive demodulation reference signal (DMRS)

Publication Date: 2022.09.27 QUALCOMM INC

AI summary

A method of wireless communication by a user equipment (UE) indicates, to a base station, a training state of a machine learning model for a given channel condition, and a request for a change in demodulation reference signal (DMRS) transmissions. The UE also receives DMRS transmissions in accordance with the training state for the given channel condition. The UE performs online training of the machine learning model with the DMRS transmissions. A UE may also request, from a base station, a specific number of demodulation reference signal (DMRS) symbols for a slot, and receive DMRS transmissions in response to the request to estimate a raw channel.