Predictive HARQ Feedback Using ML for Low-Latency Retransmission

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Solution Overview

Problem

Existing wireless communication systems face challenges in achieving stringent latency and reliability constraints, particularly in ultra-reliable low-latency communication (URLLC) services, due to bottlenecks in hybrid automatic repeat request (HARQ) feedback procedures.

Innovation Solution

Implementing machine learning-assisted predictive retransmission feedback, where user equipment (UE) predicts HARQ feedback before complete data reception using machine learning, and communicates this prediction to the base station, allowing for resource allocation adjustments and minimizing latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If traditional HARQ feedback procedure is used, then reliability is maintained through complete decoding verification, but latency increases due to waiting for complete data reception and decoding

Engineering Contradiction:
ImproveHARQ feedback latencyVSAvoidFeedback accuracy
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies preliminary action by performing channel decoding before complete data reception. The UE decodes the received portion of downlink data and generates HARQ feedback (ACK/NACK) based on this partial decoding, rather than waiting for the entire data packet to be received and decoded. This enables early feedback transmission, reducing latency while maintaining sufficient reliability through the decoding of available data portions.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If predictive retransmission feedback is implemented, then latency is reduced by early feedback transmission, but device complexity increases due to machine learning components

Engineering Contradiction:
ImproveFeedback transmission timeVSAvoidUE processing complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the UE to autonomously perform machine learning-based predictive feedback generation without requiring base station intervention in the decision-making process. The UE's machine learning model independently analyzes channel conditions and data characteristics to predict whether retransmission is needed, generating feedback automatically based on local observations and learned patterns, thereby reducing overall system complexity despite the advanced processing required.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If machine learning model is used for prediction, then feedback timing flexibility is improved, but measurement precision requirements increase for accurate prediction

Engineering Contradiction:
ImproveFeedback timing flexibilityVSAvoidChannel condition measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by adapting the machine learning model's input parameters and decision thresholds based on varying channel conditions and data characteristics. The model dynamically adjusts its prediction criteria according to factors such as signal strength, interference levels, and data encoding parameters, allowing flexible feedback timing while maintaining prediction accuracy through adaptive parameter adjustment rather than relying on fixed precision measurements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4292229B1Machine learning assisted predictive retransmission feedback
Publication Date: 2026.01.07 QUALCOMM INC
  • EP4292229B1 patent drawingFigure 1
  • EP4292229B1 patent drawingFigure 2A~2B
  • EP4292229B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communications are described. The method includes transmitting, to a base station, a capability parameter indicating one or more predictive retransmission feedback capabilities of the UE, receiving, from the base station, an activation indicator that indicates a predictive retransmission feedback procedure is enabled, receiving data from the base station, and transmitting a predictive retransmission feedback associated with the data to the base station, the predictive retransmission feedback being computed, in accordance with the activation indicator, prior to completing a decoding of the data.