Predicted NACK Transmission for Downlink Retransmission Latency

Solution Overview

Problem

Current wireless communication systems experience significant latency due to the traditional HARQ feedback timeline, which delays retransmissions of downlink data messages, especially when decoding failures are predicted only after completing the decoding process.

Innovation Solution

User Equipment (UE) transmits a predicted NACK message before finishing the decoding process, allowing the base station to retransmit the data earlier based on a shorter timeline, utilizing decoding metrics and machine learning algorithms to predict decoding failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE waits to transmit NACK after completing the decoding process according to the traditional HARQ feedback timeline, then the decoding accuracy is ensured, but the retransmission latency increases

Engineering Contradiction:

Improvedecoding accuracyVSAvoidretransmission latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The UE performs preliminary decoding stages and transmits a predicted NACK message before completing the full decoding process. This preliminary action allows the base station to initiate retransmission earlier, reducing latency while maintaining decoding accuracy through subsequent verification

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements an early feedback mechanism where the UE provides intermediate decoding status information to the base station during the decoding process. This feedback enables the base station to make informed decisions about retransmission timing without waiting for complete decoding

Inventive Principle:

Principle #23Feedback

2Loss of time

If the UE transmits a predicted NACK message before completing the decoding process, then the retransmission latency is reduced, but the risk of false prediction increases

Engineering Contradiction:

Improveretransmission latencyVSAvoidprediction accuracy

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The UE performs preliminary decoding stages and transmits a predicted NACK message before completing the full decoding process. This preliminary action allows the base station to initiate retransmission earlier, reducing latency while maintaining decoding accuracy through subsequent verification

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent incorporates verification mechanisms and threshold-based decision making to cushion against false predictions. The UE uses multiple decoding metrics and confidence thresholds to reduce the probability of erroneous predicted NACK transmissions

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the UE performs complete decoding before transmitting feedback, then the feedback reliability is improved, but the processing timeline is extended

Engineering Contradiction:

Improvefeedback reliabilityVSAvoidprocessing timeline

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent segments the decoding process into multiple stages, allowing the UE to transmit feedback after initial decoding stages rather than waiting for complete decoding. This segmentation enables earlier feedback transmission while maintaining overall system reliability through subsequent decoding completion

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The UE performs preliminary decoding stages and transmits a predicted NACK message before completing the full decoding process. This preliminary action allows the base station to initiate retransmission earlier, reducing latency while maintaining decoding accuracy through subsequent verification

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11963023B2Early negative acknowledgment indication for a data message

Publication Date: 2024.04.16 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. Some systems may support the transmission of a predicted negative acknowledgment (NACK) indication for a downlink data message. In some cases, a base station may transmit a downlink data message to a user equipment (UE). The UE may perform a decoding process for the message. The UE may determine whether the decoding process is likely to fail during a first portion of the decoding process prior to completion of the decoding process. The UE may transmit a predicted NACK message to the base station prior to a feedback opportunity configured for the UE to transmit feedback based on a result of the completed decoding process. The base station may determine whether to retransmit the downlink data message based on the predicted NACK message, such that the predicted NACK message may reduce the latency associated with retransmission of downlink data messages.