Early HARQ Feedback Mechanism for Wireless Latency Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless communication systems face challenges in reducing latency and improving transmission reliability due to the reactive nature of traditional Hybrid Automatic Repeat Request (HARQ) mechanisms.
Innovation Solution
The implementation of an Early Hybrid Automatic Repeat Request (E-HARQ) mechanism, where a wireless transmit-receive unit (WTRU) predicts channel decoder success and sends early acknowledgement (eACK) or early negative acknowledgement (eNACK) feedback, along with a transmission reliability score (TRS), to the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional reactive HARQ mechanism is used, then transmission reliability is maintained through post-decoding feedback, but latency increases due to waiting for complete decoding before sending ACK/NACK
Solution Approach 1:
The patent applies preliminary action by performing channel estimation and reliability prediction before the complete decoding process finishes. The WTRU estimates channel quality using reference signals and predicts decoding success probability in advance, enabling early feedback transmission without waiting for full decoding completion, thus reducing latency while maintaining reliability through predictive accuracy.
Solution Approach 2:
The patent enhances feedback mechanism by introducing early feedback based on predicted decoding success rather than waiting for actual decoding results. The WTRU transmits early ACK/NACK feedback signals to the base station based on channel quality predictions, enabling the base station to prepare for next transmission steps earlier, thereby reducing round-trip time while maintaining transmission reliability through continuous monitoring and adaptive feedback.
2Productivity
If early feedback is sent before decoding completion, then latency is reduced by enabling earlier next steps, but decoding process is interrupted and complexity increases
Solution Approach 1:
The patent implements preliminary action by performing channel estimation and reliability prediction before complete decoding finishes. The WTRU uses reference signals to estimate channel quality and predict decoding success probability in advance, enabling early feedback without actually interrupting the decoding process, thus maintaining throughput while avoiding the complexity of premature decoding termination.
Solution Approach 2:
The patent applies self-service by having the WTRU autonomously perform channel estimation and reliability prediction using received reference signals without requiring base station intervention. The WTRU independently computes transmission reliability scores and generates early feedback signals based on its own channel conditions, reducing system complexity by eliminating the need for base station coordination in the prediction process.
3Reliability
If adaptive retransmission packet sizing is implemented based on TRS feedback, then transmission reliability improves, but feedback mechanism complexity increases
Solution Approach 1:
The patent applies parameter changes by using transmission reliability scores (TRS) as a feedback parameter to dynamically adjust retransmission packet sizes. The WTRU calculates TRS based on channel quality predictions and feeds back this information to the base station, which then adapts the size of retransmission packets accordingly, improving transmission reliability by matching packet size to channel conditions without requiring complex feedback protocols.
Data Source
AI summary
In an embodiment, a wireless transmit-receive unit includes a receiver, a processor, and a transmitter. The receiver is configured to receive, from a base station, an encoded code block of a transport block. The processor is configured to predict whether the processor will decode the encoded code block successfully. And the transmitter is configured to transmit, to the base station, a result of the predicting.