HARQ NACK Repetition Resource Allocation for Low-Latency Reliability
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Solution Overview
Problem
HARQ feedback mechanisms in wireless communication systems, such as 5G NR, often fail to operate flawlessly, leading to erroneous interpretations that compromise latency and reliability, particularly in ultra-reliable low-latency communications (URLLC) and Industrial Internet of Things (IIoT), which can negatively impact performance and user experience.
Innovation Solution
Implementing low-overhead mechanisms where HARQ feedback is transmitted with repetitions only when indicating NACK, and not when indicating ACK, to improve reliability without exceeding acceptable latency thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is transmitted with repetitions for every feedback type (ACK and NACK), then reliability is improved, but latency increases beyond acceptable thresholds
Solution Approach 1:
The patent applies local quality by differentiating the treatment of ACK and NACK feedback messages. Instead of uniformly applying repetitions to all feedback types, the invention selectively applies repetitions only to NACK messages while leaving ACK messages without repetitions. This localized approach targets the specific reliability issues with NACK transmission without incurring the latency penalty for all feedback types, thus resolving the contradiction between reliability improvement and latency control.
2Reliability
If HARQ feedback mechanisms operate without error correction, then latency is reduced, but reliability deteriorates below required thresholds
Solution Approach 1:
The patent implements partial action by applying error correction mechanisms (repetitions) only to the extent necessary - specifically for NACK messages where reliability is most critical. ACK messages, which already indicate successful reception, do not require the same level of error correction. This partial application of error correction achieves the required reliability threshold without the excessive latency that would result from applying error correction to all feedback messages uniformly.
3Reliability
If resource allocations are increased for HARQ feedback transmissions, then reliability is improved, but system resource efficiency decreases
Solution Approach 1:
The patent applies local quality to resource allocation by dedicating specific resources only to NACK feedback transmissions rather than uniformly allocating resources for all feedback types. The network entity is configured with separate resource allocations: first resources for initial HARQ feedback and second resources specifically for NACK repetitions. This localized resource allocation improves reliability for critical NACK messages while maintaining overall system resource efficiency by not over-provisioning resources for ACK transmissions.
Data Source
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AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE or a component thereof that is configured to transmit, to a network entity on a first set of resources, feedback including an ACK or a NACK corresponding to a transmission from the network entity. The feedback may be transmitted without repetition when the feedback includes the ACK corresponding to the transmission. The apparatus may be further configured to transmit, to the network entity on a second set of resources, a repetition of the feedback when the feedback includes the NACK corresponding to the transmission.