HARQ-ACK Deferral and Retransmission for Overlapping Slot Feedback
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Solution Overview
Problem
The increasing demand for high data throughput and diverse communication services in wireless networks necessitates efficient methods for managing limited radio resources, particularly in handling HARQ-ACK responses to prevent redundancy and overlap, and ensuring reliable transmission in high-density UE environments.
Innovation Solution
Implementing a method for managing HARQ-ACK feedback in wireless communication systems, including HARQ-ACK deferral and retransmission processes to prevent redundant information transmission and optimize resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK feedback is transmitted for every PDSCH reception, then reliability of data transmission is improved, but redundancy occurs when multiple PDSCHs are received in overlapping time periods
Solution Approach 1:
The patent extracts and separates the HARQ-ACK feedback transmission for the latest PDSCH from redundant feedback transmissions. By identifying the latest PDSCH reception and deferring its HARQ-ACK feedback to a later uplink opportunity, the system eliminates redundant acknowledgments while maintaining reliable data transmission for all PDSCHs.
Solution Approach 2:
The patent applies preliminary action by determining in advance which PDSCH is the latest received and pre-deferring its HARQ-ACK feedback transmission. This preliminary identification and deferral decision prevents redundant feedback before it occurs, optimizing resource usage while ensuring reliability.
2Loss of time
If HARQ-ACK feedback is transmitted immediately for each PDSCH, then latency is reduced, but resource utilization deteriorates due to redundant transmissions in high-density UE environments
Solution Approach 1:
The patent extracts the redundant HARQ-ACK feedback transmissions and removes them from the system. By identifying and eliminating feedback for PDSCHs that are already acknowledged through the latest PDSCH's deferred feedback, the system reduces unnecessary resource usage while maintaining appropriate latency for critical acknowledgments.
Solution Approach 2:
The patent discards redundant HARQ-ACK feedback information that would otherwise be transmitted unnecessarily. By deferring and consolidating feedback for the latest PDSCH, the system recovers radio resources that would be consumed by redundant transmissions, improving overall resource utilization in high-density UE environments.
3Productivity
If HARQ-ACK deferral is implemented to prevent redundancy, then resource utilization is improved, but complexity of HARQ-ACK management increases
Solution Approach 1:
The patent applies preliminary action by establishing clear rules and procedures for identifying the latest PDSCH and determining when to defer HARQ-ACK feedback. This preliminary framework simplifies the management complexity by providing deterministic criteria rather than requiring complex real-time decisions, making the deferral mechanism easier to implement and manage.
Solution Approach 2:
The patent implements a feedback mechanism where the system monitors PDSCH receptions, identifies the latest one, and applies deferral rules systematically. This structured feedback loop manages the complexity of HARQ-ACK deferral by providing clear decision criteria and consistent processing rules, reducing management burden despite the added functionality.
Data Source
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AI summary
A UE may determine a target slot for HARQ deferral for transmission of first HARQ-ACK information, based on transmission of the first HARQ-ACK information overlapping with a downlink symbol in a first slot, transmit a second HARQ-ACK codebook including a first HARQ-ACK codebook in a second slot for retransmission of the first HARQ-ACK codebook, based on DCI triggering retransmission of the first HARQ-ACK codebook scheduled to be transmitted in the first slot, and transmit uplink control information in the target slot. The uplink control information does not include the first HARQ-ACK information, based on the second HARQ-ACK codebook including the first HARQ-ACK information.