HARQ-ACK Codebook Retransmission Under UCI Collision
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Solution Overview
Problem
The increasing demand for high data throughput and efficient communication in wireless networks, particularly in next-generation communication systems, necessitates improved methods for managing HARQ-ACK responses to avoid delays, overlaps, and inappropriate transmissions, especially in high-density UE environments.
Innovation Solution
Implementing techniques for HARQ-ACK deferral and retransmission, prioritization, and collision handling in wireless communication systems, including HARQ-ACK codebook management and PUCCH repetition strategies to optimize HARQ-ACK feedback in TDD operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK codebook retransmission is scheduled in slot n+k, then reliability of HARQ-ACK delivery is improved, but it may overlap with other UCI transmissions causing resource conflicts
Solution Approach 1:
The patent applies preliminary action by determining whether HARQ-ACK codebook retransmission overlaps with other UCI transmissions before actual transmission occurs. The UE checks the scheduled slot n+k in advance, and if overlap is detected, it proactively drops the other UCI transmissions and prioritizes HARQ-ACK codebook transmission, preventing resource conflicts before they manifest in the wireless medium.
2Productivity
If the number of UEs served by the BS increases, then network coverage and service capacity are improved, but the volume of control information and resource management complexity increase
Solution Approach 1:
The patent applies the taking out principle by extracting HARQ-ACK codebook retransmission from the general UCI transmission pool and giving it special prioritization status. When HARQ-ACK codebook retransmission is scheduled, the system separates it from other UCI transmissions by dropping conflicting other UCI, ensuring that critical HARQ feedback is delivered reliably even as the number of served UEs increases.
3Productivity
If HARQ-ACK transmission is prioritized over other UCI, then latency is reduced and throughput is improved, but other control information may be dropped
Solution Approach 1:
The patent applies the blessing in disguise principle by converting the potential harm of dropping other UCI transmissions into a benefit for overall system throughput. By deliberately dropping lower-priority other UCI transmissions when HARQ-ACK codebook retransmission is scheduled, the system ensures timely delivery of critical HARQ feedback, which enables faster retransmission decisions and improves overall network throughput, effectively trading minor information loss for significant performance gain.
Data Source
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AI summary
A UE may receive, in a slot n, DCI for triggering retransmission of a first HARQ-ACK codebook scheduled for transmission in a slot m, determine a slot n+k for retransmission of the first HARQ-ACK codebook based on the DCI, determine a second HARQ-ACK codebook, including the first HARQ-ACK codebook, to be transmitted in the slot n+k, and, based on transmission of the second HARQ-ACK codebook overlapping in time with transmission of another UCI in the slot n+k, drop transmission of the other UCI and perform transmission of the second HARQ-ACK codebook in the slot n+k.