PUCCH Codebook Determination for HARQ-ACK Reliability
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Solution Overview
Problem
In future radio communication systems, the existing LTE system's restrictions on PUCCH repetition transmission and HARQ-ACK duplication for separate PDSCHs in NR systems are not fully considered, leading to potential communication throughput and frequency utilization efficiency issues.
Innovation Solution
A user terminal is equipped with a control section that determines a codebook for PUCCH transmission based on PDSCH candidate occasions, HARQ-ACK transmission timing, and PUCCH repetition factor, enabling appropriate HARQ-ACK transmission through PUCCH repetition transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PUCCH repetition transmission is applied in future radio communication systems using existing LTE restrictions, then HARQ-ACK transmission can be performed, but communication throughput and frequency utilization efficiency deteriorate due to unclear user terminal behavior regarding HARQ-ACK duplication for separate PDSCHs
Solution Approach 1:
The patent changes the codebook determination parameters by introducing slot-based codebook determination that considers PDSCH candidate occasions, HARQ-ACK transmission timing, and PUCCH repetition factor. This parameter change enables clear user terminal behavior definition for PUCCH repetition transmission, resolving the contradiction between transmission reliability and system efficiency.
2Reliability
If HARQ-ACK repetition transmission is enabled in existing LTE systems, then transmission reliability improves, but device complexity increases due to multiple restrictions that need to be met
Solution Approach 1:
The patent segments the codebook determination process into slot-based units, where each slot independently determines its codebook based on local parameters (PDSCH candidate occasions, HARQ-ACK timing, PUCCH repetition factor). This segmentation reduces user terminal complexity by avoiding the need to track and manage complex cross-slot restrictions while maintaining transmission reliability.
Data Source
AI summary
In order to properly transmit UCI, even when PUCCH repetition transmission is used in future radio communication systems, a user terminal according to one aspect of the present disclosure includes a control section that determines a codebook for physical uplink control channel (PUCCH) transmission per slot, based on at least one of physical downlink shared channel (PDSCH) candidate occasions, a timing of hybrid automatic repeat request acknowledgement (HARQ-ACK) transmission corresponding to a received PDSCH and a PUCCH repetition factor, when PUCCH repetition transmission and a semi-static HARQ-ACK codebook are configured; and a transmitting section that transmits HARQ-ACK based on the codebook by applying the PUCCH repetition transmission.