Terminal HARQ-ACK Multiplexing Control for Missing Downlink Allocation
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Solution Overview
Problem
In 5G wireless communication systems, the determination of uplink channels to be transmitted is unclear when an uplink grant indicates multiplexing of HARQ-ACK for retransmission control, especially when the downlink allocation corresponding to the HARQ-ACK is not received.
Innovation Solution
A terminal is provided with a reception unit to receive uplink grants, a control unit to determine whether HARQ-ACK should be multiplexed with the uplink shared channel based on the DAI in the grant, and a transmission unit to transmit the uplink shared channel, even if the downlink allocation is not received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DAI in the uplink grant indicates multiplexing of HARQ-ACK, then the uplink shared channel can carry retransmission control information, but the terminal operation is undefined when the corresponding downlink allocation is not received
Solution Approach 1:
The patent applies preliminary action by defining terminal behavior in advance for the case when downlink allocation is not received. The terminal is configured to determine that HARQ-ACK should still be multiplexed with the uplink shared channel based on the DAI indication, even before knowing whether the downlink allocation was received. This pre-defined operation rule eliminates the ambiguity and ensures reliable HARQ-ACK transmission.
2Productivity
If HARQ-ACK multiplexing is indicated by DAI, then uplink control information efficiency is improved, but transmission accuracy becomes uncertain when downlink allocation is missing
Solution Approach 1:
The patent implements feedback mechanism where the terminal monitors whether the downlink allocation corresponding to HARQ-ACK is received. Based on this feedback information and the DAI indication in the uplink grant, the terminal determines whether to multiplex HARQ-ACK with the uplink shared channel. This feedback-based decision ensures transmission accuracy while maintaining uplink control information efficiency.
Data Source
AI summary
A terminal includes: a reception unit configured to receive a grant related to an uplink shared channel from a base station; a control unit configured to determine whether HARQ-ACK (Hybrid automatic repeat request—Acknowledgement) is to be multiplexed with the uplink shared channel in a case where a DAI (Downlink Assignment Index) included in the grant indicates that the HARQ-ACK is to be multiplexed with the uplink shared channel and where a downlink allocation corresponding to the HARQ-ACK that is to be multiplexed with the uplink shared channel is not received; and a transmission unit configured to transmit the uplink shared channel to the base station.