UE HARQ-ACK Bit Determination Under Missed DCI Conditions
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Solution Overview
Problem
Inconsistency in understanding the number of HARQ-ACK feedback bits between a user terminal and a base station can cause errors and reduce frequency use efficiency and throughput, particularly in unlicensed frequency bands due to interference and missed detection of downlink control information.
Innovation Solution
A user terminal determines the number of HARQ-ACK feedback bits based on information related to the number of feedback bits and transmission timing of downlink control information, using triggering DCI to prevent inconsistencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE determines HARQ-ACK feedback bits based on DCI detection, then the feedback mechanism is flexible and adaptive, but inconsistency in understanding the number of feedback bits occurs between UE and base station
Solution Approach 1:
The patent introduces a feedback mechanism where the base station sends DCI containing the actual number of HARQ-ACK feedback bits to the UE. This feedback loop ensures that the UE can adjust its feedback bit count to match the base station's expectation, resolving the inconsistency problem while maintaining flexibility in HARQ-ACK feedback mechanisms
Solution Approach 2:
The DCI message acts as an intermediary carrier that conveys the number of HARQ-ACK feedback bits from the base station to the UE. This intermediary mechanism ensures both parties have consistent understanding without requiring complex direct negotiation or rigid pre-configuration
2Object-affected harmful factors
If the UE misses detecting DCI in unlicensed frequency bands, then interference resistance is reduced, but the complexity of handling missed detection increases
Solution Approach 1:
The base station performs preliminary action by determining and communicating the number of HARQ-ACK feedback bits through DCI before the UE needs to transmit feedback. This allows the UE to prepare the correct number of feedback bits in advance, reducing the impact of missed DCI detection in interference-prone unlicensed bands
Solution Approach 2:
The system dynamically changes the parameter of HARQ-ACK feedback bit count based on the DCI received from the base station. This parameter adaptation allows the UE to adjust to different feedback requirements while simplifying the handling of missed detection scenarios through standardized fallback procedures
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3
AI summary
A user terminal includes a receiving section that receives downlink control information to request feedback of transmission confirmation information for one or more downlink shared channels, and a control section that determines the number of feedback bits of the transmission confirmation information based on at least one of information related to the number of feedback bits in the downlink control information and information related to transmission timing of last downlink control information to schedule the downlink shared channel. It is possible to prevent inconsistency in understanding of the number of feedback bits of transmission confirmation information between a UE and a base station.