HARQ-ACK Transmission Reliability on Unlicensed Channels
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Solution Overview
Problem
In 5G NR systems, the one-shot HARQ-ACK feedback mechanism can lead to errors and unnecessary retransmissions due to large interference on unlicensed channels, resulting in data transmission errors.
Innovation Solution
A method and apparatus for HARQ-ACK information transmission, where the base station and user equipment receive high-level signaling with a predetermined information field indicating the number of transmissions (N) for the one-shot HARQ-ACK feedback mechanism, allowing for repeated transmission of the same HARQ-ACK information up to N times to improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the one-shot HARQ-ACK feedback mechanism is used to transmit HARQ-ACK information on unlicensed channels, then the feedback efficiency is improved, but the transmission reliability deteriorates due to large interference
Solution Approach 1:
The base station pre-configures the UE with a predetermined information field indicating the number of transmissions N before actual HARQ-ACK transmission. This preliminary configuration enables the UE to understand how many times it should repeat the transmission, allowing the system to proactively prepare for potential interference issues rather than reacting after transmission failures occur.
Solution Approach 2:
The HARQ-ACK information is transmitted periodically N times according to the predetermined configuration. Instead of a single transmission, the same HARQ-ACK information is sent multiple times at different feedback occasions, increasing the probability that at least one transmission will succeed despite interference on unlicensed channels.
2Loss of time
If HARQ-ACK information is transmitted only once, then the transmission delay is reduced, but the error rate increases due to interference
Solution Approach 1:
The system changes the transmission parameter from a single transmission to N repeated transmissions based on the predetermined information field configuration. This parameter adjustment allows the system to balance between transmission delay and error rate by optimizing the number of repetitions according to channel conditions and interference levels.
3Reliability
If repeated transmissions are performed without predetermined configuration, then the transmission success rate improves, but the system complexity increases
Solution Approach 1:
The base station provides feedback to the UE through high-layer signaling, configuring the predetermined information field that indicates the number of transmissions N. This feedback mechanism simplifies the UE's decision-making process, as the UE simply follows the configured N value without needing to independently determine the optimal number of repetitions, thereby reducing system complexity while maintaining high transmission success rate.
Data Source
AI summary
Disclosed in the present disclosure are an HARQ-ACK information transmission method and apparatus, and a communication device. The HARQ-ACK information transmission method comprises: when a one shot HARQ-ACK feedback mechanism is configured for user equipment (UE), issuing high-level signaling comprising a predetermined information domain; and on the basis of the number of transmissions N carried by the predetermined information domain, receiving same HARQ-ACK information for N times on N feedback occasions corresponding to the one shot HARQ-ACK feedback mechanism, wherein N is a positive integer.