Uplink Control Information Transmission on Unlicensed Carrier
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Solution Overview
Problem
In the NR-U system, the failure of channel detection for the physical uplink control channel (PUCCH) can significantly impact the delay and performance of the communication link due to the inability to transmit hybrid automatic repeat request acknowledgement (HARQ-ACK) information, limiting transmission opportunities.
Innovation Solution
A method where a terminal device transmits target uplink control information, including HARQ-ACK, in a second time unit on an unlicensed carrier after determining the channel is idle, potentially using a scheduled or pre-configured physical uplink shared channel (PUSCH), even if it was not available in the first time unit, to increase transmission opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If channel detection is performed before transmitting PUCCH on unlicensed spectrum, then transmission reliability is improved, but transmission delay increases when channel is busy
Solution Approach 1:
The terminal device performs channel detection in advance before the scheduled PUCCH transmission time. If the channel is detected as idle, transmission proceeds normally. If busy, the device prepares alternative transmission resources (PUSCH) in advance, allowing rapid switching without waiting for the original transmission time to expire, thus reducing delay while maintaining reliability
Solution Approach 2:
The patent introduces PUSCH as an intermediary transmission channel. When PUCCH transmission is blocked due to busy channel, the HARQ-ACK information is transmitted through PUSCH instead. This intermediary channel provides an alternative path for control information, ensuring reliability while avoiding the delay of waiting for channel clearance
2Adaptability or versatility
If PUCCH transmission is blocked when channel is busy, then channel access rules are maintained, but transmission opportunity is reduced
Solution Approach 1:
The PUSCH channel is given multi-functionality: it serves both for data transmission and for carrying HARQ-ACK control information when PUCCH is unavailable. This universal usage of PUSCH increases transmission opportunities for control information without requiring additional dedicated resources, thereby improving adaptability while maintaining timely transmission
3Reliability
If HARQ-ACK transmission depends on single PUCCH opportunity, then resource efficiency is improved, but link performance is vulnerable to channel conditions
Solution Approach 1:
The patent changes the transmission parameter from single-channel (PUCCH only) to multi-channel (PUCCH or PUSCH). By allowing HARQ-ACK to be transmitted on either channel depending on channel conditions, the system improves link performance reliability. The complexity increase is managed through clear conditional logic: detect channel status, select appropriate channel, and transmit
Data Source
AI summary
A method for transmitting information and receiving information and a communication device are provided. The method is applied to an unlicensed carrier, a first time unit on the unlicensed carrier is used to transmit target uplink control information, and a second time unit on the unlicensed carrier is used to transmit the target uplink shared channel. The second time unit is located after the first time unit in a time domain; and the method includes: a terminal device determines the target uplink control information and the target uplink shared channel; and the terminal device transmits the target uplink control information and the target uplink shared channel in the second time unit.