Uplink Control Information Transmission on Unlicensed Spectrum
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Solution Overview
Problem
In the New Radio (NR) system, particularly in the NR-U system, there is a challenge with transmitting uplink control information (UCI) on unlicensed spectrum due to Listen-Before-Talk (LBT) failures, which can lead to incorrect transmission of UCI, affecting the demodulation of uplink data.
Innovation Solution
A method is implemented where a terminal device determines first and second time-frequency resources for transmitting uplink data and UCI, respectively, with the UCI resources occupying multiple sub-bands within the first time-frequency resources, allowing channel sensing and determining transmission based on the sensing result to ensure correct demodulation of UCI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the terminal device transmits UCI on pre-configured time-frequency resources in NR-U system, then uplink data transmission can be performed, but the UCI transmission may fail due to LBT failure on specific sub-bands
Solution Approach 1:
The patent divides the frequency domain into multiple sub-bands and allocates different UCI resources to different sub-bands. When LBT failure occurs on certain sub-bands, the terminal device can still transmit UCI on other available sub-bands, ensuring partial UCI transmission success and maintaining uplink data transmission capability.
Solution Approach 2:
The patent dynamically adjusts the frequency domain resources for UCI transmission based on LBT sensing results. When some sub-bands are unavailable due to LBT failure, the system changes the frequency parameters by selecting alternative sub-bands for UCI transmission, thereby adapting to channel conditions and maintaining transmission reliability.
2Reliability
If the UCI is mapped to multiple sub-bands to improve transmission reliability, then the probability of successful UCI transmission increases, but the device complexity increases due to additional channel sensing requirements
Solution Approach 1:
The frequency domain is segmented into multiple sub-bands, each with dedicated UCI resources. The terminal device performs LBT sensing on these sub-bands and selects appropriate ones for transmission. This segmentation allows parallel sensing operations and provides multiple transmission paths, improving reliability while managing complexity through structured resource allocation.
Solution Approach 2:
Instead of requiring LBT sensing on all sub-bands before transmission, the terminal device performs sensing on selected sub-bands and transmits UCI on those that are available. This partial action approach reduces the total sensing overhead while still achieving reliable UCI transmission by utilizing any available sub-band resources.
Data Source
AI summary
An uplink signal transmission method, a terminal device, and a network device are provided. The method comprises: a terminal device determining a first time frequency resource which is used to transmit uplink data acquired by a first transmission block performing rate matching, and a second time frequency resource which is used to transmit UCI, the UCI being used to demodulate the uplink data, the first time frequency resource occupying N sub-bands in a frequency domain, the second time frequency resource being a resource in the first time frequency resource, and the second time frequency resource occupying M sub-bands of the N sub-bands in the frequency domain, where N≥2, M≥1, and N and M are positive integers; and the terminal device performing channel detection on at least one of the N sub-bands, and determining the transmission of the uplink data and the UCI according to a detection result.