PUCCH Resource Allocation Under LBT Failure in NR-U
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Solution Overview
Problem
In the New Radio (NR) Unlicensed (NR-U) system, the limitation on Physical Uplink Control CHannel (PUCCH) transmission opportunities due to Listen-Before-Talk (LBT) failures leads to transmission delay and reduced throughput performance.
Innovation Solution
Adopting different resource configurations for PUCCH transmission scenarios based on the relationship between the target transmission time unit and a first time period, including configuring a first resource set and a second resource set to enhance transmission opportunities, especially when the transmission time unit is within or outside the Channel Occupation Time (COT).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal follows the Listen-Before-Talk (LBT) principle before transmitting PUCCH, then the system maintains fair channel access and reduces interference, but transmission delay increases and throughput performance deteriorates when LBT fails
Solution Approach 1:
The base station pre-configures multiple PUCCH resource sets (first resource set and second resource set) before the terminal needs to transmit HARQ feedback. These resource sets are prepared in advance with different time unit relationships, so when LBT fails or channel conditions change, the terminal can immediately switch to alternative pre-configured resources without waiting for new configuration or performing additional LBT attempts, thus reducing transmission delay while maintaining fair channel access
Solution Approach 2:
The patent implements dynamic PUCCH resource selection by establishing different resource determination methods based on the relationship between target transmission time units and channel occupation time (COT). When the target time unit is within COT, one resource determination method is used; when outside COT, another method is applied. This dynamic adaptation allows the system to optimize transmission timing based on real-time channel conditions, reducing unnecessary delays caused by rigid resource allocation while maintaining LBT fairness
2Device complexity
If the terminal uses a single PUCCH resource configuration, then the system complexity is reduced, but transmission success probability decreases when LBT fails
Solution Approach 1:
The patent segments PUCCH resources into multiple distinct resource sets (first resource set and second resource set) with different configuration characteristics. Each resource set is associated with specific time unit relationships relative to COT. This segmentation provides the terminal with multiple transmission opportunities and alternative paths when one resource becomes unavailable due to LBT failure, thereby increasing transmission success probability while keeping each individual resource set relatively simple to manage
Solution Approach 2:
The patent changes key parameters of PUCCH resource configuration based on the relationship between target transmission time units and COT. Different resource sets are configured with different time offsets, frequency resources, or format parameters depending on whether transmission occurs within or outside COT boundaries. These parameter changes enable adaptive resource selection that increases transmission reliability without requiring complex multi-dimensional resource management, as each resource set maintains clear, distinguishable parameter characteristics
Data Source
AI summary
Methods and apparatuses for determining and allocating resources are provided. The method for determining resources includes: the terminal determines a target sending time unit of a target channel, and determines resources of the target channel according to the relationship of the target sending time unit of the target channel and a first time period.