PUCCH Resource Configuration for Subslot HARQ-ACK Feedback
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Solution Overview
Problem
In Release 15 of the 3GPP, the available PUCCH resources are insufficient for user equipment handling Ultra Reliable and Low Latency Communications (URLLC) traffic, especially when considering the payload size, PUCCH format, and avoiding resource collisions, necessitating an extension of the PUCCH resource configuration mechanism.
Innovation Solution
The user equipment configures and selects appropriate PUCCH resource sets based on payload size and control information, allowing for subslot-based HARQ-ACK feedback by identifying sub-slots and selecting resources within uplink control channels to ensure sufficient PUCCH resources for URLLC traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the Release 15 PUCCH resource configuration mechanism is used, then the system maintains backward compatibility and simple structure, but the PUCCH resources are insufficient for URLLC traffic requiring subslot-based HARQ-ACK feedback
Solution Approach 1:
The patent divides the slot into multiple sub-slots and configures separate PUCCH resource sets for each sub-slot. This segmentation allows the system to provide sufficient PUCCH resources for URLLC traffic requiring subslot-based HARQ-ACK feedback while maintaining the original slot-based structure for other traffic, thus resolving the contradiction between resource sufficiency and system complexity
Solution Approach 2:
The patent introduces dynamic PUCCH resource configuration where the number of PUCCH resource sets and their parameters can be adjusted based on traffic requirements. For URLLC services requiring subslot-based feedback, the system dynamically configures appropriate resource sets, while maintaining static configuration for eMBB services, achieving adaptability without excessive complexity
2Reliability
If multiple PUCCH transmission opportunities are configured in one slot for URLLC, then the HARQ-ACK feedback reliability and latency are improved, but the PUCCH resource requirements and configuration complexity increase
Solution Approach 1:
The patent designs PUCCH resource sets that can serve multiple functions: the same resource set structure is used for both slot-based HARQ-ACK feedback (eMBB) and subslot-based HARQ-ACK feedback (URLLC). This multi-functionality allows the system to meet the increased resource requirements for reliable URLLC feedback while avoiding the need for entirely separate resource configurations
Solution Approach 2:
The patent changes key parameters of PUCCH resource sets to accommodate multiple transmission opportunities. By adjusting parameters such as the number of resource sets, resources per set, and their temporal distribution across sub-slots, the system provides sufficient resources for reliable URLLC feedback while maintaining efficient resource utilization
3Reliability
If PUCCH resources are increased for subslot-based HARQ-ACK feedback, then the URLLC service quality is improved, but the resource collision risk with other user equipment increases
Solution Approach 1:
The patent assigns different PUCCH resource sets to different sub-slots within a slot, creating local resource differentiation. This allows URLLC traffic in specific sub-slots to have dedicated resources while eMBB traffic in other sub-slots uses different resources, thereby improving URLLC service quality while minimizing resource collision risk through spatial (temporal) separation
Data Source
AI summary
There is provided a user equipment including a receiving unit that receives control information and data; a control unit that specifies a sub-slot for transmitting a Hybrid Automatic Repeat Request-Acknowledgment (HARQ-ACK) for the data received by the receiving unit based on the control information received by the receiving unit, configures resource sets of one or more uplink control channels used for HARQ-ACK bit transmission for the specified sub-slot, selects a resource set of one uplink control channel among the resource sets of the one or more uplink control channels based on payload size of uplink control information including the HARQ-ACK, and selects one resource among one or more resources included in the resource set of the selected one uplink control channel based on the control information received by the receiving unit; and a transmitting unit that transmits the uplink control information using the selected one resource.