Subslot PUCCH Resources for Low-Latency URLLC HARQ-ACK Feedback

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Solution Overview

Problem

Existing wireless communication systems face challenges in achieving high flexibility and efficiency, particularly in supporting ultra-reliable low-latency communication (URLLC) services, due to limitations in PUCCH resource allocation and HARQ-ACK feedback mechanisms.

Innovation Solution

The implementation of enhanced PUCCH formats with higher transmit power, transmit diversity, and subslot structures for PUCCH resource configuration, allowing multiple HARQ-ACK feedback instances within a slot to meet URLLC reliability and latency requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional PUCCH resource allocation is used, then device complexity is reduced, but reliability and latency requirements for URLLC services cannot be met

Engineering Contradiction:
ImproveURLLC reliabilityVSAvoidPUCCH resource configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the slot into multiple subslots and configures separate PUCCH resources for each subslot. This allows multiple HARQ-ACK feedback instances within a single slot, enabling the system to meet URLLC reliability requirements through diversified feedback opportunities while managing complexity through structured resource allocation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic PUCCH resource selection based on subslot boundaries and configurable parameters. The network can dynamically adjust PUCCH resource allocation, timing offsets, and feedback instances according to traffic conditions and URLLC requirements, providing flexibility to meet reliability targets while adapting to varying system states.

Inventive Principle:
Principle #15Dynamics

2Loss of time

If multiple HARQ-ACK feedback instances are implemented within a slot, then latency is reduced, but resource allocation complexity increases

Engineering Contradiction:
ImproveHARQ-ACK feedback latencyVSAvoidPUCCH resource allocation complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

By dividing the slot into subslots with dedicated PUCCH resources, the patent enables multiple HARQ-ACK feedback instances to be transmitted at different subslot boundaries. This segmentation reduces feedback latency by providing earlier acknowledgment opportunities while the structured subslot-based resource allocation manages the complexity of multiple feedback instances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent configures PUCCH resources in advance for multiple subslots, pre-establishing the timing and resource allocation for potential HARQ-ACK feedback instances. This preliminary configuration allows the system to quickly activate appropriate feedback instances without real-time decision complexity, reducing latency while managing resource allocation overhead.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If enhanced PUCCH formats with higher transmit power are used, then reliability is improved, but energy consumption increases

Engineering Contradiction:
ImprovePUCCH transmission reliabilityVSAvoidUE transmit power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent enables dynamic transmit power adjustment for PUCCH transmissions based on the selected format and subslot configuration. The UE can adapt power levels according to the specific transmission requirements, using higher power only when necessary for enhanced reliability while conserving energy in scenarios with better channel conditions or less critical transmissions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces configurable parameters that allow the network to adjust PUCCH transmit power, format selection, and resource allocation based on URLLC requirements. By changing these parameters dynamically, the system can optimize the trade-off between transmission reliability and energy consumption for each specific transmission scenario.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3909357B1Low-latency physical uplink control channel (PUCCH) enhancements and resource configuration
Publication Date: 2025.07.23 SHARP KK
  • EP3909357B1 patent drawingFigure 1
  • EP3909357B1 patent drawingFigure 2
  • EP3909357B1 patent drawingFigure 3

AI summary

A user equipment (UE) is described. The UE includes a higher layer processor configured to determine a physical uplink control channel (PUCCH) resource in a slot or a subslot for HARQ-ACK feedback for ultra-reliable low-latency communication (URLLC) physical downlink shared channel (PDSCH) transmissions. The PUCCH resource is specified as an enhanced PUCCH format configured to satisfy URLLC PUCCH reliability requirements. The UE also includes transmitting circuitry configured to transmit the HARQ-ACK feedback for the URLLC PDSCH transmissions based on the determined PUCCH resource.