ACK Feedback Resource Selection for Multiple Active SPS Downlinks

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Solution Overview

Problem

In wireless communications systems, user equipment (UE) faces challenges in providing acknowledgment feedback for multiple active downlink semi-persistent scheduling (SPS) configurations due to potential collisions and inefficiencies in managing control channel resources for multiple downlink messages.

Innovation Solution

The UE selects control channel resources based on the number of acknowledgment (ACK) information bits to be transmitted, compares this number to a threshold, and uses configured or dynamic codebooks to manage ACK feedback for multiple SPS configurations, potentially delaying transmission to available slots, thereby optimizing resource use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the UE transmits ACK feedback for multiple downlink messages using the same control channel resources, then the resource utilization is efficient, but collisions occur between acknowledgment feedback transmissions

Engineering Contradiction:
Improvecontrol channel resource usageVSAvoidACK feedback transmission
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent segments the control channel resources by creating multiple PUCCH resource sets, where each set is assigned to specific SPS configuration groups. This segmentation prevents collisions by ensuring that ACK feedback from different SPS configurations uses separate resource pools, while still maintaining efficient resource utilization within each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic resource selection where the UE dynamically chooses which PUCCH resource set to use based on the number of ACK information bits to be transmitted. This dynamic adaptation allows the system to optimize resource allocation in real-time, preventing collisions while maintaining efficiency.

Inventive Principle:
Principle #15Dynamics

2Loss of time

If the UE prepares ACK feedback for multiple downlink messages simultaneously, then the feedback is transmitted timely, but the complexity of managing control channel resources increases

Engineering Contradiction:
ImproveACK feedback preparation timeVSAvoidUE processing complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring multiple PUCCH resource sets and establishing clear selection criteria before ACK feedback transmission is needed. The UE is pre-told which resource sets correspond to which SPS configuration groups, eliminating the need for complex real-time resource management decisions and reducing processing complexity while maintaining timely feedback.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the UE uses separate control channel resources for each SPS configuration, then collisions are avoided, but the resource allocation becomes inefficient

Engineering Contradiction:
ImproveACK feedback transmissionVSAvoidcontrol channel resource consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges multiple SPS configurations into groups that share common PUCCH resource sets. Instead of allocating separate resources to each individual SPS configuration, configurations are combined into groups (e.g., first group, second group), and each group shares a dedicated resource set. This merging approach avoids collisions between groups while improving resource efficiency compared to individual allocation.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4730682A2Acknowledgment feedback for multiple active downlink semi-persistent scheduling configurations
Publication Date: 2026.04.22 QUALCOMM INC
  • EP4730682A2 patent drawingFigure 1
  • EP4730682A2 patent drawingFigure 2
  • EP4730682A2 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communications are described. A base station may configure uplink resources within a slot to enable a user equipment (UE) to transmit an acknowledgment (ACK) feedback message for multiple downlink semi-persistent scheduling (SPS) configurations. For example, the base station may transmit an additional configuration to the UE that indicates uplink resources that the UE can use to transmit acknowledgment feedbacks for multiple downlink messages received according to the SPS configurations, where the UE determines which uplink resource to use based on a number of acknowledgment information bits to be transmitted for the acknowledgment feedback message. For example, if the number of acknowledgment information bits is below a threshold value, the UE may use a first uplink resource configured by the base station. Alternatively, if the number of acknowledgment information bits is above the threshold value, the UE may use a second uplink resource.