HARQ-ACK Codebook Generation for Multiple SPS Configurations

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Solution Overview

Problem

In next-generation radio communication systems, the existing specifications do not allow for simultaneous configuration of semi-persistent scheduling (SPS) across multiple serving cells within a cell group, leading to ambiguity in Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) codebook generation, which affects appropriate HARQ control and communication throughput.

Innovation Solution

A method for generating an appropriate HARQ-ACK codebook when multiple SPS configurations are used, by multiplexing HARQ-ACK information for multiple SPSs into a single HARQ-ACK codebook, ensuring clear definition and appropriate control even with flexible SPS configurations and shorter SPS cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple SPS configurations are simultaneously configured in one cell group, then control flexibility is improved, but HARQ control reliability deteriorates due to ambiguous codebook generation

Engineering Contradiction:
Improvecontrol flexibilityVSAvoidHARQ control reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the HARQ-ACK codebook generation process by introducing distinct determination methods for different SPS configurations. Each SPS configuration can be associated with specific downlink assignments and HARQ-ACK feedback mechanisms, allowing the system to handle multiple SPS configurations within a cell group while maintaining clear codebook generation rules for each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables dynamic HARQ-ACK codebook determination based on the specific SPS configuration and associated downlink assignments. The codebook generation adapts dynamically to the configured SPS parameters, allowing flexible control while ensuring reliable HARQ feedback through context-aware codebook construction.

Inventive Principle:
Principle #15Dynamics

2Productivity

If SPS cycle is shortened to increase scheduling flexibility, then productivity is improved, but codebook generation complexity increases

Engineering Contradiction:
Improvecommunication throughputVSAvoidcodebook generation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring SPS parameters and associated HARQ-ACK codebook determination rules before actual data transmission. This allows the system to handle shorter SPS cycles efficiently, as the codebook generation logic is already established in advance, reducing real-time processing complexity despite increased scheduling frequency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by adjusting SPS cycle lengths and associated HARQ-ACK feedback timing based on traffic conditions and configuration. This enables the system to optimize throughput with shorter cycles when needed while managing codebook complexity through adaptive parameter selection and configuration.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3952509B1Terminal, radio communication method, base station and system
Publication Date: 2025.04.30 NTT DOCOMO INC
  • EP3952509B1 patent drawingFigure 1
  • EP3952509B1 patent drawingFigure 2A~2B
  • EP3952509B1 patent drawingFigure 3A~3B

AI summary

A user terminal according to one aspect of the present disclosure includes a control section that generates a Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) codebook including a first HARQ-ACK sub-codebook related to transport block (TB)-based physical downlink shared channel (PDSCH), a second HARQ-ACK sub-codebook related to code block group (CBG)-based PDSCH, and a third HARQ-ACK sub-codebook related to semi-persistent scheduling (SPS), and a transmitting section that transmits HARQ-ACK information bits corresponding to the HARQ-ACK codebook by using one uplink control channel. According to one aspect of the present disclosure, the HARQ-ACK codebook can be appropriately generated even when the multiple SPSs are used.