Multicast HARQ Codebook Segmentation for Priority-Aware PDSCH Feedback

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing and prioritizing the transmission and reception of multicast and unicast physical downlink shared channels (PDSCH) with varying priorities, requiring improved methods for generating and transmitting hybrid automatic repeat request (HARQ) codebooks.

Innovation Solution

The proposed solution involves independently generating first multicast and unicast HARQ sub-codebooks, considering priority differences, and allowing terminals to transmit HARQ codebooks to the base station with or without HARQ-ACK feedback based on base station indications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multicast and unicast PDSCHs are transmitted simultaneously with different priorities, then the communication system can support diverse service requirements, but the complexity of generating and managing HARQ codebooks increases

Engineering Contradiction:
Improvesupport for diverse service requirementsVSAvoidcomplexity of generating and managing HARQ codebooks
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the HARQ codebook into separate sub-codebooks for multicast and unicast PDSCHs. This segmentation allows independent management of each type's HARQ-ACK feedback, reducing the overall complexity while maintaining support for diverse services. The terminal generates a first sub-codebook for multicast PDSCH and a second sub-codebook for unicast PDSCH, which can be handled separately.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of organization by separating HARQ codebooks along the service type dimension (multicast vs. unicast). This dimensional separation allows the system to manage different service types independently, reducing complexity while maintaining versatility. The codebooks are organized into distinct sub-codebooks that can be processed separately.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If HARQ-ACK feedback is always transmitted for multicast PDSCH, then reliability is improved, but overhead and resource consumption increase

Engineering Contradiction:
Improvereliability of multicast transmissionVSAvoidoverhead and resource consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements dynamic HARQ-ACK feedback for multicast PDSCH, where the feedback behavior can change based on service requirements and channel conditions. The system can switch between transmitting HARQ-ACK feedback and not transmitting it, allowing optimization of reliability versus resource consumption based on current needs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of HARQ-ACK feedback transmission from a fixed state to a variable state. By controlling whether to generate and transmit the first sub-codebook for multicast PDSCH based on service type and priority, the system dynamically adjusts the feedback parameter to balance reliability and resource consumption.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If separate HARQ sub-codebooks are generated for multicast and unicast PDSCH, then management efficiency is improved, but the overall HARQ codebook structure becomes more complex

Engineering Contradiction:
Improvemanagement efficiencyVSAvoidHARQ codebook structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the HARQ codebook into distinct sub-codebooks for multicast and unicast PDSCHs. This segmentation improves management efficiency by allowing separate handling of each service type's feedback, while the overall structure remains organized and manageable through clear separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary structure where the overall HARQ codebook contains separate sub-codebooks for different service types. This intermediary organization allows efficient management of each service type independently while maintaining a unified overall structure that can be processed systematically.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4255074B1Method and device for supporting multicast transmission
Publication Date: 2025.09.10 ELECTRONICS & TELECOMM RES INST
  • EP4255074B1 patent drawingFigure 1
  • EP4255074B1 patent drawingFigure 2~3
  • EP4255074B1 patent drawingFigure 4

AI summary

A method and a device for supporting multicast transmission are disclosed. A terminal operating method comprises the steps of: receiving, from a base station, an RRC message indicating the activation of HARQ-ACK feedback; receiving, from the base station, a first DCI including information indicating deactivation of the HARQ-ACK feedback; receiving, from the base station, a first multicast PDSCH on the basis of first scheduling information included in the first DCI; generating a first HARQ-ACK bit for the first multicast PDSCH even if the first DCI indicates deactivation of the HARQ-ACK feedback; generating a HARQ codebook including the first HARQ-ACK bit; and transmitting, to the base station, the HARQ codebook through an uplink channel.