HARQ-ACK Codebook Concatenation for Multicast and Unicast Services

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Solution Overview

Problem

Existing 3GPP standards do not adequately address the construction of HARQ-ACK codebooks for multiple multicast and unicast services scheduled for transmission in the same time instance, leading to inefficiencies and miscommunication between UEs and communication nodes due to differing understandings of codebook size and content.

Innovation Solution

Simultaneously construct separate HARQ-ACK sub-codebooks for multicast and unicast services, then concatenate them based on specific ordering rules, using identifiers like G-RNTI or DRB IDs, to ensure synchronized understanding between UEs and communication nodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate sub-codebooks are constructed for multicast and unicast services and concatenated, then HARQ-ACK feedback for all services can be provided, but codebook construction complexity increases

Engineering Contradiction:
ImproveHARQ-ACK feedback reliabilityVSAvoidcodebook construction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the HARQ-ACK codebook construction into separate sub-codebooks for different services (multicast MBS services and unicast services). Each service type generates its own sub-codebook independently, which are then concatenated to form the complete feedback codebook. This segmentation allows reliable feedback for all services while managing complexity through modular construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple service-specific sub-codebooks into a single concatenated HARQ-ACK codebook. By merging the multicast service sub-codebook and unicast service sub-codebook in a defined order, the system achieves comprehensive feedback coverage for all services scheduled in the same time instance while maintaining structured organization.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If only the highest priority service is used for codebook generation, then codebook construction is simplified, but feedback for other services is lost

Engineering Contradiction:
Improvecodebook construction simplicityVSAvoidfeedback information loss
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

Instead of selecting only one service, the patent segments the feedback generation process to create separate sub-codebooks for each service type. This ensures that feedback information for all services is preserved rather than losing information by prioritizing only the highest priority service.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a dimensional aspect to codebook construction by organizing feedback along service type dimensions (multicast vs. unicast) and concatenating these dimensions. This multi-dimensional approach allows comprehensive feedback coverage without the complexity of handling all services in a single undifferentiated codebook.

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

3Productivity

If multiple services are scheduled in the same time instance, then service delivery efficiency is improved, but codebook interpretation ambiguity increases

Engineering Contradiction:
Improveservice delivery efficiencyVSAvoidcodebook interpretation clarity
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent segments the codebook into service-specific sub-codebooks with clear boundaries and ordering rules. This segmentation eliminates interpretation ambiguity by defining exactly which sub-codebook corresponds to which service type, even when multiple services are scheduled in the same time instance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the communication node and UE use the defined concatenation order to verify and synchronize their understanding of the codebook structure. This feedback loop ensures both parties interpret the concatenated codebook consistently, preventing information loss through misinterpretation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4278808B1Codebook construction for point-to-multipoint operation in telecommunication systems
Publication Date: 2025.07.09 NOKIA TECHNOLOGIES OY
  • EP4278808B1 patent drawingFigure 1
  • EP4278808B1 patent drawingFigure 2
  • EP4278808B1 patent drawingFigure 3

AI summary

This disclosure presents methods and processes to allow a user equipment (UE) to map a hybrid automatic retransmission request-acknowledgement (HARQ-ACK) feedback to one or more HARQ-ACK sub-codebooks for received services. The one or more HARQ-ACK sub-codebooks can be concatenated into one HARQ-ACK codebook and then communicated to a communication node, when those services use a HARQ-ACK feedback that is scheduled for the same time instance. Various methods can be used for the concatenation order depending on the number of multicast and broadcast services (MBS) for which HARQ feedback is to be provided, and depending on whether HARQ-ACK feedback is to be sent for unicast services at the scheduled time instance. The concatenation order can utilize an increasing order or a decreasing order of the concatenation order parameters.