DAI and Codebook Updating for Multi-CC DCI Scheduling

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Solution Overview

Problem

Current wireless communication systems face challenges in accurately updating the downlink assignment index (DAI) and corresponding codebook when scheduling multiple component carriers (CCs) using a single downlink control information (DCI), leading to inefficiencies in cross-carrier scheduling and dynamic spectrum sharing.

Innovation Solution

The proposed solution involves updating the DAI and codebook by incrementing the counter DAI and total DAI values based on the number of component carriers scheduled by a single DCI, allowing for accurate feedback reporting and efficient cross-carrier scheduling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single DCI schedules multiple component carriers, then scheduling efficiency is improved, but DAI and codebook updating accuracy deteriorates

Engineering Contradiction:
Improvescheduling efficiencyVSAvoidDAI and codebook updating accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the DAI updating process into two distinct parts: counter DAI for tracking the current DCI position and total DAI for tracking the total number of DCIs. This segmentation allows each DAI component to be updated independently based on the number of component carriers scheduled, resolving the accuracy issue while maintaining the efficiency benefit of single DCI multi-CC scheduling

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to the DAI structure by adding the total DAI field alongside the counter DAI. This dimensional expansion enables the system to track both the sequence position and the cumulative count of scheduled carriers, providing the necessary information for accurate codebook updating without compromising scheduling efficiency

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

2Productivity

If cross-carrier scheduling is implemented, then spectrum sharing efficiency is improved, but control signaling identification accuracy deteriorates

Engineering Contradiction:
Improvespectrum sharing efficiencyVSAvoidcontrol signaling identification accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the UE uses the updated DAI information (both counter DAI and total DAI) to accurately identify and update the codebook for HARQ-ACK feedback. This feedback loop ensures that control signaling messages are correctly identified and processed across multiple component carriers, maintaining identification accuracy while enabling efficient cross-carrier scheduling

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4091256B1DAI and codebook updating for DCI scheduling multiple ccs
Publication Date: 2025.05.14 QUALCOMM INC
  • EP4091256B1 patent drawingFigure 1
  • EP4091256B1 patent drawingFigure 2A~2D
  • EP4091256B1 patent drawingFigure 3

AI summary

Example implementations include a method, apparatus and computer-readable medium of wireless communication at a user equipment, including receiving on a physical downlink control channel (PDCCH) during a first PDCCH monitoring occasion a first downlink control information (DCI) that schedules a physical downlink shared channel (PDSCH) for each of at least two component carriers, wherein the DCI includes a counter downlink assignment index (DAI) that indicates a number of scheduled PDSCHs up to a point that the first DCI was received and a total DAI indicating a number of scheduled PDSCHs across the at least two component carriers. The implementations further include transmitting a physical uplink control channel (PUCCH) including a position for hybrid automatic repeat request (HARQ) -Acknowledgement (ACK) bits corresponding to the PDSCH for each of the at least two component carriers. Also included is a corresponding a method, apparatus and computer-readable medium of wireless communication at a base station.