DCI Categorization for HARQ-ACK Codebook Optimization
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Solution Overview
Problem
In 5G NR systems, particularly on higher-frequency bands, there is a challenge in reasonably adjusting the usage of Downlink Assignment Index (DAI) to determine Hybrid Automatic Repeat Request ACKnowledgement (HARQ-ACK) Codebooks when using a single Downlink Control Information (DCI) for scheduling multiple Physical Downlink Shared Channel (PDSCH) receptions, leading to complexities in bit overhead and HARQ-ACK feedback.
Innovation Solution
A method where the DCI is categorized into types based on the number of Transport Blocks (TBs) scheduled, with distinct HARQ-ACK sub-codebooks for DAI fields in DCIs scheduling TB-based PDSCH receptions with TBs greater or less than a threshold (K), optimizing bit overhead and feedback efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single DCI schedules multiple PDSCH receptions, then scheduling efficiency is improved, but HARQ-ACK feedback complexity increases
Solution Approach 1:
The patent segments the HARQ-ACK codebook into multiple sub-codebooks, where each sub-codebook corresponds to a specific DCI format or scheduling scenario. This segmentation allows the system to handle multiple PDSCH receptions scheduled by a single DCI by organizing acknowledgments in a structured manner, thereby reducing feedback complexity while maintaining scheduling efficiency.
Solution Approach 2:
The patent introduces a new dimension for organizing HARQ-ACK feedback by using multiple codebook types (e.g., Type-1 and Type-2 codebooks) differentiated by DCI format characteristics. This dimensional approach allows the system to distinguish between different scheduling scenarios and manage acknowledgments accordingly, resolving the complexity issue while preserving the benefits of multi-PDSCH scheduling.
2Loss of information
If DAI field is used to indicate total number of cells scheduled, then scheduling information is provided, but bit overhead increases
Solution Approach 1:
The patent applies local quality by making the DAI field interpretation context-dependent. Different DCI formats have different DAI field interpretations: some formats use DAI to indicate the total number of cells scheduled, while others use it to indicate the order of scheduled cells. This localized adaptation allows the system to provide complete scheduling information while minimizing bit overhead in each specific context.
Solution Approach 2:
The patent changes the parameter interpretation of the DAI field based on DCI format characteristics. Instead of using a fixed interpretation, the system dynamically adjusts whether DAI represents a count or an order indicator, allowing efficient use of limited bits while conveying complete scheduling information appropriate to each scheduling scenario.
Data Source
AI summary
The present disclosure provides a method and a device in a node for wireless communications. A first receiver receives first DCI; and a first transmitter transmits a first signal, the first signal carrying a first HARQ-ACK bit sequence; herein, the first DCI comprises a first field; for the first DCI, the first field comprised is used for indicating a total number of cells scheduled by first-type DCI(s) and by the second-type DCI(s) up to a current time interval in a first resource pool, time-domain resources occupied by the first DCI belonging to the current time interval; a said first-type DCI is used for scheduling multiple PDSCH receptions based on Transport Blocks (TBs), and a total number of TBs carried by the TB-based PDSCH receptions scheduled by the first-type DCI is greater than K, K being a positive integer; the second-type DCI is used for scheduling CBG-based PDSCH receptions.