HARQ-ACK Codebook Sub-codebook Segmentation for DCI Overhead Reduction
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Solution Overview
Problem
The existing HARQ-ACK codebook design is not adapted to report feedbacks when a single DCI is used for scheduling multiple code block group (CBG)-based transmissions, leading to increased overhead and inefficiencies, particularly with the growing number of sub-codebooks and complexities in handling Semi-Persistent Scheduling PDSCH (SPS PDSCH) and Downlink Assignment index (DAI) configurations.
Innovation Solution
An enhanced HARQ-ACK codebook is introduced that dynamically determines the number of sub-codebooks based on specific rules, allowing for bundling of HARQ feedbacks in either the time domain or spatial domain, reducing DCI overhead and improving transmission efficiency by supporting flexible configurations for CBG-based and TB-based transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single DCI is used for scheduling multiple CBG-based transmissions, then scheduling efficiency is improved, but the existing HARQ-ACK codebook design cannot properly report feedbacks leading to increased overhead
Solution Approach 1:
The HARQ-ACK codebook is divided into multiple sub-codebooks, where each sub-codebook corresponds to a specific scheduling type (CBG-based or TB-based). This segmentation allows the codebook to properly organize and report feedbacks for different scheduling modes without increasing overall overhead, as each sub-codebook handles a specific subset of feedback information systematically.
Solution Approach 2:
The patent introduces dynamic determination of the number of sub-codebooks based on the actual scheduling configuration. The network device dynamically configures the number of sub-codebooks corresponding to multi-PDSCH scheduling, allowing the HARQ-ACK codebook to adapt to different scheduling scenarios. This dynamic adjustment ensures the codebook overhead remains optimized while supporting flexible scheduling configurations.
2Adaptability or versatility
If the number of sub-codebooks is increased to support multiple scheduling scenarios, then adaptability is improved, but device complexity increases
Solution Approach 1:
The HARQ-ACK codebook is designed with multi-functionality to handle both CBG-based and TB-based scheduling scenarios within a unified structure. By introducing sub-codebooks that can be dynamically configured, the system achieves universal support for multiple scheduling types without requiring separate, independent codebook mechanisms. This multi-functional design improves adaptability while controlling complexity through a single integrated codebook framework.
Solution Approach 2:
The patent utilizes parameter changes in the DCI (Downlink Control Information) to dynamically indicate the number of sub-codebooks. Instead of hardcoding multiple configuration options, the system changes the parameter `numberOfSubCodebooks` based on the scheduling scenario. This parameter-driven approach allows the HARQ-ACK codebook to adapt to different scheduling configurations while maintaining a relatively simple and manageable structure.
3Productivity
If HARQ feedbacks are bundled in time domain or spatial domain, then transmission efficiency is improved, but the complexity of handling SPS PDSCH and DAI configurations increases
Solution Approach 1:
The patent implements feedback mechanisms where the network device provides indication information about the number of sub-codebooks corresponding to multi-PDSCH scheduling. This feedback allows the terminal device to properly construct the HARQ-ACK codebook by knowing how many sub-codebooks to include and how to organize the feedbacks. The feedback mechanism simplifies the terminal's processing by providing clear configuration information from the network side.
Solution Approach 2:
The patent introduces an intermediary mechanism through the DCI field `numberOfSubCodebooks` that mediates between the scheduling configuration and the HARQ-ACK codebook construction. This intermediary parameter acts as a bridge, translating the complex scheduling configurations (including SPS PDSCH and DAI settings) into a simplified number of sub-codebooks that the terminal needs to process. This mediation reduces the complexity at the terminal side while maintaining the necessary configuration flexibility.
Data Source
AI summary
Embodiments of the present disclosure relate to methods, devices and computer readable media for communication. A terminal device receives, from a network device, multiple code block group (CBG)-based transmissions scheduled by a first downlink control information (DCI), and at least one transport block (TB)-based transmission; and transmit, to the network device, a HARQ-acknowledgement (HARQ-ACK) codebook comprising HARQ feedbacks of the multiple CBG-based transmissions and the at least one TB-based transmission. In this way, the HARQ-ACK codebook is adapted to report HARQ feedbacks in a case where CBG-based transmission and multi-transmission scheduling are both configured. As such, the overhead of DCI can be reduced and the transmission efficiency can be improved.