HARQ-ACK Codebook Segmentation for Carrier Aggregation Feedback
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Solution Overview
Problem
In wireless communication technology, especially with carrier aggregation (CA), the determination of HARQ-ACK codebook size for multiple carriers in the carrier or time domain leads to misunderstandings between base units and remote units during data transmission, necessitating improved HARQ-ACK feedback mechanisms.
Innovation Solution
A method is introduced that generates and transmits HARQ-ACK codebooks dynamically, including a first sub-codebook for each transport block and an optional second sub-codebook for code block groups, based on indicators in downlink control information, to avoid ambiguity and ensure accurate feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a HARQ-ACK codebook consists of HARQ-ACK bits for multiple carriers in carrier domain and/or time domain for CA, then the codebook can provide feedback for multiple carriers, but the determination of codebook size becomes ambiguous leading to misunderstandings between base unit and remote unit
Solution Approach 1:
The patent divides the HARQ-ACK codebook into multiple sub-codebooks, where each sub-codebook corresponds to a specific carrier or time slot. This segmentation allows the base unit and remote unit to independently determine the size of each sub-codebook based on its specific configuration, eliminating the ambiguity in determining the overall codebook size while maintaining the ability to provide feedback for multiple carriers.
Solution Approach 2:
The patent introduces dynamic indication mechanisms where the base unit signals the remote unit about the actual size and composition of the HARQ-ACK codebook through downlink control information. This dynamic adjustment allows the codebook to adapt to different carrier configurations and transmission scenarios, ensuring both units have consistent understanding of the codebook structure without predetermined size ambiguities.
2Device complexity
If the HARQ-ACK codebook size is preconfigured, then the feedback structure is simplified, but it cannot adapt to dynamic transmission configurations across multiple carriers
Solution Approach 1:
The patent transitions from static preconfigured codebook sizes to dynamic codebook determination. The base unit uses downlink control information to dynamically indicate the actual HARQ-ACK codebook size and composition to the remote unit. This allows the feedback structure to adapt to various carrier aggregation configurations, transmission time intervals, and carrier activations while maintaining relatively simple processing through standardized indication procedures.
Solution Approach 2:
The patent enhances the feedback mechanism by having the base unit provide indication information about the HARQ-ACK codebook structure to the remote unit. This feedback loop allows the remote unit to adjust its codebook generation and transmission accordingly, ensuring compatibility with the base unit's transmission configuration while maintaining manageable system complexity through standardized feedback procedures.
Data Source
AI summary
Embodiments of the present application relate to a method and apparatus for hybrid automatic repeat request-acknowledge (HARQ-ACK) feedback for carrier aggregation (CA). A method according an embodiment of the present application may include receiving at least one downlink transmission; generating a first HARQ-ACK sub-codebook for the at least one downlink transmission; determining whether to generate a second HARQ-ACK sub-codebook; and transmitting a HARQ-ACK codebook. The HARQ-ACK codebook includes the first HARQ-ACK sub-codebook in response to the second HARQ-ACK sub-codebook determined not to be generated, or includes the first HARQ-ACK sub-codebook and the second HARQ-ACK sub-codebook in response to the second HARQ-ACK sub-codebook determined to be generated. The present application avoids misunderstanding between a base unit and a remote unit when generating the HARQ-ACK feedback for CA.