NR Sidelink CBG Transmission With Granular HARQ-ACK Feedback
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Solution Overview
Problem
The details of a code block group (CBG)-based Hybrid Automatic Repeat Request-Acknowledge (HARQ-ACK) feedback mechanism for 3GPP 5G NR sidelink communication have not been defined, leading to inefficient resource allocation for retransmissions due to imprecise decoding results of multiple CBGs.
Innovation Solution
Implementing a method and apparatus for CBG-based HARQ-ACK feedback, where a user equipment (UE) transmits CBG-based transmissions on a sidelink, receives corresponding feedback, and requests resources for retransmissions using indicators on a physical uplink control channel (PUCCH), and a base station allocates resources based on this feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If TB-based HARQ-ACK feedback is used for sidelink communication, then the feedback mechanism is simple to implement, but resource allocation efficiency deteriorates due to imprecise decoding results of multiple CBGs
Solution Approach 1:
The patent segments the transport block into multiple code block groups (CBGs) and introduces separate HARQ-ACK feedback bits for each CBG. This allows the receiver to provide granular feedback about which specific CBGs were decoded successfully and which need retransmission, thereby improving resource allocation efficiency while maintaining implementation feasibility through systematic segmentation of the feedback process.
2Productivity
If CBG-based HARQ-ACK feedback mechanism is implemented, then resource allocation efficiency is improved through precise decoding results, but the complexity of the feedback mechanism increases
Solution Approach 1:
The feedback mechanism is segmented into individual CBG-level acknowledgments, where each CBG has its own HARQ-ACK bit. This segmentation approach systematically manages complexity by breaking down the feedback process into discrete, manageable units rather than attempting to provide granular feedback for all possible error conditions simultaneously.
Solution Approach 2:
The patent changes the parameter of feedback granularity from transport-block level to code-block-group level. By adjusting this parameter, the system achieves more precise resource allocation while the complexity is managed through standardized procedures for generating and processing the increased number of feedback bits.
3Productivity
If CBG-based transmission is enabled for sidelink, then spectrum efficiency is improved through accurate retransmission resource determination, but the payload size of PUCCH resources increases
Solution Approach 1:
The PUCCH payload is segmented into multiple CBG-level HARQ-ACK bits, with each bit corresponding to a specific CBG. This segmentation enables accurate indication of which CBGs require retransmission, improving spectrum efficiency. The payload size increase is managed by efficiently packing these segmented feedback bits into the PUCCH structure.
Data Source
AI summary
Embodiments of the present application are related to a method and apparatus for code block group (CBG)-based transmission for 3GPP 5G New Radio (NR) sidelink (SL). A method for wireless communication performed by a UE according to an embodiment of the present application includes: in response to a CBG-based transmission being enabled, transmitting a CBG-based transmission on a SL, wherein the CBG-based transmission includes one or more CBGs; receiving hybrid automatic repeat request-acknowledge (HARQ-ACK) feedback corresponding to the one or more CBGs; and in response to the HARQ-ACK feedback, transmitting an indicator on a physical uplink control channel (PUCCH) resource to request a resource for a CBG-based retransmission.