HARQ-ACK Codebook Segmentation for 5G MBS Feedback
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Solution Overview
Problem
In 5G new radio (NR) networks, the ambiguity in Hybrid Automatic Repeat Request (HARQ) feedback codebook size between terminal devices and network devices leads to incorrect decoding and loss of feedback, resulting in retransmission issues, decreased spectral efficiency, and increased packet loss rates, especially when handling multicast and broadcast services.
Innovation Solution
The implementation of an enhanced HARQ feedback reporting mechanism that includes identification information within the HARQ-ACK codebook to ensure the network device and terminal device have a common understanding of the codebook content, allowing accurate identification of service sub-codebooks and preventing size mismatches, even when downlink control information is missed or decoded incorrectly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional HARQ feedback mechanisms are used for multicast and broadcast services, then the feedback can be transmitted, but ambiguity in codebook size leads to incorrect decoding and feedback loss
Solution Approach 1:
The patent segments the HARQ feedback into service-specific sub-codebooks (unicast sub-codebook and multicast sub-codebook) within a single codebook structure. Each sub-codebook contains HARQ feedback bits for specific services, allowing the network device to identify and decode feedback for different services independently, thereby eliminating ambiguity in codebook size and preventing feedback loss.
2Productivity
If multiple unicast and MBS services are multiplexed in the same PUCCH, then resource efficiency is improved, but understanding ambiguity between services increases
Solution Approach 1:
The patent divides the HARQ-ACK codebook into distinct sub-codebooks for unicast and multicast services, with each sub-codebook containing only feedback for its specific service type. This segmentation allows the network device to identify which service each feedback bit corresponds to, eliminating ambiguity while maintaining multiplexed transmission in the same PUCCH resource.
Solution Approach 2:
The patent introduces identification information as an intermediary element that indicates the service type associated with each sub-codebook. This intermediary allows the network device to correctly interpret the feedback without confusion about which service the feedback refers to, enabling reliable multiplexed transmission of multiple services.
3Reliability
If the terminal device misses or fails to decode DCI for MBS service, then transmission errors occur, but traditional HARQ feedback cannot ensure accurate retransmission scheduling
Solution Approach 1:
The patent segments the HARQ feedback into service-specific sub-codebooks, allowing the network device to track which services have been successfully received and which require retransmission. Even if the terminal device misses DCI for certain services, the segmented structure enables the network to identify gaps in feedback and schedule retransmissions accurately for affected services only.
Solution Approach 2:
The patent enhances the feedback mechanism by including identification information that explicitly indicates which services are represented in each sub-codebook. This feedback structure allows the network device to understand exactly which services have been received and which need retransmission, ensuring accurate retransmission scheduling even when DCI decoding fails for some services.
Data Source
AI summary
Example embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media for enhancement of HARQ feedback. The method comprises: upon receipt of data of at least one of a group of services from a second device, generating, at a first device, a Hybrid Automatic Repeat Request acknowledgement (HARQ-ACK) codebook comprising HARQ feedback and identification information for the at least one service, the group of services comprising at least one of multicast and broadcast services (MBSs) and unicast services; and transmitting the HARQ-ACK codebook to the second device. In this way, retransmissions of unicast and multicast services can be accurately scheduled in time, and unnecessary retransmissions can be avoided. In addition, the spectral efficiency and packet loss rate of the communication system can be improved.