Multicast HARQ Feedback Using Shared and Dedicated PUCCH Resources
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Solution Overview
Problem
The high overhead and complexity of Physical Uplink Control Channel (PUCCH) in NR multicast and/or broadcast services due to large numbers of terminals acknowledging or not acknowledging data packets, and the need to improve transmission methods between terminals and base stations for enhanced performance and reliability.
Innovation Solution
A Hybrid Automatic Repeat reQuest (HARQ) feedback method that includes indicating PDCCH detection behaviors and PDSCH reception methods, along with specific PUCCH resources for reporting HARQ information, distinguishing between terminal-specific and common PDCCHs for PTP and PTM transmissions, and configuring separate PUCCH resources for accurate feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each terminal individually feeds back ACK/NACK for multicast and/or broadcast services, then service reliability is improved, but PUCCH overhead and base station detection complexity increase significantly
Solution Approach 1:
The patent segments the feedback mechanism by introducing two types of PUCCH resources: common PUCCH resources shared by multiple terminals and terminal-specific PUCCH resources. This segmentation allows the system to handle feedback from multiple terminals efficiently by grouping them appropriately, reducing overall detection complexity while maintaining reliability.
Solution Approach 2:
Instead of having each terminal individually report ACK/NACK which increases overhead, the patent inverts the approach by using a common PUCCH resource where terminals can report feedback collectively. The base station detects feedback on this shared resource, reducing individual terminal overhead while maintaining service reliability through appropriate resource allocation.
2Productivity
If common PDCCH is used to schedule PDSCH for multiple terminals, then resource utilization is improved, but it becomes difficult to distinguish which terminal failed to decode and requires retransmission to all terminals
Solution Approach 1:
The patent applies local quality by associating different RNTIs (Radio Network Temporary Identifiers) with different PUCCH resources. When a terminal fails to decode PDSCH scheduled by common PDCCH, it reports NACK on a PUCCH resource linked to its specific RNTI. This allows the base station to identify which specific terminal failed decoding while maintaining the efficiency of common PDCCH scheduling, enabling targeted retransmissions.
3Reliability
If terminal-specific PDCCH is used for each terminal, then accurate feedback and retransmission are achieved, but resource overhead increases
Solution Approach 1:
The patent implements a dynamic approach where the system can flexibly switch between common PDCCH and terminal-specific PDCCH scheduling based on service requirements and terminal states. This dynamic scheduling allows the system to use resource-efficient common PDCCH when possible while maintaining the ability to use terminal-specific PDCCH when accurate individual feedback is needed, optimizing the balance between reliability and resource overhead.
Data Source
AI summary
A Hybrid Automatic Repeat reQuest HARQ feedback method for a multicast and/or broadcast service, a terminal and a base station are provided. The method includes: receiving, by a terminal, first indication information transmitted by a network, wherein the first indication information indicates at least one of following information: a Physical Downlink Control CHannel PDCCH detection behavior, a transmission method of the multicast and/or broadcast service, and a Physical Downlink Shared CHannel PDSCH receiving behavior; and determining, by the terminal based on the first indication information, a Physical Uplink Control CHannel PUCCH resource used for reporting HARQ of a PDSCH.