HARQ-ACK Retransmission in Multi-TRP Wireless Systems
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Solution Overview
Problem
The existing technologies do not adequately address the retransmission of Hybrid Automatic Repeat request-Acknowledgement (HARQ-ACK) feedback in multi-Transmission/Reception Point (TRP) scenarios, which is crucial for enhancing communication reliability and throughput in 5G and beyond systems.
Innovation Solution
A terminal and base station configuration that supports one-shot HARQ-ACK retransmission in multi-TRP environments, enabling appropriate HARQ-ACK Codebook (CB) retransmission through coordinated operations between multiple base stations, utilizing uplink and downlink control signals to manage resource allocation and retransmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one-shot HARQ-ACK retransmission is implemented without considering multi-TRP, then retransmission simplicity is maintained, but communication reliability in multi-TRP scenarios deteriorates
Solution Approach 1:
The patent segments the HARQ-ACK feedback process by introducing separate uplink control channel resources for multi-TRP scenarios. Different PUCCH resources are allocated for different TRPs, allowing independent retransmission control for each TRP while maintaining overall system reliability. This segmentation resolves the contradiction by enabling reliable multi-TRP feedback without requiring a completely new complex retransmission mechanism.
Solution Approach 2:
The patent introduces dynamic indication mechanisms where the network can flexibly indicate whether one-shot retransmission applies to single-TRP or multi-TRP scenarios. This dynamic adaptation allows the system to switch between simple one-shot retransmission and multi-TRP coordinated retransmission based on actual deployment needs, resolving the contradiction between simplicity and reliability.
2Reliability
If coordinated retransmission between multiple base stations is implemented, then communication reliability improves, but control signaling overhead increases
Solution Approach 1:
The patent merges the retransmission control for multiple TRPs into a unified PUCCH resource indication mechanism. Instead of requiring separate control signaling for each TRP retransmission, the system uses a single downlink control information (DCI) message to indicate the PUCCH resource for joint HARQ-ACK feedback across multiple TRPs. This merging reduces control signaling overhead while maintaining coordinated retransmission reliability.
Solution Approach 2:
The patent creates a universal PUCCH resource allocation mechanism that can serve both single-TRP and multi-TRP scenarios. The same PUCCH resource indication method is used whether one or multiple TRPs are involved, eliminating the need for separate control signaling mechanisms and reducing overall overhead while maintaining reliability across different deployment configurations.
3Reliability
If separate PUCCH resources are allocated for each TRP, then retransmission reliability improves, but resource allocation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple PUCCH resources for multi-TRP scenarios during system initialization. These pre-configured resources are stored in the terminal and can be quickly selected based on DCI indications without requiring complex real-time allocation decisions. This preliminary preparation reduces runtime complexity while ensuring reliable separate resource allocation for each TRP retransmission.
Data Source
AI summary
A terminal is disclosed including a receiving section that receives downlink control information that triggers retransmission of an acknowledgement codebook in a specific control resource set; and a control section that controls the retransmission of the acknowledgement codebook, wherein, when the acknowledgement feedback mode is set to separate, the control section determines the acknowledgement codebook to be retransmitted based on the control resource set in which the downlink control information was detected. In other aspects, a base station and a system are also disclosed.