Multi-TRP HARQ-ACK Control via Common Codebook
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Solution Overview
Problem
In next-generation mobile communication systems, the use of multiple transmission/reception points (TRPs) for downlink transmission in 5G networks leads to inadequate control of Hybrid Automatic Repeat Request ACKnowledgement (HARQ-ACK) feedback, resulting in suppressed communication throughput and inability to achieve spatial diversity gain and high rank transmission.
Innovation Solution
A user terminal is designed to receive Physical Downlink Shared Channels (PDSCH) from multiple TRPs and employs a common codebook to transmit HARQ-ACK feedback, allowing for separate or joint HARQ-ACK transmission on Physical Uplink Control Channel (PUCCH) resources, enabling effective HARQ-ACK control even with multiple TRPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-TRP transmission is implemented without updated specifications, then spatial diversity gain and high rank transmission cannot be achieved, but communication throughput is suppressed
Solution Approach 1:
The patent changes the HARQ-ACK feedback mechanism by introducing a common codebook structure that can accommodate multiple TRPs. This parameter change in the feedback system enables proper control of HARQ-ACK for multi-TRP transmissions, thereby achieving spatial diversity gain while maintaining communication throughput.
2Adaptability or versatility
If current NR specifications are followed, then HARQ-ACK control is inadequate for multi-TRP, but implementing multi-TRP without proper control increases system complexity
Solution Approach 1:
The patent segments the HARQ-ACK feedback into a common codebook structure that can handle multiple TRPs systematically. By organizing the feedback mechanism in a structured segmented way, the patent enables multi-TRP support while managing the complexity through standardized procedures for codebook generation and feedback transmission.
Solution Approach 2:
The common codebook structure designed in the patent serves multiple functions: it handles HARQ-ACK feedback for single-TRP and multi-TRP scenarios, supports both overlapping and non-overlapping PDSCH configurations, and provides a universal framework that works across different TRP configurations without requiring separate mechanisms for each case.
3Measurement precision
If separate HARQ-ACK feedback is used for each TRP, then control accuracy improves, but feedback overhead and resource usage increase
Solution Approach 1:
The patent merges the HARQ-ACK feedback for multiple TRPs into a single common codebook structure. Instead of maintaining separate feedback channels for each TRP, the invention combines them into one unified feedback mechanism that preserves the accuracy needed for each individual TRP while reducing the overall feedback overhead and resource consumption through consolidated transmission.
Data Source
AI summary
A user terminal according to an aspect of the present disclosure includes a receiving section that receives a first PDSCH (Physical Downlink Shared Channel) from a first transmission/reception point (TRP), and a second PDSCH from a second TRP, the second PDSCH overlapping the first PDSCH in at least one of time and frequency resources, and a control section that performs control for using a common codebook to transmit a first Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK) for the first PDSCH and a second HARQ-ACK for the second PDSCH. According to an aspect of the present disclosure, the HARQ-ACK control can be preferably implemented even in a case of using the multi-TRP.