Joint HARQ-ACK Codebook for Multi-TRP Uplink Control

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Solution Overview

Problem

Current radio communication systems, particularly in the context of 5G New Radio (NR), do not adequately address the control of uplink transmission when multiple transmission/reception points (TRPs) are used, leading to challenges in managing uplink control channels and HARQ-ACK feedback.

Innovation Solution

The implementation of a method where the same type of HARQ-ACK codebook is applied to HARQ-ACKs corresponding to different TRPs, using semi-statically or dynamically configured codebooks for joint ACK/NACK feedback, allowing for simplified resource specification and enhanced throughput by determining HARQ-ACK bit order and number based on specific conditions and configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multi-TRPs are used for downlink transmission, then system capacity and reliability are improved, but uplink transmission control complexity increases

Engineering Contradiction:
Improvedownlink transmission reliabilityVSAvoiduplink transmission control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the HARQ-ACK feedback control for multiple TRPs into a unified codebook structure. Instead of maintaining separate codebooks for each TRP, the invention combines them into a single joint HARQ-ACK codebook that handles feedback for all TRPs collectively, thereby simplifying uplink transmission control while maintaining multi-TRP reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal HARQ-ACK codebook that serves multiple TRPs simultaneously. This single codebook structure can accommodate feedback from any number of TRPs, making the system adaptable and simplifying control mechanisms while supporting the reliability benefits of multi-TRP operation

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If separate HARQ-ACK codebooks are maintained for each TRP, then feedback accuracy is improved, but resource overhead and system complexity increase

Engineering Contradiction:
ImproveHARQ-ACK feedback accuracyVSAvoidresource overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent combines multiple separate HARQ-ACK codebooks into a single joint codebook structure. This merging reduces the total resource overhead by eliminating redundant codebook structures while maintaining the ability to provide accurate feedback for each TRP through proper bit mapping and ordering within the unified codebook

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The unified HARQ-ACK codebook serves as a universal structure that can handle feedback for any number of TRPs. This multi-functional approach reduces resource overhead compared to maintaining separate codebooks, while still preserving feedback accuracy through systematic organization of ACK/NACK bits for different TRPs

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3944688B1User terminal and wireless communication method
Publication Date: 2024.10.09 NTT DOCOMO INC
  • EP3944688B1 patent drawingFigure 1A~1C
  • EP3944688B1 patent drawingFigure 2A~2C
  • EP3944688B1 patent drawingFigure 3

AI summary

An aspect of a user terminal according to the present invention includes: a receiving section that receives downlink shared channels respectively transmitted from a plurality of transmission/reception points; and a control section that performs control to apply a same type of a codebook for a transmission confirmation signal to a plurality of pieces of retransmission control information for each of the downlink shared channels, and include the plurality of pieces of retransmission control information in a same codebook for the transmission confirmation signal and transmit the same codebook for the transmission confirmation signal.