Terminal Feedback Timing Control for High-Frequency HARQ-ACK

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Solution Overview

Problem

In next-generation mobile communication systems, particularly in frequency bands above 52.6 GHz, the increased phase noise and peak power to average power ratio (PAPR) lead to wider subcarrier spacing, resulting in shorter symbol and slot durations, which can hinder appropriate HARQ-ACK feedback if the existing transmission timing control methods are used without adaptation.

Innovation Solution

A terminal is designed with a receiving section to handle downlink shared channels and a control section that determines feedback timing for transmission confirmation information based on notified information from downlink control information and higher layer signaling, using a reference point configured in the slot where the downlink shared channel is transmitted or subsequent slots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If subcarrier spacing is widened to reduce phase noise impact in high frequency bands, then frequency offset tolerance is improved, but symbol duration and slot duration are shortened which causes HARQ-ACK feedback timing issues

Engineering Contradiction:

Improvephase noise toleranceVSAvoidsymbol duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent changes the reference point parameter for feedback timing from the traditional start of the first symbol to a configurable reference point (such as the end of the PDSCH or a specific symbol within the slot). This parameter adjustment allows the feedback timing to be properly calculated despite the shortened symbol and slot durations caused by wider subcarrier spacing, thereby resolving the HARQ-ACK timing issue while maintaining the benefits of widened subcarrier spacing for phase noise tolerance

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If existing HARQ-ACK feedback timing control methods are used without change, then system complexity is kept low, but feedback timing accuracy deteriorates in high frequency bands with widened subcarrier spacing

Engineering Contradiction:

Improvefeedback timing controlVSAvoidfeedback timing accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces dynamic configurability to the feedback timing mechanism by allowing the reference point to be configured based on the actual transmission conditions (such as PDSCH duration, slot structure, and subcarrier spacing). This dynamic adjustment capability enables accurate feedback timing determination in high frequency bands without requiring completely new control methods, thus maintaining reasonable system complexity while achieving the required timing accuracy

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12081339B2Terminal and radio communication method

Publication Date: 2024.09.03 NTT DOCOMO INC

AI summary

One aspect of a terminal according to the present disclosure includes a receiving section that receives downlink shared channel scheduled by downlink control information, and a control section that determines a feedback timing of transmission confirmation information responding to the downlink shared channel on the basis of information related to a feedback timing notified by at least one of the downlink control information and higher layer signaling, and a reference point configured in a slot where the downlink shared channel is transmitted or subsequent slots.