HARQ-ACK Spatial Bundling for Enhanced Carrier Aggregation

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Solution Overview

Problem

The existing LTE systems are limited to configuring a maximum of five component carriers per user terminal, and the method for transmitting Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) during enhanced carrier aggregation with six or more carriers is undefined.

Innovation Solution

Implementing spatial bundling of HARQ-ACK transmission only on selected component carriers, using predetermined rules or higher layer signaling to determine which carriers to bundle, thereby maintaining a total payload of 10 bits while supporting up to 10 component carriers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a terminal transmits a scheduling request on a physical uplink control channel, then the scheduling request can be sent, but the terminal cannot send other information on the same channel

Engineering Contradiction:
Improvescheduling request transmission efficiencyVSAvoidchannel information transmission capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent segments the scheduling request information from other uplink control information by allocating dedicated resources. The terminal determines a specific physical uplink control channel resource for scheduling requests, separating it from resources used for other control information, thus allowing simultaneous or sequential transmission without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of resource allocation by assigning specific time-frequency resources and code domains for scheduling requests. This dimensional separation in the resource space allows the terminal to transmit scheduling requests while maintaining capability to send other information on different allocated resources.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If a terminal transmits information on a physical uplink control channel, then the information can be sent, but the transmission accuracy cannot be ensured

Engineering Contradiction:
Improveinformation transmission efficiencyVSAvoidtransmission accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing channel selection and resource determination before actual transmission. The terminal determines the appropriate physical uplink control channel and resources in advance based on scheduling request status and channel conditions, optimizing transmission parameters beforehand to ensure both efficiency and accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the terminal monitors transmission results and channel conditions, then adjusts resource selection and transmission parameters accordingly. This closed-loop approach ensures transmission accuracy is maintained while preserving efficient communication.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3280173B1User terminal, wireless communication system, and wireless communication method
Publication Date: 2026.05.06 NTT DOCOMO INC
  • EP3280173B1 patent drawingFigure 1A~1C
  • EP3280173B1 patent drawingFigure 2
  • EP3280173B1 patent drawingFigure 3

AI summary

HARQ-ACK is appropriately transmitted during enhanced carrier aggregation. A user terminal that can communicate with a radio base station by using six or more component carriers includes: a receiving section that receives scheduling information transmitted from the radio base station; a control section that determines based on the scheduling information to apply spatial bundling of a transmission acknowledgement signal only to a component carrier that the spatial bundling is applicable to; and a transmission section that transmits the transmission acknowledgement signal by using a PUCCH format 3.