User Terminal PUCCH Resource Selection with Implicit DCI Indication

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Solution Overview

Problem

In future radio communication systems, determining PUCCH resources for UCI transmission based on higher layer signaling and DCI can result in ambiguity when the PUCCH resource set selected by UCI payload size includes more resources than can be indicated by the given field in DCI, leading to inappropriate resource determination.

Innovation Solution

A user terminal determines PUCCH resources by using implicit indication information derived from Downlink Control Information (DCI) and additional parameters such as CORESET index, search space index, and DMRS configuration, allowing for appropriate resource selection even when the number of PUCCH resources exceeds what can be indicated by the given field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the PUCCH resource set includes more resources than can be indicated by the given field in DCI, then the adaptability of resource allocation is improved, but the user terminal cannot appropriately determine the PUCCH resources

Engineering Contradiction:
Improveresource allocation adaptabilityVSAvoidresource determination accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The PUCCH resource selection is segmented into two independent components: explicit indication via DCI field and implicit indication via derivation rules. The explicit field provides coarse selection among resource sets, while implicit rules provide fine selection within sets, allowing the system to handle more resources than the DCI field alone could indicate while maintaining determination accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Implicit indication information acts as an intermediary mechanism that bridges the gap between the limited DCI field capacity and the expanded PUCCH resource sets. By introducing this intermediate layer of resource indication through derivation rules based on downlink resource allocation, the system achieves both high adaptability and reliable resource determination.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If implicit indication information is derived from multiple parameters, then the precision of PUCCH resource determination is improved, but the complexity of resource selection process increases

Engineering Contradiction:
Improveresource determination precisionVSAvoidresource selection complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary configuration of PUCCH resource sets and their associated implicit indication rules through higher layer signaling before actual resource selection is needed. This pre-establishment of resource sets and derivation rules reduces the complexity of real-time resource selection, as the terminal only needs to apply predetermined rules rather than compute complex selections during transmission.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The implicit indication mechanism serves multiple functions simultaneously: it provides fine-grained resource selection, ensures unique determination of PUCCH resources, and maintains consistency between downlink resource allocation and uplink control channel resources. This multi-functionality achieves high precision without proportionally increasing complexity.

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

Data Source

PatentEP3745793B1User terminal and wireless communication method
Publication Date: 2025.09.03 NTT DOCOMO INC
  • EP3745793B1 patent drawingFigure 1
  • EP3745793B1 patent drawingFigure 2A~2B
  • EP3745793B1 patent drawingFigure 3A~3B

AI summary

A user terminal according to this application includes: a transmitting section that transmits Uplink Control Information (UCI) by using an uplink control channel; and a control section that, when one or more resource sets each including one or more resources for the uplink control channel are configured, determines a resource used for transmission of the UCI based on a given field value in Downlink Control Information (DCI) and implicit indication information from a resource set selected based on a number of bits of the UCI, and the control section derives the implicit indication information based on at least one of a frequency resource to be allocated to a downlink shared channel, a time resource to be allocated to the downlink shared channel and an allocation type of the frequency resource.