PUCCH Format Control for Multi-Carrier CSI Reporting

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Solution Overview

Problem

Existing LTE systems are inadequate for periodic CSI reporting when the number of component carriers (CCs) configured per user terminal exceeds five, leading to increased reporting cycles and collisions, especially with the expansion to 6 or more CCs.

Innovation Solution

Implementing a new PUCCH format with enhanced capacity to transmit P-CSI for multiple CCs in a single subframe, along with dynamic control of PUCCH formats based on the presence of transmission acknowledgment information and priority rules to manage P-CSI reporting efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the number of component carriers is expanded to six or more, then band expansion capability is improved, but periodic CSI reporting becomes inadequate due to increased reporting cycles and collisions

Engineering Contradiction:
Improveband expansion capabilityVSAvoidCSI reporting reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments CSI reporting for multiple CCs into separate reporting instances. When the number of CCs exceeds five, the terminal divides the P-CSI reporting into multiple parts, each handling a subset of CCs, thereby preventing reporting collisions and ensuring reliable CSI transmission for each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic adjustment of P-CSI reporting parameters based on the number of configured CCs. When CC count exceeds five, the system dynamically modifies reporting behavior by selecting appropriate PUCCH formats and adjusting reporting timing to avoid collisions, ensuring adaptive CSI reporting reliability.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If existing PUCCH formats are used for P-CSI reporting with six or more CCs, then device complexity is maintained, but reporting collisions increase and timing efficiency deteriorates

Engineering Contradiction:
ImprovePUCCH format complexityVSAvoidCSI reporting efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent changes key parameters of PUCCH formats to accommodate multiple CCs. It introduces new PUCCH formats with extended capacity parameters, allowing a single PUCCH to carry P-CSI for six or more CCs without increasing overall device complexity while significantly improving reporting efficiency and eliminating collisions.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If P-CSI for multiple CCs is transmitted in a single subframe using existing formats, then reporting timing is simplified, but transmission capacity becomes insufficient

Engineering Contradiction:
Improvereporting cycle durationVSAvoidP-CSI transmission capacity
Core Design Contradiction:
Loss of timeVSQuantity of substance

Solution Approach 1:

The patent extends the capacity dimension of PUCCH formats. By designing new PUCCH formats with larger payload capacities, the system can transmit P-CSI for six or more CCs within a single subframe, maintaining simplified timing while dramatically increasing transmission capacity to accommodate the expanded number of component carriers.

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

Data Source

PatentEP4319034B1User terminal, radio base station and radio communication method
Publication Date: 2025.11.26 NTT DOCOMO INC
  • EP4319034B1 patent drawingFigure 1
  • EP4319034B1 patent drawingFigure 2
  • EP4319034B1 patent drawingFigure 3

AI summary

A terminal (20) comprising a transmission section (203) configured to transmit channel state information periodically; and a control section (401) configured to control transmission of the channel state information, wherein the control section (401) is configured to control transmission, using a Physical Uplink Control Channel, PUCCH, format, of a plurality of channel state information, and of at least one amongst a scheduling request and transmission acknowledgement information, the PUCCH format being able to use a plurality of resource blocks, and characterised in that the control section (401) is configured to select at least one of the plurality of channel state information when a total amount of bits of the plurality of channel state information, and the at least one amongst the scheduling request and the transmission acknowledgment information, exceeds the number of bits that is smaller than a maximum number of bits for the PUCCH format and is determined based on a ratio of the number of bits with respect to the maximum number of bits for the PUCCH format.