Uplink Control Channel Reference Signal Mapping for Spectral Efficiency

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Solution Overview

Problem

Future radio communication systems face challenges in efficiently transmitting uplink control information due to the degradation of spectral efficiency when using uplink control channels with different numbers of symbols, leading to reduced communication throughput and spectral efficiency.

Innovation Solution

The proposed solution involves mapping reference signals (RS) to the same symbol positions across various PUCCH formats, regardless of the number of symbols, to minimize puncturing of uplink control information (UCI) and reduce RS-induced interference, thereby maintaining spectral efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple mapping method is applied to uplink control information symbols and reference signal symbols in uplink control channels, then the implementation complexity is reduced, but uplink control information cannot be efficiently transmitted and spectral efficiency deteriorates

Engineering Contradiction:
Improvemapping method complexityVSAvoiduplink control information transmission efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the mapping behavior for different symbol types within the PUCCH structure. Reference signals are mapped to specific predetermined symbol positions (e.g., first and last symbols) while uplink control information is mapped to remaining symbols. This localized differentiation ensures that reference signals maintain their interference mitigation function while UCI achieves efficient transmission, resolving the contradiction between simple mapping and transmission efficiency.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If uplink control channels with different numbers of symbols are used to fulfill varying communication requirements, then adaptability is improved, but spectral efficiency deteriorates due to puncturing and interference

Engineering Contradiction:
Improvecommunication service adaptabilityVSAvoidspectral efficiency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements universality by establishing a standardized reference signal mapping rule that applies across all PUCCH formats regardless of their symbol count. The rule that reference signals are mapped to predetermined symbol positions (such as first and last symbols) creates a universal framework that works for short PUCCH formats (2-3 symbols) and long PUCCH formats (4+ symbols) alike. This universal approach maintains spectral efficiency while supporting diverse communication requirements.

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

Solution Approach 2:

The patent applies preliminary action by pre-determining the symbol positions where reference signals will be mapped before the actual uplink transmission occurs. These predetermined positions are established based on the PUCCH format and configuration, allowing the system to proactively avoid puncturing of uplink control information and minimize reference signal-induced interference. This advance planning ensures efficient spectral utilization across different PUCCH durations.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3573397B1User terminal and wireless communication method
Publication Date: 2024.01.03 NTT DOCOMO INC
  • EP3573397B1 patent drawingFigure 1A~1B
  • EP3573397B1 patent drawingFigure 2A~2B
  • EP3573397B1 patent drawingFigure 3A~3D

AI summary

The present invention is designed so as to be able to preferably control the degradation of spectral efficiency even when communication is performed using a plurality of uplink control channel formats carrying different numbers of symbols. A user terminal according to one aspect of the present invention has a transmission section that transmits uplink control information using at least one of a plurality of uplink control channel structures carrying different numbers of symbols, and a control section that exerts control so that, regardless of which of the plurality of uplink control channel structures is used, a reference signal is mapped to a same time resource.