DMRS Base Sequence Switching for Short PUCCH UCI Multiplexing

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Solution Overview

Problem

In future radio communication systems, frequency-division-multiplexing of UCI and DMRS in the short PUCCH leads to improper generation of the DMRS base sequence, resulting in transmission issues.

Innovation Solution

A user terminal controls the generation of DMRS base sequences by switching between pseudo-random sequences and CAZAC sequences based on the sequence length, ensuring proper transmission of frequency-division-multiplexed UCI and DMRS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If UCI and DMRS are frequency-division-multiplexed in the short PUCCH, then the transmission efficiency is improved, but the base sequence generation becomes improper

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidbase sequence generation reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the parameter of sequence type selection based on the sequence length. When the sequence length is less than 36, a pseudo-random sequence is used instead of a CAZAC sequence. This parameter change resolves the generation issue while maintaining FDM capability between UCI and DMRS in short PUCCH.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If CAZAC sequences are used for DMRS base sequence generation, then the sequence generation is proper, but the design load increases

Engineering Contradiction:
Improvesequence generation reliabilityVSAvoiddesign load
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a parameter-based selection mechanism where the sequence length determines the sequence type. This avoids the need to design new CAZAC sequence tables by utilizing existing pseudo-random sequences for shorter lengths, thereby reducing design complexity while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If the sequence length is short, then the short PUCCH format is achieved, but the base sequence cannot be generated properly

Engineering Contradiction:
Improvesequence lengthVSAvoidbase sequence generation reliability
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent establishes a parameter threshold (sequence length of 36) that triggers a change in sequence type. For sequence lengths below this threshold, pseudo-random sequences are used instead of CAZAC sequences, ensuring proper generation while maintaining the short PUCCH format requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3684021B1User terminal and wireless communication method
Publication Date: 2024.12.04 NTT DOCOMO INC
  • EP3684021B1 patent drawingFigure 1A~1B
  • EP3684021B1 patent drawingFigure 2A~2D
  • EP3684021B1 patent drawingFigure 3

AI summary

According to one aspect of the present invention, a user terminal has a transmitting section that frequency-division-multiplexes and transmits a reference signal that is generated based on a base sequence, with uplink control information, and a control section that controls switching between a first sequence and a second sequence that are used to generate the base sequence, based on a sequence length of the base sequence. By this means, the reference signal that is frequency-division-multiplexed with the uplink control information can be transmitted properly.