User Terminal DMRS Control for Uplink Frequency Hopping

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In future radio communication systems, the application of frequency hopping to uplink channels can lead to deteriorated communication quality due to inadequate control of transmission processes for PUCCH and DMRS sequences.

Innovation Solution

A user terminal controls the generation of DMRS sequences based on the application of frequency hopping, regardless of the frequency-hop distance, by using higher layer parameters to determine orthogonal sequences and spreading factors for PUCCH and DMRS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If frequency hopping is applied to uplink control channel and DMRS, then communication flexibility and frequency diversity are improved, but transmission process control complexity increases and communication quality deteriorates

Engineering Contradiction:
Improvefrequency hopping capabilityVSAvoidtransmission process control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the orthogonal sequence and spreading factor based on the frequency hop distance. When frequency hopping is enabled, the system changes the sequence generation parameters (orthogonal sequence index and spreading factor) according to the hop distance, which resolves the contradiction by providing adaptability while maintaining manageable control complexity through standardized parameter mappings.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If frequency hopping is applied to uplink control channel, then frequency diversity and communication reliability are improved, but DMRS sequence generation control becomes inadequate and communication quality deteriorates

Engineering Contradiction:
Improvecommunication qualityVSAvoidDMRS sequence generation control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements feedback mechanisms where the base station provides frequency hopping configuration information to the user terminal, and the terminal adjusts its DMRS sequence generation based on this feedback. The system uses the frequency hop distance as feedback information to determine the appropriate orthogonal sequence and spreading factor, ensuring proper DMRS generation while maintaining ease of operation through automated parameter selection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the DMRS sequence generation parameters based on frequency hopping conditions. By adjusting the orthogonal sequence and spreading factor according to the frequency hop distance, the system maintains communication quality and reliability while simplifying the control operation through standardized parameter changes rather than complex manual control.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If multiple user terminals with different frequency-hop distances are multiplexed, then system capacity and resource utilization are improved, but multiplexing control complexity increases

Engineering Contradiction:
Improvesystem capacityVSAvoidmultiplexing control
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies universality by creating a unified sequence generation method that works for user terminals with different frequency-hop distances. The base station uses a common approach to configure orthogonal sequences and spreading factors based on the frequency hop distance, allowing multiple users with different hopping configurations to be multiplexed using the same control framework, thereby increasing system capacity while avoiding complex user-specific control.

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

Data Source

PatentEP3809599B1User terminal and wireless communication method
Publication Date: 2025.08.06 NTT DOCOMO INC
  • EP3809599B1 patent drawingFigure 1
  • EP3809599B1 patent drawingFigure 2A~2B
  • EP3809599B1 patent drawingFigure 3

AI summary

To perform appropriate communication even when frequency hopping is applied to a UL channel, one aspect of a user terminal according to the present disclosure includes: a receiving section that receives frequency hopping information indicating that frequency hopping of an uplink control channel is enabled, and information related to frequency hop resources; and a control section that determines a sequence to be applied to a demodulation reference signal for the uplink control channel, based on at least one of the frequency hopping information and a distance between frequency hops.