Wireless Transmitter Delay-Doppler Multiplexing for Mixed Waveforms

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Efficient multiplexing of signals using different waveforms in a wireless communication system is challenging due to incompatibilities and interference issues.

Innovation Solution

A transmitter is designed to perform sparse resource mapping and power shaping in the delay-Doppler domain, followed by inverse symplectic finite Fourier transform (ISFFT), enabling non-orthogonal multiplexing of signals with different waveforms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If signals using different waveforms are multiplexed in a wireless communication system, then spectral efficiency is improved, but interference between signals increases

Engineering Contradiction:
Improvespectral efficiencyVSAvoidinterference between signals
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by performing power shaping in the delay-Doppler domain, where different power levels are assigned to different delay-Doppler resources. This allows the signal to have different local characteristics in different regions of the delay-Doppler domain, enabling efficient multiplexing while controlling interference through localized power adjustment rather than uniform treatment across the entire signal.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes parameters by transforming the signal from the time-frequency domain to the delay-Doppler domain using ISFFT, and applying power shaping in this transformed domain. This parameter transformation allows for more effective resource allocation and interference management by operating in a domain where the signal characteristics are better suited for handling high mobility and Doppler effects.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional waveforms are used for compatibility, then ease of operation is maintained, but adaptability to high mobility environments deteriorates

Engineering Contradiction:
ImprovecompatibilityVSAvoidadaptability to high mobility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent achieves universality by designing a transmitter that can handle both conventional and advanced waveform requirements through a unified delay-Doppler domain processing framework. The ISFFT-based power shaping mechanism provides a universal solution that works for high mobility scenarios while maintaining compatibility with existing communication systems, allowing the same processing structure to serve multiple functions and different operational requirements.

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

Data Source

PatentEP4679741A1Transmitter and transmission method
Publication Date: 2026.01.14 NTT DOCOMO INC
  • EP4679741A1 patent drawingFigure 1
  • EP4679741A1 patent drawingFigure 2
  • EP4679741A1 patent drawingFigure 3~4

AI summary

A transmitter includes a control unit configured to convert a first signal into a time-frequency domain by performing sparse resource mapping and power shaping on the first signal in a delay-Doppler domain and performing an inverse symplectic finite Fourier transform (ISFFT); and a transmission unit configured to non-orthogonally multiplex the first signal with a second signal and transmit the multiplexed signal.