March 2022 Vol. 20 No. 332022

https://www.ntt-review.jp/archive/2022/202203.html

Front-line Researchers

Tomohiro Nakatani, Senior Distinguished Researcher, NTTCommunication Science Laboratories▼Abstract

Automatic-speech-recognition technology has developed rapidly and is now
commonly used in voice interfaces such as those of smartphones and smart
speakers; however, the technology must be further improved to enable smoothinteraction between computers and humans. Tomohiro Nakatani, a seniordistinguished researcher at NTT Communication Science Laboratories, has been at
the forefront of research regarding speech enhancement, which removes ambient
noise and reverberation from various sounds and accurately extracts only the soundthat the person wants to hear. We asked him about the progress of his research andattitude as a leading researcher.

Feature Articles
Technology Development for Achieving the Digital Twin Computing Initiative

The World Made Possible by IOWN Digital Twin Computing▼Abstract

Front-line Researchers

Digital Twin Computing (DTC) to achieve futureforecasting and optimization by linking the realand digital worlds is now being researched anddeveloped as one of the main pillars of theInnovative Optical and Wireless Network(IOWN) vision targeted by NTT. This article
introduces the world under DTC and four grandchallenges in making DTC a reality.

Scale andgranularity ofdigital twins
Deeper

PersonExpansion of abilities
Expand abilities to bolster
intelligent tasks and skills andcollaborate with digital twinsthat are behaving and growing
autonomously

Decision-making
Review a variety of personalpossibilities and futurescenarios for use in one’s own
decision-making

Tomohiro Nakatani, Senior Distinguished Researcher, NTT Communication Science Laboratories

GroupTownCityUse of human intelligencebeyond temporal/spatialconstraints
Combine diverse personalities
and expertise for immediate
consensus building andbrainstorming

Medical care and health
Use biosensing and lifestyleanalysis to achieve
personalized/predictive medicineand behavior modification

Rising Researchers
Yoshihiro Ogiso, Distinguished Researcher, NTT Device Innovation Center/NTT Device
Technology Laboratories

Feature Articles
Technology Development for Achieving the Digital Twin
Computing Initiative
The World Made Possible by IOWN Digital Twin Computing
Studies on Skill Level and Dialogue Satisfaction for Achieving Mind-to-Mind Communications
TechnologyTechnologies for Achieving Another Me
Initiatives toward Development of the Exploring Engine for the Future Society
Coupled Simulation Technology for Visualizing Environmental and Economic Social Cycles

Regular Articles
Experimental Evaluation of High-capacity Wireless Transmission Using Orbital AngularMomentum Multiplexing Technology

Global Standardization Activities
Recent Standardization Activities in ITU-R SG 3Nation

GlobeSpaceBroader

Optimal control ofpeople/traffic flow

Future urban design

Prediction of urban energy
demandAchieve real-time demandprediction and highly efficientuse of energy and infrastructure(electricity, gas, water, etc.) atthe city level

Digital reproductions on a
global scaleDigitalize the topography,
climatic fluctuations, etc. of theentire Earth, predict and deal
with large-scale natural disasters,
and achieve sustainable nationaland urban development

Conduct urban development andControl people/traffic flow using planning by predicting mediumspatial/temporal 4D information, and long-term changes in 4D
eliminate congestion and traffic information and achieve newjams in conjunction with weather urban design through trials andpredictions that include humanand schedules, and achieve asocial behavior
low carbon society

Regular Articles

Experimental Evaluation of High-capacity Wireless Transmission
Using Orbital Angular Momentum Multiplexing Technology▼Abstract

We are researching and developing technology to achieve
terabit-class wireless transmission toward six-generation
wireless systems. In this article, we present experimental
evaluations of high-capacity wireless transmission using orbital
angular momentum (OAM) multiplexing on a 40-GHz frequency
band with a bandwidth of 1.5 GHz at distances of 100 and 200
m. Our OAM antennas have two uniform circular arrays (UCAs)
with the same diameter using different linear polarizations andButler matrices, which are analog devices for generating andseparating OAM modes. OAM beams are generated using aButler matrix, which is an analog radio-frequency circuit, andradiated from the UCAs. We implemented an OAM multiplexing
transmitter (Tx) and receiver (Rx) on the 40-GHz band. The Tx
and Rx can generate and separate seven OAM modes (0, ±1,±2, ±3) and two polarizations (vertical and horizontal), which is a
total of 15 streams including the center antenna element totransmit OAM mode 0. Each channel carries a 1.5-Gbaud signal.

OAM mode 1
OAM multiplexing technology

OAM mode 2

OAM mode 3(a) Trace of the same phase(b) Concurrent transmission