Yasushi Takatori
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View article: Unsupervised Learning based Element Resource Allocation for Reconfigurable Intelligent Surfaces in mmWave Network
Unsupervised Learning based Element Resource Allocation for Reconfigurable Intelligent Surfaces in mmWave Network Open
The increasing demand for high data rates and seamless connectivity in wireless systems has sparked significant interest in reconfigurable intelligent surfaces (RIS) and artificial intelligence-based wireless applications. RIS typically co…
View article: Device-Free AMR Crossing Detection Using LTE Signals for Smart Factory Applications
Device-Free AMR Crossing Detection Using LTE Signals for Smart Factory Applications Open
The Third Generation Partnership Project (3GPP) is currently discussing a new network for Integrated Sensing and Communications (ISAC). ISAC aims to enhance fifth and sixth-generation networks (5G/6G) by enabling simultaneous wireless sens…
View article: B-RAN-Based Control Method of User-Equipment Accommodation for Multi-Radio Environment
B-RAN-Based Control Method of User-Equipment Accommodation for Multi-Radio Environment Open
Wireless traffic is expected to increase mainly due to the demand for high-quality services. One approach to solving this problem is temporarily sharing private base stations (BSs) installed by individuals or companies. A blockchain is con…
View article: Deep-learning path loss prediction model using side-view images
Deep-learning path loss prediction model using side-view images Open
This paper proposes a path loss prediction model based on a convolutional neural network utilizing side-view images to consider over-rooftop propagation, in addition to the top-view images around the receiving station of the conventional m…
View article: Experimental evaluation of transmission link selection in IEEE 802.11be multi-link operation
Experimental evaluation of transmission link selection in IEEE 802.11be multi-link operation Open
The IEEE 802.11be includes multi-link operation (MLO) as a crucial feature. MLO allows a multi-link device (MLD) with multiple wireless interfaces to use them simultaneously and send packets concurrently. However, the performance of the ML…
View article: Wireless Technologies for Future Network Services Tailored to the Requirements of Various Users and Applications
Wireless Technologies for Future Network Services Tailored to the Requirements of Various Users and Applications Open
For the IOWN (Innovative Optical and Wireless Network)/6G (6th-generation mobile communication system) era, wireless systems and use cases, applications, and terminals will evolve, and users and service requirements will diversify.Therefor…
View article: Resource Allocation for Reconfigurable Intelligent Surface Assisted Dual Connectivity
Resource Allocation for Reconfigurable Intelligent Surface Assisted Dual Connectivity Open
The next generation 6G wireless systems are envisioned to have higher reliability and capacity than the existing cellular systems. The reconfigurable intelligent surfaces (RISs)-assisted wireless networks are one of the promising solutions…
View article: Resource Allocation and Sharing Methodologies When Reconfigurable Intelligent Surfaces Meet Multiple Base Stations
Resource Allocation and Sharing Methodologies When Reconfigurable Intelligent Surfaces Meet Multiple Base Stations Open
The 6G wireless systems are expected to have higher capacity, reliability, and energy efficiency than the existing cellular systems. Millimeter-wave (mmWave) frequencies offer high capacity at the cost of high attenuation and blockage loss…
View article: Performance Evaluation of Uplink Multiuser MIMO-OFDM System With Single RF Chain Receiver
Performance Evaluation of Uplink Multiuser MIMO-OFDM System With Single RF Chain Receiver Open
In response to the recent increase in wireless-traffic demand in various wireless communication networks, the number of spatial multiplexings, represented by multiple input multiple output (MIMO) systems, has been increasing. Assuming a re…
View article: Resource Allocation For Reconfigurable Intelligent Surface Assisted Dual Connectivity
Resource Allocation For Reconfigurable Intelligent Surface Assisted Dual Connectivity Open
The next generation 6G wireless systems are envisioned to have higher reliability and capacity than the existing cellular systems. The reconfigurable intelligent surfaces (RISs) is one of the promising solution to control the wireless chan…
View article: Resource Allocation For Reconfigurable Intelligent Surface Assisted Dual Connectivity
Resource Allocation For Reconfigurable Intelligent Surface Assisted Dual Connectivity Open
The next generation 6G wireless systems are envisioned to have higher reliability and capacity than the existing cellular systems. The reconfigurable intelligent surfaces (RISs) is one of the promising solution to control the wireless chan…
View article: Wireless Technologies toward Extreme NaaS—Multi-radio Proactive Control Technologies (Cradio®)
Wireless Technologies toward Extreme NaaS—Multi-radio Proactive Control Technologies (Cradio®) Open
Services accommodated by wireless communications require not only improvements in basic performance such as extreme high capacity, extreme low latency, and extreme mass connectivity but also the means of satisfying requirements that combin…
View article: Massive distributed IRS aided wireless communication with ON/OFF selection
Massive distributed IRS aided wireless communication with ON/OFF selection Open
The mobile communication system beyond fifth-generation (beyond 5G) is required to maintain higher transmission capacity and reliability than existing 5G systems. To meet these requirements, one promising solution is to incorporate an Inte…
View article: Multi-radio Proactive Control Technology (Cradio®): A Natural Communication Environment where Users Do Not Need to Be Aware of the Wireless Network
Multi-radio Proactive Control Technology (Cradio®): A Natural Communication Environment where Users Do Not Need to Be Aware of the Wireless Network Open
The prospects of wireless networks 1.1 Increasing communication volume and diversifying communication requirementsThe concept of the Innovative Optical and Wireless Network (IOWN) has been proposed by NTT as a model for future implementati…
View article: Distributed user-to-multiple access points association through deep learning for beyond 5G
Distributed user-to-multiple access points association through deep learning for beyond 5G Open
Future wireless networks will be facing unprecedented difficulties arising from mobile traffic growth, network densification, as well as diversification of applications and services. Indeed, future user devices are expected to integrate di…
View article: Extension of ITU-R Site-General Path Loss Model in Urban Areas Based on Measurements from 2 to 66GHz Bands
Extension of ITU-R Site-General Path Loss Model in Urban Areas Based on Measurements from 2 to 66GHz Bands Open
Path loss in high frequency bands above 6GHz is the most fundamental and significant propagation characteristic of IMT-2020. To develop and evaluate such high frequency bands, ITU-R SG5 WP5D recently released channel models applicable up t…
View article: An Actual Stadium Verification of WLAN Using a Distributed Smart Antenna System (D-SAS)
An Actual Stadium Verification of WLAN Using a Distributed Smart Antenna System (D-SAS) Open
Dense deployments of wireless local area network (WLAN) access points (APs) are accelerating to accommodate the massive wireless traffic from various mobile devices. The AP densification improves the received power at mobile devices; howev…
View article: Experimental verification of wireless LAN with distributed smart antenna system (D-SAS) in a train environment
Experimental verification of wireless LAN with distributed smart antenna system (D-SAS) in a train environment Open
For high-density wireless LAN environment, the interference among overlapped basic service sets (OBSSs) is a serious problem. To address this issue, we have proposed distributed smart antenna system (D-SAS) for wireless LAN, which suppress…
View article: JOINT DELAY AND AZIMUTH ESTIMATION OF COHERENT WAVES FOR MILLIMETER-WAVE BAND CHANNEL SOUNDING
JOINT DELAY AND AZIMUTH ESTIMATION OF COHERENT WAVES FOR MILLIMETER-WAVE BAND CHANNEL SOUNDING Open
The user traffic in the mobile communication area has rapidly increased owing to the widespread of smartphones and various cloud services. To handle the increasing traffic, in the fifth-generation mobile communication system (5G), the mill…
View article: Wildlife Detection System Using Wireless LAN Signals
Wildlife Detection System Using Wireless LAN Signals Open
The NTT Group considers the primary industry of agriculture an important field and is promoting development of innovative technologies that integrate agriculture with information and communication technology.This article introduces initiat…
View article: A Receiving Antenna Allocation Scheme for Downlink MU-MIMO-OFDM Transmission
A Receiving Antenna Allocation Scheme for Downlink MU-MIMO-OFDM Transmission Open
This paper proposes a novel receiving antenna allocation scheme for downlink multiuser multiple input multiple output orthogonal frequency division multiplexing (MU-MIMO-OFDM) transmission; an access point (AP) simultaneously transmits dat…
View article: Performance evaluation of distributed antenna in uplink MU-MIMO using amplitude information and many-to-one switch
Performance evaluation of distributed antenna in uplink MU-MIMO using amplitude information and many-to-one switch Open
This paper proposes a hardware configuration for uplink multiuser multiple-input multiple-output (MU-MIMO) transmissions with distributed antenna systems (DASs) in real indoor environments.Beam-forming (BF) technology is used in the DAS wi…
View article: ITU-R Study Group 3 Activities towards Use of High Frequency Bands for 5G and Other Wireless Communication Systems
ITU-R Study Group 3 Activities towards Use of High Frequency Bands for 5G and Other Wireless Communication Systems Open
Before frequencies are allocated to new wireless communication systems, it is important to investigate frequency sharing to avoid interference with existing systems.The International Telecommunication Union Radiocommunication Sector Study …
View article: New Trends in Wireless LAN and Cooperative Wireless LAN Technology
New Trends in Wireless LAN and Cooperative Wireless LAN Technology Open
At NTT Access Network Service Systems Laboratories, we are researching and developing wireless local area network (LAN) technology, which is becoming more popular in homes, businesses, and public spaces.This article introduces standardizat…
View article: Constrained beam selection scheme for WLAN systems
Constrained beam selection scheme for WLAN systems Open
This letter proposes a constrained beam selection scheme for wireless local area network (WLAN) systems and elucidates its effectiveness by a ray-trace simulation in an indoor environment.In the proposed selection scheme, a control engine …
View article: Clustering small cells in heterogeneous networks with interference alignment
Clustering small cells in heterogeneous networks with interference alignment Open
In this letter, we consider heterogeneous networks (HetNets) where interference alignment (IA), which is one of the promising interference management techniques, is applied. Using IA in HetNet has an issue that as the number of small-cells…
View article: A low-complexity cell clustering algorithm in dense small cell networks
A low-complexity cell clustering algorithm in dense small cell networks Open
Clustering plays an important role in constructing practical network systems. In this paper, we propose a novel clustering algorithm with low complexity for dense small cell networks, which is a promising deployment in next-generation wire…
View article: Low complexity non-linear pre-coding on downlink multiuser MIMO systems
Low complexity non-linear pre-coding on downlink multiuser MIMO systems Open
This paper proposes low complexity non-linear pre-coding that switching among pre-coding weights per orthogonal frequency division multiplexing (OFDM) symbol according to the modulation scheme and constellation point of users, for downlink…
View article: 7. MIMO Technologies in Wireless LAN Systems
7. MIMO Technologies in Wireless LAN Systems Open
35) 35 １．まえがき 無線によるブロードバンドアクセスは，スマートフォン やタブレットなどのスマートデバイスの普及と高品質なビ デオ映像伝送などのコンテンツのリッチ化に伴って急速に 発展してきている．免許不要周波数帯で運用される無線 LAN もこの発展を支え，2014 年度には国内の無線 LAN 対 応モバイル情報端末の出荷台数が 4,693 万台となった 1) ．こ のような無線 LAN の発展を支えてきたのが無線 LAN の大 容量化であり，利用可能な周波数帯の拡…