Jin Nakazato

University of Tokyo

Increasing prevalence of Autonomous Vehicles (AVs) necessitates efficient communication with susceptible road users, especially pedestrians, in communal urban areas. To improve pedestrians' trust and safety, Smart Pole Interaction Units (SPIU) and external Human-Machine Interfaces (eHMI) have become crucial interfaces. In this study, we ask 12 auto...

The millimeter wave (mmWave) regime is expected to be widely deployed in next-generation communication technologies such as 5G and Beyond 5G (B5G)/6G. In particular, the mmWave technology can provide high-speed and large-capacity communications using high-frequency bandwidth. The barriers to this are strong directiv-ity and signal attenuation/shiel...

The millimeter wave (mmWave) regime is core to 5G technologies. It operates in the high frequency band around 30 GHz, enabling high-speed, high-capacity communications. However, due to its strong directivity, mmWave signals are highly susceptible to obstacles and have limited propagation distances, resulting in limited coverage areas. In this work,...

This paper proposes a hybrid beamforming architecture utilizing multiple distributed Roadside Units (RSUs) to improve the overall channel capacity of millimeter-wave (mmWave) vehicular networks. The proposed system leverages a cell-free mobility network architecture with distributed RSUs, enhancing communication performance in Vehicle-to-Everything...

This paper proposes broad-range null-steering (BRNS) incorporated with beam tracking for further stabilizing multiuser spatial multiplexing transmission in high-speed mobile environments. BRNS improves IUI suppression capability by steering additional location-based nulls to intrefering targets. However, desired user moves out of the beam, which le...

Our research focuses on the smart pole interaction unit (SPIU) as an infrastructure external human-machine interface (HMI) to enhance pedestrian interaction with autonomous vehicles (AVs) in shared spaces. We extensively study SPIU with external human-machine interfaces (eHMI) on AVs as an integrated solution. To discuss interaction barriers and en...

Digital twins have recently attracted attention from academia and industry as a technology connecting physical space and cyberspace. Digital twins are compatible with Augmented Reality (AR) and Virtual Reality (VR), enabling us to understand information in cyberspace. In this study, we focus on sound and design an architecture for a 3D representati...

This paper addresses the challenges of dynamic beam search in millimeter wave (mmWave) communications for vehicle-to-everything (V2X) applications. With the rapid mobility of connected autonomous vehicles (CAVs) and dense urban environments, maintaining high-quality mmWave connections is critical for the reliability and efficiency of V2X communicat...

This paper proposes a user scheduling scheme for multiuser MIMO (MU-MIMO), particularly effective in time-varying channel environments. This scheme utilizes not only the current channel state information (CSI) but also the past ones for scheduling. MU-MIMO enables to enhance spectral efficiency by multiplexing a number of user terminals (UTs) in sp...

The burgeoning Intelligent Transportation System (ITS) spurs global technological advancements, notably in innovative community development through vehicle-to-everything (V2X) communication. This study focuses on the high data rates and low latency offered by a millimeter-wave (mmWave) enabled vehicular network while addressing the significant chal...

V2X in connected autonomous vehicles (CAV) plays an important role in information sharing through communication. The integration of V2X and blockchain has the potential to create functionalities such as seamless V2X information sharing, similar to Bitcoin, and post-accident investigation utilities that leverage data immutability. However , the inte...

Recently, as networks operate as the infrastructure of modern society, the demands placed on the network by applications have become more complex. In particular, there is an increasing annual demand for high-capacity and low-latency services, including real-time streaming. 5G has been launched to meet this demand, but its stability varies depending...

Mobile ad hoc networks are self-organizing networks that do not rely on fixed infrastructure. Smart antennas employ advanced beamforming technology, enabling ultra-long-range directional transmission in wireless networks, which leads to lower power consumption and better utilization of spatial resources. The media access control (MAC) protocol desi...

Connected autonomous vehicles (CAVs) are crucial to a future society that embraces advanced technologies. For these vehicles to effectively share information with nearby vehicles or infrastructures through vehicle-to-everything (V2X) interfaces, stable mmWave communication is essential yet challenging. This paper presents an innovative approach to...

This paper presents a comprehensive exploration of federated learning applied to vehicular communications within the context of Open RAN. Through an in-depth review of existing literature and analysis of fundamental concepts, critical challenges are identified within the current methodologies employed in this sphere. A novel framework is proposed t...

In the era of Industry 5.0, advanced technologies like artificial intelligence (AI), robotics, big data, and the Internet of Things (IoT) offer promising avenues for economic growth and solutions to societal challenges. Digital twin technology is important for real-time three-dimensional space reproduction in this transition, and unmanned aerial ve...

This article proposes a millimeter-wave fast beam tracking algorithm for moving vehicles, considering a geometry of road environment. Focusing on the fact that vehicle movement is constrained on roads, horizontal and vertical beam directions are determined based on obtainable driving direction and road shape. In addition, we perform a two-pattern b...

This paper demonstrates the practical effectiveness of our proposed broad-range null-steering (BRNS) scheme through indoor experiment using 28-GHz band 4-element array antenna transmission system. For realization of cooperative automated driving, use of millimeter-wave band and multiuser multiple-input multiple-output (MIMO) are essential. However,...

In the era of Beyond 5G, the significance of interdisciplinary research has become increasingly important. Within this context, the Kalman filter, a technology integral to self-positioning estimation in autonomous driving, is already being adopted in various societal applications. This study proposes a method wherein beam tracking, in conjunction w...

This paper proposes a novel inter-user interference (IUI) suppression approach in multiuser MIMO (MU-MIMO) with time-varying channel environments. It introduces location based beam-space expansion (BSE) scheme for vehicle-to-infrastructure (V2I) MU-MIMO transmission. This scheme expands the main lobe of the beam based on vehicle location informatio...

The commercialization of 5G has been initiated for a while. Yet, we haven't seen wide penetrations of the disruptive applications as promised, like the extended reality (XR), internet of vehicles (IoV), telesurgery, etc. Digital twins (DTs) are one of these highly anticipated applications. However, DTs demand all 5G capabilities, including enhanced...

This paper proposes an intensive null-steering around the target in angular domain to effectively suppress inter-user interference (IUI) leakage caused by channel varying environment such as vehicular multiuser spatial multiplexing. Multiuser MIMO can enhance spectral efficiency by multiplexing a number of user terminals in spatial domain. Suppose...

The commercialization of 5G has been initiated for a while. Furthermore, millimeter wave (mmWave) has been introduced to small cells with small coverage due to its strong linearity and non-winding characteristics. On the other hand, in connected autonomous vehicles (CAVs), where various traffic systems can cooperatively perform recognition, decisio...

This paper focuses on coordinating Intelligent Reflective Surfaces (IRS) and UAV networks to extend coverage while maintaining Line-of-Sight (LoS) conditions. We verify our methodology through numerical analysis in a realistically modeled 3D urban environment. Our results highlight remarkable enhancements in received SINR (Signal-to-Noise ratio) fo...

Standalone autonomous vehicles primarily rely on their onboard sensors and may have blind spots or limited situational awareness in complex or dynamic traffic scenarios, leading to difficulties in making safe decisions. Collective perception enables connected autonomous vehicles (CAVs) to overcome the limitations of standalone autonomous vehicles b...

Due to the randomness of channel fading, communication devices, and malicious interference sources, unmanned aerial vehicles (UAVs) face a complex and ever-changing task scenario, which poses significant communication security challenges, such as transmission outages. Fortunately, these communication security challenges can be transformed into path...

Automated driving has the same limitations as human drivers because it functions as a replacement for humans and operates based on local information using onboard sensors and computers. Cooperative automated vehicles (CAVs) are expected to achieve both safety and efficiency, which could not be achieved by imitating human driving, by sharing sensor...

Nowadays, wireless communications are ubiquitously available. However, as pervasive as this technology is, there are distinct situations, such as during substantial public events, catastrophic disasters, or unexpected malfunctions of base stations (BSs), where the reliability of these communications might be jeopardized. Such scenarios highlight th...

Advancements in LiDAR technology have led to more cost-effective production while simultaneously improving precision and resolution. As a result, LiDAR has become integral to vehicle localiza-tion, achieving centimeter-level accuracy through techniques like Normal Distributions Transform (NDT) and other advanced 3D registration algorithms. Nonethel...

In recent years, extensive research has focused on leveraging advanced technologies beyond 5G and for Industry 5.0 to promote sustainability and prosperity in society. Our study advances this effort by seeking to create an aerial perspective using Unmanned Aerial Vehicles (UAVs). This paper introduces a method for optimizing UAV deployment strategi...

This paper presents an investigation result focused on Distributed Digital Identity (DDI) and the social factors influencing digital identification within the scope of a Trusted Inter-Reality. It introduces the architecture and mechanisms essential for managing DDI, highlighting the imperative for robust, secure, and adaptable frameworks in diverse...

In recent years, information technology has become an important element in the pursuit of a more prosperous society, and this extends to the realm of sports. The digitalization is evident across various sectors, including sports. Within the context of baseball, the introduction of automated technology for umpiring is garnering significant attention...

The increasing demand for remote collaboration and remote working has become crucial to daily life owing to the Covid-19 pandemic and the development of internet-based video distribution services. Furthermore, low-latency remote collaboration , such as teleoperation and support applications designed for in-vehicle environments, has gained considera...

Recently, there has been a growing emphasis on autonomous vehicles (AVs), and as they coexist with pedestrians, ensuring pedestrian safety at crosswalks has become paramount. While AVs exhibit commendable performance on traditional roads with established traffic infrastructure, their interaction in different environments, such as shared spaces lack...

In autonomous vehicles (AVs), ensuring pedestrian safety within intricate and dynamic settings, particularly at crosswalks, has gained substantial attention. While AVs perform admirably in standard road conditions, their integration into unique environments like shared spaces devoid of traditional traffic infrastructure control presents complex cha...

Millimeter-wave (mmWave) and terahertz (THz) technologies are under consideration for Beyond 5G (B5G) and 6G. However, mmWave/THz bands suffer from high propagation loss and blockage effects, making it challenging to deploy communication areas. To address these issues, we propose a digital twin platform for future wireless communication that expand...

Recently, there has been a growing emphasis on autonomous vehicles (AVs), and as they coexist with pedestrians, ensuring pedestrian safety at crosswalks has become paramount. While AVs exhibit commendable performance on traditional roads with established traffic infrastructure, their interaction in different environments, such as shared spaces lack...

Connected Autonomous Vehicles (CAVs) produce a variety of information within their systems. With the advancement of communication and V2X (Vehicle-to-Everything) communication technology, there is a growing challenge to effectively convey this information to pedestrians and enhance their sense of safety when encountering such vehicles. Efforts to c...

The rapid increase in the number of connected vehicles on roads has made Vehicular Ad-hoc Networks (VANETs) an attractive target for malicious actors. As a result, VANETs require secure data transmission to maintain the network's integrity. Federated Learning (FL) has been proposed as a secure data-sharing method for VANETs, but it is limited in it...

Building digital twin (BDT) is utilized throughout the lifecycle of a building. It serves for efficient operations during the design and construction phases, and during the operational and maintenance phases, it's used for asset management and as field maps for robots. Building Information Modeling (BIM), which contains both semantics and geometry...

Vehicle-to-everything (V2X) communication enables connected autonomous vehicles (CAVs) to share information and generate optimal decisions. The networking abilities of CAVs have led to the development of unsignalized autonomous intersection management (AIM) methods that leverage CAVs to significantly improve traffic flows. However, AIM methods assu...

This paper explores the potential for communication-efficient federated learning (FL) in modern distributed systems. FL is an emerging distributed machine learning technique that allows for the distributed training of a single machine learning model across multiple geographically distributed clients. This paper surveys the various approaches to com...

The exhaustion of IPv4 addresses has driven the rapid adoption of IPv6 networks, which has created challenges in the domain name resolution process, particularly for IPv6-only iterative resolvers. This paper presents an experimental analysis to quantify the extent of this problem, revealing a significantly lower success rate of name resolution usin...

Connected autonomous vehicles (CAVs), through vehicle-to-everything communication and computing resources, enable the vital exchange of information. Although deep learning is crucial in this landscape, it requires extensive and intricate datasets covering all potential scenarios. Furthermore, this situation poses a hazard, as the likelihood of acci...

Fusion of the real and virtual worlds is essential for applying digital technology to the infrastructure of human life. A digital twin is one of the technologies that aim to integrate real and virtual space. It creates a digital world with high fidelity to reality by accumulating exhaustive information from sensors to improve simulation and predict...

In addition to traditional viewing media, metadata that record the physical space from multiple perspectives will become extremely important in realizing interactive applications such as Virtual Reality (VR) and Augmented Reality (AR). This paper proposes the Software Defined Media (SDM) Ontology designed to describe spatio-temporal media and the s...

For cooperative intelligent transport systems (C-ITS), vehicle-to-everything (V2X) communication is utilized to allow autonomous vehicles to share critical information with each other. We propose AutowareV2X, an implementation of a V2X communication module that is integrated into the autonomous driving (AD) software, Autoware. AutowareV2X provides...

Path planning is critical for autonomous vehicles (AVs) to determine the optimal route while considering constraints and objectives. The potential field (PF) approach has become prevalent in path planning due to its simple structure and computational efficiency. However, current PF methods used in AVs focus solely on the path generation of the ego...

Making safe and successful lane changes (LCs) is one of the many vitally important functions of autonomous vehicles (AVs) that are needed to ensure safe driving on expressways. Recently, the simplicity and real-time performance of the potential field (PF) method have been leveraged to design decision and planning modules for AVs. However, the LC tr...

Collision avoidance (CA) has always been the foremost task for autonomous vehicles (AVs) under safety criteria. And path planning is directly responsible for generating a safe path to accomplish CA while satisfying other commands. Due to the real-time computation and simple structure, the potential field (PF) has emerged as one of the mainstream pa...

As connected autonomous vehicles (CAVs) become increasingly prevalent, there is a growing need for simulation platforms that can accurately evaluate CAV behavior in large-scale environments. In this paper, we propose Flowsim, a novel simulator specifically designed to meet these requirements. Flowsim offers a modular and extensible architecture tha...

Recently, vehicle-to-everything (V2X) has been attracting attention for its potential to improve traffic safety and increase traffic volume worldwide, improving the accuracy of data and parameters collected from moving vehicles is widely discussed in the V2X. The most common technique of GPS may not be efficient during some specific scenarios, like...

The increasing demand for remote collaboration and remote working has become crucial to daily life owing to the Covid-19 pandemic and the development of internet-based video distribution services. Furthermore, low-latency remote collaboration, such as teleoperation and support applications designed for in-vehicle environments, has gained considerab...

Big data is a rapidly growing field, and new developments are constantly emerging to address various challenges. One such development is the use of federated learning for recommendation systems (FRSs). An FRS provides a way to protect user privacy by training recommendation models using intermediate parameters instead of real user data. This approa...

Discussions have begun worldwide toward Beyond 5G/6G in the 2030s. In these challenges, the topic of intelligence is a controversial point on various layers of RAN (radio-access-network), core, edge, automation, etc. One of the ideas on that topic is a digital twin platform that integrates physical and cyberspace. This study focuses on the RAN side...

Cooperative perception is crucial for connected automated vehicles in intelligent transportation systems (ITSs); however, ensuring the authenticity of perception data remains a challenge as the vehicles cannot verify events that they do not witness independently. Various studies have been conducted on establishing the authenticity of data, such as...

In recent years the cooperative automated vehicle (CAV) concept has been gaining attention due to its potential to increase traffic safety and traffic flow by utilizing the vehicle-to-everything communication capability. One of the key requirements for CAV is ensuring every vehicle receives relevant messages at the right time and place; therefore,...

For cooperative intelligent transport systems (C-ITS), autonomous vehicles utilize vehicle-to-everything (V2X) communication to share critical information, enabling cooperatively enhanced environmental awareness and decision-making. We propose AutowareV2X, an implementation of a V2X communication module that is integrated into the autonomous drivin...

In the event of a major disaster, base stations in the disaster area will cease to function, making it impossible to obtain life-saving information. Therefore, it is necessary to provide a wireless communication infrastructure as soon as possible. To cope with this situation, we focus on NFV/SDN (Network Function Virtualization/Software-Defined Net...

To deal with recent increasing mobile traffic, ultra-broadband communication with millimeter-wave (mmWave) has been paid attention as a key technology for 5G cellular network. As a previous study, there is mmWave heterogeneous network which is composed of several mmWave small cells overlaid on the coverage of a macro cell. However, seen from optica...

The emergence of 5G-IoT opens up unprecedented connectivity possibilities for new service use cases and players. Multi-access edge computing (MEC) is a crucial technology and enabler for Beyond 5G, supporting next-generation communications with service guarantees (e.g., ultra-low latency, high security) from an end-to-end (E2E) perspective. On the...

The emergence of 5G-IoT opens up unprecedented connectivity possibilities for new service use cases and players. Multi-access edge computing (MEC) is a crucial technology and enabler for Beyond 5G, supporting next-generation communications with service guarantees (e.g., ultra-low latency, high security) from an end-to-end (E2E) perspective. On the...

For the purpose of establishing a digital twin society, this paper proposes a object recognition network architecture using high-definition (HD) camera images. HD camera is installed to the edge computing resource in RoadSide Unit (RSU). The edge computing resource detect vehicles by object detection and Re-ID function based on deep learning. Its k...

Conventional, the authors proposed a concept based on the combination of ultra-broadband mmWave (mmW) communication and edge cloud in the 5G-MiEdge Project. On the other hand, consortium activities and white papers about B5G/6G vision have been growing recently. Hence, we have developed and created Private B5G PoC Field in Ookayama Campus of Tokyo...