Kato Laboratory at Graduate School of Information Sciences, Tohoku
University, is involved in research & development, education and
scholarly activities in the broad area of communication networks and
systems. Our research focuses on next-generation Internet and pattern
recognition applied technologies. The research areas of interest
include, but are not limited to wireless and mobile communications, Low
Earth Orbit satellite communication systems, network security,
development of “smart” applications for next generation networks, and
character and document recognition using statistics and probability.
Following are brief introductions of the key research concentration
areas:
Recently, Unmanned Aerial Vehicles (UAVs) have attracted attention for various applications such as drone delivery, crop monitoring, constructing wireless mesh networks in disaster areas, and so forth. For these applications, wireless communication and network technology are essential to efficiently transmit data over Air-to-Air (A2A) and Air-to-Ground (A2G).
In our laboratory, we aim to achieve high-capacity, low-latency UAV-aided communication network. For this purpose, we analyze the effect of the mobility of UAVs, consider the efficient multiple access method and so forth. Our research regarding this topic includes the following:
A study on the efficient frequency resource allocation scheme in UAS.
UAV-aided wireless mesh network construction in disaster areas.
- Satellite networks -
Because of their extensive geographical reach, flexible and rapid deployment features, and inherent multicast capabilities, satellite network systems are seen as an attractive solution to realize the dream of personal communications at a global scale. Given the recent advances and ongoing improvements in satellite technologies, broadband satellite based services are likely to open a promising and strong market for service providers and operators. This research program includes different issues in satellite networks, mainly those related to frequent handover occurrences and unfairness among long and short RTT connections. Our research on this topic includes:
Location-aware mobility management methods for satellite networks
Efficient and fair transmission protocols for satellite networks
Design and development of an efficient integration of satellites with terrestrial networks
- Mobile, ad hoc, and sensor networks -
In places where communication infrastructure is not fully developed, such as depopulated areas and developing countries, or where communication infrastructure is damaged due to the occurrence of a large-scale disaster, it is considered difficult to transmit information over a wide range, while information communication is indispensable as a means of prompt information dissemination and confirmation of safety at the time of a disaster. To provide essential communication services, the construction of networks by only mobile devices equipped with wireless communication systems such as smart phones and drones is expected to be an effective technology.
By utilizing grouping functions of mobile devices and virtual cells, we aim to realize end-to-end communication in a situation where communication infrastructure does not function.
Our research in this topic includes:
Research on efficiency of device to device communication by grouping
Virtual cell construction method for information diffusion by inter-device communication
Control method of inter-device communication using spatial information
- Optical and wireless integrated networks -
In order to achieve high-speed communication, the wireless and optical integrated networks are emerging as an exciting research area. In such networks, both wireless communication and optical communication, have entirely different inherent characteristics. The wireless network aims to enable ubiquitous communication while the optical network aims at enabling large-capacity communication. The realization of advanced cooperation and integration of both the wireless and optical networks is essential to achieve the highly anticipated ICT society of tomorrow. The structure to exploit the characteristics of wireless and optical communication systems in an integrated manner is an intricate process which deserves adequate research attention. In this vein, our research topics include:
The advanced integration of wireless communication and optical communication
The entire network optimization technology of the communication quality control and the energy consumption control
- Resilient networks -
Devastating natural disasters such as the Great East Japan Earthquake, which we experienced here in Sendai, are capable of disabling communication infrastructure for a prolonged period of time, while the demand for communication is bound to increase significantly due to safety confirmation of victims and efforts by disaster response organizations. To provide essential communication services until the recovery of infrastructure, the construction of networks by the mutual connection of communication devices is expected to be an effective technology to provide service without depending on infrastructure.
By utilizing disaster-resistant communication equipment and network virtualization, we aim to realize disaster resilient networks which can respond to ever-changing disaster environments.
Our research in this topic includes:
Research on disaster resilient wireless mesh networks
Implementation of disaster resilient networks as a cyber physical system
Performance improvement of disaster resilient networks by network virtualization
- Machine learning, Deep learning based network control -
Recently, communication networks are witnessing a dramatic increase in the network traffic due to the rapid development of communication devices and technologies. The existing network policies are not sophisticated enough to deal with the continually changing network conditions resulting from the explosive traffic growth. With its recent breakthroughs, deep learning can be a viable technique for the network operators to configure and manage their network traffic control systems in a more intelligent manner. Other computer science research fields including computer vision, speech recognition, robotics, autonomous vehicles, natural language processing, and so forth have heavily invested and benefited from the deep learning applications. On the other hand, the applications of deep learning in network traffic control systems are relatively recent and garnered rather little attention. Our laboratory has pioneered in this field by introducing deep learning aiming to build tomorrow’s intelligent network traffic control systems with a particular emphasis on the following areas:
Deep learning based intelligent network traffic control
Deep learning based routing for wired/wireless backbone networks
Removing routing protocol from future wireless networks
Deep learning based traffic engineering in SDNs and 5G networks