Our researches are focusing on next generation wireless access technologies for cellular and ubiquitous integrated networks. Now two projects are performed in Innovative Radio Transmission Lab.

To accommodate diversified kinds of terminals into a unified mobile network effectively, a new flexible air interface is researched in this project. In this scheme, both resource allocation (such as frequency, space, and power) and transmission schemes (such as coding and modulation) are optimally changed according to propagation condition, QoS requirements and terminal configurations. For supporting this interface, synchronization, channel estimation/prediction, and MIMO technologies are also investigated in this project.

DRAN (Distributed Radio Access Network) project

Usage of high frequency band and increase of transmission rate will inherently cause a shrink of cell size. To overcome this problem, new RAN (Radio Access Network) architecture such as relay and DAS (Distributed Antenna System) are targeted in this project. Cognitive and cooperative technologies, advanced interference cancellation, and cross-layered signal multiplexing are investigated for enhancing a performance of radio networks.

As a bridge between China and Japan in mobile communication technologies

It was about the third century that Chinese characters were first introduced into Japan. After that, Chinese characters played an important role as a basis of Japanese language. This written language definitely brought a great stride to Japan. After many centuries, in the modern period, some Japanese words are conversely introduced into Chinese. To give some examples, “Bank: 银行”, “Economy:经济”, and also ‘Telephone:电话” are commonly used in both countries. These facts are highly suggestive for present-day’s researchers; that is, exchanging our wisdom between different countries caused a mutual development for both sides. I hope that our lab can be a bridge between China and Japan in future mobile communication technologies, and to contribute a mutual development for both countries.

Researches in IRT (Innovative Radio Transmission) Lab

DBL are targeting to realize the vision of NTT DOCOMO, that is, ‘From Communicationｓ infrastructure to Lifestyle infrastructure’. Following this vision, we aim at expanding our communication opportunity from human-human to human-machine and/or machine-machine with high capacity and high speed radio transmission technologies. Simultaneously, we intend to serve personalized, ubiquitous and seamless communication services to customers by integrating cellular, and ubiquitous networks with highly flexible air interface.

The researches in our lab can be categorized into two projects. One is targeting considerably different technologies with cellular ones which can open new vistas toward future ubiquitous services. In this project, we are focusing on the innovative concept and challenging without restriction by common sense of current level technologies. Another one is targeting novel wireless access technologies that can drastically expand flexibility and performance. In this research, we are paying much attention to the latest technical trends and standardization activities, cooperating with developing sections, and then challenging to establish real technologies that can directly contribute to future systems.

In last year, we have succeeded an experiment of 4x4 MIMO-OFDM transmission in which our original MIMO detection, channel estimation and synchronization schemes are implemented. As to relay technologies, two contributions for IEEE802.16j have been accepted in the draft standard. Now we are continuing our effort to go further toward innovation of wireless technologies.

In addition to the aforementioned internal researches, we have some cooperative research projects with leading Universities in China. I would like to deeply appreciate their support, and hope to contribute for our common future together.