Graduate School of Science and Engineering Electrical and Electronic Engineering
Communication Systems LaboratoryWebsite of the Laboratory 【In Japanese】
Wireless Communications Shaping the Dream of Future Society
|Master's degree course
|Doctoral degree course
- Next generation mobile communications system/transmission technologies
- Radio wave propagation in wireless communications
Communication systems laboratory conducts education and research in the field of wireless communication systems as
well as radio wave propagation. Our mission is to contribute to the realization of future wireless communications.
Researches on these research topics are carried out by investigating novel methods and technologies and evaluating
their effectiveness with computer simulations and indoor/outdoor wireless experiments.
Our major research themes are the technologies in the fields of mobile communications and other wireless communications described below.
<1> Next generation mobile communications system/technologies in order to realize communications that are seamless for users and devices to use at even higher speeds and lower costs.
<2> Radio wave propagation, wireless measurement technologies in order to establish reliable and economic service areas and to eliminate/avoid interference from other cells and wireless communications
<1> Next generation mobile communications system/technology
In the mobile communications field, in continuation of the first generation (1G) analog automobile telephone system,
the second generation (2G) early digital mobile communications system, and the third generation (3G) and the fourth
generation (4G) communications system advanced in high speeds and international standards, currently research and
development of the so-called fifth generation (5G) and beyond 5G (B5G) of the mobile communications system is moving
forward. From the 5G system, instead of a concept where a single large system comprehensively supports the entire
environment and services, a concept where heterogeneous systems are split up according to the usage environment or
application, for example cellular communications to cover wide areas and wireless LANs suited to high-speed
transmissions, is envisioned. A large increase in transmission capacity is also necessary with the personalization
and ambience of wireless communications. The implementation of broadband transmissions is a fundamental
technological challenge even in 5G and B5G. As is symbolized by the expression "anywhere, anytime, and with
anything," a major issue is also implementing technologies so as to provide easy-to-use and user-friendly
communications at low prices.
For these problems, our laboratory is researching and developing next generation wireless transmission technologies. Research on the next generation wireless transmission technologies is fundamental research about how to conduct broadband wireless transmissions within limited frequency resources on the basis of statistical behavior of wireless channels. Specifically, broadband single-carrier, OFDM, MIMO, and other topics are our research subjects. For these methods we are formulating new technologies, qualitatively evaluating their performance by computer simulations and verifying their effectiveness with the aid of software-defined radio transceiver.
<2> Radio wave propagation, measurement technology in wireless communications
When thinking about cellular systems, for example, the installation location of base stations and as a result
deciding how many base stations to install is a major issue in constructing cellular networks. In other words, there
are problems such as dead zones where radio waves do not reach, making the supply of communications impossible, if
the distance between base stations is too large, but on the other hand if base stations are densely installed, the
dead zones are reduced but the cost of wireless network infrastructure construction increases. To resolve these
issues, it is important to establish propagation models to precisely estimate propagation characteristics such as
propagation loss, multipath delay and so on in radio channels. In this way, it is possible to design an optimal
wireless network. In recent years, many forms of wireless communications have been developed such as wireless LAN
for local communications and UWB and RF-ID for short distance communications. It is also important to construct
propagation models for respective environments to establish these systems. In our laboratory we are researching
these propagation models.
The research technique in our laboratory is mainly computer simulations, but eventually the evaluation and verification of wireless communications by wireless experiments using radio waves is necessary. For this we are also working on investigating and developing wireless experimentation techniques. For example, in an environment where interference exists, performance evaluations are conducted with actual radio waves emitted for the technologies developed in the laboratory, our private key sharing method for example, and along with research on those evaluation technologies, the effectiveness of the formulated technology is verified.
- Mobile communications
- Multipath fading
- Broadband single-carrier transmission
- Orthogonal Frequency Division Multiplex (OFDM)
- Multiple-Input Multiple-Output (MIMO)
- Wireless security
- Wireless LAN
- Radio wave propagation
- Wireless measurement technology