Implementation and evaluation of wireless network systems
This laboratory promotes implementation and evaluation network systems such as wireless communication systems, radio sensors, and embedded systems, which are key technologies for establishing ubiquitous computing and network systems. The research interests does not only cover theoretical study on these systems, but also includes feasibility and implementation issues.
Digital TV on Mobile
In Japan, high-definition television (HDTV) is provided using the digital terrestrial television (DTTV) broadcasting. In addition to HDTV, a narrow band digital television service dedicated for handheld terminals, also known as "One-Seg TV", is popular now. The analog TV broadcasting will be terminated by July, 2011. After the termination of analog TV services, the multimedia broadcasting services will be started using the opened VHF analog TV band. However, it is difficult to improve the reliable reception in mobile and handheld environments. This laboratory is working for developing a low power-consumption and reliable handheld digital TV receivers using array antenna and radio signal processing techniques.
Mobile Communication Systems
Thanks to the recent research and development activities, the bit rate provided by mobile Communication systems, such as cellular systems, and wireless local area networks (W-LAN), is rapidly growing. However, its reliability is not good enough for error intolerant purposes, such as surveillance, networked robot, and so on. Inder to solve this problem, our laboratory studies key technologies including OFDM (Orthogonal Frequency Division Multiplex), MIMO (Multiple Input Multiple Output), diversity, and multi-hop mesh network. We are working on implementing these technologies onto specific systems such as W-LAN, WiMAX, and Zig-Bee.
Embedded Computer Vision
Although computer vision systems requires a huge amount of computational cost, the computational resources are strictly limited in the mobile environment. This laboratory is working for developing low computational cost algorithms for embedded computer vision systems.
Although radio wave based sensor systems, such as RADAR and GPS, is capable of measuring the positions among wide area, the resolution is limited. On the other hand, high-resolution measurement is possible by using optical sensors. However, its sensing is limited to the line of sight region. We are developing a new sensor system, which combines various kinds of sensors to improve the overall performance.
Digital Terrestrial Television Broadcasting Signal Analyzer
Feature of the Laboratory
We do not only evaluate the system in theoretical analysis and computer simulation, but also implement ones onto hardware using FPGA (Field Programmable Gate Array) and embedded systems. Students can learn theories on signal processing and communication systems. In addition, they have a chance to experience embedded system programming and digital circuit design.
Propagation Characteristics Measurement