We are interested in the fundamental design and evaluation of signal processing for wireless communications systems. In particular, our research focuses on physical layer signal processing such as modulation and demodulation, error control coding, and multiplexing to achieve higher communication performance, thereby helping to advance the state of integrated wired and wireless networks.

Our research topics generally involve (1) theoretical frameworks, (2) performance evaluations, and (3) practical system design, as described below.

(1) Theoretical frameworks
A theoretical framework is essential for grasping the upper and lower bounds of targeted wireless system performance, which helps promote reasonable architectures. In this area, we seek to develop simple theoretical tools for deriving the transmission performance of key technologies such as OFDM, multiple-antenna techniques, and multihop relay techniques.

(2) Performance evaluations
Performance evaluations are essential for assessing the potential for realizing a new system. For example, we are currently exploring ultra-wideband (UWB) systems for high speed, in-car wireless communications to grasp the potential service area.

(3) Practical system designs
In realistic scenarios, degradation in system performance arises from practical reasons such as specific hardware implementation. This means solving practical issues, as well as overcoming severe wireless channels. Currently, we are proposing an OFDM transmit power control scheme inherently capable of suppressing nonlinear distortion based on a practical high power amplifier (HPA).