Graduate School of Science and Engineering, Kagoshima University
Information and Communication Laboratory

About Research

In the Laboratory, we study about design of pseudo-noise (PN) sequences and their applications to communications, radar, and information security.
In academic societies, we have made presentations mainly to IEEE, IEICE, and Research Institute of Signal Processing, and we are a research expert committee member and secretary of the following research groups.
　　Prof. T. Matsumoto : IEICE Technical Committee on Wideband System (WBS) Steering Committee Member, IEICE Technical Committee on Information Theory (IT) Steering Committee Member, ICACT TPC Member, IWSDA TPC Member, etc.
　　Lecturer Y. Ohira : IEICE Technical Committee of Communication System (CS) Assistant

Research Theme 1: Research on the design of pseudo-noise (PN) sequences

We are designing sequences that have the same randomness and correlation characteristics as white Gaussian noise. 　In particular, we are designing ZCZ (Zero-Correlation Zone) sequence sets with ideal periodic correlation characteristics in a certain shift range, i.e., autocorrelation characteristics are impulse and cross-correlation characteristics are completely zero.

Research Theme 2: Research on optical wireless communications

We are researching optical wireless communications in space and underwater using LEDs and LDs (laser diodes) as light-emitting devices and PDs (photodiodes), APDs (avalanche photodiodes), and cameras as light-receiving devices. In particular, we are studying optical CDMA (code division multiple access) and optical OFDM (orthogonal frequency division multiplexing) systems, which are characterized by pseudo-noise sequences suitable for optical wireless communication.

Research Theme 3：Research Theme 3: Research on fast signal processing for optical CDMA and optical OFDM

We are researching on fast signal processing or miniaturization of hardware for signal processing at transmitters and receivers in optical CDMA and optical OFDM systems. 　In particular, we are researching compact code generators, compact matched filters, fast processing of orthogonal transformation, and its inverse transformation. 　In circuit design, we use hardware description languages such as verilog HDL and VHDL, and implement them using field programmable gate arrays (FPGAs), which are LSIs that can be customized at the user's hand.

Research Theme 4: Research on applications of information security such as information hiding (digital watermarking)

We are researching on information hiding (digital watermarking) technology that takes advantage of the characteristics of the pseudo-noise (PN) sequences in Theme 1. 　Digital watermarking is a type of information security technology that embeds copyright information in audio, image, video, and other content in a way that users do not understand, and it makes use of the noise-like characteristics of Theme 1.

Research Theme 5: Research on performance verification using software defined radio, etc.

We evaluate the performance of optical wireless communication in Theme 2 not only by computer simulations, but also by actual transmission experiments using a transmitter/receiver with LEDs and APD elements or LEDs and cameras. 　We also evaluate the performance of general radio communication by conducting transmission experiments using USRP (Universal Software Radio Peripheral), which is one of the software defined radios.

Research Theme 6: Research on information networks

We are also researching on the MAC (medium access control) and network layers suitable for new wireless communication schemes.