Motohiko Isaka

Major research activity

MotohikoIsakaOur research group interests are information theory and its applications, with an emphasis on coding techniques. This area focuses on the theory and techniques of digital communication with respect to efficiency, reliability, and secrecy.

More specifically, information thoery aims at answering the following questions: (i) How much can you compress given data?, (ii) How fast can you transfer messages (almost) correctly to a receiver over noisy channels?, and (iii) How much secret information can two or more people share in the presence of a malicious third party? Furthermore, an operation called coding, which transforms the message from the sender and the receiver, needs to be devised in order to approach the above three fundamental limits.

Our research group is interested in the theory and design of coding schemes for reliable communications. There have been great advances in the theory of coding in the past decade in the sense that a near theoretical limit scheme has been developed for a system with a singles ender and a receiver. We are currently seeking techniques to achieve high-performance communication in the wireless distributed network where there could be multiple senders, receivers, and relay nodes.

We are also studying unconditional security in which no computational assumptions like the difficulty of factoring a large composite number is imposed. The key resource for achieving the secrecy under such as scenario is channel noise which is usually regarded as something harmful in the context of reliable communications.

Major relevant publications

  1. M. Isaka and S. Kawata, "Signal sets for secret key agreement with public discussion based on Gaussian and fading channels", IEEE Trans. Inform. Forensics and Security, vol. 6, no. 3, pp. 523-531, Sep. 2011.
  2. M. Isaka, "Unconditionally secure oblivious transfer from algebraic signaling over the Gaussian channel", IEICE Trans. Fundamentals, vol. 93E-A, no. 11, pp. 2017-2025, Nov. 2010.
  3. M. Isaka, P.A. Martin, and M.P.C. Fossorier,"Design of high-rate serially concatenated codes with low error floor", IEICE Trans. Fundamentals, vol. 90E-A, no. 9, pp. 1754-1762, Sep. 2007.

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