2014 年 18 巻 1 号 p. 1-15
Recent communication networks has astonishingly advanced and they are widely used in the world. For the next generation networks, further researches supporting network technologies have been devoted in many areas. This paper provides an overview of the existing key technologies and future trends on communication systems such as cipher, error control coding, OCDMA (Optical Code Division Multiple Access) and UWB (Ultra Wide Band ).