Recent R &D on Digital Microwave Radio Reray Systems

As a low-loss, wide-bandwidth transmission medium that is beamed through the atmosphere, digital microwave radio has been widely used for long-haul, large capacity links by many countries around the globe. Considering the growing demand for increased diversification in networks, however, more attention should be focused on applying DMR to those areas that best exploit the medium´s original strengths-- that is, easy and flexible network construction. Today, the trend in user needs is evolving in contrary directions: toward more personalized service on the one hand and toward global-scale reach on the other. In this paper we propose what we call a Digital Microwave Radio Highway as a practical approach to reconciling these conflicting tendencies. As we describe the various enabling technologies involved, this gives us an opportunity to survey the R&D on digital microwave radio (DMR) systems that is being conducted in Japan today.