With advent of the ubiquitous network era and due to recent progress of III-V nanotechnology, the present III-V heterostructure microelectronics will turn into what one might call III-V heterostructure nanoelectronics, and may open up a new future in much wider application areas than today, combining information technology, nanotechnology and biotechnology. Instead of the traditional top-down approach, new III-V heterostructure nanoelectronics will be formed on nanostructure networks formed by combination of top-down and bottom-up approaches. In addition to communication devices, emerging devices include high speed digital LSIs, various sensors, various smart-chips, quantum LSIs and quantum computation devices covering varieties of application areas. Ultra-low power quantum LSIs may become brains of smart chips and other nano-space systems. Achievements of new functions and higher performances and their on chip integration are key issues. Key processing issue remains to be understanding and control of nanostructure surfaces and interfaces in atomic scale.

A description for high-speed communication networks for the 21st century is roughly sketched, and the technical development trends in high-frequency and high-speed devices are briefly forecasted. Four examples of devices under development are reported: 76-GHz flip-chip MMIC's for car-radar systems, a cost-effective RF module for millimeter-wave wireless systems, a 10-Gbps demultiplexer for optical fiber communication systems, and a GaAs microwave signal processor for active phased-array systems. Considering as technological trends evolve further, this paper also introduces the software radio concept and the fusion of wireless and optical technologies for cost-effective wireless communication equipment and end-user services.