研究発表

Japan's Personal Handy Phone (PHP) system for personal communication system is reviewed and a field service test is briefly described. A personal communication system as a concept comprising 'Mobile communication', 'ISDN', and 'Public Telephone' is also discussed. This system is compared with the mobiletelephone system (Cellular system) from the viewpoint of future radio access prospects. Moreover, it is emphasized that advanced radioaccess is needed to meet the diversified and sophisticated demands in telecommunications.(xxxiii+xlvii+1788+xxviii+xviii+xli) pp.

This paper describes an advanced wireless system which is composedof a wireless access node, a wireless access point, and a multimedia portable terminal. The wireless access node and access point are connected by optical fibers to realize broadband and high quality transmission. The optical fibers to realize broadband and high quality transmission. The 'fiber radio' technologies. This advanced wireless system, the multimedia wireless access system, provides video and data communications as well as voice services.（xiii+238 pp）

This paper describes NTT's approach to developing services to meetgrowing demand. First, it briefly introduces the concept of personal communications services. It then examines the network requirements and basic structure methods necessary for the development of personal communications. In addition, it outlines the development of the Personal Handy Phone (PHP), Japan's second generation digital cordless telephone. Finally, the paper summarizes NTT's Pocket Telephone concept and how it relates to NTT's future service vision of Visual Intelligent and Personal communications (VI&P).(xxviii+698+xxviii+594) pp.

Fiber-optic transmission of 256 quadrature amplitude modulation (QAM) signals at both 10 Mb/s and 50 Mb/s transmission rates are presented. Theoretical and preliminary experimental bit error rate (BER) performance results are described for two types of 256-QAM signals. Application of error correction coding using a BCH code is very effective in optical analog intensity modulation. It is feasible to use 256-QAM signals as subcarriers in fiber distribution networks.

As a low-loss, wide-bandwidth transmission medium that is beamed through the atmosphere, digital microwave radio has been widely usedfor 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. The authors propose what they　call a Digital Microwave Radio Highway as a practical approach to reconciling these conflicting tendencies. As they describe the various　enabling technologies involved, the opportunity is taken to survey the R&D　on digital microwave radio (DMR) systems that is being conducted in Japan today.

The authors propose a new concept for personal communications whose ultimate objective is to enable anyone to communicate instantly with anyone else anywhere. The system architecture and technical problems are　described. This concept offers a personal service networkwith subscriber access systems for both radio and wired access. Itsthree principal　concepts are (1) assigning a personal identity, such as a personal　telecommunication number for an individual, with the network tracking the　person's routing; (2) serving ultrasmall portable units for radio link access, and (3) servicing advanced functions, e.g. having the network play the role of secretary.'

A new personal communications system that achieves the ultimate incommunication services, I.e. anyone can communicate instantly with anyone else anywhere, is proposed. This system is a personal service network with subscriber access possible from wired and radio terminals. Its three principal concepts are: assigning a personal identity such as a personal telecommunication number to each subscriber, and the network tracks the person according to the routing address which corresponds to the PTN; inexpensive charge and ultra small portable units for radio link access; and advanced service functions such as the network playing the role of secretary. System architecture and technical problems are also presented.

A novel concept for personal communication that achieves the ultimate objectives of communications services, to enable anyone to communicate instantly with anyone anywhere, is proposed. This concept offers a　personal service network with subscriber access systems forboth wired and　radio terminals. Its three principal concepts are: (1) assigning a personal identity such as a personal telecommunication number for individual, with the network tracking the person's routing, (2) serving ultra-small portable units for radio link access, and (3) servicing advanced functions such as the network playing the role of secretary. An advanced personal communication system in which such functions as location registration and tracking exchange are handled by public communications　networks is proposed. Cost-effective and rapid service development can be realizing by using such public communication network facilities as transport systems. The proposed system enables each person to affor!　D a portable telephone set because of large cost reductions and increased capacity, The system architecture and technical problems are also presented.