Evolution of personal multimedia communications services in Japan

tions technology is about to bring dramatic changes to business and home life. In 1990, NTT announced the Visual Intelligent and Personal (VI&P) communications services plan as its service vision for the beginning of the 21st century [1], as shown in Fig. 1. We are engaged in wide-ranging research and development aiming at creating service systems for diverse applications. The phase 1 experiments based on this VI&P plan, which were conducted between 1991 and 1993, focused on narrowband integrated services digital network (N-ISDN) services to optimize the use of the existing INS Net. The phase 2 experiments were initiated in April 1993, and focused on perfecting new services and creating new applications based on optical communications and asynchronous transfer mode (ATM) technology [2]. The sudden increase in the number of pagers and cellular phones reflects the rising demand for person-toperson communication, even for private use. The P in VI&P symbolizes this latest trend. Among these VI&P services, personal communication services will become the most advanced and should receive the most attention. Taking this into consideration, the phase 3 experiments are concentrated on personal-use multimedia services based on wireless access by means of the Personal Handyphone System (PHS) and satellites [3]. This article describes the phase 3 experiments and the technology involved. To cope with future demand for wireless personal multimedia services, research and standardization activities are being strongly carried out in many countries, such as advanced Global System for Mobile Communications (GSM) systems in Europe, the IS-95based wideband code-division multiple access (CDMA) system in the United States, and a wideband CDMA system in Japan. International Mobile Telecommunications in the year 2000 (IMT2000) is to offer capacities of 144 kb/s outdoors and 2 Mb/s indoors. Under the existing wireless environment, the usable bit rate is limited to 28.8 kb/s; however, several interesting multimedia services can be provided using this level of capacity. In Japan, the introduction of Personal Handyphone Service (PHS) has led to an explosion in mobile digital services. In this article, the expectations of personal multimedia communications are introduced. The main subjects discussed in some detail are digital data communication services using PHS terminals, personal mobility using premises intelligent network, and the nomad office using communication satellites. Attractive future personal communication services are also proposed.