Development of a large-scale mobile communications network (IMN: Intelligent Mobile communications Network), as an infrastructure integrating multimedia functions, is indispensable for the support of future mobile communication services aiming toward "personalization," "intelligence," and "multimedia services." This paper discusses the aims of mobile communications and the outline of network technology aspects of PDC (Personal Digital Cellular) network which is currently in service. In addition, the future prospect of mobile communication technologies is discussed with special focuses on the support of universal mobility, network architecture including mobile communications platform, and multimedia technologies in the transport and access systems.

To provide personal, intelligent, and multimedia services through a mobile communications network, a Mobile Service Control Point (M-SCP) was developed, which performs both the location register and service control functions. The M-SCP was constructed on a common platform to allow quick introduction of new services. Software techniques to reduce the frequency of process-switching, assign the highest priority to real-time tasks, and operate a multiple-CPU structure provide faster real-time processing. This is confirmed by computer simulation and research in the field.

The advance of mobile network and radio techniques has been rapidly expanding the service area for mobile terminals. Thus, mobile communications have been devoted to the improvement of terminal mobility (TM). Recently, the personal mobility (PM) concept appeared which gives a freedom to use personal telecommunication numbers at any terminal. Therefore, mobile network must next enable a user to access telecommunication services with his/her personal telecommunication number from any terminal at any geographic location. In other words, the mobile network must implement universal mobility (UM) that integrates TM and PM. This paper first provides a definition of UM. Next, it describes the identity and number configurations for UM and then presents network techniques for UM, i.e., the network architecture and UM management procedures. It also presents the current status of standardization on UM in the Personal Digital Cellular system (PDC) and Future Public Land Mobile Telecommunication Systems (FPLMTS).