A Perspective of Mobile Communication Service Beyond IMT-2000

摘要

Mobile communication systems have been successfully deployed since about 1980 in different regions of the world to extend telephone services to mobile users. Also, it has been an evolutionary change in mobile communication systems every decade [1]. In first-generation, analog systems were developed to support manly voice service. Second-generation cellular systems in 1990s have been used for voice applications and low rate data services. The main representatives of second-generation systems are Global System for mobile Communications (GSM), which has been deployed since 1991 [2]. The radio interface is based on TDMA, digital modulation, forward error correction and digital signal processing. In addition to GSM, other digital systems were developed, such as CDMA-based IS-95 system [3]. Due to the introduction of these second-generation systems, the penetration of analog systems is decreasing. In recent years, third-generation mobile systems, IMT-2000 [4] are currently being standardized and developed worldwide. The IMT-2000 service will be deployed at the beginning of 21st century. Third-generation systems are addressing a mass market for mobile multimedia communications and enhanced multimedia services such as video on demand, image communications, and multimedia short message, etc. Based on the successful development of mobile communication system, discussions have already started on the development beyond third-generation mobile systems in Europe, North America, Japan, Korea, and many other countries. In recent years, ITU-R WP8F [5] is studying the vision of the ongoing enhancement of IMT-2000 and systems beyond IMT-2000. In WP8F, there are six working groups, Vision, Circulation, Developing IMT, Radio technology, Spectrum, and Satellite coordination. The relationships among the working groups are overlapped according to the interest areas significantly. The goal of WP8F is to establish the global focal point for the continuing vision of next generation wireless services and systems. Also, WP8F acts as a forum for user requirements and as a catalyst for translating those requirements into technical reality. It has a plan to complete the preliminary draft new recommendation (PDNR) in June, 2002 [6]. The PDNR includes vision, objectives, market trends, technology trends, spectrum implications, service applications, and other recommendations of the ongoing enhancement of IMT-2000 and of systems beyond IMT-2000. In the generation transition of mobile communication, we have experienced various kinds of services such as voice, multimedia service, etc. The evolution of service represents an increase in requirements for accessing information which requires higher bit rate significantly. Above all, in the era of next generation, it is dynamic and adaptable in all aspects with minimal user involvement and intelligence to learn and adapt with use. Also, the user will experience a wider range of services and applications such as integrated service with mobile communications and broadcasting according to user environments. Since many advanced wireless communication technologies have been being developed, the issues of system to launch the new services might be the system features as well as the future services and service-related technologies. In this paper, we presents a concept of mobile communication beyond IMT-2000 and various services which are appeared near future. Also, we consider technologies to provide advanced services to users. The rest of the paper is organized as follows: Section 2 describes service requirements of next generation mobile communication. In Section 3, we describe core technologies of service aspects. Finally, Section 4 concludes the paper.