Challenges for Broadband Wireless Technology

Convergence of mobile communications, computing and Internet is on the way. This will be the driving force towards a wireless multimedia society in 21st century. Unfortunately, since the present mobile communication systems (often referred to as 2G systems) are optimized to real-time voice services, they have quite limited capabilities in providing broadband multimedia services because of their slow data transfer rates and small displays on the portable phones. The IMT-2000 systems [1], [2] called the 3rd generation (3G) systems, are under deployment in Japan with much faster data rate of 384kbps and better representation than present 2G systems. We are now entering into wideband era. However, the capabilities of 3G systems will sooner or later be insufficient to cope with the everincreasing demands for broadband multimedia communications. Broadband multimedia services will soon be in full force in fixed networks based on the next generation Internet technology. Information transferred over the Internet will become increasingly rich. It is expected that the 4G systems should emerge around 2010; a major objective is to offer mobile users with broadband multimedia services. Demands will become stronger and stronger for downloading of ever increasing volumes of information. Giga-bit wireless technology (up to 1G bps) will be required that is optimized to broadband IP packet transport over the air. For wireless access, a random and reservation packet access and flexible wireless resource assignment between forward and reverse links will be required. The technical requirements for 4G wireless may be: n Pedestrian environment: 100M~1Gbps n Vehicular environment: ~100Mbps n Spectrum efficiency: ~10 bps/Hz The 3rd requirement is of paramount importance because of very limited available bandwidths. This paper looks at the broadband wireless technology that will be a core of 4G systems.