INVITED PAPER Special Section on Multi-dimensional Mobile Information Networks Challenges of Wireless Communications—IMT-2000 and Beyond—

SUMMARY Mobile radio and Internet communications services are penetrating our society at an exponential rate of growth. The Internet is the most important driving force towards establishing a multimedia society. Mobile communication systems add an important capability to our communications society, i.e., mobility. The third generation mobile communications system called IMT-2000 is expected to play an important role in this soon-toarrive multimedia society. Wideband mobile services based on IMT-2000 will soon become a reality (early 2001). First, we look at the trends of wireless access technologies, centering on IMT2000. Wideband direct sequence code division multiple access (W-CDMA) will be a major component of a global IMT-2000 standard. Then, we address advanced wireless techniques, i.e., interference cancellation and employing an adaptive antenna array, which can enhance W-CDMA at a later date. Finally, requirements are discussed for future wireless techniques that will

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