WIRELESS COMMUNICATIONS IN THE 21ST CENTURY - A PERSPECTIVE

Wireless communications are expected to be the dominant mode of access technology in the next century. Besides voice, a new range of service s such as multimedia, high-speed data, etc, are being offered for deli very over wireless networks. Mobility will be seamless, realizing the concept of persons' being in contact anywhere, at any time. Two develo pments are likely to have a substantial impact on the mobile communica tions systems deployed in the twenty-first century: the adoption of In ternational Mobile Telecommunications-2000 and wireless asynchronous t ransfer mode (ATM). They are two different but cooperative approaches to providing high-speed wireless access. Limitations of the radio-freq uency spectrum and radio channel propagation impose special constraint s on the technologies of systems to be deployed To make future mobile systems globally acceptable, standardization efforts are underway in t he international Telecommunications Union and the ATM Forum. This pape r reviews the international standardization efforts, the challenges to the technologies imposed by the radio spectrum limitations, radio cha nnel propagation-induced distortions, and possible solutions. Evolutio n, migration, and architecture issues also are discussed.