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“ATM Based Ultra-Wide Bandwidth Multiple-Access Radio Network For Multimedia PCS”
by Moe Z. Win, Ji-Her Ju, Xiaoxin Qiu, Victor O.K. Li, and Robert A. Scholtz
May 1997
Personal Communications System (PCS) promises to provide a variety of information exchanges among users with any type of mobility, at any time, in any place, through any available device. To achieve this ambitious goal, two of the major challenges in the system design are: (i) to provide a high speed wireless subsystem with large capacity and acceptable Quality of Service (QoS); and (ii) to design a network architecture capable of supporting the multimedia traffic and various kinds of user mobility. A novel time-hopping spread-spectrum wireless communication called Ultra-Wide Bandwidth (UWB) radio is employed to provide low power, high data rate, fade-free, and relatively shadow-free communications in a dense multipath environment. Performance of such communications systems in terms of multiple-access channel capability is estimated for digital data modulation formats under ideal multiple-access channel conditions. In our work, an Asynchronous Transfer Mode (ATM) network is used as the backbone network for PCS due to its high bandwidth, fast switching capability, flexibility, and well developed infrastructure. To minimize the impact caused by user mobility on the system performance, a hierarchical network control architecture is postulated. A wireless virtual circuit (WVC) concept is proposed to improve the transmission efficiency and simplify the network control in the wireless subsystem. The key advantage to this network architecture and WVC concept is that the handoff can be done locally most of the time due to the localization behavior of PCS users. The results of UWB signal propagation experiment demonstrate the feasibility of the UWB radio, its robustness in the multipath environment, and its potential to support multimedia traffic.