Multimedia transport in next-generation personal communication networks

This paper presents a discussion of issues related to the support of multimedia traffic in next-generation personal communication networks (PCN). Since high-speed, multimedia-capable PCN's will generally co-exist with fiber-optic based broadband networks, B-ISDN/ATM compatibility is proposed as a basis for next-generation PCN transport architectures. This implies that a multimedia-capable PCN should support ATM-type cell switching of constant bit-rate (CBR) and variable bit-rate (VBR) services, both real-time and non real-time. Media access control (MAC) protocol selection for such a multimedia traffic scenario is discussed, and specific technical issues related to alternative TDMA and CDMA approaches are identified. An example demand assigned TDMA protocol is then considered in further detail, with particular focus on a traffic mix consisting of CBR voice and VBR data with real-time constraints (e.g. compressed video). Simulation models are used to provide illustrative performance results in terms of measures such as throughput vs. cell (packet) loss rate, data delay and voice blocking probability. Time-of-expiry (TOE) based queue service disciplines are introduced as a mechanism for improving the cell loss rate experienced by time-critical data, and simulation results investigating the effect of TOE processing are presented.