Traffic performance of a software-based TDMA/CDMA system accommodating heterogeneous multimedia services

In software-based wireless multimedia communications systems, each mobile t erminal will be able to select its best-suited transmission format accordin g to its quality of service (QoS) and channel condition. In this paper, we focus attention on " access scheme selectability" in such a software-based system, and discuss the traffic performance improvement due to adaptive acc ess scheme selection. Assuming a software-based TDMA/CDMA system where time division multiple access (TDMA) and direct sequence code division multiple access (DS-CDMA) schemes are flexibly selectable, we evaluate the traffic performance in terms of average delay with a typical multimedia service mod el to be supported in future wireless communications systems. In the TDMA/C DMA system, how to determine an appropriate access scheme for a user is a k ey issue. Therefore, we discuss the selection algorithm for efficiently sup porting heterogeneous multimedia services. Our computer simulation results show that the software-based system with a simple access scheme selection a lgorithm can significantly improve the traffic performance as compared with conventional hardware-based systems.