FAST SIMULATION OF DS CDMA WITH AND WITHOUT CODING IN MULTIPATH-FADING CHANNELS/

Code-division multiple access (CDMA) has recently found widespread app lications in various applications such as advanced wireless technologi es and digital cellular communications, In this paper, we consider the error-rate performance of asynchronous direct-sequence CDMA in a wire less radio communications environment that is characterized by Rayleig h multipath fading channels, Because of the system complexity, the per formance of CDMA systems in such an environment is difficult to assess analytically, Monte Carlo simulations can offer an alternative perfor mance evaluation tool, Unfortunately, in practice, such an alternative is often limited by an excessive computational burden, Importance sam pling is a variance reduction technique which can significantly reduce the computational cost required by Monte Carlo simulations, This pape r will describe the baste principles behind this powerful technique, I n particular, it will illustrate its use as a computationally efficien t and accurate tool for computer-aided design and analysis of uncoded as well as coded CDMA in wireless communications.