CDMA and IDMA: Iterative Multiuser Detections for Near-Far Asynchronous Communications

Abstract:
This paper provides comprehensive comparison of the iterative multiuser detection techniques for code devision multiple access (CDMA) and interleave division multiple access (IDMA). We investigate the performance in various scenarios such as user-asynchronism, multipath channels, near-far problem, and overloaded scenarios. We develop our system model which is general enough to take into account the above mentioned scenarios as well as being capable of incorporating aspects relevant to these access schemes. We provide formal descriptions of both schemes using our system model that illuminates the similarities and differences of the two different schemes. Computer simulations are performed in a variety of scenarios. It is observed that IDMA performs better than or as good as CDMA despite its simplicity.