Adaptive Interference Cancellation & Signal Separation in Multi-User CDMA Communication System

Code Division Multiple Access (CDMA) communications systems are limited by multiple access interference (MAI). Multiuser detection accomplishes MAI cancellation by exploiting the knowledge of all users' signatures. Due to the complexity of the optimum multiuser detector, various sub-optimum detector structures have been considered. In this study a novel structure termed DC^3 for adaptive multiuser detection of asynchronous users, which is simple in that it does not require duplication of the hardware, as optimum detectors require. To handle errors in relative delay estimation, a special adaptive decorrelator called the 'bootstrap decorrelator' is utilized. Performance of the bootstrap decorrelator under different fading environments with different unknown delays is analyzed and convergence and stability questions are treated. Performance of the DC^3 receiver as a whole is also studied, in a realistic communications environment.