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

码分多址(CDMA)通信系统受到多址干扰(MAI)的限制。多用户检测通过利用所有用户签名的知识来完成多址干扰消除。由于最佳多用户检测器的复杂性，已经考虑了各种次最佳检测器结构。在这项研究中，一种称为DC^3的新结构用于异步用户的自适应多用户检测，该结构简单，因为它不需要复制硬件，正如最优检测器所要求的那样。为了处理相对时延估计中的误差，使用了一种特殊的自适应去相关器，称为自举去相关器。分析了Bootstrap解相关器在具有不同未知时延的不同衰落环境下的性能，并处理了收敛和稳定性问题。在实际通信环境中，还研究了DC^3接收机的整体性能。

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.