Tracking Mode Receivers for Asynchronous DS-CDMA

非技术摘要本研究集中于改进直接序列码分多址(DS-CDMA)信号的同步和检测的新的数学算法。在诸如蜂窝电话之类的DS-CDMA应用中，在基站处同时接收来自用户手机的多个信号。为了容纳最大数量的用户，必须同时跟踪所有接收信号的到达时间(延迟)和信道失真。在该项目中，使用改进的扩展卡尔曼滤波(EKF)算法来跟踪信道/时延参数，并对更复杂的EKF算法进行了评估，这些算法结合了信道/时延估计来执行前向纠错译码(Turbo-CDMA)。所得到的算法提供了降低的符号错误率，并因此增加了系统容量。研究结果适用于广泛的DS-CDMA系统，包括第三代移动电话、无线局域网和自组织网络。

Non-Technical AbstractThis research focuses on new mathematical algorithms for improved synchronization and detection of direct-sequence code-division multiple access (DS-CDMA) signals. In DS-CDMA applications such as cellular telephony, multiple signals from user handsets are received simultaneously at a base station. In order to accommodate the maximum number of users, the times-of-arrival (delays) and channel distortions of all received signals must be simultaneously tracked. In this project, the channel/delay parameters are tracked using a modified extended Kalman filtering (EKF) algorithm.More sophisticated EKF algorithms are also evaluated that perform forward error correction decoding (Turbo-CDMA) jointly with channel/delay estimation. The resulting algorithms provide reduced symbol error rates and hence increased system capacity. The results of the research are applicable to a broad range of DS-CDMA systems, including third-generation mobile telephony, wireless local-area networks, and ad-hoc networks.