Tracking Mode Receivers for Asynchronous DS-CDMA

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

Non-Technical Abstract This 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.