Iterative propagation delay estimation for asynchronous direct-sequence code division multiple access communication systems

In this paper, we propose a centralized iterative time delay estimation scheme for asynchronous DS-CDMA communication systems. The proposed algorithm utilizes known training sequences and signatures for all multiple-access users to get the initial estimates of time delays. After that, the K-1 interfering signals are reconstructed with the estimated parameters and remove from the received data. Refined estimate of a desired user's time delay is then obtained from the residual data. The estimation accuracy of the proposed algorithm is close to the centralized Cramer-Rao Bound (CRB) after only one iteration.