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

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 removed from the received data. A 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