Subspace-based synchronization using antenna array for DS-CDMA signals in multipath time-varying fading channels

The MUSIC estimator is extended to the case of using a multiple antenna array, which exploits spatial diversity, for estimating multipath timings of DS-CDMA signals on a frequency selective fading channel. The acquisition performance of the MUSIC timing estimator with a single antenna is not good for small observation windows and also low SNR. The multiple antennas based MUSIC estimator is shown to improve the performance of the MUSIC estimator with a single antenna. The Cramer-Rao bound for the parameter estimation problem given multiple antenna sensors is derived on a time-varying fading channel and is used to indicate the best performance that can be achieved by an unbiased estimator.