Time-delay and frequency-shift estimation of multi-user asynchronous CDMA signals in a multipath channel

A subspace-based MUSIC type algorithm for joint time-delay and frequency-shift estimation of asynchronous CDMA signals in a multipath channel is proposed. The algorithm provides identification and joint time-delay and frequency-shift estimation of all paths of the given CDMA user if paths are not perfectly coherent (correlated). The algorithm requires no preamble, can be applied for both single-user and multi-user estimation and it is robust to multi-user interference. The results provided by simulation prove that the proposed algorithm is well suited to fading channel analysis.